WTNT41 KNHC 210300
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER   1
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
1100 PM EDT TUE SEP 20 2011
 
THE LOW OVER THE TROPICAL ATLANTIC HAS FINALLY COALESCED ABOUT A
SINGLE CIRCULATION CENTER AND HAS ENOUGH ORGANIZED DEEP CONVECTION
TO BE CONSIDERED A TROPICAL CYCLONE. AN ASCAT PASS JUST BEFORE 00Z
SHOWED AN AREA OF 35 KT WINDS NORTH OF THE CENTER...AND THAT IS THE
INITIAL INTENSITY FOR THIS ADVISORY. THE SATELLITE PRESENTATION OF
OPHELIA IS STILL A LITTLE RAGGED...WITH CONVECTIVE BANDS LOCATED
WELL NORTHEAST AND SOUTH OF THE STILL CONSOLIDATING CENTER. WHILE
OPHELIA WILL BE MOVING OVER WARM WATERS THROUGH THE PERIOD...THE
SHEAR IS EXPECTED TO REMAIN AROUND 15 KT OR SO OVER THE NEXT COUPLE
OF DAYS.  AFTER THAT TIME...THE SHEAR SHOULD INCREASE AND BECOME
MORE WESTERLY AS THE GLOBAL MODELS SHOW AN UPPER-LEVEL LOW FORMING
NORTH OF PUERTO RICO. GIVEN THE MARGINAL ENVIRONMENT AND THE
SOMEWHAT SPRAWLING NATURE OF THE CYCLONE AT THIS TIME...ONLY MODEST
STRENGTHENING IS SHOWN IN THE SHORT TERM. BEYOND 36 HOURS...LITTLE
CHANGE IN STRENGTH IS FORECAST...FOLLOWED BY WEAKENING LATE IN THE
PERIOD. THE NHC FORECAST IS NEAR OR A LITTLE ABOVE THE IVCN
INTENSITY CONSENSUS THROUGH THE PERIOD. 

THE INITIAL MOTION ESTIMATE IS A RATHER UNCERTAIN 270/8...DUE TO THE
RECENT REFORMATION OF THE CENTER. OPHELIA IS CURRENTLY BEING
STEERED BY THE SUBTROPICAL RIDGE TO ITS NORTH...AND A WESTWARD
MOTION IS EXPECTED OVER THE NEXT COUPLE OF DAYS AS THE RIDGE BUILDS
WESTWARD. AFTER THAT TIME...THE RIDGE BEGINS TO WEAKEN AS A LARGE
MID/UPPER-LEVEL CLOSED LOW DEVELOPS OVER THE SOUTHEASTERN UNITED
STATES...WHICH SHOULD RESULT IN A TURN TOWARD THE WEST-NORTHWEST
AND A DECREASE IN FORWARD SPEED LATE IN THE PERIOD. THE NHC TRACK
FORECAST LIES TO THE RIGHT OF THE MULTI-MODEL CONSENSUS THROUGH THE
PERIOD...BUT IS A LITTLE TO THE LEFT OF THE GFS AND ECMWF MODELS. 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  21/0300Z 12.2N  40.1W   35 KT  40 MPH
 12H  21/1200Z 12.4N  42.2W   40 KT  45 MPH
 24H  22/0000Z 12.7N  44.9W   45 KT  50 MPH
 36H  22/1200Z 12.9N  47.7W   45 KT  50 MPH
 48H  23/0000Z 13.2N  50.5W   45 KT  50 MPH
 72H  24/0000Z 15.0N  55.5W   45 KT  50 MPH
 96H  25/0000Z 17.0N  60.0W   40 KT  45 MPH
120H  26/0000Z 19.0N  64.0W   40 KT  45 MPH
 
$$
FORECASTER BRENNAN
 

WTNT41 KNHC 210845
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER   2
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
500 AM EDT WED SEP 21 2011
 
CURVED CONVECTIVE BANDS OVER THE NORTHERN AND SOUTHERN PORTIONS OF
THE LARGE CIRCULATION HAVE BECOME A LITTLE BETTER DEFINED THIS
MORNING...HOWEVER THERE IS STILL A LACK OF DEEP CONVECTION NEAR 
THE CENTER OF THE TROPICAL STORM.  THE INITIAL INTENSITY OF THE
CYCLONE HAS BEEN INCREASED TO 40 KT...BASED ON DATA FROM A SHIP
LOCATED TO THE NORTH OF THE CENTER AND AN EARLIER ASCAT PASS.  
THE UPPER-LEVEL WIND PATTERN AHEAD OF OPHELIA DOES NOT FAVOR
SIGNIFICANT STRENGTHENING.  MODERATE SOUTHWESTERLY SHEAR CURRENTLY
OVER THE CYCLONE IS EXPECTED TO BECOME MORE WESTERLY AND INCREASE
IN A FEW DAYS AS AN UPPER-LEVEL LOW FORMS NORTH OF PUERTO RICO. 
MOST OF THE INTENSITY GUIDANCE AGREES WITH THIS SCENARIO AND CALLS
FOR ONLY A LITTLE ADDITIONAL STRENGTHENING.  THE NHC FORECAST IS IN
GOOD AGREEMENT WITH THE SHIPS/LGEM GUIDANCE AND IS VERY SIMILAR TO
THE PREVIOUS ADVISORY.

THE INITIAL MOTION ESTIMATE REMAINS RATHER UNCERTAIN...HOWEVER 
IT APPEARS THAT OPHELIA IS MOVING A LITTLE FASTER THAN BEFORE. THE
TRACK FORECAST REASONING IS UNCHANGED FROM THE PREVIOUS NHC
ADVISORY.  OPHELIA IS EXPECTED TO MOVE WESTWARD DURING THE NEXT
COUPLE OF DAYS TO THE SOUTH OF THE SUBTROPICAL RIDGE.  AFTER 72
HOURS...THE WESTERN PORTION OF THE RIDGE IS EXPECTED TO WEAKEN AS A
LARGE MID/UPPER-LEVEL LOW DEVELOPS OVER THE EASTERN UNITED STATES. 
THIS SHOULD RESULT IN THE CYCLONE TURNING TOWARD THE WEST-NORTHWEST
WITH SOME REDUCTION IN FORWARD SPEED.  THE UPDATED NHC FORECAST
LIES BETWEEN THE TYPICALLY RELIABLE GFS AND ECMWF MODELS...AND IS
VERY CLOSE TO THE PREVIOUS ADVISORY.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  21/0900Z 12.7N  41.8W   40 KT  45 MPH
 12H  21/1800Z 13.0N  43.8W   40 KT  45 MPH
 24H  22/0600Z 13.2N  46.5W   45 KT  50 MPH
 36H  22/1800Z 13.5N  49.2W   45 KT  50 MPH
 48H  23/0600Z 14.0N  52.0W   45 KT  50 MPH
 72H  24/0600Z 15.7N  57.0W   45 KT  50 MPH
 96H  25/0600Z 18.0N  61.5W   40 KT  45 MPH
120H  26/0600Z 20.0N  65.5W   35 KT  40 MPH
 
$$
FORECASTER BROWN
 

WTNT41 KNHC 211438
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER   3
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
1100 AM AST WED SEP 21 2011
 
ALTHOUGH OPHELIA APPEARS TO BE LESS ORGANIZED THIS MORNING...WITH
THE LOW-LEVEL CENTER PARTIALLY EXPOSED TO THE SOUTHWEST OF THE DEEP
CONVECTION...A 1200 UTC ASCAT PASS AND AN OBSERVATION FROM SHIP
PBSY INDICATES THAT THE INTENSITY HAS INCREASED TO NEAR 50 KT. 
SINCE THE SATELLITE PRESENTATION IS CURRENTLY NOT SUGGESTIVE OF
STRENGTHENING...IT IS CERTAINLY POSSIBLE THAT THE CYCLONE WAS
STRONGER THAN PREVIOUSLY ESTIMATED.  LATEST ANALYSES FROM UW-CIMSS
SHOW THAT THE STORM IS EXPERIENCING ABOUT 20 KT OF
SOUTH-SOUTHWESTERLY SHEAR.  GLOBAL MODEL GUIDANCE INDICATES THAT THE
SHEAR WILL NOT RELENT OVER THE NEXT SEVERAL DAYS...AND THE OFFICIAL
INTENSITY FORECAST CALLS FOR SLOW WEAKENING OVER THE FORECAST
PERIOD.  THIS IS IN CLOSE AGREEMENT WITH THE LGEM AND SHIPS
PREDICTIONS.  IT SHOULD BE NOTED THAT THE COAMPS-TC MODEL...WHICH
IS PART OF THE HFIP SUITE AND HAS BEEN A GOOD PERFORMER SO FAR THIS
YEAR...SHOWS A FASTER DEMISE OF THE TROPICAL CYCLONE THAN MOST OF
THE OTHER GUIDANCE.

INITIAL MOTION IS A LITTLE FASTER TOWARD THE WEST...OR 270/14.  THE
GENERAL TRACK FORECAST SCENARIO FOR OPHELIA REMAINS THE SAME.  THE
CYCLONE SHOULD MOVE ON A WEST TO WEST-NORTHWESTWARD PATH TO THE
SOUTH OF A SUBTROPICAL HIGH PRESSURE AREA DURING THE NEXT FEW DAYS. 
LATE IN THE FORECAST PERIOD A GRADUAL TURN TO THE RIGHT IS LIKELY
AS OPHELIA...IF IT SURVIVES...NEARS THE SOUTHWESTERN SIDE OF THE
HIGH.  THE OFFICIAL TRACK FORECAST LIES BETWEEN THE PREVIOUS ONE
AND THE MULTI-MODEL CONSENSUS.  IT IS ALSO FAIRLY CLOSE TO THE
RELIABLE GFS GUIDANCE.

THE WIND RADII HAVE BEEN EXPANDED BASED ON THE SCATTEROMETER DATA.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  21/1500Z 13.0N  43.6W   50 KT  60 MPH
 12H  22/0000Z 13.3N  45.6W   50 KT  60 MPH
 24H  22/1200Z 13.5N  48.4W   45 KT  50 MPH
 36H  23/0000Z 14.0N  50.8W   45 KT  50 MPH
 48H  23/1200Z 14.7N  53.2W   45 KT  50 MPH
 72H  24/1200Z 16.8N  57.8W   45 KT  50 MPH
 96H  25/1200Z 19.0N  62.0W   40 KT  45 MPH
120H  26/1200Z 21.0N  65.5W   35 KT  40 MPH
 
$$
FORECASTER PASCH
 

WTNT41 KNHC 212032
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER   4
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
500 PM AST WED SEP 21 2011

OPHELIA HAS CHANGED LITTLE IN ORGANIZATION OVER THE PAST SEVERAL
HOURS...WITH A PORTION OF THE INNER CORE LOW-LEVEL CIRCULATION
STILL EXPOSED OVER THE SOUTHWEST SEMICIRCLE.  RECENT IMAGES SHOW
THAT THE CENTER IS LOCATED JUST UNDER THE SOUTHWEST EDGE OF THE
CONVECTIVE CANOPY.  MODERATE SOUTH-SOUTHWESTERLY SHEAR...ASSOCIATED
WITH AN UPPER-LEVEL TROUGH TO THE NORTHWEST OF THE STORM...IS
FORECAST TO CONTINUE TO AFFECT OPHELIA THROUGH THE FORECAST PERIOD. 
THEREFORE NO STRENGTHENING IS FORECAST...WITH SOME WEAKENING LIKELY
IN A FEW DAYS.  SINCE THE CURRENT LGEM GUIDANCE IS A LITTLE HIGHER
THAN THE PREVIOUS ONE...THE NHC WIND FORECAST NOW SHOWS LESS
WEAKENING IN 3-5 DAYS.  TWO MODEL EXTREMES HIGHLIGHT THE
UNCERTAINTIES IN PREDICTING INTENSITY CHANGE.  THE EXPERIMENTAL
COAMPS-TC MODEL...WHICH HAS BEEN A GOOD PERFORMER SO FAR THIS
YEAR...SHOWS DISSIPATION BY 72 HOURS WHILE THE GFDL MODEL PREDICTS
OPHELIA TO BECOME A MAJOR HURRICANE BY THE END OF THE FORECAST
PERIOD.

INITIAL MOTION REMAINS AROUND 280/14 AS THE STORM REMAINS SOUTH OF A
SUBTROPICAL HIGH PRESSURE SYSTEM.  OPHELIA IS LIKELY TO MOVE ON A
WESTWARD TO WEST-NORTHWESTWARD TRACK OVER THE NEXT SEVERAL
DAYS...ALONG THE SOUTHERN PERIPHERY OF THE HIGH.  LATE IN THE
FORECAST PERIOD...AS THE CYCLONE NEARS THE SOUTHWESTERN PERIPHERY
OF THE RIDGE...THE DYNAMICAL GUIDANCE IS LEANING MORE TO THE RIGHT
OF PREVIOUS RUNS.  THE LATEST OFFICIAL FORECAST IS A LITTLE TO THE
NORTH...OR RIGHT...OF THE PREVIOUS ONE BUT NOT AS FAR TO THE RIGHT
AS MOST OF THE TRACK MODELS BY DAY 5.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  21/2100Z 13.6N  44.7W   50 KT  60 MPH
 12H  22/0600Z 13.8N  46.8W   50 KT  60 MPH
 24H  22/1800Z 14.1N  49.4W   50 KT  60 MPH
 36H  23/0600Z 14.6N  51.8W   50 KT  60 MPH
 48H  23/1800Z 15.5N  54.0W   50 KT  60 MPH
 72H  24/1800Z 17.5N  58.5W   45 KT  50 MPH
 96H  25/1800Z 20.0N  62.5W   45 KT  50 MPH
120H  26/1800Z 22.5N  65.5W   45 KT  50 MPH
 
$$
FORECASTER PASCH
 

WTNT41 KNHC 220240
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER   5
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
1100 PM AST WED SEP 21 2011

INFRARED AND MICROWAVE SATELLITE IMAGERY THIS EVENING SHOWS THAT
OPHELIA CONTINUES TO BE AFFECTED BY SOUTHWESTERLY VERTICAL WIND
SHEAR...WITH THE LOW-LEVEL CENTER REMAINING NEAR THE SOUTHWESTERN
EDGE OF THE MAIN CONVECTIVE MASS.  SATELLITE INTENSITY ESTIMATES
FROM TAFB AND SAB ARE 45 KT...AND NOAA BUOY 41041 RECENTLY REPORTED
1-MINUTE MEAN WINDS OF 45 KT.  BASED ON THE BUOY AND THE LIKELIHOOD
THAT IT DID NOT SAMPLE THE MAXIMUM WIND...THE INITIAL INTENSITY
REMAINS 50 KT.

THE INITIAL MOTION IS 280/13.  THERE IS LITTLE CHANGE TO EITHER THE
TRACK FORECAST PHILOSOPHY OR THE FORECAST TRACK SINCE THE LAST
ADVISORY.  A LOW/MID-LEVEL RIDGE TO THE NORTH OF OPHELIA SHOULD
STEER THE CYCLONE WESTWARD TO WEST-NORTHWESTWARD FOR THE NEXT 2-3
DAYS.  AFTER THAT TIME...THE STORM SHOULD APPROACH THE WESTERN
PERIPHERY OF THE RIDGE AS A DEEP-LAYER TROUGH MOVES EASTWARD INTO
THE EASTERN UNITED STATES.  THIS SHOULD ALLOW OPHELIA TO TURN
TOWARD THE NORTHWEST WITH SOME REDUCTION IN FORWARD SPEED.  THE NEW
FORECAST TRACK IS AN UPDATE OF THE PREVIOUS TRACK AND LIES IN THE
CENTER OF THE TRACK GUIDANCE ENVELOPE.

ANALYSES FROM CIMSS AT THE UNIVERSITY OF WISCONSIN INDICATE THAT
OPHELIA IS EXPERIENCING 20-25 KT OF SHEAR DUE IN PART TO AN
UPPER-LEVEL TROUGH TO THE NORTHWEST OF THE STORM.  ALL OF THE
DYNAMICAL MODELS INDICATE THAT MODERATE TO STRONG SHEAR IS LIKELY
TO CONTINUE FOR THE NEXT 72 HOURS...AND IN RESPONSE MOST GUIDANCE
SHOWS LITTLE CHANGE IN STRENGTH OR WEAKENING DURING THAT TIME.  THE
INTENSITY FORECAST IS MORE UNCERTAIN AFTER 72 HR.  THE UPPER-LEVEL
TROUGH IS FORECAST TO SLOW ITS WESTWARD MOTION AS IT MOVES NORTH OF
HISPANIOLA.  THIS COULD ALLOW OPHELIA TO CATCH UP WITH THE TROUGH
AND ENCOUNTER STRONGER SHEAR...OR TURN NORTHWARD EAST OF THE TROUGH
AND ENCOUNTER LIGHTER SHEAR.  THE GFS TENDS TOWARD THE LATTER
SOLUTION...WHILE THE GFDL MAKE OPHELIA A HURRICANE AFTER 96 HR.  ON
THE OTHER HAND...THE ECMWF SHOWS VERY STRONG UPPER-LEVEL WINDS NEAR
THE STORM FROM 96-120 HR.  DUE TO THE UNCERTAINTY...THERE IS NO
CHANGE TO THE PREVIOUS INTENSITY FORECAST. 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  22/0300Z 13.7N  46.2W   50 KT  60 MPH
 12H  22/1200Z 14.0N  48.1W   50 KT  60 MPH
 24H  23/0000Z 14.3N  50.9W   50 KT  60 MPH
 36H  23/1200Z 15.2N  53.4W   50 KT  60 MPH
 48H  24/0000Z 16.3N  55.8W   50 KT  60 MPH
 72H  25/0000Z 18.5N  60.0W   45 KT  50 MPH
 96H  26/0000Z 21.5N  64.0W   45 KT  50 MPH
120H  27/0000Z 23.5N  66.5W   45 KT  50 MPH
 
$$
FORECASTER BEVEN
 

WTNT41 KNHC 220856
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER   6
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
500 AM AST THU SEP 22 2011

ALTHOUGH OPHELIA IS NOT WELL ORGANIZED ON SATELLITE IMAGES WITH ALL
OF THE CONVECTION LOCATED NORTHEAST OF THE CENTER...NOAA BUOY 41041
REPORTED PEAK ONE-MINUTE SUSTAINED WINDS OF 54 KT WITH A GUST TO 68
KT DURING THE PAST COUPLE OF HOURS.  THUS THE INITIAL INTENSITY IS
INCREASED TO 55 KT FOR THIS ADVISORY...AND THIS MIGHT BE A LITTLE
CONSERVATIVE GIVEN THE REMOTE CHANCES OF MEASURING THE INTENSITY OF
A SYSTEM WITH JUST ONE OBSERVING STATION.

THE INTENSIFICATION OF OPHELIA IS EXPECTED TO BE SHORT-LIVED AS 
SOUTHWESTERLY VERTICAL WIND SHEAR SHOULD INCREASE OVER THE NEXT DAY
OR SO.  GLOBAL MODELS ARE IN GOOD AGREEMENT ON A MID-OCEANIC
UPPER-LEVEL TROUGH REMAINING ENHANCED FOR THE NEXT SEVERAL
DAYS...WHICH SHOULD CAUSE SOME WEAKENING OF THE TROPICAL CYCLONE. 
AT THE END OF THE FORECAST PERIOD...THE MID-OCEANIC TROUGH COULD
FRACTURE...RESULTING IN A LOWER SHEAR ENVIRONMENT MORE CONDUCIVE
FOR STRENGTHENING.  THE NHC INTENSITY FORECAST SHOWS WEAKENING
EARLY ON...AND IS CLOSEST TO THE FSU SUPERENSEMBLE...ON THE LOW
SIDE OF THE GUIDANCE ENVELOPE.  IT WOULD NOT BE SURPRISING IF
OPHELIA ENDED UP WEAKENING FASTER THAN SHOWN BELOW GIVEN THE
SOMEWHAT HOSTILE UPPER-LEVEL WINDS EXPECTED.  
 
MICROWAVE AND ASCAT DATA INDICATED THAT THE CENTER IS A LITTLE
FARTHER SOUTH THAN ANTICIPATED...WHICH REQUIRED A SMALL
REPOSITIONING OF THE CENTER.  THIS CHANGE RESULTS IN AN ESTIMATED
MOTION OF 275/12.  MOST OF THE RELIABLE GUIDANCE SHOW OPHELIA
TURNING TO THE WEST-NORTHWEST BY FRIDAY MORNING AS THE MID-LEVEL
RIDGE WEAKENS SOMEWHAT.  A TURN TO THE NORTHWEST IS ANTICIPATED
OVER THE WEEKEND DUE TO THE TROPICAL CYCLONE REACHING THE
SOUTHWESTWARD EDGE OF THE SUBTROPICAL RIDGE...WITH A MORE POLEWARD
TRACK ANTICIPATED FOR EARLY NEXT WEEK.  THERE IS FAIR AGREEMENT IN
THE GLOBAL MODEL GUIDANCE ON THIS SOLUTION...THOUGH THE SPEED
DIFFERENCES ARE NOTABLE BY DAY 5.  THE NHC TRACK FORECAST IS
SHIFTED TO THE RIGHT AFTER 24 HOURS...BUT REMAINS TO THE WEST OF
THE DYNAMICAL MODEL CONSENSUS...AND THE TOP-PERFORMING ECMWF/GFS
MODELS.   
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  22/0900Z 13.4N  47.0W   55 KT  65 MPH
 12H  22/1800Z 13.8N  49.0W   55 KT  65 MPH
 24H  23/0600Z 14.5N  51.6W   50 KT  60 MPH
 36H  23/1800Z 15.4N  53.8W   50 KT  60 MPH
 48H  24/0600Z 16.7N  55.8W   45 KT  50 MPH
 72H  25/0600Z 19.3N  59.6W   45 KT  50 MPH
 96H  26/0600Z 21.5N  63.0W   45 KT  50 MPH
120H  27/0600Z 24.5N  65.5W   50 KT  60 MPH
 
$$
FORECASTER BLAKE
 

WTNT41 KNHC 221432
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER   7
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
1100 AM AST THU SEP 22 2011
 
OPHELIA REMAINS QUITE DISORGANIZED IN ITS APPEARANCE ON SATELLITE
IMAGES.  EVEN WITH VISIBLE PICTURES THE LOW-LEVEL CENTER...SUCH AS
IT IS...IS DIFFICULT TO DISCERN.  MOST OF THE DEEP CONVECTION IS
SHEARED TO THE NORTHEAST AND EAST OF THE ESTIMATED CENTER.  FROM A
DVORAK PERSPECTIVE...THE SYSTEM IS RATED AS A LOW-END TROPICAL
STORM.  HOWEVER...BUOY...SHIP...AND SCATTEROMETER DATA HAVE BEEN
SAYING OTHERWISE AND THE CURRENT INTENSITY ESTIMATE REMAINS 55 KT. 
AS OPHELIA APPROACHES AN UPPER-LEVEL TROUGH TO ITS NORTHWEST...THE
SOUTHWESTERLY SHEAR THAT HAS BEEN IMPACTING THE STORM IS LIKELY TO
INCREASE FURTHER.  SLOW WEAKENING IS PREDICTED THROUGH 48 HOURS DUE
TO THE STRONG SHEAR.  AFTERWARDS...GLOBAL MODELS SUGGEST THAT THE
TROUGH WILL WEAKEN AND THE UPPER-TROPOSPHERIC FLOW NEAR THE STORM
WILL BECOME MORE ANTICYCLONIC.  BASED ON THIS SCENARIO...THE
OFFICIAL FORECAST SHOWS RE-INTENSIFICATION LATE IN THE FORECAST
PERIOD.  THIS IS CONSISTENT WITH THE LGEM AND SOME OF THE OTHER
NUMERICAL MODELS.

IT HAS BEEN A CHALLENGE TO TRACK THE CENTER BUT A ROUGH ESTIMATE OF
THE INITIAL MOTION IS 280/11.  THE TRACK FORECAST REASONING IS
ESSENTIALLY UNCHANGED FROM THE PREVIOUS PACKAGE.  A GRADUAL TURN
TOWARD THE WEST-NORTHWEST IS EXPECTED AS OPHELIA MOVES AROUND THE
SOUTHERN PERIPHERY OF A SUBTROPICAL HIGH PRESSURE SYSTEM.  LATER IN
THE PERIOD...A TURN TOWARD THE NORTHWEST IS ANTICIPATED AS THE
TROPICAL CYCLONE NEARS THE SOUTHWEST SIDE OF THE HIGH.  THE
OFFICIAL FORECAST IS A LITTLE NORTH OF THE PREVIOUS ONE...BUT ON
THE SOUTHERN SIDE OF THE GUIDANCE SUITE.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  22/1500Z 13.6N  47.6W   55 KT  65 MPH
 12H  23/0000Z 14.0N  49.8W   55 KT  65 MPH
 24H  23/1200Z 15.0N  52.3W   50 KT  60 MPH
 36H  24/0000Z 16.2N  54.4W   50 KT  60 MPH
 48H  24/1200Z 17.4N  56.5W   45 KT  50 MPH
 72H  25/1200Z 20.5N  60.5W   45 KT  50 MPH
 96H  26/1200Z 22.5N  63.0W   50 KT  60 MPH
120H  27/1200Z 25.5N  65.5W   55 KT  65 MPH
 
$$
FORECASTER PASCH
 

WTNT41 KNHC 222033
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER   8
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
500 PM AST THU SEP 22 2011
 
STRONG SOUTHWESTERLY SHEAR CONTINUES TO AFFECT OPHELIA...AND MOST OF
THE DEEP CONVECTION IS DISPLACED WELL TO THE NORTHEAST AND EAST OF
THE CENTER.  THE LOW-LEVEL CENTER IS PERHAPS A LITTLE BETTER
DEFINED ON VISIBLE SATELLITE IMAGES THAN IT WAS EARLIER TODAY...
HOWEVER IT IS STILL NOT VERY OBVIOUS.  THE STORM IS QUITE
DISORGANIZED...AND SATELLITE INTENSITY ESTIMATES ONLY SUPPORT A
LOW-END TROPICAL STORM.  HOWEVER...AN ASCAT PASS FROM SEVERAL HOURS
AGO SUGGESTED THAT THE SYSTEM HAD NOT WEAKENED...SO THE INTENSITY
WILL BE HELD AT 55 KT FOR THE TIME BEING.  GLOBAL MODELS INDICATE
THAT OPHELIA WILL CONTINUE TO EXPERIENCE SHEAR ASSOCIATED WITH THE
FLOW ON THE SOUTHEAST SIDE OF AN UPPER-LEVEL CYCLONE CENTERED TO
THE NORTH OF THE GREATER ANTILLES OVER THE NEXT FEW DAYS. 
THEREFORE SOME WEAKENING IS LIKELY OVER THE NEXT 72 HOURS OR SO. 
BY THE END OF THE PERIOD...THE GLOBAL MODELS SUGGEST SOME LESSENING
OF THE SHEAR AS OPHELIA NEARS THE SUBTROPICS...SO RESTRENGTHENING
COULD OCCUR IN 4 TO 5 DAYS...IF THE SYSTEM SURVIVES THAT LONG.  THE
OFFICIAL WIND SPEED FORECAST IS VERY CLOSE TO THE LATEST
STATISTICAL-DYNAMICAL LGEM GUIDANCE.

THE MOTION REMAINS ABOUT THE SAME...280/11...AS OPHELIA CONTINUES TO
BE STEERED BY THE FLOW ON THE SOUTHERN SIDE OF A SUBTROPICAL HIGH
PRESSURE AREA.  A GRADUAL TURN TOWARD THE WEST-NORTHWEST AND
NORTHWEST IS EXPECTED AS THE STORM APPROACHES THE SOUTHWESTERN
PERIPHERY OF THE HIGH LATER IN THE FORECAST PERIOD.  THE OFFICIAL
TRACK FORECAST IS...AGAIN...SHIFTED A LITTLE TOWARD THE NORTH IN
COMPARISON TO THE PREVIOUS ONE.  THIS IS STILL ON THE SOUTHERN SIDE
OF THE MODEL GUIDANCE SUITE.

FORECAST POSITIONS AND MAX WINDS
 
INIT  22/2100Z 13.8N  48.9W   55 KT  65 MPH
 12H  23/0600Z 14.5N  50.7W   50 KT  60 MPH
 24H  23/1800Z 15.7N  53.0W   50 KT  60 MPH
 36H  24/0600Z 17.1N  55.3W   50 KT  60 MPH
 48H  24/1800Z 18.5N  57.3W   45 KT  50 MPH
 72H  25/1800Z 21.5N  61.0W   45 KT  50 MPH
 96H  26/1800Z 23.5N  63.5W   45 KT  50 MPH
120H  27/1800Z 25.5N  65.0W   50 KT  60 MPH
 
$$
FORECASTER PASCH
 

WTNT41 KNHC 230242
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER   9
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
1100 PM AST THU SEP 22 2011
 
ALTHOUGH THE LOW-LEVEL CENTER OF OPHELIA HAS BECOME BETTER DEFINED
AS COMPARED TO EARLIER TODAY...THE DEEP CONVECTION HAS BECOME
FURTHER REMOVED FROM THE CENTER DUE TO STRONG SOUTHWESTERLY SHEAR. 
SATELLITE CURRENT INTENSITY ESTIMATES FROM TAFB AND SAB ONLY
SUPPORT A 35-KT TROPICAL STORM.  SINCE THE WINDS FROM THIS STORM
HAVE HISTORICALLY BEEN HIGHER THAN THE SATELLITE PRESENTATION WOULD
SUGGEST...THE INITIAL INTENSITY IS BEING CONSERVATIVELY REDUCED TO
45 KT ON THIS ADVISORY.

IT APPEARS THAT OPHELIA MAY BE MAKING A LITTLE MORE NORTHWARD
PROGRESS AND IS NOW MOVING TO THE WEST-NORTHWEST AT 10 KT.  THE
TRACK MODEL GUIDANCE IS IN GENERALLY GOOD AGREEMENT ON TURNING
OPHELIA NORTHWESTWARD WITHIN THE NEXT 24 HOURS AND THEN MAINTAINING
THAT HEADING THROUGH DAY 5.  HOWEVER...THERE ARE SOME SPEED
DIFFERENCES THAT APPEAR TO BE RELATED TO THE ORIENTATION OF THE
MID-LEVEL HIGH RELATIVE TO THE CYCLONE.  MOST NOTABLY...THE ECMWF
SHOWS THE HIGH WEAKENING AND SLIDING SOUTHEASTWARD MORE THAN THE
OTHER MODELS BY DAYS 4 AND 5 AND THEREFORE HAS OPHELIA MAKING MORE
NORTHWESTWARD PROGRESS DURING THAT TIME.  THE NEW OFFICIAL FORECAST
IS JUST A LITTLE SLOWER THAN THE PREVIOUS ONE BUT IS STILL FASTER
THAN THE VARIOUS CONSENSUS MODELS.

AS FAR AS INTENSITY...OPHELIA HAS A TOUGH ROAD AHEAD OF IT...AND 
THE CYCLONE IS ALREADY WEAKENING DUE TO ABOUT 25 KT OF
SOUTHWESTERLY SHEAR.  THE UPPER-LEVEL TROUGH RESPONSIBLE FOR THIS
SHEAR IS EXPECTED TO CUT-OFF AND MOVE WESTWARD IN TANDEM WITH
OPHELIA...REMAINING ABOUT 600 N MI NORTHWEST OF THE STORM AT LEAST
FOR THE NEXT 3 DAYS.  YOU WOULD THINK THAT OPHELIA WOULD NOT
SURVIVE AN ENVIRONMENT LIKE THIS...BUT IT IS OFTEN HARD TO TELL IF
SYSTEMS LIKE THIS WILL HANG BY A THREAD DESPITE THE CONDITIONS. 
DUE TO THE HIGH UNCERTAINTY...THE OFFICIAL INTENSITY FORECAST SHOWS
VERY LITTLE CHANGE FOR THE NEXT 5 DAYS.  IT WOULD NOT BE
SURPRISING...HOWEVER...IF OPHELIA DEGENERATED INTO A REMNANT LOW
OVER THE NEXT DAY OR TWO.

FORECAST POSITIONS AND MAX WINDS
 
INIT  23/0300Z 14.1N  49.9W   45 KT  50 MPH
 12H  23/1200Z 14.8N  51.6W   45 KT  50 MPH
 24H  24/0000Z 16.2N  53.8W   40 KT  45 MPH
 36H  24/1200Z 17.5N  55.8W   40 KT  45 MPH
 48H  25/0000Z 18.8N  57.6W   40 KT  45 MPH
 72H  26/0000Z 21.0N  61.0W   40 KT  45 MPH
 96H  27/0000Z 22.5N  63.0W   40 KT  45 MPH
120H  28/0000Z 25.0N  65.0W   40 KT  45 MPH
 
$$
FORECASTER BERG
 

WTNT41 KNHC 230852
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER  10
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
500 AM AST FRI SEP 23 2011

OPHELIA CONTINUES TO STRUGGLE AGAINST STRONG SOUTHWESTERLY SHEAR.  
THE CENTER OF THE TROPICAL STORM REMAINS EXPOSED WELL TO THE WEST OF
A LARGE CURVED BAND...ALTHOUGH THIS BAND IS AT A CONSIDERABLE
DISTANCE FROM THE CENTER.  WITH LITTLE CONVECTION NEAR THE
CENTER...IT IS LIKELY THE WINDS HAVE DROPPED SINCE THE LAST
ADVISORY...AND THE INITIAL WIND SPEED IS 40 KT.  FURTHER WEAKENING
IS FORECAST DUE TO THE PERSISTENT SHEAR FROM AN UPPER-LEVEL
TROUGH...AND THE INTENSITY FORECAST IS LOWERED FROM THE PREVIOUS
PREDICTION.  IT IS ALSO QUITE POSSIBLE THAT OPHELIA WILL WEAKEN
INTO A REMNANT LOW SOMETIME DURING THE NEXT COUPLE OF DAYS.  IF
OPHELIA SURVIVES...THE UPPER-LEVEL ENVIRONMENT COULD BECOME MORE
FAVORABLE FOR STRENGTHENING AT DAYS 4 AND 5...SO SOME
INTENSIFICATION IS SHOWN AT THOSE TIMES.  

THE INITIAL MOTION IS 290/11.  A GRADUAL TURN TO THE RIGHT IS
ANTICIPATED OVER THE NEXT DAY OR SO AS OPHELIA MOVES AROUND THE
SOUTHERN PERIPHERY OF A RIDGE OVER THE WESTERN ATLANTIC OCEAN. 
THERE ARE SOME RATHER LARGE DIFFERENCES IN THE GLOBAL MODEL TRACKS
ALMOST IMMEDIATELY...WHICH SEEM TO BE RELATED TO THE DEPTH OF THE
TROPICAL CYCLONE.  GENERALLY...THE MODELS THAT SHOW A WEAKER
CYCLONE...SUCH AS THE ECMWF...SHOW THE WEST-NORTHWESTWARD MOTION
CONTINUING FOR THE NEXT SEVERAL DAYS UNDER THE RIDGE.  THE
GFS/HWRF/GFDL MODELS HAVE A MORE VERTICALLY COHERENT TROPICAL
CYCLONE WHICH IS AFFECTED MORE BY THE SOUTHWESTERLY UPPER-LEVEL
FLOW.  THIS DEEPER STRUCTURE CAUSES THE CYCLONE TO MOVE TOWARD THE
NORTHWEST AND NORTH-NORTHWEST...TO THE RIGHT OF THE BULK OF THE
GUIDANCE. GIVEN THAT OPHELIA IS EXPECTED TO WEAKEN AND BECOME MORE
SHALLOW...THE NHC FORECAST IS SHIFTED TO THE LEFT...BUT NOT QUITE
AS FAR TO THE WEST AS THE ECMWF OR BAM SHALLOW MODELS.  

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  23/0900Z 14.5N  51.0W   40 KT  45 MPH
 12H  23/1800Z 15.3N  52.7W   35 KT  40 MPH
 24H  24/0600Z 16.7N  55.0W   30 KT  35 MPH
 36H  24/1800Z 18.0N  57.0W   30 KT  35 MPH
 48H  25/0600Z 19.2N  58.9W   30 KT  35 MPH
 72H  26/0600Z 21.0N  62.0W   30 KT  35 MPH
 96H  27/0600Z 23.0N  64.5W   35 KT  40 MPH
120H  28/0600Z 25.5N  66.0W   40 KT  45 MPH
 
$$
FORECASTER BLAKE
 

WTNT41 KNHC 231455
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER  11
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
1100 AM AST FRI SEP 23 2011
 
THE SATELLITE APPEARANCE OF OPHELIA HAS CONTINUED TO DEGRADE AND THE
SYSTEM IS LOOKING LESS AND LESS LIKE A TROPICAL CYCLONE. DRY AIR
COUPLED WITH MODERATE TO STRONG SOUTH-SOUTHWESTERLY WIND SHEAR HAS
ERODED NEARLY ALL OF THE INNER CORE CONVECTION...AND WHAT DEEP
CONVECTION THAT DOES EXIST IS OCCURRING IN A RAGGED BAND MORE THAN
200 NMI EAST THROUGH SOUTH OF THE CENTER. THE INITIAL INTENSITY IS
DECREASED TO 35 KT BASED ON AN EARLIER WIND REPORT OF 31 KT FROM
NOAA BUOY 41041 LOCATED WELL EAST OF THE CENTER. NOAA BUOY 41040
JUST WEST OF THE CENTER HAS NOT SHOWN SIGNS OF THE SURFACE WINDS
BACKING AROUND TO A WESTERLY DIRECTION...WHICH SUGGESTS THAT
OPHELIA MIGHT JUST BE A SHARP OPEN WAVE. AN AIR FORCE RESERVE
RECONNAISSANCE AIRCRAFT WILL INVESTIGATE THE CYCLONE THIS AFTERNOON
BETWEEN 18-00Z TO SEE IF OPHELIA HAS A CLOSED SURFACE CIRCULATION.

THE INITIAL MOTION IS 280/14. SMOOTHING THROUGH ALL OF THE WIGGLES
AND WOBBLES...CAUSED BY BRIEF CONVECTIVE BURSTS NEAR THE CENTER...
OVER THE PAST 48 HOURS ALSO YIELDS A MOTION VECTOR OF 280 DEGREES.
AS CONTINUED STRONG VERTICAL SHEAR AND DRY AIR ENTRAINMENT TAKE
THEIR TOLL ON THE CONVECTIVE STRUCTURE AND ORGANIZATION OF
OPHELIA...THE VERTICAL DEPTH OF THE CYCLONE IS EXPECTED TO BECOME
INCREASINGLY SHALLOW. THE RESULT IS THAT THE CYCLONE SHOULD BE
STEERED MORE WESTWARD LIKE THE ECMWF AND UKMET ARE
FORECASTING...AND LESS POLEWARD LIKE THE MORE ROBUST GFDL AND HWRF
MODELS ARE INDICATING. ASSUMING OPHELIA STILL EXISTS BY DAYS 4 AND
5...A TURN TOWARD THE NORTHWEST AND NORTH IS EXPECTED AS THE
CYCLONE ROUNDS THE WESTERN PERIPHERY OF THE BERMUDA HIGH AND LIFTS
OUT POLEWARD AHEAD OF AN UPPER-LEVEL LOW EAST OF THE BAHAMAS. THE
OFFICIAL FORECAST TRACK IS TO THE LEFT OF THE PREVIOUS TRACK AND
THE CONSENSUS MODELS DUE TO THE UNREALISTIC NORTHWARD TRACK OF THE
HWRF MODEL...AND LIES ALONG THE SOUTHERN EDGE OF THE GUIDANCE
ENVELOPE NEAR A BLEND OF THE ECMWF...UKMET...AND SHALLOW BAM
MODELS.
 
THE 25-30 KT OF SOUTHWESTERLY TO WESTERLY VERTICAL SHEAR IS NOT
FORECAST TO ABATE FOR THE NEXT 4 DAYS OR SO...ALL THE WHILE THE
CYCLONE MOVES INTO AN EVEN DRIER AIR MASS. IT IS...THEREFORE...
POSSIBLE THAT OPHELIA COULD DEGENERATE INTO A REMNANT LOW OR EVEN
AN OPEN WAVE BY 48 HOURS LIKE THE STATISTICAL-DYNAMICAL MODELS
SHIPS AND LGEM ARE FORECASTING. HOWEVER...GIVEN THE RATHER LARGE
CIRCULATION OF OPHELIA AND THAT SSTS OF NEAR 29C LIE AHEAD OF THE
CYCLONE...THE OFFICIAL FORECAST CALLS FOR OPHELIA TO MAINTAIN SOME
CONVECTION AND AT LEAST TROPICAL DEPRESSION STATUS THROUGH DAY 4.
BY DAY 5...SOME SLIGHT INTENSIFICATION IS POSSIBLE ON AS THE SHEAR
DECREASES AND OPHELIA MOVES UNDER OR NEAR A SMALL UPPER-LEVEL
ANTICYCLONE.

FORECAST POSITIONS AND MAX WINDS
 
INIT  23/1500Z 14.6N  52.6W   35 KT  40 MPH
 12H  24/0000Z 15.6N  54.6W   35 KT  40 MPH
 24H  24/1200Z 16.8N  56.9W   30 KT  35 MPH
 36H  25/0000Z 17.9N  58.8W   30 KT  35 MPH
 48H  25/1200Z 19.1N  60.9W   30 KT  35 MPH
 72H  26/1200Z 21.2N  64.3W   30 KT  35 MPH
 96H  27/1200Z 23.0N  66.5W   30 KT  35 MPH
120H  28/1200Z 25.5N  67.5W   35 KT  40 MPH
 
$$
FORECASTER STEWART
 

WTNT41 KNHC 232056
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER  12
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
500 PM AST FRI SEP 23 2011
 
DEEP CONVECTION HAS REDEVELOPED NEAR AND OVER THE LOW-LEVEL CENTER
DURING THE PAST 6 HOURS...AND REPORTS FROM AN AIR FORCE RESERVE
RECONNAISSANCE AIRCRAFT INDICATE THE INTENSITY HAS INCREASED TO 50
KT BASED ON FLIGHT-LEVEL WINDS OF 60 KT AND BELIEVABLE SFMR SURFACE
WINDS OF 50-51 KT.
 
THE INITIAL MOTION IS 285/13...AFTER ONCE AGAIN HAVING TO SMOOTH
THROUGH ALL OF THE WIGGLES AND WOBBLES IN THE TRACK. THE
DEVELOPMENT OF THE DEEP CONVECTION NEAR THE CENTER LIKELY PULLED
THE BARELY-CLOSED LOW-LEVEL CIRCULATION CENTER NORTHWESTWARD...
WHICH IS BELIEVED TO BE A TEMPORARY MOTION.  OTHERWISE...THERE HAS
BEEN NO SIGNIFICANT CHANGE TO THE PREVIOUS FORECAST TRACK. MOST OF
THE MODEL GUIDANCE SHIFTED TO THE RIGHT DUE TO THE MORE NORTHWARD
INITIAL POSITION...BUT THE SUBTROPICAL RIDGE TO THE NORTH OF
OPHELIA IS FORECAST BY ALL OF THE GLOBAL MODELS TO REMAIN QUITE
STRONG...WHICH SHOULD KEEP THE CYCLONE MOVING IN A GENERAL
WEST-NORTHWESTWARD MOTION FOR THE NEXT 48 HOURS OR SO. BY 72 HOURS
AND BEYOND...THE WESTERN PORTION OF THE RIDGE IS FORECAST TO ERODE
AS A MID-/UPPER-LEVEL TROUGH MOVES EASTWARD ACROSS FLORIDA AND THE
BAHAMAS. THIS SHOULD CAUSE OPHELIA TO SLOW DOWN AND TURN
NORTHWESTWARD BY DAYS 3-4...AND THEN ALLOW FOR A GRADUAL NORTHWARD
TURN BY DAY 5. THE OFFICIAL FORECAST TRACK IS SIMILAR TO THE
PREVIOUS ADVISORY TRACK...AND LIES NEAR THE SOUTHERN OR LEFT SIDE
OF THE NHC GUIDANCE ENVELOPE.

ALTHOUGH THE GFS-BASED SHIPS MODEL IS ASSESSING NEAR 20 KT OF
SOUTHWESTERLY SHEAR ACROSS THE CYCLONE...THE UW-CIMSS MID-LEVEL
SHEAR ANALYSES INDICATE THE SHEAR IS 15 KT OR LESS. THIS HAS LIKELY
ALLOWED THE RECENT RESURGENCE IN INNER CORE CONVECTION. HOWEVER...
THIS BRIEF RESPITE IS EXPECTED TO BE SHORT-LIVED AS ALL OF THE
GLOBAL MODELS ARE FORECASTING THE VERTICAL SHEAR TO INCREASE TO
MORE THAN 25 KT IN 12-18 HOURS. THERE WILL CONTINUE TO BE
FLUCTUATIONS IN THE MAGNITUDE OF THE VERTICAL SHEAR FOR THE NEXT 96
HOURS...WHICH WILL RESULT IN THE WAXING AND WANING OF THE CENTRAL
DEEP CONVECTION...BUT THE GENERAL TREND SHOULD BE FOR GRADUAL
WEAKENING TO OCCUR. HOWEVER...BY DAY 5...SOME SLIGHT STRENGTHENING
IS POSSIBLE AS THE SHEAR DECREASES AND OPHELIA MOVES UNDERNEATH OR
NEAR A SMALL UPPER-LEVEL ANTICYCLONE.

FORECAST POSITIONS AND MAX WINDS
 
INIT  23/2100Z 15.5N  53.8W   50 KT  60 MPH
 12H  24/0600Z 16.3N  55.7W   50 KT  60 MPH
 24H  24/1800Z 17.5N  58.0W   45 KT  50 MPH
 36H  25/0600Z 18.6N  60.0W   45 KT  50 MPH
 48H  25/1800Z 19.7N  61.8W   40 KT  45 MPH
 72H  26/1800Z 21.8N  64.9W   40 KT  45 MPH
 96H  27/1800Z 24.0N  66.6W   40 KT  45 MPH
120H  28/1800Z 26.5N  67.5W   45 KT  50 MPH
 
$$
FORECASTER STEWART
 

WTNT41 KNHC 240255
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER  13
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
1100 PM AST FRI SEP 23 2011
 
EASY COME...EASY GO.  AFTER STRENGTHENING EARLIER THIS AFTERNOON...
OPHELIA NOW APPEARS TO BE ON A WEAKENING TREND.  AN AIR FORCE
HURRICANE HUNTER AIRCRAFT INVESTIGATING THE SYSTEM MEASURED A
MAXIMUM 925-MB FLIGHT-LEVEL WIND OF 47 KT AND HAS YET TO MEASURE
ANY TROPICAL-STORM-FORCE WINDS FROM THE SFMR.  IN ADDITION...THE
LAST CENTRAL PRESSURE MEASURED BY THE PLANE WAS 1006 MB. 
HOWEVER...THE PLANE IS JUST GETTING READ TO SAMPLE THE DEEP
CONVECTION LOCATED ABOUT 100-200 N MI NORTHEAST OF THE LOW-LEVEL
CENTER...AND THE INITIAL INTENSITY IS ONLY BEING LOWERED TO 45 KT
FOR NOW UNTIL WE CAN GET DATA FROM THAT PART OF THE STORM.  STRONG
SOUTHWESTERLY SHEAR IS EXPECTED TO CONTINUE AFFECTING OPHELIA FOR
AT LEAST THE NEXT 3 DAYS.  AFTER THAT...THE POSITION OF THE CYCLONE
RELATIVE TO THE UPPER-LEVEL TROUGH TO ITS NORTHWEST WILL MEAN THE
DIFFERENCE BETWEEN A HOSTILE OR FAVORABLE ENVIRONMENT FOR
STRENGTHENING.  GIVEN THE UNCERTAINTY...IT IS NOT WORTH HAGGLING
OVER 5 OR 10 KT FROM DAY TO DAY...AND THE OFFICIAL FORECAST HOLDS
THE INTENSITY CONSTANT THROUGH 5 DAYS WITH THE UNDERSTANDING THAT
FLUCTUATIONS ARE LIKELY.

BASED ON RECENT FIXES FROM THE PLANE...THE CENTER OF OPHELIA IS
EITHER JUMPING AROUND OR IS BECOMING LESS WELL DEFINED.  A 12-HOUR
AVERAGE GIVES A MOTION OF 300/12.  OPHELIA IS FORECAST TO TURN
NORTHWESTWARD IN THE NEXT 12 HOURS OR SO AND SHOULD BEGIN TO
DECREASE IN FORWARD SPEED AS IT BECOMES BLOCKED BY THE MID-LEVEL
HIGH TO ITS NORTH.  THE GUIDANCE ENVELOPE HAS SHIFTED SOMEWHAT
SIGNIFICANTLY TO THE EAST WITH A SLOWER MOTION AND IS BOUNDED BY
THE WESTERNMOST ECMWF AND THE EASTERNMOST HWRF AND GFDL.  THE NEW
OFFICIAL FORECAST HAS BEEN SHIFTED EASTWARD AND LIES ON THE WESTERN
EDGE OF THE MAIN CLUSTER OF MODELS...CLOSE TO THE ECMWF.  IT SHOULD
BE NOTED THAT SOME OF THE MODELS ARE SHOWING A SLOW NORTHEASTWARD
MOTION BY DAY 5...BUT THAT SCENARIO IS NOT YET INDICATED BY THE
OFFICIAL FORECAST.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/0300Z 16.0N  54.5W   45 KT  50 MPH
 12H  24/1200Z 16.9N  56.1W   45 KT  50 MPH
 24H  25/0000Z 18.2N  58.0W   45 KT  50 MPH
 36H  25/1200Z 19.4N  59.7W   45 KT  50 MPH
 48H  26/0000Z 20.3N  61.1W   45 KT  50 MPH
 72H  27/0000Z 22.0N  63.5W   45 KT  50 MPH
 96H  28/0000Z 24.0N  64.5W   45 KT  50 MPH
120H  29/0000Z 26.0N  65.0W   45 KT  50 MPH
 
$$
FORECASTER BERG
 

WTNT41 KNHC 240853
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER  14
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
500 AM AST SAT SEP 24 2011
 
OPHELIA HAS NOT CHANGED A LOT DURING THE PAST SEVERAL HOURS...WITH
THE CENTER STAYING MOSTLY EXPOSED TO THE SOUTHWEST OF A LARGE AREA
OF CONVECTION. THE INITIAL INTENSITY WILL REMAIN 45 KT FOR THIS
ADVISORY...ALTHOUGH THE CYCLONE MIGHT BE A LITTLE WEAKER THAN THAT.
MODERATE TO STRONG SOUTHWESTERLY SHEAR SHOULD REMAIN IN PLACE FOR
THE NEXT SEVERAL DAYS DUE TO A PERSISTENT UPPER-LEVEL TROUGH TO THE
WEST OF OPHELIA. GIVEN THE HOSTILE CONDITIONS...IT SEEMS LIKELY
THAT THE CYCLONE WILL GRADUALLY WEAKEN DURING THE NEXT 2 OR 3
DAYS...AND THE NHC INTENSITY FORECAST HAS BEEN ADJUSTED DOWNWARD
THROUGH THAT TIME. AFTER 72 HOURS...THE GLOBAL MODELS ARE STILL
HINTING THAT THE UPPER-LEVEL TROUGH COULD FRACTURE AND ALLOW
RESTRENGTHENING OF THE TROPICAL CYCLONE. THIS IDEA IS REFLECTED IN
THE OFFICIAL FORECAST...WHICH SHOWS A MODEST INCREASE IN STRENGTH
AT DAYS 4 AND 5. THE NHC FORECAST IS SHADED TOWARD THE STATISTICAL
LGEM/SHIPS GUIDANCE...AND IS BELOW THE INTENSITY CONSENSUS. 

NIGHT-VISIBLE IMAGERY SUGGESTS THAT OPHELIA HAS TURNED TOWARD THE
NORTHWEST WITH A FORWARD SPEED OF ABOUT 12 KT. WHILE THE MODEL
GUIDANCE IS IN FAIR AGREEMENT ON THIS TRACK CONTINUING FOR A DAY OR
SO...THE DIFFERENCES BECOME QUITE LARGE AFTER THAT TIME. THESE
DIFFERENCES APPEAR TO BE RELATED TO THE STRENGTH OF THE TROPICAL
CYCLONE. IF SYSTEM IS WEAK...OPHELIA IS MORE LIKELY TO CONTINUE
MOVING TOWARD THE WEST-NORTHWEST OR NORTHWEST UNDER THE LOW-LEVEL
RIDGE. HOWEVER...IF OPHELIA IS DEEP ENOUGH TO FEEL A BREAK IN THE
MID-LEVEL RIDGE AROUND 65W...A TURN TOWARD THE NORTH IS MORE LIKELY
WITH A LARGE DECREASE IN FORWARD SPEED. SINCE THE OFFICIAL FORECAST
SHOWS SOME INCREASE IN STRENGTH AT THE END OF THE PERIOD...IT WILL
LEAN TOWARD THE LATTER SCENARIO...AND RESULTS IN AN EASTWARD SHIFT
OF THE NHC TRACK FROM THE PREVIOUS PACKAGE. 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/0900Z 16.9N  55.2W   45 KT  50 MPH
 12H  24/1800Z 18.0N  56.6W   45 KT  50 MPH
 24H  25/0600Z 19.2N  58.4W   40 KT  45 MPH
 36H  25/1800Z 20.2N  60.0W   40 KT  45 MPH
 48H  26/0600Z 21.0N  61.5W   35 KT  40 MPH
 72H  27/0600Z 22.5N  63.0W   35 KT  40 MPH
 96H  28/0600Z 24.5N  63.5W   40 KT  45 MPH
120H  29/0600Z 26.5N  63.5W   50 KT  60 MPH
 
$$
FORECASTER BLAKE
 

WTNT41 KNHC 241455
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER  15
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
1100 AM AST SAT SEP 24 2011

DURING THE PAST 6 HOURS...DEEP CONVECTION HAS REDEVELOPED OVER AND
TO THE NORTHEAST OF THE PREVIOUSLY EXPOSED LOW-LEVEL CIRCULATION
CENTER. SATELLITE CURRENT INTENSITY ESTIMATES ARE T3.0/45 KT FROM
TAFB AND T3.1/47 KT FROM UW-CIMSS ADT. THEREFORE...THE INITIAL
INTENSITY WILL REMAIN AT 45 KT FOR THIS ADVISORY.

THE INITIAL MOTION ESTIMATE IS 310/11 KT. THERE IS NO SIGNIFICANT
CHANGE TO THE PREVIOUS FORECAST TRACK REASONING. A FAIRLY LARGE
SPREAD REMAINS IN THE MODEL GUIDANCE WITH THE GFS AND GFS ENSEMBLE
MODELS SHOWING A MORE WESTWARD MOTION DUE TO A WEAKER CYCLONE
EXPECTED...WHEREAS THE GFDL AND HWRF MODELS SHOW A MORE NORTHERLY
TRACK DUE TO A MORE ROBUST AND STRONGER SYSTEM. THE ECMWF...
UKMET...AND NOGAPS MODELS ARE IN BETWEEN THESE TWO EXTREMES AND ARE
FAIRLY SIMILAR TO EACH OTHER IN BOTH TRACK AND INTENSITY. AS A
RESULT...THE OFFICIAL FORECAST TRACK IS VERY NEAR THE PREVIOUS
ADVISORY TRACK...AND LIES DOWN THE MIDDLE OF THE GUIDANCE ENVELOPE 
AND TO THE LEFT OF THE CONSENSUS MODEL..TVCN...AFTER 72 HOURS.

SIMILAR TO THIS TIME YESTERDAY...VERY COLD-TOPPED CONVECTION HAS
REDEVELOPED IN THE FORM OF A CURVED BAND IN THE NORTHEAST QUADRANT.
GIVEN THAT OPHELIA IS EXPECTED TO REMAIN A LARGER THAN AVERAGE
TROPICAL CYCLONE...AND THE FACT THAT IT HAS ALREADY SURVIVED
SOUTHWESTERLY VERTICAL SHEAR OF NEAR 30 KT...I SEE NO REASON WHY
THIS CYCLONE SHOULD DISSIPATE DURING THE FORECAST PERIOD LIKE SOME
OF THE GUIDANCE IS INDICATING. THE CURRENT SHEAR OF 25 KT IS
EXPECTED TO CONTINUE FOR THE NEXT 48 HOURS OR SO...WITH A GRADUAL
INCREASE TO 30 KT AFTER THAT. HOWEVER...AS THE PREVIOUS DISCUSSION
ALLUDED TO...THE GLOBAL MODELS ARE STILL SUGGESTING THAT AN
UPPER-LEVEL TROUGH NORTH OF THE LESSER ANTILLES COULD FRACTURE AND
ALLOW RESTRENGTHENING OF THE TROPICAL CYCLONE AFTER 72 HOURS AS THE
OPHELIA MOVES INTO THIS REGION OF UPPER-LEVEL DIVERGENCE. THIS
SCENARIO IS MAINTAINED IN THE OFFICIAL INTENSITY FORECAST...WHICH
SHOWS MODEST STRENGTHENING AT DAYS 4 AND 5 WHILE THE CYCLONE IS
STILL OVER SSTS OF NEAR 28C. THE INTENSITY FORECAST LEANS TOWARD
THE INTENSITY CONSENSUS MODEL...ICON...THROUGH 72 HOURS...AND IS A
LITTLE LOWER THAN THE CONSENSUS AFTER THAT.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/1500Z 17.8N  56.0W   45 KT  50 MPH
 12H  25/0000Z 18.8N  57.4W   40 KT  45 MPH
 24H  25/1200Z 19.9N  59.1W   40 KT  45 MPH
 36H  26/0000Z 20.9N  60.7W   35 KT  40 MPH
 48H  26/1200Z 21.6N  61.8W   35 KT  40 MPH
 72H  27/1200Z 23.3N  63.1W   35 KT  40 MPH
 96H  28/1200Z 25.3N  63.4W   40 KT  45 MPH
120H  29/1200Z 27.3N  63.4W   50 KT  60 MPH
 
$$
FORECASTER STEWART
 

WTNT41 KNHC 242040
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER  16
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
500 PM AST SAT SEP 24 2011
 
DURING THE PAST 6 HOURS...CONVECTION HAS WAXED AND WANED...AND THE
INNER CORE WIND FIELD HAS BECOME RATHER AMORPHOUS. BOTH NOAA AND
AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT HAVE HAD GREAT DIFFICULTY
IN TRYING TO IDENTIFY A WELL-DEFINED CIRCULATION CENTER. IN FACT...
THE PREVIOUS ALLEGED CENTER THAT WE HAVE BEEN TRACKING FOR THE PAST
24 HOURS NO LONGER EXISTS BASED ON RECON DATA...AND THE LONE VORTEX
REPORTED APPEARS TO HAVE DEGENERATED AS WELL. THE INITIAL POSITION
IS THE MEAN POSITION OF ALL OF THE PREVIOUS AND NEWLY-FORMED SMALL
SWIRLS NOTED IN SATELLITE IMAGERY AND RECON DATA. THE INITIAL
INTENSITY OF 40 KT IS BASED ON AN EARLIER NOAA DROPSONDE REPORT OF
40 KT IN THE NORTHEAST QUADRANT.
 
THE INITIAL MOTION ESTIMATE IS 295/10 KT BASED ON A 24-HOUR TREND.
OTHER THAN THE UNCERTAINTY IN THE EXACT LOCATION OF OPHELIA...
THERE IS NO SIGNIFICANT CHANGE TO THE PREVIOUS FORECAST TRACK
REASONING. A LARGE SPREAD REMAINS IN THE NHC MODEL GUIDANCE WITH
THE GFS AND GFS ENSEMBLE MODELS ALONG THE SOUTHERN EDGE OF THE
GUIDANCE ENVELOP INDICATING MORE WESTWARD MOTION...WHEREAS THE GFDL
AND HWRF MODELS ARE ON THE FAR RIGHT SIDE INDICATING A MORE
NORTHERLY TRACK. THE REMAINDER OF THE GUIDANCE IS SPREAD OUT EVENLY
BETWEEN THESE TWO EXTREMES. THE OPHELIA CIRCULATION IS EXPECTED TO
MOVE NORTHWESTWARD AND EVENTUALLY NORTHWARD AROUND THE SOUTHWESTERN
PERIPHERY OF A LARGE SUBTROPICAL RIDGE THAT IS FORECAST TO WEAKEN
AND SHIFT SLOWLY EASTWARD THROUGHOUT THE FORECAST PERIOD. THE
OFFICIAL FORECAST TRACK IS LEFT OF THE PREVIOUS ADVISORY...AND LIES
DOWN THE MIDDLE OF THE GUIDANCE ENVELOPE CLOSE TO THE CONSENSUS
MODEL..TVCN.
 
ALTHOUGH THE CONVECTIVE PATTERN IS SOMEWHAT RAGGED IN OVERALL
APPEARANCE...NEW CONVECTION HAS BEEN DEVELOPING IN THE INNER CORE
REGION NEAR THE ALLEGED LOW-LEVEL CENTER...WHICH MIGHT PRODUCE SOME
SHORT TERM STRENGTHENING. IN THE LONGER TERM...HOWEVER...VERTICAL
SHEAR IS EXPECTED TO GRADUALLY INCREASE FROM THE SOUTHWEST THROUGH
THE NEXT 72 HOURS...WHICH SHOULD INDUCE GRADUAL WEAKENING. SINCE
OPHELIA HAS BEEN ABLE TO MAINTAIN A FAIRLY LARGE CIRCULATION...ANY
WEAKENING SHOULD BE LESS THAN WHAT WOULD USUALLY OCCUR FOR A MORE
TYPICAL TROPICAL CYCLONE. AFTER THAT TIME...SOME OF THE GLOBAL
MODELS...LIKE THE ECMWF...ARE STILL FORECASTING AN UPPER-LEVEL
TROUGH NORTH OF THE LESSER ANTILLES TO FRACTURE...WHICH ALLOWS A
SMALL ANTICYCLONE TO DEVELOP ABOVE OPHELIA. THIS SCENARIO IS
EXPECTED TO RESULT IN SOME RESTRENGTHENING OF THE CYCLONE AT 96 AND 
120 HOURS WHILE THE OPHELIA IS STILL OVER SSTS OF 28C. THE INTENSITY
FORECAST LEANS TOWARD THE INTENSITY CONSENSUS MODEL ICON.  
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/2100Z 17.9N  57.4W   40 KT  45 MPH
 12H  25/0600Z 18.7N  58.8W   40 KT  45 MPH
 24H  25/1800Z 19.6N  60.4W   40 KT  45 MPH
 36H  26/0600Z 20.5N  61.6W   35 KT  40 MPH
 48H  26/1800Z 21.4N  62.7W   35 KT  40 MPH
 72H  27/1800Z 23.0N  64.0W   35 KT  40 MPH
 96H  28/1800Z 24.5N  64.5W   40 KT  45 MPH
120H  29/1800Z 27.0N  64.5W   50 KT  60 MPH
 
$$
FORECASTER STEWART
 

WTNT41 KNHC 250238
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER  17
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
1100 PM AST SAT SEP 24 2011
 
IT IS UNCLEAR WHETHER OR NOT OPHELIA STILL HAS A WELL-DEFINED
CENTER...BUT IN THE INTEREST OF CONTINUITY ADVISORIES ARE STILL
BEING ISSUED. WITHOUT ANY NEW DATA TO CONTRADICT EARLIER
ESTIMATES...THE INTENSITY IS BEING HELD AT 40 KT...AND THE INITIAL
MOTION WILL BE MAINTAINED AT 295/10 KT.  

THE TRACK AND INTENSITY FORECASTS ARE MORE LINKED TONIGHT THAN
USUAL.  OPHELIA WILL BE MOVING ALONG THE SOUTHERN EDGE OF
A LOW- TO MID-LEVEL AREA OF HIGH PRESSURE OVER THE NEXT FEW
DAYS...AND THE EXACT TRACK WILL DEPEND ON WHAT KIND OF INTENSITY
OPHELIA CAN MAINTAIN.  THE GFS AND ECMWF...USUALLY THE MOST
RELIABLE GLOBAL MODELS...SHOW OPHELIA CONTINUING TO BE BATTERED BY
STRONG SOUTHWESTERLY OR WESTERLY SHEAR AND THEREFORE SHOW A WEAKER
VORTEX MOVING FARTHER WEST.  ON THE OTHER HAND...MANY OF THE OTHER
MODELS INDICATE THAT OPHELIA WILL STRENGTHEN AND CONSEQUENTLY TURN
NORTHWARD STEERED BY DEEPER FLOW.  BASED ON THE OVERALL SYNOPTIC
ENVIRONMENT AND THE MORE LIKELY SCENARIO THAT THE VERTICAL SHEAR
WILL NOT DECREASE SIGNIFICANTLY IN THE COMING DAYS...THE OFFICIAL
FORECAST KEEPS OPHELIA AS A LOW-END TROPICAL STORM AND LEANS IN THE
DIRECTION OF THE GFS AND ECMWF...WHICH IS ALSO JUST TO THE WEST OF
THE TRACK MODEL CONSENSUS.

THERE IS A POSSIBILITY THAT OPHELIA COULD DEGENERATE INTO A TROUGH
OF LOW PRESURE AT ANY TIME IF IT IS DETERMINED THAT IT NO LONGER
HAS A WELL-DEFINED CENTER.  SHOULD THAT HAPPEN...NHC WOULD NO
LONGER ISSUE ADVISORIES UNLESS IT REGENERATES INTO A TROPICAL
CYCLONE.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  25/0300Z 18.3N  58.4W   40 KT  45 MPH
 12H  25/1200Z 18.9N  59.8W   40 KT  45 MPH
 24H  26/0000Z 19.8N  61.3W   35 KT  40 MPH
 36H  26/1200Z 20.6N  62.6W   35 KT  40 MPH
 48H  27/0000Z 21.3N  63.6W   35 KT  40 MPH
 72H  28/0000Z 23.0N  65.0W   40 KT  45 MPH
 96H  29/0000Z 24.5N  65.5W   45 KT  50 MPH
120H  30/0000Z 26.5N  66.0W   45 KT  50 MPH
 
$$
FORECASTER BERG
 

WTNT41 KNHC 250844
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER  18
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
500 AM AST SUN SEP 25 2011
 
OPHELIA REMAINS STRONGLY SHEARED WITH THE BULK OF THE THUNDERSTORM
ACTIVITY NOW DISPLACED ABOUT 200 N MI TO THE EAST OF THE LOW-LEVEL
CENTER. IF DEEP CONVECTION DOES NOT REDEVELOP NEAR THE CENTER LATER
TODAY...OPHELIA WOULD LACK THE NECESSARY ORGANIZED DEEP CONVECTION
TO BE CONSIDERED A TROPICAL CYCLONE. THE INITIAL INTENSITY IS
LOWERED TO 35 KT...WHICH IS STILL ABOVE THE SATELLITE INTENSITY
ESTIMATES. SOUTHWESTERLY WIND SHEAR OF AT LEAST 20 KT...DUE IN PART
TO AN UPPER-LEVEL LOW TO THE WEST OF OPHELIA...IS EXPECTED TO
PERSIST FOR THE NEXT COUPLE OF DAYS. THIS UNFAVORABLE ATMOSPHERIC
ENVIRONMENT SHOULD PROHIBIT STRENGTHENING DURING THAT TIME. IF
OPHELIA SURVIVES BEYOND A COUPLE OF DAYS...SLIGHT STRENGTHENING IS
POSSIBLE AS SUGGESTED BY THE REGIONAL HURRICANE MODELS.
 
THE TROPICAL STORM HAS BEEN MOVING MORE WESTWARD SINCE IT HAS BECOME
DECOUPLED FROM THE CONVECTION...AND THE LATEST INITIAL MOTION
ESTIMATE IS 280/10. THE FUTURE TRACK OF OPHELIA WILL DEPEND ON ITS
VERTICAL COHERENCY. MOST OF THE MODELS...WHICH SHOW OPHELIA AS A
RELATIVELY DEEP CYCLONE...TURN THE CYCLONE GRADUALLY NORTHWARD
DURING THE NEXT SEVERAL DAYS. THE GFS MODEL...HOWEVER...KEEPS A
SHALLOWER SYSTEM ON A MORE WEST-NORTHWESTWARD PATH. GIVEN THE
CURRENT SATELLITE PRESENTATION OF OPHELIA...THE GFS SOLUTION IS
PREFERRED AND THE OFFICIAL FORECAST HAS BEEN ADJUSTED TOWARD THAT
MODEL AND THE SHALLOW BAM.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  25/0900Z 18.4N  59.5W   35 KT  40 MPH
 12H  25/1800Z 19.1N  60.7W   35 KT  40 MPH
 24H  26/0600Z 19.9N  61.8W   35 KT  40 MPH
 36H  26/1800Z 20.7N  63.0W   35 KT  40 MPH
 48H  27/0600Z 21.4N  64.1W   35 KT  40 MPH
 72H  28/0600Z 22.8N  65.6W   40 KT  45 MPH
 96H  29/0600Z 25.0N  66.5W   45 KT  50 MPH
120H  30/0600Z 27.0N  67.5W   45 KT  50 MPH
 
$$
FORECASTER CANGIALOSI
 

WTNT41 KNHC 251454
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER  19
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
1100 AM AST SUN SEP 25 2011
 
OPHELIA IS EXPERIENCING SOUTHWESTERLY VERTICAL SHEAR OF 25-30 KT...
WHICH HAS DISPLACED MOST OF THE DEEP CONVECTION WELL TO THE
NORTHEAST AND EAST OF THE ALLEGED LOW-LEVEL CENTER. HOWEVER...SOME
CONVECTION HAS RECENTLY BEGUN TO DEVELOP CLOSER TO THE CENTER OF
THE CYCLONE. THE INITIAL INTENSITY IS BEING MAINTAINED AT 35 KT
BASED ON AN EARLIER ASCAT PASS AT 0410Z THAT INDICATED A LARGE AREA
OF 35-40 KT WINDS WINDS BETWEEN 150-225 NMI EAST OF THE CENTER IN A
BAND OF DEEP CONVECTION. GIVEN THAT THAT BAND OF CONVECTION HAS
PERSISTED SINCE THE ASCAT PASS...IT IS ASSUMED THAT AT LEAST 35-KT
WINDS STILL EXIST IN THAT RAINBAND. 

THE INITIAL MOTION ESTIMATE IS 280/08 KT OVER THE PAST 12 HOURS.
OPHELIA HAS ACTUALLY MADE A SHARP JOG TO THE WEST OR EVEN SOUTH OF
DUE WEST OVER THE PAST 6 HOURS. THIS IS DUE TO THE VERTICAL
CIRCULATION BECOMING MORE SHALLOW AS A RESULT OF THE LOSS OF INNER
CORE CONVECTION. HOWEVER...THE SHIPS MODEL IS FORECASTING THE
CURRENT STRONG SOUTHWESTERLY SHEAR TO ABATE TO AROUND 15-20 KT
DURING THE NEXT 6-48 HOURS...WHICH IS EXPECTED TO ALLOW MORE
CONVECTION TO REDEVELOP NEAR THE CENTER AND CREATE A MORE
VERTICALLY DEEP CIRCULATION.  AS A RESULT...OPHELIA SHOULD
GRADUALLY TURN TOWARD THE NORTHWEST OVER THE NEXT COUPLE OF DAYS AS
AN EASTWARD-MOVING UPPER-LEVEL TROUGH ERODES THE RIDGE TO THE NORTH
OF THE CYCLONE. ALTHOUGH THE ECMWF DISSIPATES THE CURRENT LOW-LEVEL
CIRCULATION AND SPINS UP ANOTHER CENTER TO THE EAST OF OPHELIA...
THERE IS MUCH LESS SPREAD IN THE MODEL GUIDANCE COMPARED TO 24
HOURS AGO. THE ECMWF SOLUTION IS BEING DISCOUNTED DUE TO VERY HIGH
SURFACE PRESSURES IN THE NORTHEAST QUADRANT OF THE OPHELIA
CIRCULATION...AND THE OFFICIAL FORECAST TRACK LIES A LITTLE WEST OF
THE PREVIOUS TRACK AND IS NEAR THE MIDDLE OF THE GUIDANCE ENVELOPE.

AS MENTIONED PREVIOUSLY...THE VERTICAL SHEAR IS FORECAST TO DECREASE
TO NEARLY HALF ITS CURRENT VALUE DURING THE NEXT 48 HOURS OR SO...
WHICH SHOULD ALLOW FOR SOME DEEP CONVECTION TO REDEVELOP NEAR THE
CENTER. THE RESULT SHOULD BE AT LEAST A MAINTENANCE OF THE CURRENT
INTENSITY. ALTHOUGH THE VERTICAL SHEAR IS EXPECTED TO INCREASE
AGAIN BY 72 HOURS AND BEYOND...SOME FAVORABLE UPPER-LEVEL DYNAMICS
MAY ALSO COME INTO PLAY...WHICH COULD INDUCE SOME MODEST
STRENGTHENING AS INDICATED BY ALL OF THE GLOBAL MODELS. THE NHC
INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY AND REMAINS
ABOVE THE SHIPS/LGEM MODELS AND THE CONSENSUS MODEL...ICON.
HOWEVER...IF DEEP CONVECTION DOES NOT REDEVELOP SOON NEAR THE
ALLEGED CENTER...THE SYSTEM COULD DEGENERATE INTO JUST AN OPEN WAVE
BY THIS AFTERNOON.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  25/1500Z 18.3N  60.4W   35 KT  40 MPH
 12H  26/0000Z 18.8N  61.5W   35 KT  40 MPH
 24H  26/1200Z 19.6N  62.8W   35 KT  40 MPH
 36H  27/0000Z 20.6N  64.1W   35 KT  40 MPH
 48H  27/1200Z 21.4N  65.0W   35 KT  40 MPH
 72H  28/1200Z 22.9N  66.0W   40 KT  45 MPH
 96H  29/1200Z 25.0N  67.0W   45 KT  50 MPH
120H  30/1200Z 27.5N  67.5W   45 KT  50 MPH
 
$$
FORECASTER STEWART
 

WTNT41 KNHC 272034
TCDAT1
 
TROPICAL DEPRESSION OPHELIA DISCUSSION NUMBER  21
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
500 PM AST TUE SEP 27 2011
 
A HURRICANE HUNTER AIRCRAFT INVESTIGATING THE REMNANTS OF OPHELIA
HAS FOUND THAT THE LOW-LEVEL CIRCULATION...ALTHOUGH SLIGHTLY
ELONGATED...HAS A SUFFICIENTLY WELL-DEFINED CENTER TO BE CONSIDERED
AS A TROPICAL CYCLONE AGAIN.  BASED ON THE AIRCRAFT DATA...THE
INITIAL INTENSITY IS SET TO 25 KT.  ONLY MODERATE SOUTHWESTERLY
SHEAR IS ANTICIPATED TO AFFECT THE CYCLONE FOR THE NEXT FEW
DAYS...SO GRADUAL STRENGTHENING IS FORECAST THROUGH 36-48 HOURS.
LATER IN THE FORECAST PERIOD...THE SHEAR IS EXPECTED TO DIMINISH AS
OPHELIA MOVES THROUGH AN UPPER-LEVEL RIDGE AT SUBTROPICAL
LATITUDES.  THIS...ALONG WITH SUFFICIENTLY WARM SEA SURFACE
TEMPERATURES...SHOULD ALLOW OPHELIA TO EVENTUALLY BECOME A
HURRICANE.  THE OFFICIAL NHC WIND SPEED FORECAST IS A BLEND OF THE
STATISTICAL-DYNAMICAL DSHIPS AND LGEM GUIDANCE.
 
THE INITIAL MOTION IS A HIGHLY UNCERTAIN 285/4.  OPHELIA IS EXPECTED
TO MOVE AROUND THE SOUTHWESTERN PERIPHERY OF A MID-LEVEL ANTICYCLONE
FOR THE NEXT COUPLE OF DAYS.  BY 72 HOURS OR SO...THE FLOW ON THE
SOUTHEAST SIDE OF A LARGE TROUGH NEARING THE U.S. EAST COAST SHOULD
TURN THE TROPICAL CYCLONE TO THE NORTH.  THE TRACK OFFICIAL
FORECAST IS QUITE CLOSE TO THE MULTI-MODEL CONSENSUS...TVCN.
 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  27/2100Z 17.6N  60.5W   25 KT  30 MPH
 12H  28/0600Z 18.0N  61.0W   30 KT  35 MPH
 24H  28/1800Z 18.7N  61.4W   35 KT  40 MPH
 36H  29/0600Z 19.5N  61.6W   40 KT  45 MPH
 48H  29/1800Z 21.0N  62.0W   50 KT  60 MPH
 72H  30/1800Z 25.0N  63.0W   65 KT  75 MPH
 96H  01/1800Z 29.5N  62.5W   75 KT  85 MPH
120H  02/1800Z 37.5N  59.0W   75 KT  85 MPH
 
$$
FORECASTER PASCH
 

WTNT41 KNHC 280251
TCDAT1
 
TROPICAL DEPRESSION OPHELIA DISCUSSION NUMBER  22
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
1100 PM AST TUE SEP 27 2011
 
FROM THE BIG PICTURE...OPHELIA APPEARS TO BE REASONABLY WELL
ORGANIZED WITH AN EXPANDING OUTFLOW PATTERN AND A ROUND BALL OF
DEEP CONVECTION NEAR THE APPARENT CENTER.  HOWEVER...THE AIR FORCE
RESERVE HURRICANE HUNTER AIRCRAFT DATA SHOW A MUCH DIFFERENT
PERSPECTIVE WITH THE LOW-LEVEL CIRCULATION ELONGATED FROM
EAST-NORTHEAST TO WEST-SOUTHWEST...AND PEAK SFMR VALUES OF ONLY
ABOUT 29 KT.  THE INITIAL WINDS ARE SET TO 30 KT IN ACCORDANCE WITH
THE SFMR ESTIMATES.  

THE INTENSITY FORECAST IS A CHALLENGING ONE THIS EVENING.  WHILE THE
CURRENT OUTFLOW PATTERN WOULD SEEM TO FAVOR SIGNIFICANT
INTENSIFICATION...WATER VAPOR IMAGES SHOW AN UPPER-LEVEL TROUGH
OVER THE WESTERN ATLANTIC MOVING EASTWARD TOWARD THE TROPICAL
CYCLONE.  THIS TROUGH SHOULD SOON RAISE THE SHEAR NEAR OPHELIA...
AND SINCE THE CYCLONE HAS A RATHER POOR INITIAL LOW-LEVEL
STRUCTURE...ONLY A SLOW INCREASE IN WINDS IS FORECAST FOR THE FIRST
DAY OR SO.  THEREAFTER...THE TROUGH SHOULD WEAKEN AS AN UPPER HIGH
BUILDS CLOSER TO THE TROPICAL CYCLONE...WHICH COULD SUPPORT A
FASTER INTENSIFICATION.  IT IS INTERESTING TO NOTE THAT THE
STATISTICAL GUIDANCE IS CONSIDERABLY LOWER THAN THE LAST
RUN...SHOWING OPHELIA ONLY BECOMING A MODERATE TROPICAL STORM
BECAUSE OF MUCH HIGHER FORECAST SHEAR.  SOME OF THIS CHANGE MIGHT
BE DUE TO THE INTERPOLATED OLD OFFICIAL FORECAST WHICH IS A GOOD
DEAL FASTER THAN THE GFS...AND IN THIS CASE INTRODUCES SOME
ARTIFICIAL SHEAR AS IT IS CLOSER TO THE STRONG UPPER-LEVEL WINDS. 
I HAVE ELECTED NOT TO CHANGE THE PREVIOUS FORECAST PEAK INTENSITY
GIVEN THE GFDL/HWRF STILL SHOWING CATEGORY 2 HURRICANE STATUS...BUT
THE TREND IN THESE STATISTICAL MODELS SHOULD BE WATCHED.

MICROWAVE AND AIRCRAFT DATA SUGGEST THE CENTER...SUCH AS IT IS...HAS
REFORMED TO THE NORTHEAST...A BIT CLOSER TO THE MID-LEVEL CENTER. 
A LONG-TERM MOTION ESTIMATE IS 305/3...BUT THIS IS HIGHLY
UNCERTAIN.  OPHELIA IS EXPECTED TO MOVE A BIT FASTER TO THE
NORTHWEST BY EARLY THURSDAY AS IT IS STEERED AROUND THE
SOUTHWESTERN PORTION OF A STRENGTHENING SUBTROPICAL RIDGE.   A TURN
TO THE NORTH AND NORTHEAST SHOULD OCCUR BY THE WEEKEND DUE TO A
LARGE MID-LATITUDE TROUGH DIVING OFFSHORE OF THE EASTERN UNITED
STATES.  THE MODEL GUIDANCE IS IN BETTER AGREEMENT THAN SIX HOURS
AGO...ALTHOUGH THE SPEED DIFFERENCES ARE SIGNIFICANT.  THE NHC
FORECAST IS ADJUSTED EAST OF THE PREVIOUS ONE FOR THE FIRST COUPLE
OF DAYS TO ACCOUNT FOR THE CENTER REPOSITIONING...AND IS VERY CLOSE
TO THE TRACK AFTER THAT TIME...A BIT FASTER THAN THE MULTI-MODEL
CONSENSUS.  

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  28/0300Z 18.4N  59.5W   30 KT  35 MPH
 12H  28/1200Z 18.8N  59.8W   35 KT  40 MPH
 24H  29/0000Z 19.5N  60.2W   40 KT  45 MPH
 36H  29/1200Z 20.9N  60.9W   45 KT  50 MPH
 48H  30/0000Z 22.4N  61.6W   55 KT  65 MPH
 72H  01/0000Z 26.3N  62.7W   65 KT  75 MPH
 96H  02/0000Z 32.0N  61.5W   75 KT  85 MPH
120H  03/0000Z 40.0N  57.5W   70 KT  80 MPH
 
$$
FORECASTER BLAKE
 

WTNT41 KNHC 280900
TCDAT1
 
TROPICAL DEPRESSION OPHELIA DISCUSSION NUMBER  23
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
500 AM AST WED SEP 28 2011
 
OPHELIA APPEARS TO BE GRADUALLY ORGANIZING. DEEP CONVECTION HAS
INCREASED IN A CURVED BAND OVER THE SOUTHEASTERN PORTION OF THE
CIRCULATION...AND THE LOW-LEVEL CLOUD LINES HAVE GAINED SOME
CURVATURE TO THE NORTH OF THE CENTER.  ALTHOUGH OPHELIA COULD BE
NEARING TROPICAL STORM STRENGTH...THE INITIAL WIND SPEED IS
HELD AT 30 KT...IN AGREEMENT WITH THE LATEST DVORAK CLASSIFICATIONS.
 
THE TROPICAL CYCLONE HAS BEEN MEANDERING DURING THE PAST COUPLE OF
HOURS...BUT THE LONGER-TERM INITIAL MOTION ESTIMATE IS 305/3.  A
SLOW NORTH-NORTHWESTWARD TRACK IS FORECAST DURING THE NEXT 12 TO 24
HOURS AS OPHELIA REMAINS NEAR THE SOUTHWESTERN PERIPHERY OF A WEAK
SUBTROPICAL RIDGE.  BEYOND THAT TIME...THE CYCLONE IS EXPECTED TO
GAIN SPEED AND GRADUALLY TURN NORTHWARD AND THEN NORTHEASTWARD AS
IT BECOMES EMBEDDED IN STRONGER FLOW BETWEEN THE STRENGTHENING
SUBTROPICAL HIGH AND A LARGE TROUGH MOVING ACROSS THE EASTERN
UNITED STATES. THIS SYNOPTIC PATTERN SHOULD MOVE OPHELIA AWAY FROM
THE NORTHERN LEEWARD ISLANDS TODAY AND NEAR OR TO THE EAST OF
BERMUDA THIS WEEKEND.  THE OFFICIAL FORECAST IS A TOUCH TO THE
LEFT OF THE PREVIOUS ONE...BUT REMAINS ON THE EASTERN SIDE OF THE
GUIDANCE ENVELOPE IN GOOD AGREEMENT WITH THE GFS AND ECMWF MODELS.
 
ALTHOUGH THE ATMOSPHERIC ENVIRONMENT IS NOT IDEAL FOR
STRENGTHENING...IT SHOULD ALLOW OPHELIA TO INTENSIFY GRADUALLY. THE
OFFICIAL FORECAST FOLLOWS THE MULTI-MODEL AND HFIP CONSENSUS AIDS...
BRINGING THE CYCLONE TO HURRICANE STRENGTH IN A FEW DAYS.  WEAKENING
IS EXPECTED BY THE END OF THE FORECAST PERIOD AS OPHELIA CROSSES A
SHARP SEA SURFACE TEMPERATURE GRADIENT AND ENCOUNTERS SOME INCREASE
IN SOUTHWESTERLY SHEAR.

FORECAST POSITIONS AND MAX WINDS
 
INIT  28/0900Z 18.6N  60.0W   30 KT  35 MPH
 12H  28/1800Z 19.2N  60.1W   40 KT  45 MPH
 24H  29/0600Z 20.4N  60.7W   45 KT  50 MPH
 36H  29/1800Z 21.8N  61.5W   50 KT  60 MPH
 48H  30/0600Z 23.4N  62.2W   55 KT  65 MPH
 72H  01/0600Z 27.7N  62.9W   65 KT  75 MPH
 96H  02/0600Z 34.0N  61.0W   75 KT  85 MPH
120H  03/0600Z 43.5N  55.5W   65 KT  75 MPH
 
$$
FORECASTER CANGIALOSI
 

WTNT41 KNHC 281432
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER  24
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
1100 AM AST WED SEP 28 2011
 
AN AIR FORCE HURRICANE HUNTER AIRCRAFT FOUND THAT OPHELIA HAS
REGAINED TROPICAL STORM INTENSITY.  MAXIMUM FLIGHT-LEVEL WINDS WERE
52 KT AND THE HIGHEST BELIEVABLE SFMR-OBSERVED SURFACE WINDS WERE
40 TO 45 KT.  BASED ON THESE DATA THE INITIAL WIND SPEED IS SET TO
45 KT.  THE STORM HAS BECOME BETTER ORGANIZED ON SATELLITE IMAGES
WITH A CURVED CONVECTIVE BAND NOW EVIDENT OVER THE EASTERN
SEMICIRCLE.  THE ENVIRONMENT AHEAD OF OPHELIA IS NOT IDEAL FOR
STRENGTHENING AS MODERATE WESTERLY SHEAR IS LIKELY TO PREVAIL OVER
THE SYSTEM DURING THE NEXT FEW DAYS.  HOWEVER...THIS SHEAR IS NOT
EXPECTED TO BE STRONG ENOUGH TO PREVENT SOME STRENGTHENING.  THE
OFFICIAL INTENSITY FORECAST IS VERY CLOSE TO THE MODEL CONSENSUS
THAT INCLUDES THE HURRICANE FORECAST IMPROVEMENT PROJECT GUIDANCE.
 
FIXES FROM THE HURRICANE HUNTERS SHOW THAT THE CENTER HAS BEEN
WOBBLING...BUT THE OVERALL MOTION IS ESTIMATED TO BE NORTH-
NORTHWESTWARD OR 340/03.  THERE IS LITTLE CHANGE TO THE NHC
TRACK FORECAST REASONING OR TO THE FORECAST ITSELF.  OPHELIA SHOULD
MOVE NORTH-NORTHWESTWARD...ALONG THE WESTERN PERIPHERY OF A
SUBTROPICAL RIDGE...TODAY AND TOMORROW.  BY 72 HOURS OR SO...A
LARGE MID-TROPOSPHERIC TROUGH MOVING OFF THE U.S. EAST COAST SHOULD
CAUSE THE TROPICAL CYCLONE TO TURN NORTHWARD.  LATER IN THE
FORECAST PERIOD...OPHELIA IS LIKELY TO ACCELERATE NORTH-
NORTHEASTWARD IN THE FLOW AHEAD OF THE TROUGH.  THE OFFICIAL
TRACK FORECAST IS CLOSE TO THE LATEST MULTI-MODEL CONSENSUS AND A
LITTLE FASTER THAN THE GFS.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  28/1500Z 18.7N  59.9W   45 KT  50 MPH
 12H  29/0000Z 19.5N  60.5W   50 KT  60 MPH
 24H  29/1200Z 20.9N  61.1W   50 KT  60 MPH
 36H  30/0000Z 22.5N  61.8W   55 KT  65 MPH
 48H  30/1200Z 24.2N  62.4W   60 KT  70 MPH
 72H  01/1200Z 28.5N  62.7W   65 KT  75 MPH
 96H  02/1200Z 36.0N  60.0W   70 KT  80 MPH
120H  03/1200Z 45.0N  54.0W   50 KT  60 MPH
 
$$
FORECASTER PASCH
 

WTNT41 KNHC 282033
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER  25
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
500 PM AST WED SEP 28 2011
 
THE CLOUD PATTERN OF OPHELIA HAS NOT CHANGED MUCH SINCE THIS
MORNING...WITH A CURVED CONVECTIVE BAND PREVAILING AROUND THE
EASTERN AND NORTHERN PORTIONS OF THE CIRCULATION.  SINCE THERE HAS
BEEN LITTLE CHANGE IN APPEARANCE SINCE THE HURRICANE HUNTER MISSION
INTO THE STORM EARLIER TODAY...THE INITIAL WIND SPEED ESTIMATE
REMAINS AT 45 KT.   AN UPPER-LEVEL TROUGH LOCATED SEVERAL HUNDRED
MILES TO THE NORTHWEST OF OPHELIA IS PRODUCING WEST-SOUTHWESTERLY
VERTICAL SHEAR OVER THE STORM.  HOWEVER...THE SHEAR IS NOT EXPECTED
TO BE STRONG ENOUGH TO PREVENT SLOW STRENGTHENING.  IN 48 TO 72
HOURS...DYNAMICAL MODELS INDICATE SOME RELAXATION OF THE SHEAR AND
AROUND THIS TIME THE OFFICIAL FORECAST CALLS FOR OPHELIA TO BECOME
A HURRICANE.  THE OFFICIAL WIND SPEED FORECAST IS AGAIN CLOSE TO A
MULTI-MODEL CONSENSUS THAT INCLUDES THE NEW GUIDANCE FROM THE
HURRICANE FORECAST IMPROVEMENT PROJECT.  BY THE END OF THE FORECAST
PERIOD...GLOBAL MODELS SHOW THE SYSTEM EMBEDDED WITHIN A FRONT...
AND THEREFORE HAVING UNDERGONE EXTRATROPICAL TRANSITION.

THERE HAS BEEN SOME INCREASE IN FORWARD SPEED AND THE MOTION IS NOW
ABOUT 330/7.  THE TROPICAL CYCLONE IS EXPECTED TO MOVE ALONG THE
SOUTHWESTERN PERIPHERY OF A SUBTROPICAL HIGH PRESSURE AREA FOR THE
NEXT COUPLE OF DAYS.  BY AROUND 72 HOURS...THE FLOW BETWEEN THE
HIGH AND A LARGE MID-TROPOSPHERIC TROUGH MOVING OFF THE U.S. EAST
COAST SHOULD TURN OPHELIA NORTHWARD.  THE CYCLONE SHOULD ACCELERATE
NORTH-NORTHEASTWARD WITHIN THE FLOW ON THE EAST SIDE OF THE TROUGH
THEREAFTER.  THE OFFICIAL FORECAST IS A LITTLE FASTER AND A LITTLE
TO THE LEFT OF THE PREVIOUS ONE.  THIS IS BETWEEN THE MULTI-MODEL
CONSENSUS AND THE NEW GFS RUN...WHICH IS SIGNIFICANTLY FASTER THEN
THE 0600 UTC RUN.   

FORECAST POSITIONS AND MAX WINDS
 
INIT  28/2100Z 19.3N  60.6W   45 KT  50 MPH
 12H  29/0600Z 20.2N  61.0W   50 KT  60 MPH
 24H  29/1800Z 21.6N  61.7W   55 KT  65 MPH
 36H  30/0600Z 23.3N  62.5W   60 KT  70 MPH
 48H  30/1800Z 25.2N  63.2W   65 KT  75 MPH
 72H  01/1800Z 31.0N  62.5W   70 KT  80 MPH
 96H  02/1800Z 40.0N  59.0W   70 KT  80 MPH
120H  03/1800Z 52.0N  49.0W   50 KT  60 MPH...POST-TROP/EXTRATROP
 
$$
FORECASTER PASCH
 

WTNT41 KNHC 290249
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER  26
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
1100 PM AST WED SEP 28 2011

AIRCRAFT DATA INDICATE THAT OPHELIA HAS STRENGTHENED.  PEAK
FLIGHT-LEVEL WINDS WERE 64 KT...WITH BELIEVABLE SFMR VALUES NEAR 50
KT.  THUS THE INITIAL WIND SPEED IS RAISED TO 50 KT.  ALTHOUGH THE
STORM HAS BECOME A LITTLE STRONGER...INFRARED SATELLITE IMAGES ARE
NOT PARTICULARLY IMPRESSIVE WITH A SMALL AREA OF CONVECTION
NORTHEAST OF THE CENTER ALONG WITH A LARGER CURVED BAND IN THE
SOUTHEAST QUADRANT.  MICROWAVE DATA...HOWEVER...DOES SHOW A
BETTER-ORGANIZED CORE WITH PERHAPS THE PRIMITIVE STAGES OF AN EYE. 
IT IS INTERESTING THAT OPHELIA HAS INTENSIFIED A GOOD DEAL TODAY
DESPITE AN UPPER-LEVEL TROUGH CAUSING 20-25 KT OF SOUTHWESTERLY
SHEAR.  AS THIS TROUGH TO THE NORTHWEST OF OPHELIA PULLS
AWAY...UPPER RIDGING SHOULD BUILD IN CLOSER TO THE CYCLONE
AND CAUSE THE SHEAR TO RELAX TO MORE MODERATE LEVELS.  STEADY
INTENSIFICATION WOULD SEEM TO BE THE BEST BET...AND THE NHC
FORECAST COULD BE ON THE CONSERVATIVE SIDE IF AN INNER CORE BECOMES
ORGANIZED.  THE NEW FORECAST IS SIMILAR TO THE PREVIOUS ONE BUT
SHOWS A HIGHER PEAK INTENSITY AT 72 HOURS...SPLITTING THE
DIFFERENCE BETWEEN THE STATISTICAL AND DYNAMICAL GUIDANCE. 
WEAKENING SHOULD BEGIN AFTER DAY 3 DUE TO COOLING WATERS AND
INCREASING SOUTHWESTERLY SHEAR.  
 
THE AIRCRAFT FIXES INDICATE THAT CYCLONE IS MOVING A BIT SLOWER...
ABOUT 325/5.  THE GLOBAL MODELS ARE IN RATHER GOOD AGREEMENT ON
OPHELIA PICKING UP SOME FORWARD SPEED AS IT MOVES ON A TRACK TOWARD
THE NORTH-NORTHWEST AND NORTH OVER THE NEXT COUPLE OF DAYS ALONG
THE SOUTHWESTERN PERIPHERY OF THE SUBTROPICAL RIDGE.  THEREAFTER...
THE CYCLONE SHOULD START TO ACCELERATE TO THE NORTH-NORTHEAST DUE
TO INCREASING SOUTHWESTERLY FLOW BETWEEN THE RIDGE AND A LARGE
MID-TROPOSPHERIC TROUGH MOVING OFF THE U.S. EAST COAST.  WHILE THE
GUIDANCE HAS BEEN STRUGGLING WITH THE INTERACTION OF THE TROPICAL
CYCLONE WITH THE MID-LATITUDE FLOW...IN GENERAL THE GUIDANCE HAS
SHIFTED A BIT TO THE LEFT AFTER DAY 3...AND THE NHC FORECAST
FOLLOWS SUIT.  THE MOST CONSISTENT MODEL HAS BEEN THE ECMWF SINCE
YESTERDAY...AND THE OFFICIAL FORECAST WILL STAY BETWEEN THAT MODEL
AND THE HFIP MULTI-MODEL CONSENSUS.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  29/0300Z 19.4N  60.7W   50 KT  60 MPH
 12H  29/1200Z 20.3N  61.3W   55 KT  65 MPH
 24H  30/0000Z 21.9N  62.0W   60 KT  70 MPH
 36H  30/1200Z 23.7N  62.8W   65 KT  75 MPH
 48H  01/0000Z 26.1N  63.1W   70 KT  80 MPH
 72H  02/0000Z 32.5N  62.0W   80 KT  90 MPH
 96H  03/0000Z 43.0N  57.5W   65 KT  75 MPH
120H  04/0000Z 54.0N  47.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
 
$$
FORECASTER BLAKE
 

WTNT41 KNHC 290849
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER  27
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
500 AM AST THU SEP 29 2011
 
DEEP CONVECTION HAS BEEN INCREASING NEAR AND JUST NORTH OF THE
ESTIMATED CENTER...AND THE AREA OF CONVECTION THAT WAS WELL
SOUTHEAST OF THE CENTER IS DIMINISHING. THIS INDICATES THAT OPHELIA
IS BECOMING BETTER ORGANIZED AND MAY BE STRENGTHENING...
HOWEVER...PENDING VISIBLE IMAGERY LATER THIS MORNING THE
INTENSITY...IS HELD AT 50 KT. ALTHOUGH WESTERLY SHEAR IS EXPECTED
TO CONTINUE TO AFFECT OPHELIA...SOME DECREASE IN SHEAR IS PREDICTED
IN 24 TO 36 HOURS AS AN UPPER-LEVEL RIDGE DEVELOPS OVER THE
TROPICAL CYCLONE. THIS EVOLUTION IS EXPECTED TO ALLOW OPHELIA TO
STRENGTHEN INTO A HURRICANE. THE OFFICIAL WIND SPEED FORECAST IS
SIMILAR TO THE PREVIOUS ONE AND LIES BETWEEN THE STATISTICAL-
DYNAMICAL GUIDANCE AT THE LOW END AND THE HWRF...GFDL...AND GFDN
MODELS AT THE HIGH END. WEAKENING SHOULD COMMENCE AFTER 72 HOURS AS
THE TROPICAL CYCLONE ENCOUNTERS SIGNIFICANTLY COOLER WATERS AND
INCREASING SHEAR. GLOBAL MODELS SHOW THE SYSTEM BECOMING EMBEDDED
IN A BAROCLINIC ZONE BY DAY 5...AND THE OFFICIAL FORECAST HAS
OPHELIA BECOMING AN EXTRATROPICAL CYCLONE BY THAT TIME. 

THE INITIAL MOTION...330/6...IS ONLY A TAD FASTER THAN THE PREVIOUS
ESTIMATE.  THERE HAVE BEEN NO IMPORTANT CHANGES TO THE TRACK
FORECAST SCENARIO...AND THE MODELS REMAIN IN FARILY GOOD AGREEMENT
THROUGH THE FIRST HALF OF THE FORECAST PERIOD.  OPHELIA SHOULD MOVE
FASTER TOWARD THE NORTH-NORTHWEST AND NORTH OVER THE NEXT COUPLE OF
DAYS ALONG THE SOUTHWESTERN SIDE OF A SUBTROPICAL HIGH PRESSURE
AREA.  THEN...THE CYCLONE SHOULD TURN TOWARD THE NORTH-NORTHEAST
AND ACCELERATE AS IT MOVES IN THE FLOW ON THE EASTERN SIDE OF A
LARGE MID-LEVEL TROUGH NEAR THE U.S. EAST COAST.  NEAR THE END OF
THE FORECAST PERIOD...THE TRACK GUIDANCE BECOMES MORE DIVERGENT AS
THE DYNAMICAL MODELS DIFFER ON HOW OPHELIA WILL INTERACT WITH A
HIGH-LATITUDE EXTRATROPICAL CYCLONE.  THE OFFICIAL TRACK FORECAST
IS VERY CLOSE TO THE PREVIOUS ONE...AND ROUGHLY BETWEEN THE
MULTI-MODEL CONSENSUS AND THE LATEST ECMWF TRACK. 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  29/0900Z 20.0N  61.1W   50 KT  60 MPH
 12H  29/1800Z 21.1N  61.6W   55 KT  65 MPH
 24H  30/0600Z 22.8N  62.4W   60 KT  70 MPH
 36H  30/1800Z 24.9N  62.9W   70 KT  80 MPH
 48H  01/0600Z 27.8N  63.0W   75 KT  85 MPH
 72H  02/0600Z 35.5N  61.0W   75 KT  85 MPH
 96H  03/0600Z 46.5N  55.0W   55 KT  65 MPH
120H  04/0600Z 54.0N  44.0W   35 KT  40 MPH...POST-TROP/EXTRATROP
 
$$
FORECASTER PASCH
 

WTNT41 KNHC 291447
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER  28
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
1100 AM AST THU SEP 29 2011
 
THE CLOUD PATTERN HAS DEFINITELY BECOME BETTER ORGANIZED SINCE
YESTERDAY...AND NOW IT IS VERY SYMMETRIC WITH A WELL-DEFINED
CONVECTIVE BAND WRAPPING AROUND THE CENTER. I EVEN SUSPECT THAT AN
EYE FEATURE COULD BE FORMING. THE OUTFLOW IS TRYING TO EXPAND
WESTWARD...BUT UPPER-LEVEL HOSTILE WINDS JUST WEST OF THE CYCLONE
ARE DISRUPTING IT AT THIS TIME. T-NUMBERS FROM TAFB AND SAB HAVE
INCREASED TO 3.5 AND 4.0 ON THE DVORAK SCALE. ON THAT BASIS..THE
INITIAL INTENSITY HAS BEEN INCREASED TO 60 KNOTS. THE UPPER-LEVEL
ENVIRONMENT IS FORECAST TO REMAIN UNFAVORABLE BUT NOT HOSTILE
ENOUGH TO PREVENT OPHELIA FROM BECOMING A HURRICANE BY THE END OF
THE DAY...AS INDICATED BY MOST OF THE GUIDANCE. THE OFFICIAL
FORECAST IS VERY SIMILAR TO THE STATISTICAL LGEM. BEYOND 72 HOURS
THE SHEAR IS FORECAST TO INCREASE SIGNIFICANTLY...AND THE SEA
SURFACE TEMPERATURES WILL DECREASE. THIS SHOULD RESULT IN
WEAKENING...AND MOST LIKELY OPHELIA WILL BECOME POST-TROPICAL BY 96
HOURS.
 
THE BEST ESTIMATE OF THE INITIAL MOTION IS 335 DEGREES AT 7 KNOTS.
THE STEERING PATTERN HAS NOT CHANGED...AND I FACT...IT IS VERY
SIMILAR TO THE ONE THAT HAS PREVAILED THIS SEASON SO FAR. THE
COMBINATION OF A TROUGH ALONG THE EASTERN UNITED STATES AND THE
SUBTROPICAL RIDGE OVER THE ATLANTIC CALLS FOR A GENERAL NORTHWARD
TRACK FOR THE NEXT TWO DAYS. THEREAFTER...A TURN TO THE
NORTH-NORTHEAST WITH INCREASING FORWARD SPEED IS FORECAST AS
OPHELIA BECOMES EMBEDDED WITHIN THE MID-LATITUDE FLOW. THE
TRACK...AT LEAST FOR THE NEXT 2 TO 3 DAYS IS CENTERED WITHIN THE
GUIDANCE ENVELOPE AND BETWEEN THE GFS AND THE ECMWF. AT THIS
TIME...THE WESTERN EDGE OF THE GUIDANCE ENVELOPE...ALTHOUGH VERY
CLOSE...DOES NOT REACH BERMUDA.
 
BASED ON DATA FROM NOAA BUOY 41044 THE TROPICAL STORM FORCE WIND
RADII HAVE BEEN EXPANDED IN THE NORTHEAST QUADRANT. ONCE AGAIN THESE
BUOYS ARE PROVING TO BE VERY VALUABLE IN TRACKING TROPICAL CYCLONE. 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  29/1500Z 20.9N  61.8W   60 KT  70 MPH
 12H  30/0000Z 22.1N  62.3W   65 KT  75 MPH
 24H  30/1200Z 24.0N  63.0W   70 KT  80 MPH
 36H  01/0000Z 26.5N  63.5W   75 KT  85 MPH
 48H  01/1200Z 29.5N  63.5W   75 KT  85 MPH
 72H  02/1200Z 38.5N  60.0W   70 KT  80 MPH
 96H  03/1200Z 50.0N  52.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
120H  04/1200Z 55.0N  40.0W   30 KT  35 MPH...POST-TROP/EXTRATROP
 
$$
FORECASTER AVILA
 

WTNT41 KNHC 292037
TCDAT1
 
HURRICANE OPHELIA DISCUSSION NUMBER  29
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
500 PM AST THU SEP 29 2011
 
SATELLITE IMAGES AND MICROWAVE DATA INDICATE THAT THE CLOUD PATTERN
HAS CONTINUED TO ACQUIRE ORGANIZATION. THERE IS A CYCLONICALLY
CURVED CONVECTIVE BAND WRAPPING AROUND THE CENTER AND THE
UPPER-LEVEL OUTFLOW HAS EXPANDED IN ALL QUADRANTS. THERE HAS BEEN
AN EYE FEATURE INTERMITTENTLY APPEARING ON VISIBLE IMAGES...BUT
THERE IS DEFINITELY A DISTINCT ONE AT THE MID-LEVELS ON EARLIER
MICROWAVE DATA. T-NUMBERS FROM TAFB AND SAB HAVE INCREASED TO 4.0
ON THE DVORAK SCALE AND ON THIS BASIS...OPHELIA HAS BEEN UPGRADED
TO HURRICANE STATUS...THE FOURTH OF THE 2011 SEASON.

OPHELIA HAS KICKED OUT THE SHEAR AND GLOBAL MODELS INSIST ON KEEPING
AN UPPER-LEVEL RIDGE OVER THE CYCLONE. THIS PATTERN SHOULD ALLOW
SOME ADDITIONAL STRENGTHENING DURING THE NEXT DAY OR SO. THE
OFFICIAL FORECAST CONTINUE TO BE VERY SIMILAR TO THE STATISTICAL
LGEM...ALTHOUGH SOME MODELS FORECAST A STRONGER HURRICANE.
BEYOND 72 HOURS THE SHEAR IS FORECAST TO INCREASE SIGNIFICANTLY...
AND THE SEA SURFACE TEMPERATURES WILL DECREASE. THIS SHOULD RESULT
IN WEAKENING...AND MOST LIKELY OPHELIA WILL BECOME POST-TROPICAL BY
96 HOURS OR SOONER.
 
OPHELIA HAS BEEN MOVING TOWARD THE NORTH-NORTHWEST OR 340 DEGREES AT
8 KNOTS. THERE HAS BEEN NO CHANGE IN THE STEERING TO REPORT. THE
OFFICIAL FORECAST REMAINS UNCHANGED AND CONTINUES IN THE MIDDLE OF
THE GUIDANCE ENVELOPE IN BETWEEN THE GFS AND THE ECMWF FOR THE NEXT
2 TO 3 DAYS. OPHELIA SHOULD GRADUALLY TURN TO THE NORTH BY FRIDAY
AND THEN RECURVE NEAR THE LATITUDE OF BERMUDA IN ABOUT 48 HOURS.
THE WESTERN EDGE OF THE GUIDANCE ENVELOPE BARELY REACHES BERMUDA
AT THIS TIME.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  29/2100Z 21.4N  62.3W   65 KT  75 MPH
 12H  30/0600Z 22.8N  62.9W   75 KT  85 MPH
 24H  30/1800Z 25.0N  63.5W   75 KT  85 MPH
 36H  01/0600Z 27.5N  63.5W   80 KT  90 MPH
 48H  01/1800Z 30.5N  63.0W   75 KT  85 MPH
 72H  02/1800Z 41.0N  59.5W   70 KT  80 MPH
 96H  03/1800Z 51.5N  48.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
120H  04/1800Z 53.0N  30.0W   30 KT  35 MPH...POST-TROP/EXTRATROP
 
$$
FORECASTER AVILA
 

WTNT41 KNHC 300258
TCDAT1
 
HURRICANE OPHELIA DISCUSSION NUMBER  30
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
1100 PM AST THU SEP 29 2011
 
OPHELIA IS STRENGTHENING WITH AN EYE FEATURE OCCASIONALLY APPARENT
ON BOTH INFRARED AND NIGHT-VISIBLE SATELLITE IMAGES. ALTHOUGH THERE
IS SOME TILT ON THE LATEST MICROWAVE PASSES WITH THE LOW-LEVEL
CENTER A BIT TO THE WEST OF THE MID-LEVEL CENTER...A SOLID EYEWALL
HAS FORMED.  SATELLITE INTENSITY ESTIMATES WERE 65 KT AND 77 KT FROM
SAB/TAFB...AND GIVEN THE WELL-DEFINED INNER CORE...THE INITIAL
WINDS WILL BE INCREASED TO 75 KT ON THIS ADVISORY.  

WATER VAPOR IMAGES SHOW A LARGE FETCH OF UPPER-LEVEL WESTERLY WINDS
HEADED TOWARD THE TROPICAL CYCLONE.  HOWEVER...GLOBAL MODEL INSIST
THAT THESE STRONG WINDS WILL BE DIVERTED AROUND THE CIRCULATION OF
THE HURRICANE AND NOT IMPACT OPHELIA DUE TO A BUILDING UPPER-LEVEL
RIDGE.  SINCE THE WATERS STAY WARM FOR AT LEAST TWO DAYS AND 
BOTH THE SHIPS MODEL AND LARGE-SCALE GLOBAL MODEL FIELDS FORECAST
DECREASING SHEAR VALUE...THE NHC FORECAST IS RAISED FROM THE
PREVIOUS ONE..  THE NEW FORECAST IS BELOW THE HWRF/GFDL
CONSENSUS...WHICH SHOW THE CYCLONE AT THE THRESHOLD OF MAJOR
HURRICANE STATUS IN A FEW DAYS.  
 
THE INITIAL MOTION IS ABOUT THE SAME AS BEFORE...335/8.  THERE IS
NOT A LOT OF CHANGE TO REPORT IN THE MODELS FOR THE FIRST COUPLE OF
DAYS WITH GOOD AGREEMENT ON A GRADUALLY ACCELERATING AND BENDING
TRACK TOWARD THE NORTH AND NORTH-NORTHEAST.  THE NHC FORECAST
DURING THAT TIME IS BASICALLY AN UPDATE OF THE PREVIOUS ADVISORY. 
AFTER RECURVATURE...HOWEVER...THE MODEL GUIDANCE HAS SHIFTED
LEFTWARD DUE TO A STRONGER RIDGE OVER THE CENTRAL ATLANTIC.  THE
NHC FORECAST IS SHIFTED TO THE WEST AFTER DAY 2 AND IS CLOSE TO A
BLEND OF THE ECMWF AND GFS MODELS.  GLOBAL MODELS INDICATE THAT
OPHELIA WILL BE ABSORBED BY A FRONTAL SYSTEM IN ABOUT 5 DAYS.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  30/0300Z 21.9N  62.3W   75 KT  85 MPH
 12H  30/1200Z 23.2N  62.8W   80 KT  90 MPH
 24H  01/0000Z 25.7N  63.3W   85 KT 100 MPH
 36H  01/1200Z 28.8N  63.1W   90 KT 105 MPH
 48H  02/0000Z 32.8N  62.3W   90 KT 105 MPH
 72H  03/0000Z 43.5N  58.5W   70 KT  80 MPH
 96H  04/0000Z 52.0N  43.5W   45 KT  50 MPH...POST-TROP/EXTRATROP
120H  05/0000Z...ABSORBED
 
$$
FORECASTER BLAKE
 

WTNT41 KNHC 300844
TCDAT1
 
HURRICANE OPHELIA DISCUSSION NUMBER  31
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
500 AM AST FRI SEP 30 2011
 
OPHELIA HAS BEEN RAPIDLY STRENGTHENING DURING THE PAST 12 HOURS
BASED ON AN EYE FEATURE OCCASIONALLY APPARENT ON BOTH INFRARED AND
NIGHT-VISIBLE SATELLITE IMAGES. MICROWAVE IMAGERY INDICATES A
WELL-DEVELOPED AND CLOSED DEEP-LAYER EYE...ALBEIT TILTED SLIGHTLY
TO THE NORTHEAST. A BLEND OF SATELLITE INTENSITY ESTIMATES OF
T5.0/90 KT FROM SAB...T4.5/77 KT FROM TAFB...AND UW-CIMSS AVERAGE
ADT OF T4.7/82 KT IS THE BASIS FOR THE 85-KT ADVISORY INTENSITY.
 
THE INITIAL MOTION ESTIMATE IS 345/08 KT. THERE IS NO SIGNIFICANT
CHANGE TO THE PREVIOUS FORECAST TRACK REASONING. OPHELIA IS
CURRENTLY ROUNDING THE SOUTHWESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE SITUATED ALONG 32N LATITUDE. AN UNSEASONABLY
STRONG MID-TROPOSPHERIC TROUGH IS FORECAST TO DEEPEN AND MOVE
EASTWARD TO THE U.S. EAST COAST BY 48 HOURS...AND WILL ACT TO
ACCELERATE AND LIFT OPHELIA NORTHWARD OVER THE NEXT 72 HOURS. BY
DAYS 3-4...OPHELIA IS FORECAST TO MERGE WITH A FRONTAL SYSTEM AND
BE OVER MUCH COLDER WATER...WHICH WILL RESULT IN THE CYCLONE
BECOMING A STRONG POST-TROPICAL WINTER-TYPE LOW PRESSURE SYSTEM
THAT WILL TURN EASTWARD NEAR THE CANADIAN MARITIMES. THE ONLY
NOTICEABLE CHANGE IN THE MODEL GUIDANCE IS A SOUTHWARD SHIFT IN THE
GUIDANCE TRACKS AFTER 72 HOURS. IN FACT...THE NEW ECMWF RUN BARELY
TAKES OPHELIA AS FAR NORTH AS 45N LATITUDE. THE OFFICIAL FORECAST
TRACK WAS NUDGED SLIGHTLY TO THE LEFT THROUGH 72 HOURS...AND THEN
BROUGHT FARTHER SOUTH IN LINE WITH THE CONSENSUS MODEL...TVCN...BUT
NOT AS FAR SOUTH AS THE ECMWF MODEL TRACK.

THE OUTFLOW OF OPHELIA REMAINS QUITE IMPRESSIVE...EXCEPT THAT THE
WESTERN EDGE OF THE CIRRUS OUTFLOW HAS STARTED TO FLATTEN AND
DISSIPATE AS WESTERLY UPPER-LEVEL WINDS ENCROACH ON THE CYCLONE.
HOWEVER...THE LIGHT TO MODERATE WESTERLY VERTICAL WIND SHEAR THAT
IS CURRENTLY AFFECTING THE CYCLONE IS FORECAST TO TURN MORE FROM
SOUTH-SOUTHWEST BY 36-48 HOURS...WHICH SHOULD ALLOW FOR SOME
ADDITIONAL STRENGTHENING TO OCCUR. ALTHOUGH FURTHER RAPID
STRENGTHENING IS A POSSIBILITY...THE VERTICAL SHEAR IS FORECAST BY
THE SHIPS MODEL TO FLUCTUATE BETWEEN 5 AND 15 KT DURING THE NEXT 48
HOURS...WHICH SHOULD ACT TO KEEP THE EYE TILTED AT TIMES AND LIKELY
DISRUPT THE RAPID INTENSIFICATION PROCESS. AS A RESULT...ONLY
MODEST STRENGTHENING IS FORECAST UNTIL OPHELIA REACHES 22C AND
COLDER SSTS SHORTLY AFTER THE 48-HOUR TIME PERIOD...WHICH IS ALSO
COINCIDENT WITH AN EXPECTED SHARP INCREASE IN THE VERTICAL SHEAR.
THE INTENSITY FORECAST IS SIMILAR TO THE INTENSITY CONSENSUS
MODEL...ICON...THROUGH 72 HOURS...AND THEN LEANS CLOSE TO THE LGEM
MODEL AFTER THAT. IT IS WORTH NOTING THAT SOME OF THE GLOBAL MODELS
ARE NOW HOLDING ON TO OPHELIA AS A ROBUST EXTRATROPICAL LOW
PRESSURE SYSTEM BEYOND 96 HOURS.

FORECAST POSITIONS AND MAX WINDS
 
INIT  30/0900Z 22.4N  62.6W   85 KT 100 MPH
 12H  30/1800Z 24.2N  63.1W   90 KT 105 MPH
 24H  01/0600Z 27.0N  63.4W   90 KT 105 MPH
 36H  01/1800Z 30.1N  62.9W   95 KT 110 MPH
 48H  02/0600Z 34.6N  61.7W   95 KT 110 MPH
 72H  03/0600Z 44.3N  57.0W   65 KT  75 MPH...POST-TROP/EXTRATROP
 96H  04/0600Z 51.5N  38.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
120H  05/0600Z...DISSIPATED
 
$$
FORECASTER STEWART
 

WTNT41 KNHC 301433
TCDAT1
 
HURRICANE OPHELIA DISCUSSION NUMBER  32
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
1100 AM AST FRI SEP 30 2011
 
OPHELIA HAS DEVELOPED A DISTINCT EYE SURROUNDED BY A CIRCULAR
CENTRAL DENSE OVERCAST. THE EYE WAS ALREADY CLEARLY OBSERVED ON
EARLIER MICROWAVE IMAGES. T-NUMBERS FROM TAFB AND SAB WERE 5.0 ON
THE DVORAK SCALE THIS MORNING. SINCE THEN...THE EYE HAS BECOME EVEN
MORE DISTINCT...AND THE ADT OBJECTIVE ESTIMATES FROM UW-CIMSS HAVE
BEEN AVERAGING NEAR 5.5 WITH RAW NUMBERS RECENTLY REACHING 6.0.  ON
THIS BASIS...THE INITIAL INTENSITY HAS BEEN INCREASED TO 100
KNOTS...MAKING OPHELIA A CATEGORY THREE HURRICANE ON A SAFFIR
SIMPSON HURRICANE WIND SCALE...THE THIRD MAJOR HURRICANE OF THE
SEASON.
 
THERE IS A STRONG LIKELIHOOD THAT OPHELIA HAS ALREADY REACHED ITS
PEAK INTENSITY...AND ONLY SMALL INTENSITY FLUCTUATIONS ARE
ANTICIPATED DURING THE NEXT DAY OR SO. THEREAFTER...THE HURRICANE
SHOULD BE MOVING INTO INCREASING SHEAR AND ENCOUNTER COLD WATERS
RESULTING IN WEAKENING. OPHELIA SHOULD BECOME A POST-TROPICAL
CYCLONE AS IT MOVES TO THE SOUTHEAST OF NEWFOUNDLAND.
 
OPHELIA IS MOVING TOWARD THE NORTH-NORTHWEST OR 345 DEGREES AT 10
KNOTS EMBEDDED WITHIN THE FLOW BETWEEN THE ATLANTIC SUBTROPICAL
HIGH AND A LARGE MID-LATITUDE TROUGH OVER THE EASTERN UNITED STATES.
THIS PATTERN SHOULD FORCE OPHELIA TO MOVE ON A NORTHWARD TRACK
DURING THE NEXT DAY OR SO AND THEN RECURVE WITH AN INCREASE IN
FORWARD SPEED...AS THE CORE OF THE CYCLONE PASSES EAST OF BERMUDA.
THERE IS HIGH CONFIDENCE IN THE NHC FORECAST SINCE IT IS IN THE
MIDDLE OF THE TIGHTLY CLUSTERED GUIDANCE ENVELOPE THROUGH 48 HOURS.
THE WESTERN EDGE OF THE ENVELOPE CONTINUES TO GRADUALLY SHIFT
EASTWARD AWAY FROM BERMUDA. 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  30/1500Z 23.5N  62.8W  100 KT 115 MPH
 12H  01/0000Z 25.2N  63.1W  100 KT 115 MPH
 24H  01/1200Z 28.5N  63.0W   95 KT 110 MPH
 36H  02/0000Z 32.1N  62.2W   90 KT 105 MPH
 48H  02/1200Z 37.0N  60.5W   85 KT 100 MPH
 72H  03/1200Z 46.0N  52.0W   60 KT  70 MPH...POST-TROP/EXTRATROP
 96H  04/1200Z 52.0N  32.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
120H  05/1200Z...DISSIPATED
 
$$
FORECASTER AVILA
 

WTNT41 KNHC 302043
TCDAT1
 
HURRICANE OPHELIA DISCUSSION NUMBER  33
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
500 PM AST FRI SEP 30 2011
 
OPHELIA HAS MAINTAINED A DISTINCT EYE ON SATELLITE IMAGES DURING THE
DAY. THE INTENSITY OF THE CONVECTION SURROUNDING THE EYE HAS BEEN
FLUCTUATING AND THERE IS A SALIENT THUNDERSTORM BAND WRAPPING AROUND
THE NORTH AND EAST OF THE CENTRAL DENSE OVERCAST. SUBJECTIVE
T-NUMBERS HAVE NOT CHANGED WHILE THE ADT OBJECTIVE ESTIMATES FROM
UW-CIMSS HAVE BEEN NEAR 5.9 DURING THE PAST FEW HOURS. THE AVERAGE
OF THESE TWO ESTIMATES SUPPORT KEEPING THE INITIAL INTENSITY AT 100
KNOTS.
 
SOME INTENSITY FLUCTUATIONS ARE ANTICIPATED DURING THE NEXT DAY OR
SO WHILE OPHELIA IS OVER WARM WATERS AND EMBEDDED WITHIN A LOW
SHEAR ENVIRONMENT AS DIAGNOSED BY THE SHIPS MODELS. THEREAFTER...
THE HURRICANE SHOULD BE MOVING INTO INCREASING SHEAR AND ENCOUNTER
COLD WATERS...RESULTING IN WEAKENING. OPHELIA SHOULD BECOME A
POST-TROPICAL CYCLONE AS IT MOVES TO THE SOUTHEAST OF NEWFOUNDLAND
IN 72 HOURS AND THEN BECOME ABSORBED BY A LARGER FRONTAL SYSTEM. 

OPHELIA IS MOVING TOWARD THE NORTH OR 350 DEGREES AT 12 KNOTS
EMBEDDED WITHIN THE FLOW BETWEEN THE ATLANTIC SUBTROPICAL HIGH AND
A LARGE MID-LATITUDE TROUGH OVER THE EASTERN UNITED STATES. THIS
PATTERN SHOULD FORCE OPHELIA TO CONTINUE MOVING NORTHWARD DURING
THE NEXT 24 HOURS AND THEN RECURVE WITH AN INCREASE IN FORWARD
SPEED...AS THE CORE OF THE CYCLONE PASSES EAST OF BERMUDA.
THE CONFIDENCE IN THE NHC TRACK FORECAST REMAINS HIGH SINCE THE
TRACK GUIDANCE IS TIGHTLY CLUSTERED. AS INDICATED IN PREVIOUS
ADVISORIES...THE WESTERN EDGE OF THE TRACK ENVELOPE CONTINUES TO BE
EAST OF BERMUDA.
   
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  30/2100Z 24.7N  63.0W  100 KT 115 MPH
 12H  01/0600Z 26.5N  63.2W  100 KT 115 MPH
 24H  01/1800Z 29.8N  62.8W  100 KT 115 MPH
 36H  02/0600Z 34.0N  62.0W   90 KT 105 MPH
 48H  02/1800Z 39.0N  60.0W   85 KT 100 MPH
 72H  03/1800Z 48.0N  47.0W   50 KT  60 MPH...POST-TROP/EXTRATROP
 96H  04/1800Z...ABSORBED BY A FRONTAL SYSTEM
 
$$
FORECASTER AVILA
 

WTNT41 KNHC 010248
TCDAT1
 
HURRICANE OPHELIA DISCUSSION NUMBER  34
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
1100 PM AST FRI SEP 30 2011
 
DURING THE PAST SEVERAL HOURS...THE EYE OF OPHELIA HAS BECOME WARMER
WITH CONVECTIVE ACTIVITY IN THE EYEWALL STAYING DEEP. DVORAK
ESTIMATES HAVE INCREASED SLIGHTLY...RANGING FROM 102-112 KT...SO
THE INITIAL WIND SPEED WILL NUDGED UPWARD TO 105 KT. VERTICAL WIND
SHEAR AND SSTS ARE EXPECTED TO REMAIN AT ABOUT THE SAME VALUES
DURING THE NEXT DAY OR SO...SO LITTLE CHANGE IN INTENSITY IS
FORECAST FOR THAT PERIOD. A STEADY WEAKENING SHOULD COMMENCE
THEREAFTER DUE TO INCREASING SOUTHWESTERLY SHEAR AND DECREASING
WATER TEMPERATURES. AFTER DAY 2...A COMBINATION OF VERY COLD WATERS
AND STRONG SHEAR SHOULD PROMOTE RAPID WEAKENING OF OPHELIA AND
EXTRATROPICAL TRANSITION IN A BAROCLINIC LOW-LEVEL ENVIRONMENT NEAR
THE CANADIAN MARITIMES. THE OFFICIAL FORECAST IS VERY CLOSE TO THE
PREVIOUS ONE AND THE DYNAMICAL MODEL CONSENSUS.
 
OPHELIA IS MOVING DUE NORTH AT ABOUT 15 KT.  THE CYCLONE SHOULD HAVE
A GRADUAL INCREASE IN FORWARD SPEED DURING THE NEXT FEW DAYS AS THE
STEERING CURRENTS BECOME STRONGER BETWEEN A DEEP MID-LATITUDE
TROUGH OVER THE EASTERN UNITED STATES AND A RIDGE OVER THE CENTRAL
ATLANTIC OCEAN.  LITTLE CHANGE WAS MADE TO THE OFFICIAL FORECAST
FOR THE FIRST 24 TO 36 HOURS AS MODEL GUIDANCE IS IN VERY GOOD
AGREEMENT.  AFTER THAT TIME...THERE HAS BEEN A NOTABLE SHIFT IN THE
LATEST GUIDANCE TO THE LEFT...SOMEWHAT SIMILAR TO LAST NIGHT...WITH
THE GLOBAL MODELS SHOWING OPHELIA COMING CLOSER TO SOUTHEASTERN
NEWFOUNDLAND.  IN GENERAL...THE GUIDANCE HAS BEEN TRENDING TOWARD
THE ECMWF SOLUTION...AND THE NHC FORECAST WILL BE SHIFTED TO THE
NORTHWEST BEYOND 36 HOURS.  FUTURE LEFTWARD ADJUSTMENTS MIGHT HAVE
TO BE MADE BECAUSE THE NEW FORECAST IS STILL TO THE RIGHT OF THE
MODEL CONSENSUS.
 

FORECAST POSITIONS AND MAX WINDS
 
INIT  01/0300Z 26.2N  63.1W  105 KT 120 MPH
 12H  01/1200Z 28.5N  63.1W  105 KT 120 MPH
 24H  02/0000Z 32.4N  62.5W  100 KT 115 MPH
 36H  02/1200Z 37.2N  61.3W   90 KT 105 MPH
 48H  03/0000Z 42.5N  59.0W   80 KT  90 MPH
 72H  04/0000Z 50.0N  42.0W   50 KT  60 MPH...POST-TROP/EXTRATROP
 96H  05/0000Z...ABSORBED
 
$$
FORECASTER BLAKE
 

WTNT41 KNHC 010855
TCDAT1
 
HURRICANE OPHELIA DISCUSSION NUMBER  35
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
500 AM AST SAT OCT 01 2011
 
SINCE THE PREVIOUS ADVISORY...THE EYE HAS BECOME MORE DISTINCT IN
INFRARED IMAGERY AND THE EYE TEMPERATURE HAS WARMED TO ABOUT 11
DEGREES CELSIUS. THE EYE OF OPHELIA PASSED DIRECTLY OVER NOAA BUOY
41049 AROUND 08Z...AND THE BUOY REPORTED A 1-MINUTE SUSTAINED WIND
OF 84 KT WITH A GUST OF 101 KT AT A HEIGHT OF 5 METERS...AND A
PRESSURE OF 951.9 MB. BASED ON THE BUOY PRESSURE AND SATELLITE
INTENSITY ESTIMATES OF T5.5/102 KT FROM BOTH TAFB AND SAB...THE
ADVISORY INTENSITY WILL REMAIN AT 105 KT. WIND RADII WERE ADJUSTED
SLIGHTLY BASED ON WINDS OBTAINED FROM A 01/0106Z ASCAT OVERPASS.

THE INITIAL MOTION IS A STEADY 360/15 KT.  OPHELIA IS FORECAST TO
CONTINUE MOVING NORTHWARD FOR THE NEXT 12 HOURS OR SO...AND THEN
GRADUALLY TURN TOWARD THE NORTHEAST AND ACCELERATE AS THE HURRICANE
COMES UNDER THE INFLUENCE OF INCREASING SOUTHWESTERLY STEERING FLOW
AHEAD OF A DEEP-LAYER TROUGH CURRENTLY MOVING EASTWARD OFF THE U.S.
EAST COAST. BY 48 HOURS...THE CYCLONE IS EXPECTED TO TURN SHARPLY
EASTWARD AS IT ENTERS A BAND OF FAST-MOVING WESTERLIES NORTH OF 45N
LATITUDE. BY THAT TIME...OPHELIA IS FORECAST TO BE OVER WATERS
COLDER THAN 20C AND ALSO BEGIN TO MERGE WITH A STRONG FRONTAL
SYSTEM...WHICH SHOULD INDUCE A QUICK TRANSITION INTO A POWERFUL
POST-TROPICAL WINTER-TYPE CYCLONE. THE OFFICIAL FORECAST TRACK IS
SIMILAR TO THE PREVIOUS ADVISORY...AND LIES DOWN THE MIDDLE OF THE
TIGHTLY PACKED NHC MODEL GUIDANCE SUITE.

THERE IS NO SIGNIFICANT CHANGE TO THE PREVIOUS INTENSITY FORECAST.
OPHELIA COULD STRENGTHEN SLIGHTLY TODAY AS THE MAJOR HURRICANE
REMAINS OVER SSTS NEAR 28C AND IN A VERTICAL SHEAR CONDITIONS OF
LESS THAN 5 KT. BY 24 HOURS...HOWEVER...INCREASING SOUTHWESTERLY
WIND SHEAR AND COOLER WATERS SHOULD INDUCE GRADUAL WEAKENING UNTIL
THE 36-HOUR TIME PERIOD. AFTER THAT...OPHELIA WILL MOVE OVER MUCH
COLDER WATER AND ENCOUNTER STRONG VERTICAL SHEAR OF MORE THAN 30
KT...WHICH SHOULD CAUSE MORE RAPID WEAKENING AND ALSO TRANSITION
INTO AN EXTRATROPICAL CYCLONE. THE OFFICIAL INTENSITY FORECAST IS
SIMILAR TO THE PREVIOUS ADVISORY AND IS CLOSE TO THE INTENSITY
CONSENSUS MODEL...ICON.

FORECAST POSITIONS AND MAX WINDS
 
INIT  01/0900Z 27.7N  63.1W  105 KT 120 MPH
 12H  01/1800Z 30.4N  62.8W  100 KT 115 MPH
 24H  02/0600Z 34.8N  61.9W   95 KT 110 MPH
 36H  02/1800Z 40.1N  60.3W   90 KT 105 MPH
 48H  03/0600Z 44.8N  55.9W   60 KT  70 MPH
 72H  04/0600Z 51.0N  36.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
 96H  05/0600Z...ABSORBED
 
$$
FORECASTER STEWART
 

WTNT41 KNHC 011445
TCDAT1
 
HURRICANE OPHELIA DISCUSSION NUMBER  36
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
1100 AM AST SAT OCT 01 2011
 
OPHELIA HAS AN IMPRESSIVE CLOUD PATTERN ON BOTH CONVENTIONAL AND
MICROWAVE SATELLITE IMAGERY. THE HURRICANE HAS A CLEAR EYE
SURROUNDED BY A SYMMETRIC CENTRAL DENSE OVERCAST. ALTHOUGH BOTH
OBJECTIVE AND SUBJECTIVE T-NUMBERS ARE DECREASING SLIGHTLY...THEY
STILL SUPPORT AN INITIAL INTENSITY OF 105 KNOTS. BECAUSE OPHELIA IS
STILL EMBEDDED IN LIGHT SHEAR AND MOVING OVER HIGH SEA SURFACE
TEMPERATURES...ONLY SMALL FLUCTUATIONS IN INTENSITY ARE EXPECTED
TODAY. A GRADUAL WEAKENING SHOULD BEGIN ON SUNDAY AS OPHELIA
REACHES COOLER WATERS...AND MOST LIKELY OPHELIA WILL BECOME
POST-TROPICAL IN ABOUT 48 HOURS AS IT PASSES NOT TOO FAR TO THE
SOUTHEAST OF THE AVALON PENINSULA IN NEWFOUNDLAND.
 
OPHELIA IS MOVING TOWARD THE NORTH OR 360 DEGREES AT 18 KNOTS. THE
HURRICANE IS ALREADY EMBEDDED IN THE FAST SOUTHERLY FLOW BETWEEN
THE SUBTROPICAL HIGH AND THE LARGE TROUGH OVER THE EASTERN
UNITED STATES. AS THE TROUGH MOVES EASTWARD...OPHELIA SHOULD TURN
MORE TO THE NORTH-NORTHEAST WITH AN INCREASE IN FORWARD SPEED.
TRACK GUIDANCE CONTINUES TO BE TIGHTLY PACKED AND IS VERY
CONSISTENT AT LEAST TO 48 HOURS IN BOTH DIRECTION AND SPEED. THE
OFFICIAL FORECAST IS IN THE MIDDLE OF THE GUIDANCE ENVELOPE AND
KEEPS THE CORE OF THE HURRICANE PASSING EAST OF BERMUDA LATER
TODAY.
 
  
FORECAST POSITIONS AND MAX WINDS
 
INIT  01/1500Z 29.5N  62.9W  105 KT 120 MPH
 12H  02/0000Z 32.5N  62.5W  100 KT 115 MPH
 24H  02/1200Z 37.0N  61.0W   95 KT 110 MPH
 36H  03/0000Z 42.0N  58.5W   75 KT  85 MPH
 48H  03/1200Z 46.5N  52.0W   55 KT  65 MPH...POST-TROP/EXTRATROP
 72H  04/1200Z 50.5N  33.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 96H  05/1200Z...ABSORBED BY A FRONTAL SYSTEM
 
$$
FORECASTER AVILA
 

WTNT41 KNHC 012034
TCDAT1
 
HURRICANE OPHELIA DISCUSSION NUMBER  37
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
500 PM AST SAT OCT 01 2011
 
OPHELIA HAS MAINTAINED ITS IMPRESSIVE CLOUD PATTERN...WITH A
DISTINCT EYE SURROUNDED BY A SYMMETRIC CENTRAL DENSE OVERCAST.
BECAUSE OBJECTIVE AND SUBJECTIVE T-NUMBERS HAVE NOT CHANGED...THE
INITIAL INTENSITY IS KEPT AT 105 KNOTS. SMALL FLUCTUATIONS IN
INTENSITY ARE EXPECTED IN THE NEXT 12 HOURS...BUT A GRADUAL
WEAKENING SHOULD BEGIN ON SUNDAY AS OPHELIA REACHES COOLER WATERS.
THERE IS A STRONG LIKELIHOOD THAT OPHELIA WILL BEGIN TO BECOME
POST-TROPICAL ON MONDAY AS IT PASSES NEAR OR OVER THE AVALON
PENINSULA IN NEWFOUNDLAND.

OPHELIA HAS BEGUN TO RECURVE AND IS NOW MOVING TOWARD THE NORTH OR
010 DEGREES AT 23 KNOTS. THE HURRICANE CONTINUES TO BE EMBEDDED IN
THE FAST SOUTHERLY FLOW BETWEEN THE SUBTROPICAL HIGH AND THE LARGE
TROUGH OVER THE EASTERN UNITED STATES. AS THE TROUGH MOVES
EASTWARD...OPHELIA SHOULD TURN MORE TOWARD THE NORTH-NORTHEAST WITH
AN INCREASE IN FORWARD SPEED. THE TRACK GUIDANCE CONTINUES TO BE
TIGHTLY PACKED...BUT THE ENTIRE ENVELOPE HAS SHIFTED A LITTLE BIT
NORTHWARD FOR THIS CYCLE. THE OFFICIAL FORECAST IS IN THE MIDDLE OF
THE GUIDANCE ENVELOPE AND TAKES THE CORE OF THE HURRICANE EAST OF
BERMUDA IN THE NEXT FEW HOURS AND BRINGS THE CENTER OF THE CYCLONE
NEAR THE AVALON PENINSULA ON MONDAY.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  01/2100Z 31.6N  62.6W  105 KT 120 MPH
 12H  02/0600Z 35.0N  62.0W  100 KT 115 MPH
 24H  02/1800Z 40.0N  60.4W   90 KT 105 MPH
 36H  03/0600Z 45.0N  56.0W   65 KT  75 MPH
 48H  03/1800Z 48.0N  48.0W   50 KT  60 MPH...POST-TROP/EXTRATROP
 72H  04/1800Z 50.0N  31.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 96H  05/1800Z...DISSIPATED
 
$$
FORECASTER AVILA
 

WTNT41 KNHC 020254
TCDAT1
 
HURRICANE OPHELIA DISCUSSION NUMBER  38
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
1100 PM AST SAT OCT 01 2011
 
DURING ITS SECOND LIFETIME...OPHELIA HAS BEEN AN OVERACHIEVER AND
HAS CONTINUED TO INTENSIFY.  THE BERMUDA RADAR EARLIER INDICATED
THAT THE EYEWALL WAS QUITE STRONG WITH A CLOSED PRESENTATION.  MORE
RECENTLY...SATELLITE IMAGES SHOW A WARM WELL-DEFINED EYE...A MORE
SYMMETRIC CLOUD PATTERN...AND COOLING CLOUD TOPS IN THE EYEWALL.
SUBJECTIVE DVORAK DATA-T VALUES WERE NEAR 115 KT AT 00Z...WITH
CIMSS ADT VALUES REACHING 122 KT.  A BLEND OF THESE DATA GIVES AN
INITIAL WIND SPEED OF 120 KT.  WEAKENING SHOULD BEGIN SOON AS THE
HURRICANE MOVES OVER COOLER SSTS...AND THE DECREASE IN STRENGTH
SHOULD BE QUITE RAPID BY MIDDAY TOMORROW DUE TO AN INCREASE IN
SHEAR AND OPHELIA CROSSING THE NORTH WALL OF THE GULF STREAM.  THE
NHC FORECAST IS CLOSE TO THE LGEM MODEL AND THE PREVIOUS FORECAST.  
 
THE INITIAL MOTION IS ABOUT THE SAME AS BEFORE...010/23.  A
GRADUALLY ACCELERATING TRACK TOWARD THE NORTH-NORTHEAST SHOULD
BEGIN EARLY SUNDAY AS THE CYCLONE MOVES BETWEEN A DEEP TROUGH
ALONG THE U.S. EAST COAST AND A RIDGE OVER THE CENTRAL ATLANTIC.
THE HURRICANE WILL LIKELY TURN TOWARD THE NORTHEAST BY MONDAY
MORNING AS IT MOVES AROUND THE NORTHERN PORTION OF THE RIDGE.
ALMOST ALL OF THE GLOBAL MODELS SHOW OPHELIA NEAR OR JUST TO THE
SOUTH OF NEWFOUNDLAND IN ABOUT 36 HOURS...AND THE OFFICIAL FORECAST
HAS BEEN SHIFTED LEFTWARD AND LIES BETWEEN THE GFS AND ECMWF MODELS. 
IT IS WORTH NOTING THAT OF THE GENERALLY RELIABLE GUIDANCE...ONLY
THE ECMWF KEEPS THE CENTER OFFSHORE.  HOWEVER...THE STORM WILL
LIKELY BE RAPIDLY TRANSITIONING TO AN EXTRATROPICAL CYCLONE BY THAT
TIME...WITH THE STRONGEST WINDS OCCURRING AT SOME DISTANCE
SOUTHEAST OF THE CENTER.  
 
THE WIND RADII HAVE BEEN ADJUSTED BASED ON A 0046 UTC ASCAT PASS.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  02/0300Z 33.8N  62.2W  120 KT 140 MPH
 12H  02/1200Z 37.4N  61.1W  110 KT 125 MPH
 24H  03/0000Z 42.5N  59.0W   85 KT 100 MPH
 36H  03/1200Z 46.5N  53.3W   60 KT  70 MPH
 48H  04/0000Z 49.5N  44.0W   50 KT  60 MPH...POST-TROP/EXTRATROP
 72H  05/0000Z 53.0N  22.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
 96H  06/0000Z...DISSIPATED
 
$$
FORECASTER BLAKE/BRENNAN
 

WTNT41 KNHC 020836
TCDAT1
 
HURRICANE OPHELIA DISCUSSION NUMBER  39
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
500 AM AST SUN OCT 02 2011
 
JUST PRIOR TO 06Z...UW-CIMSS ADT ESTIMATES WERE AVERAGING BETWEEN
T62/119 KT AND T6.3/121 KT. SINCE THAT TIME...HOWEVER... THE ADT
ESTIMATES HAVE BEEN STEADILY DECREASING BELOW T6.0/115 KT. AS A
RESULT...THE INTENSITY HAS BEEN LOWERED TO 110 KT ON THIS ADVISORY.

THE INITIAL MOTION ESTIMATE IS 010/25 KT. THERE IS NO SIGNIFICANT
CHANGE TO THE PREVIOUS FORECAST TRACK REASONING. THE NHC MODEL
GUIDANCE REMAINS TIGHTLY PACKED THROUGH 36 HOURS. OPHELIA IS
EXPECTED TO MOVE NORTH-NORTHEASTWARD DURING THE NEXT 12 HOURS OR SO
AND THEN TURN NORTHEASTWARD...BRINGING THE CENTER OF THE HURRICANE
OVER OR NEAR THE AVALON PENINSULA OF NEWFOUNDLAND IN ABOUT 30
HOURS. AFTER THAT...THE MODELS DIVERGE ON WHETHER THE EXTRATROPICAL
LOW PRESSURE SYSTEM WILL MOVE OVER OR NORTH OF THE BRITISH ISLES.
THE OFFICIAL FORECAST TRACK IS SIMILAR TO THE PREVIOUS ADVISORY
TRACK THROUGH 36 HOURS...AND IS A LITTLE NORTH OF THE PREVIOUS
FORECAST AFTER THAT BASED ON GUIDANCE FROM THE NOAA OCEAN
PREDICTION CENTER...AND THE ECMWF AND GFS MODELS.

OPHELIA IS MOVING OVER SUB-27C SSTS NOW AND THE CLOUD PATTERN HAS
BECOME ELONGATED NORTHWEST-TO-SOUTHEAST...SUGGESTING THAT SOUTHERLY
TO SOUTHWESTERLY WIND SHEAR IS BEGINNING TO AFFECT THE CYCLONE.
MUCH COOLER WATER LIES NORTH OF 40N LATITUDE AND THE VERTICAL SHEAR
IS FORECAST TO INCREASE TO ABOVE 35 KT IN ABOUT 24 HOURS. THE
COMBINATION OF STRONG SHEAR AND COLD WATER SHOULD INDUCE STEADY TO
RAPID WEAKENING DURING THE NEXT 24 HOURS...WITH TRANSITION TO A
POST-TROPICAL EXTRATROPICAL CYCLONE BY 36 HOURS...IF NOT SOONER.
THE NHC INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY...
AND IS A BLEND OF THE SHIPS/LGEM INTENSITY MODELS AND GUIDANCE FROM
THE NOAA OCEAN PREDICTION CENTER.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  02/0900Z 36.2N  61.8W  110 KT 125 MPH
 12H  02/1800Z 39.9N  60.2W   95 KT 110 MPH
 24H  03/0600Z 44.4N  56.4W   75 KT  85 MPH
 36H  03/1800Z 47.9N  48.8W   55 KT  65 MPH...POST-TROP/EXTRATROP
 48H  04/0600Z 50.5N  39.0W   50 KT  60 MPH...POST-TROP/EXTRATROP
 72H  05/0600Z 56.0N  17.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
 96H  06/0600Z...DISSIPATED
 
$$
FORECASTER STEWART
 

WTNT41 KNHC 021446
TCDAT1
 
HURRICANE OPHELIA DISCUSSION NUMBER  40
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
1100 AM AST SUN OCT 02 2011
 
OPHELIA HAS BEGUN TO STEADILY WEAKEN WITH THE EYE NO LONGER
DISCERNIBLE IN VISIBLE OR INFRARED SATELLITE IMAGERY.  EARLIER
MICROWAVE DATA INDICATED THAT THE LOW- TO MID-LEVEL EYE WAS
TILTED SOUTHWEST TO NORTHEAST AND THAT THE EYEWALL WAS OPEN
TO THE SOUTH.  BASED ON DVORAK INTENSITY ESTIMATES AND RECENT
SATELLITE TRENDS THE INITIAL WIND SPEED IS LOWERED TO 95 KT.
OPHELIA WILL BE MOVING OVER MUCH COLDER SSTS WITHIN THE NEXT
12 TO 18 HOURS.  THE NEGATIVE OCEANIC CONDITIONS AND INCREASING
SOUTHWESTERLY SHEAR ARE EXPECTED TO CAUSE RAPID WEAKENING OF THE
CYCLONE DURING THE NEXT 24 HOURS.  OPHELIA IS ALSO FORECAST TO
INTERACT WITH A FRONTAL ZONE AND WILL LIKELY BECOME A POST-TROPICAL
EXTRATROPICAL CYCLONE NEAR OR JUST AFTER PASSING THE AVALON
PENINSULA OF NEWFOUNDLAND ON MONDAY.
 
THE HURRICANE HAS TURNED NORTH-NORTHEASTWARD WITH AN INITIAL
MOTION OF 015/27 KT.  OPHELIA WILL CONTINUE MOVING NORTH-
NORTHEASTWARD TODAY IN SOUTHWESTERLY FLOW AROUND THE EASTERN
SIDE OF A DEEP-LAYER LOW OVER THE NORTHEASTERN UNITED STATES.
AFTER PASSING NEAR OR OVER THE AVALON PENINSULA...THE CYCLONE 
SHOULD TURN EAST-NORTHEASTWARD IN MID-LATITUDE WESTERLY FLOW OVER
THE NORTH ATLANTIC.  THE POST-TROPICAL CYCLONE IS FORECAST TO BE
ABSORBED BY A COLD FRONT OVER THE NORTH ATLANTIC IN 2 TO 3 DAYS.
THE OFFICIAL TRACK FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY 
AND IS IN GOOD AGREEMENT WITH THE GFS AND ECMWF MODELS...AS WELL
AS GUIDANCE PROVIDED BY THE NOAA OCEAN PREDICTION CENTER.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  02/1500Z 38.7N  60.9W   95 KT 110 MPH
 12H  03/0000Z 42.4N  59.0W   80 KT  90 MPH
 24H  03/1200Z 46.4N  53.2W   60 KT  70 MPH
 36H  04/0000Z 49.6N  43.8W   50 KT  60 MPH...POST-TROP/EXTRATROP
 48H  04/1200Z 52.0N  32.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  05/1200Z...ABSORBED BY FRONT
 
$$
FORECASTER BROWN
 

WTNT41 KNHC 022043
TCDAT1
 
HURRICANE OPHELIA DISCUSSION NUMBER  41
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
500 PM AST SUN OCT 02 2011
 
ALTHOUGH THE CLOUD PATTERN OF OPHELIA HAS GRADUALLY DEGRADED IN
CONVENTIONAL SATELLITE IMAGERY TODAY...A RECENT AMSR-E MICROWAVE
IMAGE SHOWED THAT THE INNER-CORE STRUCTURE REMAINS INTACT. THE EYE
HAS BECOME LARGER...BUT REMAINS CLOSED. THE MICROWAVE DATA CONTINUE
TO SUGGEST THAT THE CIRCULATION IS TILTED...WITH THE SURFACE CENTER
LOCATED TO THE SOUTHWEST OF MID-LEVEL EYE AND ROTATION SEEN IN
VISIBLE SATELLITE PICTURES. DVORAK T-NUMBERS ARE GRADUALLY
DECREASING AND THE INITIAL INTENSITY IS LOWERED TO 85 KT. OPHELIA
IS CURRENTLY TRAVERSING THE NORTH WALL OF THE GULF STREAM AND WILL
BE MOVING OVER MUCH COLDER WATERS DURING THE NEXT DAY OR SO. THE
COLD WATER AND INCREASING SOUTHWESTERLY SHEAR SHOULD CAUSE RAPID
WEAKENING TONIGHT AND MONDAY. OPHELIA WILL ALSO INTERACT WITH A
FRONTAL BOUNDARY AND IS FORECAST TO BECOME AN EXTRATROPICAL CYCLONE
WITHIN 24 HOURS. 

THE INITIAL MOTION ESTIMATE IS 015/29 KT. THE TRACK FORECAST
REASONING REMAINS UNCHANGED FROM THE PREVIOUS ADVISORY. THE
HURRICANE IS FORECAST TO TURN NORTHEASTWARD LATER TONIGHT AND PASS
NEAR OR OVER THE AVALON PENINSULA OF NEWFOUNDLAND BY EARLY MONDAY
MORNING. AFTER THAT...THE CYCLONE IS EXPECTED TO TURN NORTH-
NORTHEAST IN THE MID-LATITUDE WESTERLY FLOW OVER THE NORTH ATLANTIC
AND BE ABSORBED BY A COLD FRONT IN 2 TO 3 DAYS. THE TRACK GUIDANCE
IS IN GOOD AGREEMENT ON THIS SCENARIO. THE NEW NHC FORECAST HAS
BEEN SHIFTED SLIGHTLY WEST OF THE PREVIOUS FORECAST AT 12 AND 24
HOURS TO BE CLOSER TO THE GFS AND ECMWF MODELS.

THE TROPICAL STORM FORCE WIND RADII OVER THE EASTERN PORTION OF THE
CIRCULATION HAVE BEEN EXPANDED BASED ON RECENT ASCAT AND SHIP DATA. 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  02/2100Z 41.6N  59.9W   85 KT 100 MPH
 12H  03/0600Z 45.2N  56.6W   65 KT  75 MPH
 24H  03/1800Z 48.6N  48.2W   50 KT  60 MPH...POST-TROP/EXTRATROP
 36H  04/0600Z 51.0N  37.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
 48H  04/1800Z 56.0N  25.5W   35 KT  40 MPH...POST-TROP/EXTRATROP
 72H  05/1800Z...ABSORBED BY FRONT
 
$$
FORECASTER BROWN
 

WTNT41 KNHC 030248
TCDAT1
 
HURRICANE OPHELIA DISCUSSION NUMBER  42
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
1100 PM AST SUN OCT 02 2011
 
THE SATELLITE PRESENTATION OF OPHELIA HAS CONTINUED TO DETERIORATE
THIS EVENING...WITH CLOUD TOPS WARMING AND DRY AIR WORKING ITS WAY
INTO THE CORE OF THE CYCLONE FROM THE SOUTH. ALSO...RECENT
MICROWAVE IMAGERY AND SURFACE OBSERVATIONS INDICATE THAT THE
LOW-LEVEL CENTER IS DISPLACED ABOUT A DEGREE TO THE SOUTH-SOUTHWEST
OF THE MID-LEVEL CIRCULATION AND THE REMAINING DEEP CONVECTION.
THIS TILT IS DUE TO THE 30 KT OF SOUTHWESTERLY SHEAR SHOWN OVER THE
CYCLONE IN ANALYSES FROM THE SHIPS MODEL AND UW-CIMSS. THE INITIAL
INTENSITY IS LOWERED TO 70 KT FOR THIS ADVISORY...LEANING TOWARD
THE HIGH END OF A BLEND OF DVORAK CI- AND FINAL-T NUMBERS FROM TAFB
AND SAB. OPHELIA SHOULD CONTINUE TO STEADILY WEAKEN OVER THE NEXT
12 TO 24 HOURS AS THE CYCLONE MOVES OVER VERY COLD WATERS AND THE
SHEAR INCREASES EVEN MORE. BY 24 HOURS...OPHELIA WILL BE 
EXTRATROPICAL AND SLOWLY WEAKEN UNTIL IT IS ABSORBED BY A FRONTAL
SYSTEM IN ABOUT 48 HOURS.
 
BASED ON MICROWAVE FIXES AND SURFACE OBSERVATIONS...THE INITIAL
MOTION ESTIMATE IS A RATHER UNCERTAIN 025/29. HOWEVER...THE TRACK
FORECAST REASONING REMAINS STRAIGHTFORWARD. OPHELIA WILL TURN
TOWARD THE NORTHEAST OVERNIGHT AS IT MOVES AROUND THE NORTHWESTERN
SIDE OF THE SUBTROPICAL RIDGE. THIS MOTIONS WILL BRING THE CENTER
OF OPHELIA NEAR THE AVALON PENINSULA OF NEWFOUNDLAND ON MONDAY
MORNING. AFTER THAT TIME...OPHELIA WILL BECOME EMBEDDED IN THE
MID-LATITUDE WESTERLIES AND ACCELERATE TOWARD THE EAST-NORTHEAST
UNTIL IT IS ABSORBED IN 36 TO 48 HOURS. THE NEW NHC TRACK FORECAST
IS SIMILAR TO THE PREVIOUS ONE AND CLOSE TO A BLEND OF THE ECMWF
AND GFS MODELS.
 
THE TROPICAL-STORM-FORCE WIND RADII HAVE BEEN ADJUSTED INWARD BASED
ON RECENT SURFACE OBSERVATIONS.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  03/0300Z 43.9N  58.6W   70 KT  80 MPH
 12H  03/1200Z 46.6N  53.7W   55 KT  65 MPH
 24H  04/0000Z 49.8N  43.7W   45 KT  50 MPH...POST-TROP/EXTRATROP
 36H  04/1200Z 53.0N  32.5W   35 KT  40 MPH...POST-TROP/EXTRATROP
 48H  05/0000Z...DISSIPATED
 
$$
FORECASTER BRENNAN
 

WTNT41 KNHC 030252
TCDAT1
 
HURRICANE OPHELIA DISCUSSION NUMBER  42...CORRECTED
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
1100 PM AST SUN OCT 02 2011
 
CORRECTED FOR 48-HOUR STATUS IN FORECAST TABLE

THE SATELLITE PRESENTATION OF OPHELIA HAS CONTINUED TO DETERIORATE
THIS EVENING...WITH CLOUD TOPS WARMING AND DRY AIR WORKING ITS WAY
INTO THE CORE OF THE CYCLONE FROM THE SOUTH. ALSO...RECENT
MICROWAVE IMAGERY AND SURFACE OBSERVATIONS INDICATE THAT THE
LOW-LEVEL CENTER IS DISPLACED ABOUT A DEGREE TO THE SOUTH-SOUTHWEST
OF THE MID-LEVEL CIRCULATION AND THE REMAINING DEEP CONVECTION.
THIS TILT IS DUE TO THE 30 KT OF SOUTHWESTERLY SHEAR SHOWN OVER THE
CYCLONE IN ANALYSES FROM THE SHIPS MODEL AND UW-CIMSS. THE INITIAL
INTENSITY IS LOWERED TO 70 KT FOR THIS ADVISORY...LEANING TOWARD
THE HIGH END OF A BLEND OF DVORAK CI- AND FINAL-T NUMBERS FROM TAFB
AND SAB. OPHELIA SHOULD CONTINUE TO STEADILY WEAKEN OVER THE NEXT
12 TO 24 HOURS AS THE CYCLONE MOVES OVER VERY COLD WATERS AND THE
SHEAR INCREASES EVEN MORE. BY 24 HOURS...OPHELIA WILL BE 
EXTRATROPICAL AND SLOWLY WEAKEN UNTIL IT IS ABSORBED BY A FRONTAL
SYSTEM IN ABOUT 48 HOURS.
 
BASED ON MICROWAVE FIXES AND SURFACE OBSERVATIONS...THE INITIAL
MOTION ESTIMATE IS A RATHER UNCERTAIN 025/29. HOWEVER...THE TRACK
FORECAST REASONING REMAINS STRAIGHTFORWARD. OPHELIA WILL TURN
TOWARD THE NORTHEAST OVERNIGHT AS IT MOVES AROUND THE NORTHWESTERN
SIDE OF THE SUBTROPICAL RIDGE. THIS MOTIONS WILL BRING THE CENTER
OF OPHELIA NEAR THE AVALON PENINSULA OF NEWFOUNDLAND ON MONDAY
MORNING. AFTER THAT TIME...OPHELIA WILL BECOME EMBEDDED IN THE
MID-LATITUDE WESTERLIES AND ACCELERATE TOWARD THE EAST-NORTHEAST
UNTIL IT IS ABSORBED IN 36 TO 48 HOURS. THE NEW NHC TRACK FORECAST
IS SIMILAR TO THE PREVIOUS ONE AND CLOSE TO A BLEND OF THE ECMWF
AND GFS MODELS.
 
THE TROPICAL-STORM-FORCE WIND RADII HAVE BEEN ADJUSTED INWARD BASED
ON RECENT SURFACE OBSERVATIONS.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  03/0300Z 43.9N  58.6W   70 KT  80 MPH
 12H  03/1200Z 46.6N  53.7W   55 KT  65 MPH
 24H  04/0000Z 49.8N  43.7W   45 KT  50 MPH...POST-TROP/EXTRATROP
 36H  04/1200Z 53.0N  32.5W   35 KT  40 MPH...POST-TROP/EXTRATROP
 48H  05/0000Z...ABSORBED BY FRONT
 
$$
FORECASTER BRENNAN
 

WTNT41 KNHC 030855
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER  43
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
500 AM AST MON OCT 03 2011

THE SATELLITE PRESENTATION OF OPHELIA HAS CONTINUED TO DETERIORATE
THIS MORNING...AND THE CYCLONE IS QUICKLY LOSING ITS TROPICAL
CHARACTERISTICS OVER WATER TEMPERATURES BETWEEN 10-15 CELSIUS.
THERE REMAINS A SMALL AREA OF MODERATE CONVECTION WITH CLOUD TOPS
COLDER THAN -50C JUST NORTHEAST OF THE ALLEGED CENTER...BUT THE
AREAL COVERAGE OF THIS CONVECTION HAS BEEN RAPIDLY SHRINKING. 
HOWEVER...A 03/0556Z AMSU OVERPASS STILL INDICATED A VERTICALLY
STACKED WARM CORE THROUGH AT LEAST THE 250/200 MB LEVEL...AND THAT
IS THE JUSTIFICATION FOR MAINTAINING OPHELIA AS A TROPICAL CYCLONE
ON THIS ADVISORY.

THE INITIAL MOTION ESTIMATE IS AN UNCERTAIN 055/37 KT...BASED ON
EXTRAPOLATION...CONVENTIONAL SATELLITE FIXES...AND A 03/0621 AMSR-E
MICROWAVE OVERPASS. OPHELIA IS EXPECTED TO MOVE NORTHEASTWARD THIS
MORNING AND MAKE LANDFALL ALONG THE AVALON PENINSULA BETWEEN
ROUGHLY 10-12Z THIS MORNING. VERY COLD WATER BENEATH OPHELIA AND
INCREASING VERTICAL WIND SHEAR IN EXCESS OF 40 KT SHOULD RESULT IN
COMPLETE TRANSITION TO AN EXTRATROPICAL LOW PRESSURE SYSTEM BY
18Z...IF NOT SOONER. THE OFFICIAL TRACK FORECAST IS DOWN THE MIDDLE
OF THE TIGHTLY PACKED NHC MODEL GUIDANCE SUITE...AND LIES CLOSE TO
THE GUIDANCE PROVIDED BY THE NOAA OCEAN PREDICTION CENTER.

A 03/0027Z ASCAT OVERPASS INDICATED A LARGE SWATH OF 50-55 KT WIND
VECTORS IN THE EAST AND SOUTHEAST OCTANTS OF THE CIRCULATION. GIVEN
THE KNOWN LOW BIAS OF THIS REMOTE SENSING INSTRUMENT...OPHELIA WAS
KEPT AS A 65-KT HURRICANE AT 06Z...AND IS NOW A 60-KT TROPICAL
STORM DUE TO THE LOSS OF CENTRAL DEEP CONVECTION IN THE REGION OF
STRONGEST WINDS NOTED IN THE ASCAT DATA. CANADIAN RADAR DATA FROM
THE AVALON PENINSULA INDICATE THE RAIN SHIELD AHEAD OF THE CENTER
IS MOSTLY STRATIFORM IN NATURE...FURTHER INDICATING THAT OPHELIA IS
UNDERGOING EXTRATROPICAL TRANSITION. OPHELIA SHOULD CONTINUE TO
WEAKEN OVER COLDER WATER AND EVENTUALLY MERGE WITH A FRONTAL SYSTEM
IN 24-36 HOURS. THE OFFICIAL INTENSITY FORECAST AND FORECAST WIND
RADII ARE BASED ON GUIDANCE PROVIDED BY THE NOAA OCEAN PREDICTION
CENTER.
 
ADVISORY WIND RADII WERE ADJUSTED BASED ON A 03/0027Z ASCAT OVERPASS
AND SURROUNDING SURFACE OBSERVATIONS.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  03/0900Z 46.5N  54.2W   60 KT  70 MPH
 12H  03/1800Z 49.1N  48.4W   50 KT  60 MPH...POST-TROP/EXTRATROP
 24H  04/0600Z 51.0N  38.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 36H  04/1800Z 53.0N  28.0W   35 KT  40 MPH...POST-TROP/EXTRATROP
 48H  05/0600Z...ABSORBED BY FRONTAL SYSTEM
 
$$
FORECASTER STEWART
 

