WTNT43 KNHC 192055
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   1
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
500 PM EDT TUE JUN 19 2012
 
CONVECTION ASSOCIATED WITH THE LOW PRESSURE AREA LOCATED WELL
SOUTHEAST OF THE CANADIAN MARITIMES HAS ACQUIRED ENOUGH ORGANIZATION
AND COVERAGE FOR THE SYSTEM TO BE CLASSIFIED AS A TROPICAL CYCLONE.
THIS IS SUPPORTED BY RECENT DVORAK CLASSIFICATIONS OF T2.5 FROM
TAFB AND T1.5 FROM SAB.  FSU CYCLONE PHASE SPACE DIAGRAMS ALSO SHOW
THE SYSTEM AS A SYMMETRIC WARM CORE...ALBEIT SHALLOW...SYSTEM.  THE
INITIAL WIND SPEED OF 40 KT IS BASED ON EARLIER SCATTEROMETER DATA
AND A SHIP THAT REPORTED 35-KT WINDS TO THE SOUTHEAST OF THE CENTER
THIS MORNING.
 
THE INITIAL MOTION ESTIMATE IS 090/7.  THE TROPICAL STORM IS
FORECAST TO ACCELERATE EASTWARD IN THE MID-LATITUDE WESTERLY
FLOW DURING THE NEXT DAY OR SO.  AFTER THAT TIME...IT IS FORECAST
TO TURN NORTHEASTWARD...THEN NORTHWARD AROUND A DEVELOPING CUT-OFF
LOW.  THE TRACK GUIDANCE IS IN GOOD AGREEMENT ON THIS GENERAL
SCENARIO...BUT THERE IS SOME SPREAD AS TO HOW SHARP THE CYCLONE
TURNS NORTHWARD.  FOR NOW...THE OFFICIAL FORECAST LIES NEAR THE
MIDDLE OF THE GUIDANCE ENVELOPE...BETWEEN THE GFS AND ECMWF 
MODELS.
 
LITTLE CHANGE IN STRENGTH IS EXPECTED DURING THE NEXT DAY OR SO AS
CHRIS TRAVERSES THE MARGINALLY WARM WATERS NEAR THE SOUTHERN EDGE
OF THE GULF STREAM.  THE CYCLONE SHOULD MOVE OVER COLDER WATERS IN
36-48 HOURS...ALTHOUGH GLOBAL MODELS SHOW THE LOW STRENGTHENING AS
A BAROCLINIC SYSTEM AT THAT TIME.  THE CYCLONE IS LIKELY TO BE
ABSORBED BY A LARGER EXTRATROPICAL LOW PRESSURE AREA IN 3 TO 4
DAYS...AND THIS IS REFLECTED IN THE NHC FORECAST.

ONLY TWICE BEFORE...IN 1887 AND 1959...HAS THE THIRD STORM OF THE
SEASON FORMED EARLIER THAN THIS DATE.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  19/2100Z 39.3N  57.7W   40 KT  45 MPH
 12H  20/0600Z 39.2N  54.8W   40 KT  45 MPH
 24H  20/1800Z 39.5N  50.5W   40 KT  45 MPH
 36H  21/0600Z 40.9N  46.1W   40 KT  45 MPH...POST-TROP/EXTRATROP
 48H  21/1800Z 43.3N  44.1W   45 KT  50 MPH...POST-TROP/EXTRATROP
 72H  22/1800Z 45.5N  45.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 96H  23/1800Z...ABSORBED BY EXTRATROPICAL LOW
 
$$
FORECASTER BROWN
 

WTNT43 KNHC 200247
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   2
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
1100 PM AST TUE JUN 19 2012
 
CHRIS IS PRODUCING A CURLED...COMPACT AREA OF DEEP CONVECTION THAT
IS DISPLACED JUST TO THE EAST AND SOUTHEAST OF THE LOW-LEVEL
CENTER.  TAFB AND SAB PROVIDED DVORAK ESTIMATES OF 35 KT...AND THE
LATEST UW-CIMSS ADT IS ABOUT 40 KT.  SINCE THE OVERALL ORGANIZATION
HAS CHANGED LITTLE SINCE THIS AFTERNOON...THE INTENSITY WILL BE
HELD AT 40 KT.
 
CHRIS IS EMBEDDED WITHIN A DIGGING MID- TO UPPER-LEVEL TROUGH...SO
IT IS NOW MOVING TOWARD THE EAST-SOUTHEAST AT A FASTER SPEED...OR
110/11 KT.  A CLOSED LOW IS FORECAST TO DEVELOP AT THE NORTHERN END
OF THE TROUGH OVER THE NEXT 24 TO 48 HOURS...WHICH WILL ENHANCE THE
MID-LATITUDE WESTERLY FLOW AND CAUSE CHRIS TO FURTHER ACCELERATE
TOWARD THE EAST AND EAST-NORTHEAST THROUGH EARLY THURSDAY.  AFTER
THE LOW CLOSES OFF AND STALLS...CHRIS WILL BEGIN TO LOOP
CYCLONICALLY AROUND THE LOW BY 48 AND 72 HOURS.  THE TRACK MODELS
ALL AGREE ON THIS SCENARIO.  THE GFS AND ECMWF LIE ON THE WESTERN
SIDE OF THE ENVELOPE WHILE THE GFDL AND HWRF LIE ON THE EASTERN
SIDE.  GIVEN THE MID-LATITUDE ENVIRONMENT...THE NHC FORECAST LEANS
MORE HEAVILY TOWARD THE GLOBAL MODEL SOLUTIONS.  DISSIPATION IS
FORECAST BY 96 HOURS WHEN CHRIS SHOULD BE FULLY ABSORBED WITHIN THE
CLOSED LOW.
 
THE GLOBAL MODEL GUIDANCE DOES NOT PROVIDE A CLEAR-CUT ANSWER OF
WHEN EXTRATROPICAL TRANSITION WILL END.  THE FSU PHASE-SPACE
DIAGRAMS BASED OFF THE GFS SUGGEST THAT THE THERMAL STRUCTURE WILL
BECOME INCREASINGLY ASYMMETRIC WITH A SHALLOWER WARM CORE DURING
THE NEXT 24 HOURS.  THEREAFTER...THE DIAGRAMS INDICATE THAT CHRIS
WILL AGAIN DEVELOP A DEEPER WARM CORE...BUT THIS MOST LIKELY IS
REPRESENTATIVE OF AN EXTRATROPICAL WARM SECLUSION.  ON THIS
BASIS...CHRIS IS FORECAST TO BE FULLY EXTRATROPICAL BY 36 HOURS. 
DUE TO RELATIVELY COOL SEA SURFACE TEMPERATURES AND MODERATE
VERTICAL SHEAR...CHRIS IS EXPECTED TO CHANGE LITTLE IN STRENGTH
UNTIL IT BECOMES EXTRATROPICAL AND FEEDS OFF BAROCLINIC ENERGY
ASSOCIATED WITH THE CLOSED MID/UPPER-LEVEL LOW.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  20/0300Z 38.8N  56.0W   40 KT  45 MPH
 12H  20/1200Z 38.7N  52.9W   40 KT  45 MPH
 24H  21/0000Z 39.5N  48.4W   40 KT  45 MPH
 36H  21/1200Z 41.4N  44.7W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  22/0000Z 43.7N  43.8W   45 KT  50 MPH...POST-TROP/EXTRATROP
 72H  23/0000Z 44.5N  45.5W   35 KT  40 MPH...POST-TROP/EXTRATROP
 96H  24/0000Z...ABSORBED BY ANOTHER EXTRATROPICAL LOW
 
$$
FORECASTER BERG
 

WTNT43 KNHC 200839
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   3
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
500 AM AST WED JUN 20 2012
 
CHRIS CONTINUES TO PRODUCE A COMMA-SHAPED BAND OF HEAVY SHOWERS THAT
IS WRAPPING AROUND THE NORTHERN AND EASTERN PORTION OF THE
CIRCULATION.  GIVEN THAT THE SATELLITE-OBSERVED STRUCTURE OF THE
STORM HAS SHOWN LITTLE CHANGE AND DVORAK INTENSITY ESTIMATES ARE
ALSO UNCHANGED SINCE THE PREVIOUS ADVISORY...THE CURRENT INTENSITY
IS MAINTAINED AT 40 KT.  CHRIS WILL BE MOVING OVER RELATIVELY COOL
WATERS AND IN AN ENVIRONMENT OF MODERATE SHEAR FOR THE NEXT DAY OR
SO...SO LITTLE CHANGE IN STRENGTH IS FORECAST FOR THE EARLY PART OF
THE FORECAST PERIOD.  BY 36 HOURS...THE GLOBAL MODELS INDICATE THAT
THE CYCLONE WILL BECOME INVOLVED WITH A FRONTAL ZONE SO
EXTRATROPICAL TRANSITION IS FORECAST TO OCCUR AROUND THAT TIME. 
SOME SLIGHT INTENSIFICATION DUE TO BAROCLINIC PROCESSES IS POSSIBLE
WITHIN A COUPLE OF DAYS.  HOWEVER...LATER IN THE FORECAST PERIOD...
THE POST-TROPICAL CYCLONE IS FORECAST TO WEAKEN AND MERGE WITH
ANOTHER EXTRATROPICAL CYCLONE OVER THE NORTH ATLANTIC.

THE FORWARD MOTION HAS ACCELERATED TO 100/15.  THE CYCLONE IS
EMBEDDED WITHIN AN AMPLIFYING MID-TROPOSPHERIC TROUGH...AND A
CLOSED LOW IS DEVELOPING OVER THE NORTHERN PORTION OF THIS TROUGH. 
CHRIS SHOULD ACCELERATE EASTWARD TO EAST-NORTHEASTWARD AROUND THE
SOUTHERN PORTION OF THE LOW TODAY...AND AFTERWARDS THE POST-TROPICAL
CYCLONE IS LIKELY TO CURVE CYCLONICALLY AROUND THE EASTERN AND
NORTHERN PORTIONS OF THE LOW.  THE OFFICIAL FORECAST IS FAIRLY
CLOSE TO THE LATEST DYNAMICAL MODEL CONSENSUS.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  20/0900Z 38.2N  53.5W   40 KT  45 MPH
 12H  20/1800Z 38.3N  50.4W   40 KT  45 MPH
 24H  21/0600Z 39.6N  45.7W   40 KT  45 MPH
 36H  21/1800Z 42.0N  42.7W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  22/0600Z 44.0N  43.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
 72H  23/0600Z 44.0N  45.5W   35 KT  40 MPH...POST-TROP/EXTRATROP
 96H  24/0600Z...MERGED WITH ANOTHER EXTRATROPICAL LOW
 
$$
FORECASTER PASCH
 

WTNT43 KNHC 201441
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   4
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
1100 AM AST WED JUN 20 2012
 
THE SATELLITE APPEARANCE OF CHRIS HAS IMPROVED SINCE YESTERDAY.
THE TROPICAL CYCLONE HAS BECOME MORE SYMMETRIC WITH SEVERAL BANDS
OF SHOWERS WRAPPING AROUND THE CENTER.  THE LATEST DVORAK INTENSITY
ESTIMATE FROM TAFB AND RECENT UW/CIMSS ADVANCED DVORAK TECHNIQUE
T-NUMBERS SUPPORT AN INITIAL WIND SPEED OF 45 KT.  ENVIRONMENTAL
CONDITIONS ARE EXPECTED TO REMAIN MARGINALLY CONDUCIVE FOR SOME
SLIGHT STRENGTHENING DURING THE NEXT 12-18 HOURS.  AFTER THAT
TIME...CHRIS WILL BE INTERACTING WITH A FRONTAL BOUNDARY AND MOVING
OVER MUCH COLDER WATERS. HOWEVER...THE GLOBAL MODELS INDICATE THAT
THE CYCLONE WILL INITIALLY MAINTAIN ITS STRENGTH AS AN
EXTRATROPICAL CYCLONE...BEFORE WEAKENING IN 2-3 DAYS.  RECENT RUNS
OF THE GLOBAL MODELS SUGGEST THAT THE POST-TROPICAL LOW COULD
REMAIN THE DOMINANT SYSTEM AND NOT BE THE ONE ABSORBED BY ANOTHER
EXTRATROPICAL LOW.  FOR NOW THE NHC FORECAST WILL CONTINUE TO CALL
FOR POST-TROPICAL CHRIS TO BE ABSORBED...BUT CHANGES TO THIS
SCENARIO MAY BE REQUIRED IF MODEL TRENDS CONTINUE.
 
CHRIS APPEARS TO HAVE TURNED EASTWARD WITH AN INITIAL MOTION OF
090/19 KT.  THE OFFICIAL FORECAST REASONING REMAINS UNCHANGED FROM
THE PREVIOUS ADVISORY.  CHRIS IS EXPECTED TO TURN TOWARD THE
NORTHEAST...THEN NORTHWARD WITHIN THE NEXT 24-36 HOURS AS A CLOSED
LOW FORMS OVER THE NORTH ATLANTIC. LATER IN THE PERIOD...THE
POST-TROPICAL CYCLONE IS FORECAST TO ROTATE CYCLONICALLY AROUND THE
UPPER-LEVEL LOW.  THE NHC FORECAST IS CLOSE TO THE GFS...
ECMWF...AND ON THE POST-TROPICAL PORTION OF THE TRACK PROVIDED BY
THE NOAA OCEAN PREDICTION CENTER.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  20/1500Z 38.1N  51.3W   45 KT  50 MPH
 12H  21/0000Z 38.6N  47.6W   50 KT  60 MPH
 24H  21/1200Z 40.5N  43.3W   45 KT  50 MPH
 36H  22/0000Z 43.6N  41.8W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  22/1200Z 45.0N  43.2W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  23/1200Z 43.0N  45.5W   30 KT  35 MPH...POST-TROP/EXTRATROP
 96H  24/1200Z...ABSORBED BY A LARGER EXTRATROPICAL LOW
 
$$
FORECASTER BROWN
 

WTNT43 KNHC 202033
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   5
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
500 PM AST WED JUN 20 2012
 
ALTHOUGH ONLY A FEW BANDING FEATURES ARE SEEN IN INFRARED SATELLITE
PICTURES...VISIBLE IMAGERY SHOWS SEVERAL BANDS OF SHOWERS ROTATING
AROUND THE CENTER.  IN FACT...A RECENT SSMI MICROWAVE IMAGE
REVEALED A RING OF CONVECTION THAT WRAPPED A LITTLE MORE THAN
HALFWAY AROUND THE CENTER.  AN ASCAT PASS THAT ARRIVED SHORTLY
AFTER THE RELEASE OF THE PREVIOUS ADVISORY HAD A COUPLE 40-KT WIND
VECTORS OVER THE SOUTHEASTERN QUADRANT.  GIVEN THE LOW BIAS OF THAT
INSTRUMENT AND THE IMPROVED STRUCTURE IN MICROWAVE IMAGERY SINCE
THAT TIME...THE INITIAL INTENSITY IS INCREASED TO 50 KT.
 
IT IS DOUBTFUL THAT CHRIS WILL STRENGTHEN ANY FURTHER AS A TROPICAL
CYCLONE SINCE IT WILL BE MOVING OVER COLDER WATER WITHIN 12 HOURS. 
THE GLOBAL MODELS CONTINUE TO PREDICT THAT THE CYCLONE WILL
MAINTAIN ITS INTENSITY OR PERHAPS STRENGTHEN A LITTLE AS A
BAROCLINIC SYSTEM ON THURSDAY.  AFTER 36 HOURS...GRADUAL WEAKENING
IS EXPECTED...AND THE SYSTEM IS LIKELY TO MERGE WITH A LARGER
EXTRATROPICAL LOW IN ABOUT 3 DAYS.

CHRIS IS MOVING EASTWARD OR 085 DEGREES AT 18 KT. THE CYCLONE SHOULD
TURN NORTHEASTWARD...THEN NORTHWARD AS AN UPPER-LEVEL TROUGH TO ITS
NORTHWEST CUTS OFF.  THE POST-TROPICAL CYCLONE IS FORECAST TO
ROTATE CYCLONICALLY AROUND THE UPPER-LOW BEFORE THE MERGER TAKES
PLACE.
  
FORECAST POSITIONS AND MAX WINDS
 
INIT  20/2100Z 38.5N  49.0W   50 KT  60 MPH
 12H  21/0600Z 39.4N  45.8W   50 KT  60 MPH
 24H  21/1800Z 41.7N  42.9W   50 KT  60 MPH...POST-TROPICAL
 36H  22/0600Z 44.3N  42.7W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  22/1800Z 44.2N  44.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  23/1800Z 42.5N  43.5W   30 KT  35 MPH...POST-TROP/EXTRATROP
 96H  24/1800Z...DISSIPATED
 
$$
FORECASTER BROWN
 

WTNT43 KNHC 210250
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   6
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
1100 PM AST WED JUN 20 2012
 
CHRIS HAS HAD WHAT COULD BE CONSIDERED AN EYE FOR THE PAST SEVERAL
HOURS.  HOWEVER...SUBJECTIVE AND OBJECTIVE SATELLITE INTENSITY
ESTIMATES DO NOT SUPPORT ANY SIGNIFICANT CHANGE IN STRENGTH.  THE
MAXIMUM WINDS ARE THEREFORE BEING KEPT AT 50 KT.  EVEN IF CHRIS IS
A LITTLE STRONGER...THE CYCLONE IS NOW MOVING OVER SEA SURFACE
TEMPERATURES LESS THAN 22C...AND THE MARINE BOUNDARY LAYER COULD BE
TOO STABLE TO ALLOW STRONGER WINDS TO BE MIXED TO THE OCEAN
SURFACE.

THE INITIAL MOTION IS 075 DEGREES AT 19 KT...AND CHRIS WILL LIKELY
BEGIN TO DECELERATE AND LOOP COUNTERCLOCKWISE WHILE INTERACTING
WITH A DEVELOPING UPPER LOW TO ITS NORTH.  THERE IS VERY LITTLE
DISPARITY BETWEEN THE TRACK MODELS OVER THE NEXT COUPLE OF DAYS. 
THE GLOBAL MODELS ALSO SEEM TO AGREE THAT CHRIS WILL BE ABSORBED BY
OR MERGE WITH ANOTHER EXTRATROPICAL LOW BY 72 HOURS.

THE POST-TROPICAL TRANSITION IS THE TRICKIEST PART OF THE FORECAST. 
THE FSU PHASE SPACE DIAGRAMS STILL ARGUE THAT CHRIS WILL DEVELOP A
DEEPER WARM CORE OVER THE NEXT FEW DAYS.  HOWEVER...THE GFS FIELDS
SHOW CHRIS BEGINNING TO INTERACT WITH A FRONTAL BOUNDARY TO ITS
NORTH IN ABOUT 24 HOURS...ENDING UP ON THE COLD SIDE OF THE
BOUNDARY BY 48 HOURS.  CHRIS COULD BECOME POST-TROPICAL SOMETIME
OVER THE NEXT 24 HOURS IF IT LOSES ITS DEEP CONVECTION...AND IT
SHOULD BE INVOLVED WITH THE FRONT ENOUGH TO BE EXTRATROPICAL BY 36
HOURS.

THE INTENSITY IS EXPECTED TO CHANGE LITTLE OVER THE NEXT 24 HOURS. 
GRADUAL WEAKENING SHOULD START WHEN CHRIS BECOMES EXTRATROPICAL.


FORECAST POSITIONS AND MAX WINDS
 
INIT  21/0300Z 38.9N  46.4W   50 KT  60 MPH
 12H  21/1200Z 40.3N  43.6W   50 KT  60 MPH
 24H  22/0000Z 43.0N  42.1W   50 KT  60 MPH...POST-TROPICAL
 36H  22/1200Z 44.5N  43.2W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  23/0000Z 43.8N  45.4W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  24/0000Z...ABSORBED BY ANOTHER EXTRATROPICAL LOW
 
$$
FORECASTER BERG
 

WTNT43 KNHC 210836
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   7
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
500 AM AST THU JUN 21 2012
 
CHRIS HAS MAINTAINED AN EYE-LIKE FEATURE SURROUNDED BY A RING OF
CONVECTION WITH CLOUD TOP TEMPERATURES OF -50C TO -60C DURING THE
PAST FEW HOURS.  SUBJECTIVE AND OBJECTIVE DVORAK T-NUMBERS ARE
ESSENTIALLY UNCHANGED SINCE THE LAST ADVISORY AND DO NOT SUPPORT A
HIGHER INTENSITY...SO THE INITIAL INTENSITY IS KEPT AT 50 KT. EVEN
IF CHRIS IS STRONGER THAN ESTIMATED...THE PASSAGE OF THE CYCLONE
OVER SUB-22C SEA SURFACE TEMPERATURES COULD BE INHIBITING AN
EFFICIENT CONVECTIVE TRANSPORT OF THE STRONGEST WINDS TO THE
OCEAN SURFACE.
 
THE INITIAL MOTION IS 065/17...WHICH IS A BIT SLOWER AND TO THE LEFT
OF THE PREVIOUS ESTIMATE.  CHRIS IS EXPECTED TO TURN NORTH-
NORTHEASTWARD AND THEN NORTHWARD AS IT DECELERATES AND DUMBBELLS
CYCLONICALLY AROUND A LARGE MID- TO UPPER-LEVEL LOW FORECAST TO CUT
OFF SOUTHEAST OF THE CANADIAN MARITIME PROVINCES DURING THE NEXT
24-36 HOURS. MODEL GUIDANCE GENERALLY SHOWS CHRIS BEING ABSORBED BY
THIS WEATHER FEATURE IN 36-48 HOURS...WITH THE NEW ENTITY
COMPLETING A CYCLONIC LOOP AND THEN MOVING EASTWARD TO EAST-
NORTHEASTWARD OVER THE FAR NORTH ATLANTIC. GLOBAL MODELS ARE IN
GOOD AGREEMENT WITH REGARD TO THIS SCENARIO...AND THE TRACK
FORECAST IS BASICALLY AN UPDATE OF THE PREVIOUS ONE.
 
DESPITE THE FACT THAT CHRIS IS MOVING OVER RATHER COOL WATERS...
A 0505 UTC AMSU PASSES STILL SHOWED THE PRESENCE OF A WELL-DEFINED
MODERATE TO DEEP WARM CORE IN ASSOCIATION WITH THE CYCLONE.
ALTHOUGH CHRIS IS EXPECTED TO MAINTAIN WARM-CORE CHARACTERISTICS
DURING THE NEXT 24 HOURS OR SO...IT COULD LOSE ITS DEEP CONVECTION
WHILE MOVING OVER EVEN COOLER WATERS AND BE DECLARED POST-TROPICAL. 
SHOULD IT MAINTAIN DEEP CONVECTION LONGER...EITHER ITS INTERACTION
WITH A LOW-LEVEL BAROCLINIC ZONE TO THE NORTH AND/OR ITS
INTERACTION WITH THE CUT-OFF LOW TO ITS WEST SHOULD RESULT IN
EXTRATROPICAL TRANSITION IN ABOUT 36 HOURS.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  21/0900Z 39.9N  44.8W   50 KT  60 MPH
 12H  21/1800Z 41.6N  43.1W   50 KT  60 MPH
 24H  22/0600Z 43.6N  43.0W   50 KT  60 MPH...POST-TROPICAL
 36H  22/1800Z 44.3N  44.8W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  23/0600Z 43.0N  46.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  24/0600Z...ABSORBED BY ANOTHER EXTRATROPICAL LOW
 
$$
FORECASTER KIMBERLAIN
 

WTNT43 KNHC 211454
TCDAT3
 
HURRICANE CHRIS DISCUSSION NUMBER   8
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
1100 AM AST THU JUN 21 2012
 
CHRIS HAS MAINTAINED ITS EYE FEATURE THIS MORNING...AND IN FACT THE
SATELLITE SIGNATURE HAS IMPROVED.  A 1111Z SSMIS OVERPASS ALSO
INDICATED A SOLID CLOSED RING ON THE 37 GHZ COLOR COMPOSITE IMAGE. 
THE EYE TEMPERATURE HAS WARMED AND THE COLD INNER CORE CLOUD TOPS
ARE -60C TO -70C...RESULTING IN A DVORAK SATELLITE DATA-T ESTIMATES
OF 4.5 AND CONSTRAINED FINAL T-NUMBERS OF 4.0 FROM BOTH TAFB AND
SAB.  IN ADDITION...NOW THAT THE CIMSS ADT HAS OBJECTIVELY
IDENTIFIED AN EYE SCENE TYPE...THE LAST FEW RAW T-NUMBERS WERE ALSO
4.4 TO 4.5.  BASED ON THESE DATA AND CONSIDERING THE RELATIVELY
COOL SSTS...THE INITIAL INTENSITY IS RAISED TO 65 KT...MAKING CHRIS
THE FIRST HURRICANE OF THE SEASON.  GRADUAL WEAKENING IS STILL
EXPECTED THROUGH THE FORECAST PERIOD AS THE SYSTEM MOVES NORTHWARD
OVER COOLER WATER AND INTO A MORE STABLE AIR MASS.

THE CYCLONE HAS BEGUN ITS EXPECTED TURN TOWARD THE NORTHEAST...AT AN
ESTIMATED 050/17.  DURING THE NEXT 24 HOURS...CHRIS IS EXPECTED TO
LOSE ITS TROPICAL CYCLONE CHARACTERISTICS AS THE CYCLONE TURNS
CYCLONICALLY...NORTHWARD AND NORTHWESTWARD AROUND A LARGER MID- TO
UPPER-LEVEL BAROCLINIC SYSTEM.  AFTERWARD...CHRIS SHOULD ULTIMATELY
TURN TOWARD THE SOUTH AND BECOME ABSORBED WITHIN THE AFOREMENTIONED
MID-LATITUDE LOW IN 48 HOURS.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  21/1500Z 41.1N  43.2W   65 KT  75 MPH
 12H  22/0000Z 42.8N  42.7W   60 KT  70 MPH
 24H  22/1200Z 44.0N  43.6W   50 KT  60 MPH...POST-TROPICAL
 36H  23/0000Z 43.5N  45.3W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  23/1200Z 42.5N  45.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  24/1200Z...DISSIPATED
 
$$
FORECASTER ROBERTS
 

WTNT43 KNHC 212035
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   9
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
500 PM AST THU JUN 21 2012
 
COOLER SEA SURFACE TEMPERATURES OF 19-20C AND A MORE STABLE
THERMODYNAMIC SURROUNDING ENVIRONMENT ARE FINALLY TAKING ITS TOLL
ON CHRIS. CONVENTIONAL SATELLITE AND AMSU-B MICROWAVE IMAGERY
INDICATE THAT THE EYE FEATURE HAS OPENED UP OVER THE EASTERN
PORTION OF THE CYCLONE.  SATELLITE INTENSITY ESTIMATES HAVE COME
DOWN AND THE CIMSS AMSU INTENSITY ESTIMATES SHOW AN INTENSITY BELOW
HURRICANE STRENGTH.  THEREFORE...THE INITIAL INTENSITY WILL BE
LOWERED TO 60 KT FOR THIS ADVISORY.  FURTHER WEAKENING IS EXPECTED
AND CHRIS IS FORECAST TO LOSE ITS TROPICAL CYCLONE CHARACTERISTICS
IN ABOUT 12 HOURS.  GLOBAL MODELS CONTINUE TO SHOW CHRIS BECOMING
ABSORBED BY A LARGER BAROCLINIC LOW IN 48 HOURS...AND THE OFFICIAL
FORECAST REFLECTS THIS SCENARIO.
 
THE CYCLONE IS MOVING IN A GENERAL NORTHWARD MOTION...015/12 KT.
CHRIS IS FORECAST TO MOVE NORTHWESTWARD...THEN WESTWARD DURING THE
NEXT 24 HOURS IN THE PERIPHERAL FLOW OF A MID- TO UPPER-LEVEL LOW. 
A SUBSEQUENT TURN TOWARD THE SOUTH COULD FOLLOW...WITH CHRIS BEING
ABSORBED WITHIN THE LARGER LOW IN 48 HOURS OR LESS.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  21/2100Z 42.4N  42.9W   60 KT  70 MPH
 12H  22/0600Z 43.9N  43.2W   50 KT  60 MPH...POST-TROPICAL
 24H  22/1800Z 43.8N  44.9W   45 KT  50 MPH...POST-TROP/EXTRATROP
 36H  23/0600Z 42.8N  44.9W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  23/1800Z...ABSORBED BY ANOTHER EXTRATROPICAL LOW
 
$$
FORECASTER ROBERTS
 

WTNT43 KNHC 220246
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER  10
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
1100 PM AST THU JUN 21 2012
 
TROPICAL STORM CHRIS RETAINS A TIGHT CIRCULATION THIS EVENING AS
BEST OBSERVED BY A 2349Z METOP-A MICROWAVE SATELLITE IMAGE FROM THE
NRL WEBSITE.  AS THE CONVECTION IN THE INNER CORE HAS WARMED...THE
DVORAK TECHNIQUE CANNOT PROVIDE A DATA-T NUMBER FOR INTENSITY
ESTIMATES.  THE MODEL EXPECTED T-NUMBER FROM SAB AND TAFB PROVIDE A
RANGE BETWEEN 45 AND 65 KT.  A 2221Z AMSU PASS SUGGESTED AN
INTENSITY AROUND 55 KT FROM THE CIMSS TECHNIQUE.  THE CURRENT
INTENSITY IS ASSESSED AT 55 KT...THOUGH WITH SUBSTANTIAL
UNCERTAINTY.  THE CYCLONE SHOULD GRADUALLY SPIN DOWN WHILE OVER
QUITE CHILLY WATERS AND IT IS LIKELY THAT IT WILL BECOME A
POST-TROPICAL CYCLONE IN ABOUT 12 HOURS...OR SOONER...IF RELATIVELY
DEEP CONVECTION DOES NOT REDEVELOP OVER THE SYSTEM.
 
CHRIS IS MOVING NORTHWARD AT ABOUT 12 KT.  THE TROPICAL STORM SHOULD
TURN TOWARD THE SOUTHWEST WITHIN A DAY AS IT IS ADVECTED AROUND
THE PERIPHERY OF A LARGE DEEP-LAYER CYCLONE.  A SECONDARY SURFACE
LOW CURRENTLY SOUTHWEST OF CHRIS IS PROJECTED BY ALL OF THE
DYNAMICAL MODELS...EXCEPT FOR HWRF...TO ABSORB THE CIRCULATION OF
CHRIS IN ABOUT 24-36 HOURS.  THE FORECAST TRACK IS NEAR THE
CONSENSUS OF THE DYNAMICAL MODELS AND SLIGHTLY TO THE WEST OF THE
PREVIOUS ADVISORY.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  22/0300Z 43.6N  42.9W   55 KT  65 MPH
 12H  22/1200Z 44.2N  44.0W   50 KT  60 MPH...POST-TROPICAL
 24H  23/0000Z 43.0N  45.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
 36H  23/1200Z...DISSIPATED
 
$$
FORECASTER LANDSEA
 

WTNT43 KNHC 220836
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER  11
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
500 AM AST FRI JUN 22 2012
 
CHRIS CONTINUES TO WEAKEN AND IS TRANSITIONING TO A POST-TROPICAL
CYCLONE OVER THE NORTH ATLANTIC. SATELLITE IMAGES INDICATE THAT THE
STORM IS NOW DEVOID OF DEEP CONVECTION AND ONLY CONSISTS OF A TIGHT
SWIRL OF LOW- TO MID-LEVEL CLOUDS. THE INITIAL INTENSITY IS LOWERED
TO 45 KT...FOLLOWING THE DOWNWARD TREND IN THE DVORAK
CLASSIFICATIONS. CHRIS IS FORECAST TO WEAKEN FURTHER AND WILL
LIKELY COMPLETE ITS TRANSITION TO A POST-TROPICAL CYCLONE LATER
THIS MORNING.
 
THE CYCLONE HAS TURNED TO THE NORTHWEST AND THE LATEST INITIAL
MOTION ESTIMATE IS 315/12. CHRIS...OR ITS POST-TROPICAL
REMNANT...IS EXPECTED TO ROTATE COUNTER-CLOCKWISE AROUND A LARGER
EXTRATROPICAL LOW CURRENTLY LOCATED A FEW HUNDRED N MI TO ITS
SOUTH. THIS LARGER LOW WILL ULTIMATELY ABSORB WHATEVER IS LEFT OF
CHRIS IN 24 TO 36 HOURS.  THE OFFICIAL FORECAST FOLLOWS THE
GUIDANCE PROVIDED BY THE OCEAN PREDICTION CENTER.
 
THE 34-KT WIND RADII HAVE BEEN MODIFIED BASED ON AN OSCAT PASS
AROUND 0200 UTC.

FORECAST POSITIONS AND MAX WINDS
 
INIT  22/0900Z 44.8N  44.5W   45 KT  50 MPH
 12H  22/1800Z 44.3N  45.7W   40 KT  45 MPH...POST-TROPICAL
 24H  23/0600Z 43.2N  45.5W   35 KT  40 MPH...POST-TROP/EXTRATROP
 36H  23/1800Z...DISSIPATED
 
$$
FORECASTER CANGIALOSI
 

WTNT43 KNHC 192055
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   1
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
500 PM EDT TUE JUN 19 2012
 
CONVECTION ASSOCIATED WITH THE LOW PRESSURE AREA LOCATED WELL
SOUTHEAST OF THE CANADIAN MARITIMES HAS ACQUIRED ENOUGH ORGANIZATION
AND COVERAGE FOR THE SYSTEM TO BE CLASSIFIED AS A TROPICAL CYCLONE.
THIS IS SUPPORTED BY RECENT DVORAK CLASSIFICATIONS OF T2.5 FROM
TAFB AND T1.5 FROM SAB.  FSU CYCLONE PHASE SPACE DIAGRAMS ALSO SHOW
THE SYSTEM AS A SYMMETRIC WARM CORE...ALBEIT SHALLOW...SYSTEM.  THE
INITIAL WIND SPEED OF 40 KT IS BASED ON EARLIER SCATTEROMETER DATA
AND A SHIP THAT REPORTED 35-KT WINDS TO THE SOUTHEAST OF THE CENTER
THIS MORNING.
 
THE INITIAL MOTION ESTIMATE IS 090/7.  THE TROPICAL STORM IS
FORECAST TO ACCELERATE EASTWARD IN THE MID-LATITUDE WESTERLY
FLOW DURING THE NEXT DAY OR SO.  AFTER THAT TIME...IT IS FORECAST
TO TURN NORTHEASTWARD...THEN NORTHWARD AROUND A DEVELOPING CUT-OFF
LOW.  THE TRACK GUIDANCE IS IN GOOD AGREEMENT ON THIS GENERAL
SCENARIO...BUT THERE IS SOME SPREAD AS TO HOW SHARP THE CYCLONE
TURNS NORTHWARD.  FOR NOW...THE OFFICIAL FORECAST LIES NEAR THE
MIDDLE OF THE GUIDANCE ENVELOPE...BETWEEN THE GFS AND ECMWF 
MODELS.
 
LITTLE CHANGE IN STRENGTH IS EXPECTED DURING THE NEXT DAY OR SO AS
CHRIS TRAVERSES THE MARGINALLY WARM WATERS NEAR THE SOUTHERN EDGE
OF THE GULF STREAM.  THE CYCLONE SHOULD MOVE OVER COLDER WATERS IN
36-48 HOURS...ALTHOUGH GLOBAL MODELS SHOW THE LOW STRENGTHENING AS
A BAROCLINIC SYSTEM AT THAT TIME.  THE CYCLONE IS LIKELY TO BE
ABSORBED BY A LARGER EXTRATROPICAL LOW PRESSURE AREA IN 3 TO 4
DAYS...AND THIS IS REFLECTED IN THE NHC FORECAST.

ONLY TWICE BEFORE...IN 1887 AND 1959...HAS THE THIRD STORM OF THE
SEASON FORMED EARLIER THAN THIS DATE.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  19/2100Z 39.3N  57.7W   40 KT  45 MPH
 12H  20/0600Z 39.2N  54.8W   40 KT  45 MPH
 24H  20/1800Z 39.5N  50.5W   40 KT  45 MPH
 36H  21/0600Z 40.9N  46.1W   40 KT  45 MPH...POST-TROP/EXTRATROP
 48H  21/1800Z 43.3N  44.1W   45 KT  50 MPH...POST-TROP/EXTRATROP
 72H  22/1800Z 45.5N  45.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 96H  23/1800Z...ABSORBED BY EXTRATROPICAL LOW
 
$$
FORECASTER BROWN
 

WTNT43 KNHC 200247
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   2
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
1100 PM AST TUE JUN 19 2012
 
CHRIS IS PRODUCING A CURLED...COMPACT AREA OF DEEP CONVECTION THAT
IS DISPLACED JUST TO THE EAST AND SOUTHEAST OF THE LOW-LEVEL
CENTER.  TAFB AND SAB PROVIDED DVORAK ESTIMATES OF 35 KT...AND THE
LATEST UW-CIMSS ADT IS ABOUT 40 KT.  SINCE THE OVERALL ORGANIZATION
HAS CHANGED LITTLE SINCE THIS AFTERNOON...THE INTENSITY WILL BE
HELD AT 40 KT.
 
CHRIS IS EMBEDDED WITHIN A DIGGING MID- TO UPPER-LEVEL TROUGH...SO
IT IS NOW MOVING TOWARD THE EAST-SOUTHEAST AT A FASTER SPEED...OR
110/11 KT.  A CLOSED LOW IS FORECAST TO DEVELOP AT THE NORTHERN END
OF THE TROUGH OVER THE NEXT 24 TO 48 HOURS...WHICH WILL ENHANCE THE
MID-LATITUDE WESTERLY FLOW AND CAUSE CHRIS TO FURTHER ACCELERATE
TOWARD THE EAST AND EAST-NORTHEAST THROUGH EARLY THURSDAY.  AFTER
THE LOW CLOSES OFF AND STALLS...CHRIS WILL BEGIN TO LOOP
CYCLONICALLY AROUND THE LOW BY 48 AND 72 HOURS.  THE TRACK MODELS
ALL AGREE ON THIS SCENARIO.  THE GFS AND ECMWF LIE ON THE WESTERN
SIDE OF THE ENVELOPE WHILE THE GFDL AND HWRF LIE ON THE EASTERN
SIDE.  GIVEN THE MID-LATITUDE ENVIRONMENT...THE NHC FORECAST LEANS
MORE HEAVILY TOWARD THE GLOBAL MODEL SOLUTIONS.  DISSIPATION IS
FORECAST BY 96 HOURS WHEN CHRIS SHOULD BE FULLY ABSORBED WITHIN THE
CLOSED LOW.
 
THE GLOBAL MODEL GUIDANCE DOES NOT PROVIDE A CLEAR-CUT ANSWER OF
WHEN EXTRATROPICAL TRANSITION WILL END.  THE FSU PHASE-SPACE
DIAGRAMS BASED OFF THE GFS SUGGEST THAT THE THERMAL STRUCTURE WILL
BECOME INCREASINGLY ASYMMETRIC WITH A SHALLOWER WARM CORE DURING
THE NEXT 24 HOURS.  THEREAFTER...THE DIAGRAMS INDICATE THAT CHRIS
WILL AGAIN DEVELOP A DEEPER WARM CORE...BUT THIS MOST LIKELY IS
REPRESENTATIVE OF AN EXTRATROPICAL WARM SECLUSION.  ON THIS
BASIS...CHRIS IS FORECAST TO BE FULLY EXTRATROPICAL BY 36 HOURS. 
DUE TO RELATIVELY COOL SEA SURFACE TEMPERATURES AND MODERATE
VERTICAL SHEAR...CHRIS IS EXPECTED TO CHANGE LITTLE IN STRENGTH
UNTIL IT BECOMES EXTRATROPICAL AND FEEDS OFF BAROCLINIC ENERGY
ASSOCIATED WITH THE CLOSED MID/UPPER-LEVEL LOW.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  20/0300Z 38.8N  56.0W   40 KT  45 MPH
 12H  20/1200Z 38.7N  52.9W   40 KT  45 MPH
 24H  21/0000Z 39.5N  48.4W   40 KT  45 MPH
 36H  21/1200Z 41.4N  44.7W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  22/0000Z 43.7N  43.8W   45 KT  50 MPH...POST-TROP/EXTRATROP
 72H  23/0000Z 44.5N  45.5W   35 KT  40 MPH...POST-TROP/EXTRATROP
 96H  24/0000Z...ABSORBED BY ANOTHER EXTRATROPICAL LOW
 
$$
FORECASTER BERG
 

WTNT43 KNHC 200839
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   3
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
500 AM AST WED JUN 20 2012
 
CHRIS CONTINUES TO PRODUCE A COMMA-SHAPED BAND OF HEAVY SHOWERS THAT
IS WRAPPING AROUND THE NORTHERN AND EASTERN PORTION OF THE
CIRCULATION.  GIVEN THAT THE SATELLITE-OBSERVED STRUCTURE OF THE
STORM HAS SHOWN LITTLE CHANGE AND DVORAK INTENSITY ESTIMATES ARE
ALSO UNCHANGED SINCE THE PREVIOUS ADVISORY...THE CURRENT INTENSITY
IS MAINTAINED AT 40 KT.  CHRIS WILL BE MOVING OVER RELATIVELY COOL
WATERS AND IN AN ENVIRONMENT OF MODERATE SHEAR FOR THE NEXT DAY OR
SO...SO LITTLE CHANGE IN STRENGTH IS FORECAST FOR THE EARLY PART OF
THE FORECAST PERIOD.  BY 36 HOURS...THE GLOBAL MODELS INDICATE THAT
THE CYCLONE WILL BECOME INVOLVED WITH A FRONTAL ZONE SO
EXTRATROPICAL TRANSITION IS FORECAST TO OCCUR AROUND THAT TIME. 
SOME SLIGHT INTENSIFICATION DUE TO BAROCLINIC PROCESSES IS POSSIBLE
WITHIN A COUPLE OF DAYS.  HOWEVER...LATER IN THE FORECAST PERIOD...
THE POST-TROPICAL CYCLONE IS FORECAST TO WEAKEN AND MERGE WITH
ANOTHER EXTRATROPICAL CYCLONE OVER THE NORTH ATLANTIC.

THE FORWARD MOTION HAS ACCELERATED TO 100/15.  THE CYCLONE IS
EMBEDDED WITHIN AN AMPLIFYING MID-TROPOSPHERIC TROUGH...AND A
CLOSED LOW IS DEVELOPING OVER THE NORTHERN PORTION OF THIS TROUGH. 
CHRIS SHOULD ACCELERATE EASTWARD TO EAST-NORTHEASTWARD AROUND THE
SOUTHERN PORTION OF THE LOW TODAY...AND AFTERWARDS THE POST-TROPICAL
CYCLONE IS LIKELY TO CURVE CYCLONICALLY AROUND THE EASTERN AND
NORTHERN PORTIONS OF THE LOW.  THE OFFICIAL FORECAST IS FAIRLY
CLOSE TO THE LATEST DYNAMICAL MODEL CONSENSUS.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  20/0900Z 38.2N  53.5W   40 KT  45 MPH
 12H  20/1800Z 38.3N  50.4W   40 KT  45 MPH
 24H  21/0600Z 39.6N  45.7W   40 KT  45 MPH
 36H  21/1800Z 42.0N  42.7W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  22/0600Z 44.0N  43.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
 72H  23/0600Z 44.0N  45.5W   35 KT  40 MPH...POST-TROP/EXTRATROP
 96H  24/0600Z...MERGED WITH ANOTHER EXTRATROPICAL LOW
 
$$
FORECASTER PASCH
 

WTNT43 KNHC 201441
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   4
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
1100 AM AST WED JUN 20 2012
 
THE SATELLITE APPEARANCE OF CHRIS HAS IMPROVED SINCE YESTERDAY.
THE TROPICAL CYCLONE HAS BECOME MORE SYMMETRIC WITH SEVERAL BANDS
OF SHOWERS WRAPPING AROUND THE CENTER.  THE LATEST DVORAK INTENSITY
ESTIMATE FROM TAFB AND RECENT UW/CIMSS ADVANCED DVORAK TECHNIQUE
T-NUMBERS SUPPORT AN INITIAL WIND SPEED OF 45 KT.  ENVIRONMENTAL
CONDITIONS ARE EXPECTED TO REMAIN MARGINALLY CONDUCIVE FOR SOME
SLIGHT STRENGTHENING DURING THE NEXT 12-18 HOURS.  AFTER THAT
TIME...CHRIS WILL BE INTERACTING WITH A FRONTAL BOUNDARY AND MOVING
OVER MUCH COLDER WATERS. HOWEVER...THE GLOBAL MODELS INDICATE THAT
THE CYCLONE WILL INITIALLY MAINTAIN ITS STRENGTH AS AN
EXTRATROPICAL CYCLONE...BEFORE WEAKENING IN 2-3 DAYS.  RECENT RUNS
OF THE GLOBAL MODELS SUGGEST THAT THE POST-TROPICAL LOW COULD
REMAIN THE DOMINANT SYSTEM AND NOT BE THE ONE ABSORBED BY ANOTHER
EXTRATROPICAL LOW.  FOR NOW THE NHC FORECAST WILL CONTINUE TO CALL
FOR POST-TROPICAL CHRIS TO BE ABSORBED...BUT CHANGES TO THIS
SCENARIO MAY BE REQUIRED IF MODEL TRENDS CONTINUE.
 
CHRIS APPEARS TO HAVE TURNED EASTWARD WITH AN INITIAL MOTION OF
090/19 KT.  THE OFFICIAL FORECAST REASONING REMAINS UNCHANGED FROM
THE PREVIOUS ADVISORY.  CHRIS IS EXPECTED TO TURN TOWARD THE
NORTHEAST...THEN NORTHWARD WITHIN THE NEXT 24-36 HOURS AS A CLOSED
LOW FORMS OVER THE NORTH ATLANTIC. LATER IN THE PERIOD...THE
POST-TROPICAL CYCLONE IS FORECAST TO ROTATE CYCLONICALLY AROUND THE
UPPER-LEVEL LOW.  THE NHC FORECAST IS CLOSE TO THE GFS...
ECMWF...AND ON THE POST-TROPICAL PORTION OF THE TRACK PROVIDED BY
THE NOAA OCEAN PREDICTION CENTER.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  20/1500Z 38.1N  51.3W   45 KT  50 MPH
 12H  21/0000Z 38.6N  47.6W   50 KT  60 MPH
 24H  21/1200Z 40.5N  43.3W   45 KT  50 MPH
 36H  22/0000Z 43.6N  41.8W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  22/1200Z 45.0N  43.2W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  23/1200Z 43.0N  45.5W   30 KT  35 MPH...POST-TROP/EXTRATROP
 96H  24/1200Z...ABSORBED BY A LARGER EXTRATROPICAL LOW
 
$$
FORECASTER BROWN
 


WTNT43 KNHC 202033
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   5
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
500 PM AST WED JUN 20 2012
 
ALTHOUGH ONLY A FEW BANDING FEATURES ARE SEEN IN INFRARED SATELLITE
PICTURES...VISIBLE IMAGERY SHOWS SEVERAL BANDS OF SHOWERS ROTATING
AROUND THE CENTER.  IN FACT...A RECENT SSMI MICROWAVE IMAGE
REVEALED A RING OF CONVECTION THAT WRAPPED A LITTLE MORE THAN
HALFWAY AROUND THE CENTER.  AN ASCAT PASS THAT ARRIVED SHORTLY
AFTER THE RELEASE OF THE PREVIOUS ADVISORY HAD A COUPLE 40-KT WIND
VECTORS OVER THE SOUTHEASTERN QUADRANT.  GIVEN THE LOW BIAS OF THAT
INSTRUMENT AND THE IMPROVED STRUCTURE IN MICROWAVE IMAGERY SINCE
THAT TIME...THE INITIAL INTENSITY IS INCREASED TO 50 KT.
 
IT IS DOUBTFUL THAT CHRIS WILL STRENGTHEN ANY FURTHER AS A TROPICAL
CYCLONE SINCE IT WILL BE MOVING OVER COLDER WATER WITHIN 12 HOURS. 
THE GLOBAL MODELS CONTINUE TO PREDICT THAT THE CYCLONE WILL
MAINTAIN ITS INTENSITY OR PERHAPS STRENGTHEN A LITTLE AS A
BAROCLINIC SYSTEM ON THURSDAY.  AFTER 36 HOURS...GRADUAL WEAKENING
IS EXPECTED...AND THE SYSTEM IS LIKELY TO MERGE WITH A LARGER
EXTRATROPICAL LOW IN ABOUT 3 DAYS.

CHRIS IS MOVING EASTWARD OR 085 DEGREES AT 18 KT. THE CYCLONE SHOULD
TURN NORTHEASTWARD...THEN NORTHWARD AS AN UPPER-LEVEL TROUGH TO ITS
NORTHWEST CUTS OFF.  THE POST-TROPICAL CYCLONE IS FORECAST TO
ROTATE CYCLONICALLY AROUND THE UPPER-LOW BEFORE THE MERGER TAKES
PLACE.
  
FORECAST POSITIONS AND MAX WINDS
 
INIT  20/2100Z 38.5N  49.0W   50 KT  60 MPH
 12H  21/0600Z 39.4N  45.8W   50 KT  60 MPH
 24H  21/1800Z 41.7N  42.9W   50 KT  60 MPH...POST-TROPICAL
 36H  22/0600Z 44.3N  42.7W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  22/1800Z 44.2N  44.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  23/1800Z 42.5N  43.5W   30 KT  35 MPH...POST-TROP/EXTRATROP
 96H  24/1800Z...DISSIPATED
 
$$
FORECASTER BROWN
 

WTNT43 KNHC 210250
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   6
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
1100 PM AST WED JUN 20 2012
 
CHRIS HAS HAD WHAT COULD BE CONSIDERED AN EYE FOR THE PAST SEVERAL
HOURS.  HOWEVER...SUBJECTIVE AND OBJECTIVE SATELLITE INTENSITY
ESTIMATES DO NOT SUPPORT ANY SIGNIFICANT CHANGE IN STRENGTH.  THE
MAXIMUM WINDS ARE THEREFORE BEING KEPT AT 50 KT.  EVEN IF CHRIS IS
A LITTLE STRONGER...THE CYCLONE IS NOW MOVING OVER SEA SURFACE
TEMPERATURES LESS THAN 22C...AND THE MARINE BOUNDARY LAYER COULD BE
TOO STABLE TO ALLOW STRONGER WINDS TO BE MIXED TO THE OCEAN
SURFACE.

THE INITIAL MOTION IS 075 DEGREES AT 19 KT...AND CHRIS WILL LIKELY
BEGIN TO DECELERATE AND LOOP COUNTERCLOCKWISE WHILE INTERACTING
WITH A DEVELOPING UPPER LOW TO ITS NORTH.  THERE IS VERY LITTLE
DISPARITY BETWEEN THE TRACK MODELS OVER THE NEXT COUPLE OF DAYS. 
THE GLOBAL MODELS ALSO SEEM TO AGREE THAT CHRIS WILL BE ABSORBED BY
OR MERGE WITH ANOTHER EXTRATROPICAL LOW BY 72 HOURS.

THE POST-TROPICAL TRANSITION IS THE TRICKIEST PART OF THE FORECAST. 
THE FSU PHASE SPACE DIAGRAMS STILL ARGUE THAT CHRIS WILL DEVELOP A
DEEPER WARM CORE OVER THE NEXT FEW DAYS.  HOWEVER...THE GFS FIELDS
SHOW CHRIS BEGINNING TO INTERACT WITH A FRONTAL BOUNDARY TO ITS
NORTH IN ABOUT 24 HOURS...ENDING UP ON THE COLD SIDE OF THE
BOUNDARY BY 48 HOURS.  CHRIS COULD BECOME POST-TROPICAL SOMETIME
OVER THE NEXT 24 HOURS IF IT LOSES ITS DEEP CONVECTION...AND IT
SHOULD BE INVOLVED WITH THE FRONT ENOUGH TO BE EXTRATROPICAL BY 36
HOURS.

THE INTENSITY IS EXPECTED TO CHANGE LITTLE OVER THE NEXT 24 HOURS. 
GRADUAL WEAKENING SHOULD START WHEN CHRIS BECOMES EXTRATROPICAL.


FORECAST POSITIONS AND MAX WINDS
 
INIT  21/0300Z 38.9N  46.4W   50 KT  60 MPH
 12H  21/1200Z 40.3N  43.6W   50 KT  60 MPH
 24H  22/0000Z 43.0N  42.1W   50 KT  60 MPH...POST-TROPICAL
 36H  22/1200Z 44.5N  43.2W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  23/0000Z 43.8N  45.4W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  24/0000Z...ABSORBED BY ANOTHER EXTRATROPICAL LOW
 
$$
FORECASTER BERG
 

WTNT43 KNHC 210836
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   7
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
500 AM AST THU JUN 21 2012
 
CHRIS HAS MAINTAINED AN EYE-LIKE FEATURE SURROUNDED BY A RING OF
CONVECTION WITH CLOUD TOP TEMPERATURES OF -50C TO -60C DURING THE
PAST FEW HOURS.  SUBJECTIVE AND OBJECTIVE DVORAK T-NUMBERS ARE
ESSENTIALLY UNCHANGED SINCE THE LAST ADVISORY AND DO NOT SUPPORT A
HIGHER INTENSITY...SO THE INITIAL INTENSITY IS KEPT AT 50 KT. EVEN
IF CHRIS IS STRONGER THAN ESTIMATED...THE PASSAGE OF THE CYCLONE
OVER SUB-22C SEA SURFACE TEMPERATURES COULD BE INHIBITING AN
EFFICIENT CONVECTIVE TRANSPORT OF THE STRONGEST WINDS TO THE
OCEAN SURFACE.
 
THE INITIAL MOTION IS 065/17...WHICH IS A BIT SLOWER AND TO THE LEFT
OF THE PREVIOUS ESTIMATE.  CHRIS IS EXPECTED TO TURN NORTH-
NORTHEASTWARD AND THEN NORTHWARD AS IT DECELERATES AND DUMBBELLS
CYCLONICALLY AROUND A LARGE MID- TO UPPER-LEVEL LOW FORECAST TO CUT
OFF SOUTHEAST OF THE CANADIAN MARITIME PROVINCES DURING THE NEXT
24-36 HOURS. MODEL GUIDANCE GENERALLY SHOWS CHRIS BEING ABSORBED BY
THIS WEATHER FEATURE IN 36-48 HOURS...WITH THE NEW ENTITY
COMPLETING A CYCLONIC LOOP AND THEN MOVING EASTWARD TO EAST-
NORTHEASTWARD OVER THE FAR NORTH ATLANTIC. GLOBAL MODELS ARE IN
GOOD AGREEMENT WITH REGARD TO THIS SCENARIO...AND THE TRACK
FORECAST IS BASICALLY AN UPDATE OF THE PREVIOUS ONE.
 
DESPITE THE FACT THAT CHRIS IS MOVING OVER RATHER COOL WATERS...
A 0505 UTC AMSU PASSES STILL SHOWED THE PRESENCE OF A WELL-DEFINED
MODERATE TO DEEP WARM CORE IN ASSOCIATION WITH THE CYCLONE.
ALTHOUGH CHRIS IS EXPECTED TO MAINTAIN WARM-CORE CHARACTERISTICS
DURING THE NEXT 24 HOURS OR SO...IT COULD LOSE ITS DEEP CONVECTION
WHILE MOVING OVER EVEN COOLER WATERS AND BE DECLARED POST-TROPICAL. 
SHOULD IT MAINTAIN DEEP CONVECTION LONGER...EITHER ITS INTERACTION
WITH A LOW-LEVEL BAROCLINIC ZONE TO THE NORTH AND/OR ITS
INTERACTION WITH THE CUT-OFF LOW TO ITS WEST SHOULD RESULT IN
EXTRATROPICAL TRANSITION IN ABOUT 36 HOURS.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  21/0900Z 39.9N  44.8W   50 KT  60 MPH
 12H  21/1800Z 41.6N  43.1W   50 KT  60 MPH
 24H  22/0600Z 43.6N  43.0W   50 KT  60 MPH...POST-TROPICAL
 36H  22/1800Z 44.3N  44.8W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  23/0600Z 43.0N  46.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  24/0600Z...ABSORBED BY ANOTHER EXTRATROPICAL LOW
 
$$
FORECASTER KIMBERLAIN
 

WTNT43 KNHC 211454
TCDAT3
 
HURRICANE CHRIS DISCUSSION NUMBER   8
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
1100 AM AST THU JUN 21 2012
 
CHRIS HAS MAINTAINED ITS EYE FEATURE THIS MORNING...AND IN FACT THE
SATELLITE SIGNATURE HAS IMPROVED.  A 1111Z SSMIS OVERPASS ALSO
INDICATED A SOLID CLOSED RING ON THE 37 GHZ COLOR COMPOSITE IMAGE. 
THE EYE TEMPERATURE HAS WARMED AND THE COLD INNER CORE CLOUD TOPS
ARE -60C TO -70C...RESULTING IN A DVORAK SATELLITE DATA-T ESTIMATES
OF 4.5 AND CONSTRAINED FINAL T-NUMBERS OF 4.0 FROM BOTH TAFB AND
SAB.  IN ADDITION...NOW THAT THE CIMSS ADT HAS OBJECTIVELY
IDENTIFIED AN EYE SCENE TYPE...THE LAST FEW RAW T-NUMBERS WERE ALSO
4.4 TO 4.5.  BASED ON THESE DATA AND CONSIDERING THE RELATIVELY
COOL SSTS...THE INITIAL INTENSITY IS RAISED TO 65 KT...MAKING CHRIS
THE FIRST HURRICANE OF THE SEASON.  GRADUAL WEAKENING IS STILL
EXPECTED THROUGH THE FORECAST PERIOD AS THE SYSTEM MOVES NORTHWARD
OVER COOLER WATER AND INTO A MORE STABLE AIR MASS.

THE CYCLONE HAS BEGUN ITS EXPECTED TURN TOWARD THE NORTHEAST...AT AN
ESTIMATED 050/17.  DURING THE NEXT 24 HOURS...CHRIS IS EXPECTED TO
LOSE ITS TROPICAL CYCLONE CHARACTERISTICS AS THE CYCLONE TURNS
CYCLONICALLY...NORTHWARD AND NORTHWESTWARD AROUND A LARGER MID- TO
UPPER-LEVEL BAROCLINIC SYSTEM.  AFTERWARD...CHRIS SHOULD ULTIMATELY
TURN TOWARD THE SOUTH AND BECOME ABSORBED WITHIN THE AFOREMENTIONED
MID-LATITUDE LOW IN 48 HOURS.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  21/1500Z 41.1N  43.2W   65 KT  75 MPH
 12H  22/0000Z 42.8N  42.7W   60 KT  70 MPH
 24H  22/1200Z 44.0N  43.6W   50 KT  60 MPH...POST-TROPICAL
 36H  23/0000Z 43.5N  45.3W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  23/1200Z 42.5N  45.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  24/1200Z...DISSIPATED
 
$$
FORECASTER ROBERTS
 


WTNT43 KNHC 212035
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   9
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
500 PM AST THU JUN 21 2012
 
COOLER SEA SURFACE TEMPERATURES OF 19-20C AND A MORE STABLE
THERMODYNAMIC SURROUNDING ENVIRONMENT ARE FINALLY TAKING ITS TOLL
ON CHRIS. CONVENTIONAL SATELLITE AND AMSU-B MICROWAVE IMAGERY
INDICATE THAT THE EYE FEATURE HAS OPENED UP OVER THE EASTERN
PORTION OF THE CYCLONE.  SATELLITE INTENSITY ESTIMATES HAVE COME
DOWN AND THE CIMSS AMSU INTENSITY ESTIMATES SHOW AN INTENSITY BELOW
HURRICANE STRENGTH.  THEREFORE...THE INITIAL INTENSITY WILL BE
LOWERED TO 60 KT FOR THIS ADVISORY.  FURTHER WEAKENING IS EXPECTED
AND CHRIS IS FORECAST TO LOSE ITS TROPICAL CYCLONE CHARACTERISTICS
IN ABOUT 12 HOURS.  GLOBAL MODELS CONTINUE TO SHOW CHRIS BECOMING
ABSORBED BY A LARGER BAROCLINIC LOW IN 48 HOURS...AND THE OFFICIAL
FORECAST REFLECTS THIS SCENARIO.
 
THE CYCLONE IS MOVING IN A GENERAL NORTHWARD MOTION...015/12 KT.
CHRIS IS FORECAST TO MOVE NORTHWESTWARD...THEN WESTWARD DURING THE
NEXT 24 HOURS IN THE PERIPHERAL FLOW OF A MID- TO UPPER-LEVEL LOW. 
A SUBSEQUENT TURN TOWARD THE SOUTH COULD FOLLOW...WITH CHRIS BEING
ABSORBED WITHIN THE LARGER LOW IN 48 HOURS OR LESS.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  21/2100Z 42.4N  42.9W   60 KT  70 MPH
 12H  22/0600Z 43.9N  43.2W   50 KT  60 MPH...POST-TROPICAL
 24H  22/1800Z 43.8N  44.9W   45 KT  50 MPH...POST-TROP/EXTRATROP
 36H  23/0600Z 42.8N  44.9W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  23/1800Z...ABSORBED BY ANOTHER EXTRATROPICAL LOW
 
$$
FORECASTER ROBERTS
 

WTNT43 KNHC 220246
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER  10
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
1100 PM AST THU JUN 21 2012
 
TROPICAL STORM CHRIS RETAINS A TIGHT CIRCULATION THIS EVENING AS
BEST OBSERVED BY A 2349Z METOP-A MICROWAVE SATELLITE IMAGE FROM THE
NRL WEBSITE.  AS THE CONVECTION IN THE INNER CORE HAS WARMED...THE
DVORAK TECHNIQUE CANNOT PROVIDE A DATA-T NUMBER FOR INTENSITY
ESTIMATES.  THE MODEL EXPECTED T-NUMBER FROM SAB AND TAFB PROVIDE A
RANGE BETWEEN 45 AND 65 KT.  A 2221Z AMSU PASS SUGGESTED AN
INTENSITY AROUND 55 KT FROM THE CIMSS TECHNIQUE.  THE CURRENT
INTENSITY IS ASSESSED AT 55 KT...THOUGH WITH SUBSTANTIAL
UNCERTAINTY.  THE CYCLONE SHOULD GRADUALLY SPIN DOWN WHILE OVER
QUITE CHILLY WATERS AND IT IS LIKELY THAT IT WILL BECOME A
POST-TROPICAL CYCLONE IN ABOUT 12 HOURS...OR SOONER...IF RELATIVELY
DEEP CONVECTION DOES NOT REDEVELOP OVER THE SYSTEM.
 
CHRIS IS MOVING NORTHWARD AT ABOUT 12 KT.  THE TROPICAL STORM SHOULD
TURN TOWARD THE SOUTHWEST WITHIN A DAY AS IT IS ADVECTED AROUND
THE PERIPHERY OF A LARGE DEEP-LAYER CYCLONE.  A SECONDARY SURFACE
LOW CURRENTLY SOUTHWEST OF CHRIS IS PROJECTED BY ALL OF THE
DYNAMICAL MODELS...EXCEPT FOR HWRF...TO ABSORB THE CIRCULATION OF
CHRIS IN ABOUT 24-36 HOURS.  THE FORECAST TRACK IS NEAR THE
CONSENSUS OF THE DYNAMICAL MODELS AND SLIGHTLY TO THE WEST OF THE
PREVIOUS ADVISORY.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  22/0300Z 43.6N  42.9W   55 KT  65 MPH
 12H  22/1200Z 44.2N  44.0W   50 KT  60 MPH...POST-TROPICAL
 24H  23/0000Z 43.0N  45.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
 36H  23/1200Z...DISSIPATED
 
$$
FORECASTER LANDSEA
 

WTNT43 KNHC 220836
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER  11
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
500 AM AST FRI JUN 22 2012
 
CHRIS CONTINUES TO WEAKEN AND IS TRANSITIONING TO A POST-TROPICAL
CYCLONE OVER THE NORTH ATLANTIC. SATELLITE IMAGES INDICATE THAT THE
STORM IS NOW DEVOID OF DEEP CONVECTION AND ONLY CONSISTS OF A TIGHT
SWIRL OF LOW- TO MID-LEVEL CLOUDS. THE INITIAL INTENSITY IS LOWERED
TO 45 KT...FOLLOWING THE DOWNWARD TREND IN THE DVORAK
CLASSIFICATIONS. CHRIS IS FORECAST TO WEAKEN FURTHER AND WILL
LIKELY COMPLETE ITS TRANSITION TO A POST-TROPICAL CYCLONE LATER
THIS MORNING.
 
THE CYCLONE HAS TURNED TO THE NORTHWEST AND THE LATEST INITIAL
MOTION ESTIMATE IS 315/12. CHRIS...OR ITS POST-TROPICAL
REMNANT...IS EXPECTED TO ROTATE COUNTER-CLOCKWISE AROUND A LARGER
EXTRATROPICAL LOW CURRENTLY LOCATED A FEW HUNDRED N MI TO ITS
SOUTH. THIS LARGER LOW WILL ULTIMATELY ABSORB WHATEVER IS LEFT OF
CHRIS IN 24 TO 36 HOURS.  THE OFFICIAL FORECAST FOLLOWS THE
GUIDANCE PROVIDED BY THE OCEAN PREDICTION CENTER.
 
THE 34-KT WIND RADII HAVE BEEN MODIFIED BASED ON AN OSCAT PASS
AROUND 0200 UTC.

FORECAST POSITIONS AND MAX WINDS
 
INIT  22/0900Z 44.8N  44.5W   45 KT  50 MPH
 12H  22/1800Z 44.3N  45.7W   40 KT  45 MPH...POST-TROPICAL
 24H  23/0600Z 43.2N  45.5W   35 KT  40 MPH...POST-TROP/EXTRATROP
 36H  23/1800Z...DISSIPATED
 
$$
FORECASTER CANGIALOSI
 

WTNT43 KNHC 192055
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   1
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
500 PM EDT TUE JUN 19 2012
 
CONVECTION ASSOCIATED WITH THE LOW PRESSURE AREA LOCATED WELL
SOUTHEAST OF THE CANADIAN MARITIMES HAS ACQUIRED ENOUGH ORGANIZATION
AND COVERAGE FOR THE SYSTEM TO BE CLASSIFIED AS A TROPICAL CYCLONE.
THIS IS SUPPORTED BY RECENT DVORAK CLASSIFICATIONS OF T2.5 FROM
TAFB AND T1.5 FROM SAB.  FSU CYCLONE PHASE SPACE DIAGRAMS ALSO SHOW
THE SYSTEM AS A SYMMETRIC WARM CORE...ALBEIT SHALLOW...SYSTEM.  THE
INITIAL WIND SPEED OF 40 KT IS BASED ON EARLIER SCATTEROMETER DATA
AND A SHIP THAT REPORTED 35-KT WINDS TO THE SOUTHEAST OF THE CENTER
THIS MORNING.
 
THE INITIAL MOTION ESTIMATE IS 090/7.  THE TROPICAL STORM IS
FORECAST TO ACCELERATE EASTWARD IN THE MID-LATITUDE WESTERLY
FLOW DURING THE NEXT DAY OR SO.  AFTER THAT TIME...IT IS FORECAST
TO TURN NORTHEASTWARD...THEN NORTHWARD AROUND A DEVELOPING CUT-OFF
LOW.  THE TRACK GUIDANCE IS IN GOOD AGREEMENT ON THIS GENERAL
SCENARIO...BUT THERE IS SOME SPREAD AS TO HOW SHARP THE CYCLONE
TURNS NORTHWARD.  FOR NOW...THE OFFICIAL FORECAST LIES NEAR THE
MIDDLE OF THE GUIDANCE ENVELOPE...BETWEEN THE GFS AND ECMWF 
MODELS.
 
LITTLE CHANGE IN STRENGTH IS EXPECTED DURING THE NEXT DAY OR SO AS
CHRIS TRAVERSES THE MARGINALLY WARM WATERS NEAR THE SOUTHERN EDGE
OF THE GULF STREAM.  THE CYCLONE SHOULD MOVE OVER COLDER WATERS IN
36-48 HOURS...ALTHOUGH GLOBAL MODELS SHOW THE LOW STRENGTHENING AS
A BAROCLINIC SYSTEM AT THAT TIME.  THE CYCLONE IS LIKELY TO BE
ABSORBED BY A LARGER EXTRATROPICAL LOW PRESSURE AREA IN 3 TO 4
DAYS...AND THIS IS REFLECTED IN THE NHC FORECAST.

ONLY TWICE BEFORE...IN 1887 AND 1959...HAS THE THIRD STORM OF THE
SEASON FORMED EARLIER THAN THIS DATE.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  19/2100Z 39.3N  57.7W   40 KT  45 MPH
 12H  20/0600Z 39.2N  54.8W   40 KT  45 MPH
 24H  20/1800Z 39.5N  50.5W   40 KT  45 MPH
 36H  21/0600Z 40.9N  46.1W   40 KT  45 MPH...POST-TROP/EXTRATROP
 48H  21/1800Z 43.3N  44.1W   45 KT  50 MPH...POST-TROP/EXTRATROP
 72H  22/1800Z 45.5N  45.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 96H  23/1800Z...ABSORBED BY EXTRATROPICAL LOW
 
$$
FORECASTER BROWN
 

WTNT43 KNHC 200247
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   2
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
1100 PM AST TUE JUN 19 2012
 
CHRIS IS PRODUCING A CURLED...COMPACT AREA OF DEEP CONVECTION THAT
IS DISPLACED JUST TO THE EAST AND SOUTHEAST OF THE LOW-LEVEL
CENTER.  TAFB AND SAB PROVIDED DVORAK ESTIMATES OF 35 KT...AND THE
LATEST UW-CIMSS ADT IS ABOUT 40 KT.  SINCE THE OVERALL ORGANIZATION
HAS CHANGED LITTLE SINCE THIS AFTERNOON...THE INTENSITY WILL BE
HELD AT 40 KT.
 
CHRIS IS EMBEDDED WITHIN A DIGGING MID- TO UPPER-LEVEL TROUGH...SO
IT IS NOW MOVING TOWARD THE EAST-SOUTHEAST AT A FASTER SPEED...OR
110/11 KT.  A CLOSED LOW IS FORECAST TO DEVELOP AT THE NORTHERN END
OF THE TROUGH OVER THE NEXT 24 TO 48 HOURS...WHICH WILL ENHANCE THE
MID-LATITUDE WESTERLY FLOW AND CAUSE CHRIS TO FURTHER ACCELERATE
TOWARD THE EAST AND EAST-NORTHEAST THROUGH EARLY THURSDAY.  AFTER
THE LOW CLOSES OFF AND STALLS...CHRIS WILL BEGIN TO LOOP
CYCLONICALLY AROUND THE LOW BY 48 AND 72 HOURS.  THE TRACK MODELS
ALL AGREE ON THIS SCENARIO.  THE GFS AND ECMWF LIE ON THE WESTERN
SIDE OF THE ENVELOPE WHILE THE GFDL AND HWRF LIE ON THE EASTERN
SIDE.  GIVEN THE MID-LATITUDE ENVIRONMENT...THE NHC FORECAST LEANS
MORE HEAVILY TOWARD THE GLOBAL MODEL SOLUTIONS.  DISSIPATION IS
FORECAST BY 96 HOURS WHEN CHRIS SHOULD BE FULLY ABSORBED WITHIN THE
CLOSED LOW.
 
THE GLOBAL MODEL GUIDANCE DOES NOT PROVIDE A CLEAR-CUT ANSWER OF
WHEN EXTRATROPICAL TRANSITION WILL END.  THE FSU PHASE-SPACE
DIAGRAMS BASED OFF THE GFS SUGGEST THAT THE THERMAL STRUCTURE WILL
BECOME INCREASINGLY ASYMMETRIC WITH A SHALLOWER WARM CORE DURING
THE NEXT 24 HOURS.  THEREAFTER...THE DIAGRAMS INDICATE THAT CHRIS
WILL AGAIN DEVELOP A DEEPER WARM CORE...BUT THIS MOST LIKELY IS
REPRESENTATIVE OF AN EXTRATROPICAL WARM SECLUSION.  ON THIS
BASIS...CHRIS IS FORECAST TO BE FULLY EXTRATROPICAL BY 36 HOURS. 
DUE TO RELATIVELY COOL SEA SURFACE TEMPERATURES AND MODERATE
VERTICAL SHEAR...CHRIS IS EXPECTED TO CHANGE LITTLE IN STRENGTH
UNTIL IT BECOMES EXTRATROPICAL AND FEEDS OFF BAROCLINIC ENERGY
ASSOCIATED WITH THE CLOSED MID/UPPER-LEVEL LOW.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  20/0300Z 38.8N  56.0W   40 KT  45 MPH
 12H  20/1200Z 38.7N  52.9W   40 KT  45 MPH
 24H  21/0000Z 39.5N  48.4W   40 KT  45 MPH
 36H  21/1200Z 41.4N  44.7W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  22/0000Z 43.7N  43.8W   45 KT  50 MPH...POST-TROP/EXTRATROP
 72H  23/0000Z 44.5N  45.5W   35 KT  40 MPH...POST-TROP/EXTRATROP
 96H  24/0000Z...ABSORBED BY ANOTHER EXTRATROPICAL LOW
 
$$
FORECASTER BERG
 

WTNT43 KNHC 200839
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   3
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
500 AM AST WED JUN 20 2012
 
CHRIS CONTINUES TO PRODUCE A COMMA-SHAPED BAND OF HEAVY SHOWERS THAT
IS WRAPPING AROUND THE NORTHERN AND EASTERN PORTION OF THE
CIRCULATION.  GIVEN THAT THE SATELLITE-OBSERVED STRUCTURE OF THE
STORM HAS SHOWN LITTLE CHANGE AND DVORAK INTENSITY ESTIMATES ARE
ALSO UNCHANGED SINCE THE PREVIOUS ADVISORY...THE CURRENT INTENSITY
IS MAINTAINED AT 40 KT.  CHRIS WILL BE MOVING OVER RELATIVELY COOL
WATERS AND IN AN ENVIRONMENT OF MODERATE SHEAR FOR THE NEXT DAY OR
SO...SO LITTLE CHANGE IN STRENGTH IS FORECAST FOR THE EARLY PART OF
THE FORECAST PERIOD.  BY 36 HOURS...THE GLOBAL MODELS INDICATE THAT
THE CYCLONE WILL BECOME INVOLVED WITH A FRONTAL ZONE SO
EXTRATROPICAL TRANSITION IS FORECAST TO OCCUR AROUND THAT TIME. 
SOME SLIGHT INTENSIFICATION DUE TO BAROCLINIC PROCESSES IS POSSIBLE
WITHIN A COUPLE OF DAYS.  HOWEVER...LATER IN THE FORECAST PERIOD...
THE POST-TROPICAL CYCLONE IS FORECAST TO WEAKEN AND MERGE WITH
ANOTHER EXTRATROPICAL CYCLONE OVER THE NORTH ATLANTIC.

THE FORWARD MOTION HAS ACCELERATED TO 100/15.  THE CYCLONE IS
EMBEDDED WITHIN AN AMPLIFYING MID-TROPOSPHERIC TROUGH...AND A
CLOSED LOW IS DEVELOPING OVER THE NORTHERN PORTION OF THIS TROUGH. 
CHRIS SHOULD ACCELERATE EASTWARD TO EAST-NORTHEASTWARD AROUND THE
SOUTHERN PORTION OF THE LOW TODAY...AND AFTERWARDS THE POST-TROPICAL
CYCLONE IS LIKELY TO CURVE CYCLONICALLY AROUND THE EASTERN AND
NORTHERN PORTIONS OF THE LOW.  THE OFFICIAL FORECAST IS FAIRLY
CLOSE TO THE LATEST DYNAMICAL MODEL CONSENSUS.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  20/0900Z 38.2N  53.5W   40 KT  45 MPH
 12H  20/1800Z 38.3N  50.4W   40 KT  45 MPH
 24H  21/0600Z 39.6N  45.7W   40 KT  45 MPH
 36H  21/1800Z 42.0N  42.7W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  22/0600Z 44.0N  43.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
 72H  23/0600Z 44.0N  45.5W   35 KT  40 MPH...POST-TROP/EXTRATROP
 96H  24/0600Z...MERGED WITH ANOTHER EXTRATROPICAL LOW
 
$$
FORECASTER PASCH
 

WTNT43 KNHC 201441
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   4
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
1100 AM AST WED JUN 20 2012
 
THE SATELLITE APPEARANCE OF CHRIS HAS IMPROVED SINCE YESTERDAY.
THE TROPICAL CYCLONE HAS BECOME MORE SYMMETRIC WITH SEVERAL BANDS
OF SHOWERS WRAPPING AROUND THE CENTER.  THE LATEST DVORAK INTENSITY
ESTIMATE FROM TAFB AND RECENT UW/CIMSS ADVANCED DVORAK TECHNIQUE
T-NUMBERS SUPPORT AN INITIAL WIND SPEED OF 45 KT.  ENVIRONMENTAL
CONDITIONS ARE EXPECTED TO REMAIN MARGINALLY CONDUCIVE FOR SOME
SLIGHT STRENGTHENING DURING THE NEXT 12-18 HOURS.  AFTER THAT
TIME...CHRIS WILL BE INTERACTING WITH A FRONTAL BOUNDARY AND MOVING
OVER MUCH COLDER WATERS. HOWEVER...THE GLOBAL MODELS INDICATE THAT
THE CYCLONE WILL INITIALLY MAINTAIN ITS STRENGTH AS AN
EXTRATROPICAL CYCLONE...BEFORE WEAKENING IN 2-3 DAYS.  RECENT RUNS
OF THE GLOBAL MODELS SUGGEST THAT THE POST-TROPICAL LOW COULD
REMAIN THE DOMINANT SYSTEM AND NOT BE THE ONE ABSORBED BY ANOTHER
EXTRATROPICAL LOW.  FOR NOW THE NHC FORECAST WILL CONTINUE TO CALL
FOR POST-TROPICAL CHRIS TO BE ABSORBED...BUT CHANGES TO THIS
SCENARIO MAY BE REQUIRED IF MODEL TRENDS CONTINUE.
 
CHRIS APPEARS TO HAVE TURNED EASTWARD WITH AN INITIAL MOTION OF
090/19 KT.  THE OFFICIAL FORECAST REASONING REMAINS UNCHANGED FROM
THE PREVIOUS ADVISORY.  CHRIS IS EXPECTED TO TURN TOWARD THE
NORTHEAST...THEN NORTHWARD WITHIN THE NEXT 24-36 HOURS AS A CLOSED
LOW FORMS OVER THE NORTH ATLANTIC. LATER IN THE PERIOD...THE
POST-TROPICAL CYCLONE IS FORECAST TO ROTATE CYCLONICALLY AROUND THE
UPPER-LEVEL LOW.  THE NHC FORECAST IS CLOSE TO THE GFS...
ECMWF...AND ON THE POST-TROPICAL PORTION OF THE TRACK PROVIDED BY
THE NOAA OCEAN PREDICTION CENTER.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  20/1500Z 38.1N  51.3W   45 KT  50 MPH
 12H  21/0000Z 38.6N  47.6W   50 KT  60 MPH
 24H  21/1200Z 40.5N  43.3W   45 KT  50 MPH
 36H  22/0000Z 43.6N  41.8W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  22/1200Z 45.0N  43.2W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  23/1200Z 43.0N  45.5W   30 KT  35 MPH...POST-TROP/EXTRATROP
 96H  24/1200Z...ABSORBED BY A LARGER EXTRATROPICAL LOW
 
$$
FORECASTER BROWN
 


WTNT43 KNHC 202033
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   5
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
500 PM AST WED JUN 20 2012
 
ALTHOUGH ONLY A FEW BANDING FEATURES ARE SEEN IN INFRARED SATELLITE
PICTURES...VISIBLE IMAGERY SHOWS SEVERAL BANDS OF SHOWERS ROTATING
AROUND THE CENTER.  IN FACT...A RECENT SSMI MICROWAVE IMAGE
REVEALED A RING OF CONVECTION THAT WRAPPED A LITTLE MORE THAN
HALFWAY AROUND THE CENTER.  AN ASCAT PASS THAT ARRIVED SHORTLY
AFTER THE RELEASE OF THE PREVIOUS ADVISORY HAD A COUPLE 40-KT WIND
VECTORS OVER THE SOUTHEASTERN QUADRANT.  GIVEN THE LOW BIAS OF THAT
INSTRUMENT AND THE IMPROVED STRUCTURE IN MICROWAVE IMAGERY SINCE
THAT TIME...THE INITIAL INTENSITY IS INCREASED TO 50 KT.
 
IT IS DOUBTFUL THAT CHRIS WILL STRENGTHEN ANY FURTHER AS A TROPICAL
CYCLONE SINCE IT WILL BE MOVING OVER COLDER WATER WITHIN 12 HOURS. 
THE GLOBAL MODELS CONTINUE TO PREDICT THAT THE CYCLONE WILL
MAINTAIN ITS INTENSITY OR PERHAPS STRENGTHEN A LITTLE AS A
BAROCLINIC SYSTEM ON THURSDAY.  AFTER 36 HOURS...GRADUAL WEAKENING
IS EXPECTED...AND THE SYSTEM IS LIKELY TO MERGE WITH A LARGER
EXTRATROPICAL LOW IN ABOUT 3 DAYS.

CHRIS IS MOVING EASTWARD OR 085 DEGREES AT 18 KT. THE CYCLONE SHOULD
TURN NORTHEASTWARD...THEN NORTHWARD AS AN UPPER-LEVEL TROUGH TO ITS
NORTHWEST CUTS OFF.  THE POST-TROPICAL CYCLONE IS FORECAST TO
ROTATE CYCLONICALLY AROUND THE UPPER-LOW BEFORE THE MERGER TAKES
PLACE.
  
FORECAST POSITIONS AND MAX WINDS
 
INIT  20/2100Z 38.5N  49.0W   50 KT  60 MPH
 12H  21/0600Z 39.4N  45.8W   50 KT  60 MPH
 24H  21/1800Z 41.7N  42.9W   50 KT  60 MPH...POST-TROPICAL
 36H  22/0600Z 44.3N  42.7W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  22/1800Z 44.2N  44.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  23/1800Z 42.5N  43.5W   30 KT  35 MPH...POST-TROP/EXTRATROP
 96H  24/1800Z...DISSIPATED
 
$$
FORECASTER BROWN
 

WTNT43 KNHC 210250
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   6
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
1100 PM AST WED JUN 20 2012
 
CHRIS HAS HAD WHAT COULD BE CONSIDERED AN EYE FOR THE PAST SEVERAL
HOURS.  HOWEVER...SUBJECTIVE AND OBJECTIVE SATELLITE INTENSITY
ESTIMATES DO NOT SUPPORT ANY SIGNIFICANT CHANGE IN STRENGTH.  THE
MAXIMUM WINDS ARE THEREFORE BEING KEPT AT 50 KT.  EVEN IF CHRIS IS
A LITTLE STRONGER...THE CYCLONE IS NOW MOVING OVER SEA SURFACE
TEMPERATURES LESS THAN 22C...AND THE MARINE BOUNDARY LAYER COULD BE
TOO STABLE TO ALLOW STRONGER WINDS TO BE MIXED TO THE OCEAN
SURFACE.

THE INITIAL MOTION IS 075 DEGREES AT 19 KT...AND CHRIS WILL LIKELY
BEGIN TO DECELERATE AND LOOP COUNTERCLOCKWISE WHILE INTERACTING
WITH A DEVELOPING UPPER LOW TO ITS NORTH.  THERE IS VERY LITTLE
DISPARITY BETWEEN THE TRACK MODELS OVER THE NEXT COUPLE OF DAYS. 
THE GLOBAL MODELS ALSO SEEM TO AGREE THAT CHRIS WILL BE ABSORBED BY
OR MERGE WITH ANOTHER EXTRATROPICAL LOW BY 72 HOURS.

THE POST-TROPICAL TRANSITION IS THE TRICKIEST PART OF THE FORECAST. 
THE FSU PHASE SPACE DIAGRAMS STILL ARGUE THAT CHRIS WILL DEVELOP A
DEEPER WARM CORE OVER THE NEXT FEW DAYS.  HOWEVER...THE GFS FIELDS
SHOW CHRIS BEGINNING TO INTERACT WITH A FRONTAL BOUNDARY TO ITS
NORTH IN ABOUT 24 HOURS...ENDING UP ON THE COLD SIDE OF THE
BOUNDARY BY 48 HOURS.  CHRIS COULD BECOME POST-TROPICAL SOMETIME
OVER THE NEXT 24 HOURS IF IT LOSES ITS DEEP CONVECTION...AND IT
SHOULD BE INVOLVED WITH THE FRONT ENOUGH TO BE EXTRATROPICAL BY 36
HOURS.

THE INTENSITY IS EXPECTED TO CHANGE LITTLE OVER THE NEXT 24 HOURS. 
GRADUAL WEAKENING SHOULD START WHEN CHRIS BECOMES EXTRATROPICAL.


FORECAST POSITIONS AND MAX WINDS
 
INIT  21/0300Z 38.9N  46.4W   50 KT  60 MPH
 12H  21/1200Z 40.3N  43.6W   50 KT  60 MPH
 24H  22/0000Z 43.0N  42.1W   50 KT  60 MPH...POST-TROPICAL
 36H  22/1200Z 44.5N  43.2W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  23/0000Z 43.8N  45.4W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  24/0000Z...ABSORBED BY ANOTHER EXTRATROPICAL LOW
 
$$
FORECASTER BERG
 

WTNT43 KNHC 210836
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   7
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
500 AM AST THU JUN 21 2012
 
CHRIS HAS MAINTAINED AN EYE-LIKE FEATURE SURROUNDED BY A RING OF
CONVECTION WITH CLOUD TOP TEMPERATURES OF -50C TO -60C DURING THE
PAST FEW HOURS.  SUBJECTIVE AND OBJECTIVE DVORAK T-NUMBERS ARE
ESSENTIALLY UNCHANGED SINCE THE LAST ADVISORY AND DO NOT SUPPORT A
HIGHER INTENSITY...SO THE INITIAL INTENSITY IS KEPT AT 50 KT. EVEN
IF CHRIS IS STRONGER THAN ESTIMATED...THE PASSAGE OF THE CYCLONE
OVER SUB-22C SEA SURFACE TEMPERATURES COULD BE INHIBITING AN
EFFICIENT CONVECTIVE TRANSPORT OF THE STRONGEST WINDS TO THE
OCEAN SURFACE.
 
THE INITIAL MOTION IS 065/17...WHICH IS A BIT SLOWER AND TO THE LEFT
OF THE PREVIOUS ESTIMATE.  CHRIS IS EXPECTED TO TURN NORTH-
NORTHEASTWARD AND THEN NORTHWARD AS IT DECELERATES AND DUMBBELLS
CYCLONICALLY AROUND A LARGE MID- TO UPPER-LEVEL LOW FORECAST TO CUT
OFF SOUTHEAST OF THE CANADIAN MARITIME PROVINCES DURING THE NEXT
24-36 HOURS. MODEL GUIDANCE GENERALLY SHOWS CHRIS BEING ABSORBED BY
THIS WEATHER FEATURE IN 36-48 HOURS...WITH THE NEW ENTITY
COMPLETING A CYCLONIC LOOP AND THEN MOVING EASTWARD TO EAST-
NORTHEASTWARD OVER THE FAR NORTH ATLANTIC. GLOBAL MODELS ARE IN
GOOD AGREEMENT WITH REGARD TO THIS SCENARIO...AND THE TRACK
FORECAST IS BASICALLY AN UPDATE OF THE PREVIOUS ONE.
 
DESPITE THE FACT THAT CHRIS IS MOVING OVER RATHER COOL WATERS...
A 0505 UTC AMSU PASSES STILL SHOWED THE PRESENCE OF A WELL-DEFINED
MODERATE TO DEEP WARM CORE IN ASSOCIATION WITH THE CYCLONE.
ALTHOUGH CHRIS IS EXPECTED TO MAINTAIN WARM-CORE CHARACTERISTICS
DURING THE NEXT 24 HOURS OR SO...IT COULD LOSE ITS DEEP CONVECTION
WHILE MOVING OVER EVEN COOLER WATERS AND BE DECLARED POST-TROPICAL. 
SHOULD IT MAINTAIN DEEP CONVECTION LONGER...EITHER ITS INTERACTION
WITH A LOW-LEVEL BAROCLINIC ZONE TO THE NORTH AND/OR ITS
INTERACTION WITH THE CUT-OFF LOW TO ITS WEST SHOULD RESULT IN
EXTRATROPICAL TRANSITION IN ABOUT 36 HOURS.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  21/0900Z 39.9N  44.8W   50 KT  60 MPH
 12H  21/1800Z 41.6N  43.1W   50 KT  60 MPH
 24H  22/0600Z 43.6N  43.0W   50 KT  60 MPH...POST-TROPICAL
 36H  22/1800Z 44.3N  44.8W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  23/0600Z 43.0N  46.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  24/0600Z...ABSORBED BY ANOTHER EXTRATROPICAL LOW
 
$$
FORECASTER KIMBERLAIN
 

WTNT43 KNHC 211454
TCDAT3
 
HURRICANE CHRIS DISCUSSION NUMBER   8
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
1100 AM AST THU JUN 21 2012
 
CHRIS HAS MAINTAINED ITS EYE FEATURE THIS MORNING...AND IN FACT THE
SATELLITE SIGNATURE HAS IMPROVED.  A 1111Z SSMIS OVERPASS ALSO
INDICATED A SOLID CLOSED RING ON THE 37 GHZ COLOR COMPOSITE IMAGE. 
THE EYE TEMPERATURE HAS WARMED AND THE COLD INNER CORE CLOUD TOPS
ARE -60C TO -70C...RESULTING IN A DVORAK SATELLITE DATA-T ESTIMATES
OF 4.5 AND CONSTRAINED FINAL T-NUMBERS OF 4.0 FROM BOTH TAFB AND
SAB.  IN ADDITION...NOW THAT THE CIMSS ADT HAS OBJECTIVELY
IDENTIFIED AN EYE SCENE TYPE...THE LAST FEW RAW T-NUMBERS WERE ALSO
4.4 TO 4.5.  BASED ON THESE DATA AND CONSIDERING THE RELATIVELY
COOL SSTS...THE INITIAL INTENSITY IS RAISED TO 65 KT...MAKING CHRIS
THE FIRST HURRICANE OF THE SEASON.  GRADUAL WEAKENING IS STILL
EXPECTED THROUGH THE FORECAST PERIOD AS THE SYSTEM MOVES NORTHWARD
OVER COOLER WATER AND INTO A MORE STABLE AIR MASS.

THE CYCLONE HAS BEGUN ITS EXPECTED TURN TOWARD THE NORTHEAST...AT AN
ESTIMATED 050/17.  DURING THE NEXT 24 HOURS...CHRIS IS EXPECTED TO
LOSE ITS TROPICAL CYCLONE CHARACTERISTICS AS THE CYCLONE TURNS
CYCLONICALLY...NORTHWARD AND NORTHWESTWARD AROUND A LARGER MID- TO
UPPER-LEVEL BAROCLINIC SYSTEM.  AFTERWARD...CHRIS SHOULD ULTIMATELY
TURN TOWARD THE SOUTH AND BECOME ABSORBED WITHIN THE AFOREMENTIONED
MID-LATITUDE LOW IN 48 HOURS.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  21/1500Z 41.1N  43.2W   65 KT  75 MPH
 12H  22/0000Z 42.8N  42.7W   60 KT  70 MPH
 24H  22/1200Z 44.0N  43.6W   50 KT  60 MPH...POST-TROPICAL
 36H  23/0000Z 43.5N  45.3W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  23/1200Z 42.5N  45.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  24/1200Z...DISSIPATED
 
$$
FORECASTER ROBERTS
 


WTNT43 KNHC 212035
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   9
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
500 PM AST THU JUN 21 2012
 
COOLER SEA SURFACE TEMPERATURES OF 19-20C AND A MORE STABLE
THERMODYNAMIC SURROUNDING ENVIRONMENT ARE FINALLY TAKING ITS TOLL
ON CHRIS. CONVENTIONAL SATELLITE AND AMSU-B MICROWAVE IMAGERY
INDICATE THAT THE EYE FEATURE HAS OPENED UP OVER THE EASTERN
PORTION OF THE CYCLONE.  SATELLITE INTENSITY ESTIMATES HAVE COME
DOWN AND THE CIMSS AMSU INTENSITY ESTIMATES SHOW AN INTENSITY BELOW
HURRICANE STRENGTH.  THEREFORE...THE INITIAL INTENSITY WILL BE
LOWERED TO 60 KT FOR THIS ADVISORY.  FURTHER WEAKENING IS EXPECTED
AND CHRIS IS FORECAST TO LOSE ITS TROPICAL CYCLONE CHARACTERISTICS
IN ABOUT 12 HOURS.  GLOBAL MODELS CONTINUE TO SHOW CHRIS BECOMING
ABSORBED BY A LARGER BAROCLINIC LOW IN 48 HOURS...AND THE OFFICIAL
FORECAST REFLECTS THIS SCENARIO.
 
THE CYCLONE IS MOVING IN A GENERAL NORTHWARD MOTION...015/12 KT.
CHRIS IS FORECAST TO MOVE NORTHWESTWARD...THEN WESTWARD DURING THE
NEXT 24 HOURS IN THE PERIPHERAL FLOW OF A MID- TO UPPER-LEVEL LOW. 
A SUBSEQUENT TURN TOWARD THE SOUTH COULD FOLLOW...WITH CHRIS BEING
ABSORBED WITHIN THE LARGER LOW IN 48 HOURS OR LESS.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  21/2100Z 42.4N  42.9W   60 KT  70 MPH
 12H  22/0600Z 43.9N  43.2W   50 KT  60 MPH...POST-TROPICAL
 24H  22/1800Z 43.8N  44.9W   45 KT  50 MPH...POST-TROP/EXTRATROP
 36H  23/0600Z 42.8N  44.9W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  23/1800Z...ABSORBED BY ANOTHER EXTRATROPICAL LOW
 
$$
FORECASTER ROBERTS
 

WTNT43 KNHC 220246
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER  10
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
1100 PM AST THU JUN 21 2012
 
TROPICAL STORM CHRIS RETAINS A TIGHT CIRCULATION THIS EVENING AS
BEST OBSERVED BY A 2349Z METOP-A MICROWAVE SATELLITE IMAGE FROM THE
NRL WEBSITE.  AS THE CONVECTION IN THE INNER CORE HAS WARMED...THE
DVORAK TECHNIQUE CANNOT PROVIDE A DATA-T NUMBER FOR INTENSITY
ESTIMATES.  THE MODEL EXPECTED T-NUMBER FROM SAB AND TAFB PROVIDE A
RANGE BETWEEN 45 AND 65 KT.  A 2221Z AMSU PASS SUGGESTED AN
INTENSITY AROUND 55 KT FROM THE CIMSS TECHNIQUE.  THE CURRENT
INTENSITY IS ASSESSED AT 55 KT...THOUGH WITH SUBSTANTIAL
UNCERTAINTY.  THE CYCLONE SHOULD GRADUALLY SPIN DOWN WHILE OVER
QUITE CHILLY WATERS AND IT IS LIKELY THAT IT WILL BECOME A
POST-TROPICAL CYCLONE IN ABOUT 12 HOURS...OR SOONER...IF RELATIVELY
DEEP CONVECTION DOES NOT REDEVELOP OVER THE SYSTEM.
 
CHRIS IS MOVING NORTHWARD AT ABOUT 12 KT.  THE TROPICAL STORM SHOULD
TURN TOWARD THE SOUTHWEST WITHIN A DAY AS IT IS ADVECTED AROUND
THE PERIPHERY OF A LARGE DEEP-LAYER CYCLONE.  A SECONDARY SURFACE
LOW CURRENTLY SOUTHWEST OF CHRIS IS PROJECTED BY ALL OF THE
DYNAMICAL MODELS...EXCEPT FOR HWRF...TO ABSORB THE CIRCULATION OF
CHRIS IN ABOUT 24-36 HOURS.  THE FORECAST TRACK IS NEAR THE
CONSENSUS OF THE DYNAMICAL MODELS AND SLIGHTLY TO THE WEST OF THE
PREVIOUS ADVISORY.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  22/0300Z 43.6N  42.9W   55 KT  65 MPH
 12H  22/1200Z 44.2N  44.0W   50 KT  60 MPH...POST-TROPICAL
 24H  23/0000Z 43.0N  45.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
 36H  23/1200Z...DISSIPATED
 
$$
FORECASTER LANDSEA
 

WTNT43 KNHC 220836
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER  11
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
500 AM AST FRI JUN 22 2012
 
CHRIS CONTINUES TO WEAKEN AND IS TRANSITIONING TO A POST-TROPICAL
CYCLONE OVER THE NORTH ATLANTIC. SATELLITE IMAGES INDICATE THAT THE
STORM IS NOW DEVOID OF DEEP CONVECTION AND ONLY CONSISTS OF A TIGHT
SWIRL OF LOW- TO MID-LEVEL CLOUDS. THE INITIAL INTENSITY IS LOWERED
TO 45 KT...FOLLOWING THE DOWNWARD TREND IN THE DVORAK
CLASSIFICATIONS. CHRIS IS FORECAST TO WEAKEN FURTHER AND WILL
LIKELY COMPLETE ITS TRANSITION TO A POST-TROPICAL CYCLONE LATER
THIS MORNING.
 
THE CYCLONE HAS TURNED TO THE NORTHWEST AND THE LATEST INITIAL
MOTION ESTIMATE IS 315/12. CHRIS...OR ITS POST-TROPICAL
REMNANT...IS EXPECTED TO ROTATE COUNTER-CLOCKWISE AROUND A LARGER
EXTRATROPICAL LOW CURRENTLY LOCATED A FEW HUNDRED N MI TO ITS
SOUTH. THIS LARGER LOW WILL ULTIMATELY ABSORB WHATEVER IS LEFT OF
CHRIS IN 24 TO 36 HOURS.  THE OFFICIAL FORECAST FOLLOWS THE
GUIDANCE PROVIDED BY THE OCEAN PREDICTION CENTER.
 
THE 34-KT WIND RADII HAVE BEEN MODIFIED BASED ON AN OSCAT PASS
AROUND 0200 UTC.

FORECAST POSITIONS AND MAX WINDS
 
INIT  22/0900Z 44.8N  44.5W   45 KT  50 MPH
 12H  22/1800Z 44.3N  45.7W   40 KT  45 MPH...POST-TROPICAL
 24H  23/0600Z 43.2N  45.5W   35 KT  40 MPH...POST-TROP/EXTRATROP
 36H  23/1800Z...DISSIPATED
 
$$
FORECASTER CANGIALOSI
 

