WTNT44 KNHC 232052
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER   1
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
400 PM CDT SAT JUN 23 2012
 
AIRCRAFT RECONNAISSANCE...SATELLITE...AND BUOY DATA INDICATE THAT
THE CIRCULATION ASSOCIATED WITH THE AREA OF LOW PRESSURE IN THE
GULF OF MEXICO HAS BECOME SUFFICIENTLY DEFINED TO CLASSIFY THIS
SYSTEM AS A TROPICAL STORM.  THE INITIAL INTENSITY IS BASED ON A
HIGHEST 1000-FT FLIGHT-LEVEL WIND OF 61 KT AND SFMR WINDS NEAR 45
KT.  THESE WINDS ARE ONLY OCCURRING TO THE EAST OF THE CENTER.
 
DEBBY IS MOVING SLOWLY NORTHWARD...OR 360 DEGREES AT 5 KT.  THE
CYCLONE IS IN A WEAK STEERING ENVIRONMENT BETWEEN TWO MID-LEVEL
RIDGES LOCATED OVER THE GREATER ANTILLES AND THE SOUTHERN UNITED
STATES...AND DEBBY IS NOT EXPECTED TO MOVE MUCH DURING THE NEXT
COUPLE OF DAYS.  THE TRACK GUIDANCE IS SPLIT IN TWO BRANCHES...WITH
THE GFS AND GFDL SHOWING AN EASTWARD MOTION ACROSS FLORIDA...AND
THE REST OF THE MODELS BRINGING DEBBY WESTWARD ACROSS THE NORTHERN
GULF TOWARDS TEXAS.  EVEN THOUGH THE DETERMINISTIC GFS SHOWS AN
EASTWARD TRACK...MORE THAN HALF OF THE GFS ENSEMBLE MEMBERS ARE IN
AGREEMENT WITH THE WESTWARD-MOVING MODELS...MAKING THE WESTWARD
SCENARIO SEEM MORE LIKELY.  IT IS IMPORTANT TO NOTE TOO THAT THE
ECMWF MODEL SHOWS A FASTER WESTWARD MOTION THAN INDICATED IN THE
NHC FORECAST...SO IT IS POSSIBLE THAT DEBBY COULD REACH THE COAST
EARLIER THAN INDICATED.
 
DEBBY IS CURRENTLY A SHEARED CYCLONE WITH NEARLY ALL OF THE DEEP
CONVECTION LOCATED IN A CURVED BAND TO THE EAST OF THE CENTER.
HOWEVER...AN UPPER-LEVEL LOW OVER THE NORTHWESTERN GULF OF MEXICO
IS FORECAST TO DIG SOUTHWESTWARD...WHICH WILL RESULT IN A DECREASE
OF VERTICAL SHEAR AFFECTING THE SYSTEM...AND A GREATER CHANCE OF
INTENSIFICATION OVER THE NEXT FEW DAYS.  BECAUSE THE OFFICIAL TRACK
FORECAST IS SO DIFFERENT FROM THE GFS SOLUTION...THE GFS FIELDS USED
BY THE SHIPS AND LGEM MODELS ARE NOT LIKELY TO BE REPRESENTATIVE OF
THE CONDITIONS ENCOUNTERED BY DEBBY.  THE NHC FORECAST THEREFORE
SHOWS MORE STRENGTHENING THAN INDICATED BY THE INTENSITY GUIDANCE.
 
DEBBY IS THE EARLIEST 4TH STORM IN THE HISTORICAL RECORDS...
SURPASSING HURRICANE DENNIS OF 2005...WHICH BECAME A TROPICAL STORM
ON JULY 5TH.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  23/2100Z 26.2N  87.6W   45 KT  50 MPH
 12H  24/0600Z 26.9N  87.8W   45 KT  50 MPH
 24H  24/1800Z 27.3N  88.1W   50 KT  60 MPH
 36H  25/0600Z 27.4N  88.5W   50 KT  60 MPH
 48H  25/1800Z 27.5N  89.5W   55 KT  65 MPH
 72H  26/1800Z 27.5N  91.5W   55 KT  65 MPH
 96H  27/1800Z 27.5N  93.5W   60 KT  70 MPH
120H  28/1800Z 27.5N  95.0W   60 KT  70 MPH
 
$$
FORECASTER BERG/AVILA
 

WTNT44 KNHC 240257
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER   2
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
1000 PM CDT SAT JUN 23 2012
 
DEBBY IS GRADUALLY SHOWING SIGNS OF IMPROVED ORGANIZATION AS THE
UPPER-LEVEL SHEAR SHIFTS FROM SOUTHWESTERLY TO MORE OF A SOUTHERLY
COMPONENT. SHIP ZCDJ2 LOCATED ABOUT 80 NMI EAST OF THE CENTER AND
NEAR NOAA BUOY 42003 REPORTED A PRESSURE OF 1001.6 MB AND 38 KT
WINDS AT 24/00Z. BASED ON THIS INFORMATION...THE CENTRAL PRESSURE
IS CONSERVATIVELY ESTIMATED TO BE 998 MB. AIRCRAFT RECONNAISSANCE
DATA AT 23/2020Z INDICATED 850 MB FLIGHT-LEVEL WINDS OF 61 KT IN
THE NORTHEAST QUADRANT...WHICH IS EQUAL TO ABOUT 49 KT SURFACE
WINDS. CONVECTION WAS SOMEWHAT MEAGER AT THAT...BUT SINCE THEN HAS
INCREASED RATHER MARKEDLY IN THAT AREA. THEREFORE THE INITIAL
INTENSITY ESTIMATE IS A SOLID 45 KT.

DEBBY HAS BEEN NEARLY STATIONARY DURING THE PAST 6 HOURS. MULTIPLE
LOW-LEVEL VORTICES HAVE BEEN OUT FROM UNDERNEATH THE EASTERN
SEMICIRCLE CONVECTIVE CLOUD MASS ABOUT A MEAN CENTER OF ROTATION OF
A LARGER GYRE...AND THE LOCATION OF THE LARGER STATIONARY GYRE IS
THE ADVISORY POSITION. ALTHOUGH THERE MAY BE SOME SLIGHT
NORTHEASTWARD MOTION DUE TO REDEVELOPMENT OF THE CENTER CLOSER TO
THE DEEP CONVECTION...THE GENERAL MOTION FOR THE NEXT 24 HOURS OR
SO SHOULD BE SLOWLY POLEWARD. THE LONGWAVE PATTERN ACROSS THE U.S.
HAS A DEEPENING TROUGH OFF THE WEST COAST...WHICH IS CREATING
DOWNSTREAM RIDGING ACROSS THE CENTRAL AND EASTERN UNITED STATES.
THIS INCREASED RIDGING IS REFLECTED BY 20-40 METER 500 MB HEIGHT
RISES AT 00Z ACROSS THE CENTRAL AND SOUTHERN PLAINS...AND EXTENDING
AS FAR EAST AS THE CAROLINA COASTS. THIS BLOCKING RIDGE PATTERN TO
THE NORTH OF DEBBY IS EXPECTED TO GRADUALLY TURN THE CYCLONE
WESTWARD ACROSS THE NORTH-CENTRAL GULF OF MEXICO BY 36-48
HOURS...WITH A CONTINUED WESTWARD MOTION ACROSS THE NORTHWESTERN
GULF AFTER THAT. ALL OF THE AVAILABLE NHC MODEL GUIDANCE...EXCEPT
FOR THE GFS AND GFS-ENSEMBLE MODELS...SUPPORTS THE GENERAL WESTWARD
MOTION SCENARIO. THE MAIN REASON THAT THE GFS MOVES DEBBY EASTWARD
ACROSS THE NORTHEASTERN GULF IS DUE TO IT HAVING A WEAKER AND MORE
VERTICALLY SHALLOW STORM DEPICTED IN THE MODEL. GIVEN THE EXPECTED
FAVORABLE UPPER-LEVEL FLOW PATTERN WITH WEAKER VERTICAL SHEAR
FORECAST TO DEVELOP AFTER 24 HOURS...A DEEPER AND MORE ROBUST
WESTWARD MOVING TROPICAL CYCLONE AS DEPICTED IN THE
ECMWF...UKMET... NOGAPS MODELS SEEMS A MORE REASONABLE SCENARIO.
THE OFFICIAL FORECAST TRACK IS JUST AN UPDATE OF THE PREVIOUS
ADVISORY TRACK.

MODERATE SOUTHWESTERLY VERTICAL WIND SHEAR IS EXPECTED TO GRADUALLY
GIVE WAY TO SOUTHERLY AND EVENTUALLY SOUTHEASTERLY WEAKER WIND
SHEAR BY 36-48 HOURS AS AN UPPER-LEVEL LOW NORTHWEST OF THE CYCLONE
MOVES SOUTHWESTWARD...WHICH ALLOWS DEBBY TO MOVE UNDERNEATH A 200
MB RIDGE AXIS. THE OFFICIAL INTENSITY FORECAST LEANS TOWARD THE
ECMWF MODEL...WHICH IS FORECASTING A HURRICANE CENTRAL PRESSURE BY
96 HOURS...AND IS ABOVE THE GFS-BASED SHIPS AND LGEM MODELS SINCE
THAT OUTPUT LIKELY DOES NOT REPRESENT THE ENVIRONMENTAL CONDITIONS
THAT DEBBY WILL ENCOUNTER. THE OFFICIAL INTENSITY FORECAST IS A
LITTLE HIGHER THAN THE PREVIOUS ADVISORY...AND BRINGS DEBBY TO
HURRICANE STRENGTH BY 72 HOURS.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/0300Z 26.3N  87.5W   45 KT  50 MPH
 12H  24/1200Z 26.7N  87.8W   50 KT  60 MPH
 24H  25/0000Z 27.0N  88.1W   50 KT  60 MPH
 36H  25/1200Z 27.1N  88.8W   55 KT  65 MPH
 48H  26/0000Z 27.2N  89.8W   60 KT  70 MPH
 72H  27/0000Z 27.2N  91.8W   65 KT  75 MPH
 96H  28/0000Z 27.2N  93.7W   70 KT  80 MPH
120H  29/0000Z 27.2N  95.2W   70 KT  80 MPH
 
$$
FORECASTER STEWART
 

WTNT44 KNHC 240837
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER   3
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
400 AM CDT SUN JUN 24 2012
 
THE CLOUD PATTERN OF THE TROPICAL STORM HAS NOT BECOME SIGNIFICANTLY
BETTER ORGANIZED OVER THE PAST FEW HOURS.  DEBBY HAS BEEN PRODUCING
VERY COLD-TOPPED DEEP CONVECTION BUT THESE THUNDERSTORMS...AND
LIKELY THE STRONGEST WINDS...ARE OCCURRING SOME 100 TO 150 MILES
NORTHEAST OF THE LOW-LEVEL CENTER.  THE CURRENT INTENSITY IS KEPT
AT 45 KT...WHICH IS IN AGREEMENT WITH DATA FROM AN ASCAT PASS
SEVERAL HOURS AGO.  NO CHANGE IS MADE TO THE PREVIOUS INTENSITY
FORECAST...HOWEVER THIS FORECAST IS BASED ON THE PREMISE THAT THE
VERTICAL SHEAR WILL DECREASE OVER THE NEXT FEW DAYS AND THE GLOBAL
MODELS ARE NOT UNANIMOUS ON THIS.  THE OFFICIAL WIND SPEED FORECAST
IS CLOSEST TO THE MOST RECENT HWRF GUIDANCE...AND IT SHOULD BE
NOTED THAT WE HAVE LIMITED SKILL IN PREDICTING TROPICAL CYCLONE
INTENSITY CHANGE. 

WITH INFRARED IMAGERY THE CENTER...ALTHOUGH PARTIALLY EXPOSED...HAS
BECOME A LITTLE MORE DIFFICULT TO LOCATE AND THE FIXES FROM TAFB
AND SAB ARE ABOUT 50 MILES APART.  MY BEST ESTIMATE OF INITIAL
MOTION IS SLOWLY NORTHWARD...OR 360/3.  THE TRACK FORECAST FOR THIS
STORM IS EXTREMELY CHALLENGING.  THE SYNOPTIC REASONING IN PREVIOUS
ADVISORIES WAS BASED ON A MID-LEVEL RIDGE BUILDING TO THE NORTH OF
THE TROPICAL CYCLONE...WHICH WOULD CAUSE DEBBY TO MOVE TOWARD THE
NORTHWEST GULF OF MEXICO COAST IN SEVERAL DAYS.  THAT TRACK
SCENARIO WAS SUPPORTED BY THE ECMWF MODEL...WHICH HAS BEEN THE
BEST-PERFORMING GUIDANCE OVER THE PAST FEW YEARS.  HOWEVER...THE
0000 RUN OF THAT MODEL HAS SHIFTED SUBSTANTIALLY TO THE NORTH AND
EAST OF THE PREVIOUS RUNS.  THE U.K. MET. OFFICE MODEL HAS ALSO
SHIFTED SIGNIFICANTLY TO THE RIGHT.  IN FACT...ONLY THE HWRF MODEL
IS CLOSE TO THE PREVIOUS OFFICIAL FORECASTS...AND EVEN IT IS TO THE
NORTH OF THEM.  THEREFORE AN UNUSUALLY LARGE RIGHTWARD ADJUSTMENT
TO THE NHC FORECAST IS REQUIRED...AND ADDITIONAL SHIFTS TO THE
NORTH AND EAST MAY BE NECESSARY IN SUBSEQUENT ADVISORY PACKAGES.

NEEDLESS TO SAY...THIS IS A LOW CONFIDENCE FORECAST.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/0900Z 27.3N  87.3W   45 KT  50 MPH
 12H  24/1800Z 27.5N  87.4W   50 KT  60 MPH
 24H  25/0600Z 27.9N  87.8W   50 KT  60 MPH
 36H  25/1800Z 28.2N  88.4W   55 KT  65 MPH
 48H  26/0600Z 28.3N  89.0W   60 KT  70 MPH
 72H  27/0600Z 28.5N  90.5W   65 KT  75 MPH
 96H  28/0600Z 28.5N  92.0W   70 KT  80 MPH
120H  29/0600Z 28.5N  93.5W   70 KT  80 MPH
 
$$
FORECASTER PASCH
 

WTNT44 KNHC 241159
TCDAT4
 
TROPICAL STORM DEBBY SPECIAL DISCUSSION NUMBER   4
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
700 AM CDT SUN JUN 24 2012
 
THE PURPOSE OF THIS SPECIAL ADVISORY IS TO ISSUE A TROPICAL STORM
WARNING FROM THE MISSISSIPPI ALABAMA BORDER EASTWARD TO THE
OCHOLOCKONEE RIVER. THIS IS BASED ON THE EXPANSION OF TROPICAL
STORM FORCE WINDS IN THE NORTHEAST QUADRANT. THERE HAVE BEEN NO
CHANGES TO THE FORECAST TRACK NOR INTENSITY.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/1200Z 27.5N  87.0W   50 KT  60 MPH
 12H  24/1800Z 27.5N  87.4W   50 KT  60 MPH
 24H  25/0600Z 27.9N  87.8W   50 KT  60 MPH
 36H  25/1800Z 28.2N  88.4W   55 KT  65 MPH
 48H  26/0600Z 28.3N  89.0W   60 KT  70 MPH
 72H  27/0600Z 28.5N  90.5W   65 KT  75 MPH
 96H  28/0600Z 28.5N  92.0W   70 KT  80 MPH
120H  29/0600Z 28.5N  93.5W   70 KT  80 MPH
 
$$
FORECASTER AVILA
 

WTNT44 KNHC 241458
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER   5
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
1000 AM CDT SUN JUN 24 2012
 
IT IS A VERY DIFFICULT AND HIGHLY UNCERTAIN FORECAST THIS MORNING.
DEBBY HAS BEEN MOVING VERY SLOWLY TOWARD THE NORTHEAST...040 AT 3
KNOTS...WHILE THE WIND RADII HAVE BEEN EXPANDING IN THE EASTERN
SEMICIRCLE.  THIS HAS PROMPTED ADDITIONAL TROPICAL STORM WARNINGS
AND WATCHES FOR PORTIONS OF THE FLORIDA COAST. 

DEBBY CONTINUES TO BE SHEARED WITH MOST OF THE THUNDERSTORM ACTIVITY
NORTH AND EAST OF THE CENTER.  THIS SHEAR IS EXPECTED TO CONTINUE
FOR THE NEXT DAY OR SO...ALTHOUGH SOME DECREASE IN THE SHEAR IS
POSSIBLE AFTER THAT...PARTICULARLY IF THE ECMWF VERIFIES.  THE
OFFICIAL FORECAST IS A LITTLE LESS AGGRESSIVE THAN THE PREVIOUS
FORECAST...BUT REMAINS ABOVE MOST OF THE EXPLICIT INTENSITY
GUIDANCE.   

THE TRACK FORECAST IS EVEN MORE COMPLEX. THE GFS INSISTS ON A TRACK
TOWARD THE NORTHEAST AS DEBBY BECOMES EMBEDDED WITHIN A LARGE
MID-LATITUDE TROUGH. HOWEVER...THE ECMWF AND THE HWRF BUILD A RIDGE
TO THE NORTH OF DEBBY AND FORECAST A WESTWARD TRACK.  GIVEN THE
WESTWARD TURN INHERITED FROM THE PREVIOUS FORECAST...AS WELL AS THE
HISTORICAL STRONG RECORD OF THE ECMWF...THE NEW OFFICIAL FORECAST
MOVES DEBBY INITIALLY A LITTLE BIT TO THE NORTHEAST TO REFLECT
CURRENT TRENDS BUT THEN TURNS THE CYCLONE BACK TOWARD THE WEST OR
WEST-NORTHWEST IN 24 TO 36 HOURS.  A MAJORITY OF THE GFS ENSEMBLE
MEMBERS NOW ARE CONSISTENT WITH THE DETERMINISTIC RUN...WHICH WAS
NOT THE CASE YESTERDAY...MAKING A STRONGER CASE FOR THE EASTWARD
SOLUTION.  WE MUST BE READY TO MAKE A CHANGE OF THE FORECAST TRACK
AT ANY TIME.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/1500Z 28.0N  86.2W   50 KT  60 MPH
 12H  25/0000Z 28.5N  85.8W   50 KT  60 MPH
 24H  25/1200Z 28.5N  85.8W   50 KT  60 MPH
 36H  26/0000Z 28.5N  86.2W   55 KT  65 MPH
 48H  26/1200Z 28.7N  87.0W   60 KT  70 MPH
 72H  27/1200Z 29.0N  88.4W   65 KT  75 MPH
 96H  28/1200Z 29.5N  90.5W   45 KT  50 MPH
120H  29/1200Z 30.0N  91.5W   30 KT  35 MPH
 
$$
FORECASTER AVILA
 

WTNT44 KNHC 242034
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER   6
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
400 PM CDT SUN JUN 24 2012
 
THERE HAS BEEN A SIGNIFICANT CHANGE IN THE FORECAST TRACK WITH THIS
ADVISORY. THE OFFICIAL FORECAST NO LONGER BRINGS DEBBY WESTWARD
ALONG THE NORTHERN GULF OF MEXICO AND INSTEAD KEEPS THE CYCLONE
MEANDERING OVER THE NORTHEASTERN GULF FOR THE NEXT 3 TO 4 DAYS.
THIS FORECAST IS A COMPROMISE BETWEEN THE CONSISTENT EASTWARD
SOLUTION PROVIDED BY THE GFS FOR THE PAST SEVERAL DAYS AND THE NEW
TWIST OF THE ECMWF. THE ECMWF MODEL...WHICH HAS BEEN
FORECASTING DEBBY TO MOVE WESTWARD ALONG THE GULF OF MEXICO... NOW
HAS THE CYCLONE MEANDERING FOR THE NEXT 3 DAYS OVER THE
NORTHEASTERN GULF. SINCE THESE TWO RELIABLE MODELS ARE IN
MARGINALLY BETTER AGREEMENT...I AM A LITTLE MORE CONFIDENT...BUT
NOT COMPLETELY...THAT DEBBY IS NOT GOING TO TURN WESTWARD OVER THE
GULF. HOWEVER...NEW OFFICIAL TRACK REMAINS A LOW-CONFIDENCE
FORECAST.
 
DEBBY IS A SPRAWLING SYSTEM...WITH MOST OF THE THUNDERSTORM ACTIVITY
IN A CURVED BAND WELL REMOVED FROM THE CENTER.  DATA FROM THE
RECONNAISSANCE PLANE A FEW HOURS AGO INDICATE THAT THE INITIAL
INTENSITY REMAINS 50 KNOTS. THE SHEAR IS NOT EXPECTED TO CHANGE
MUCH FOR THE NEXT DAY OR SO...BUT BECAUSE DEBBY IS FORECAST TO
REMAIN OVER WATER...THERE WILL BE SOME OPPORTUNITY FOR A SLIGHT
STRENGTHENING BEFORE THE CENTER MOVES INLAND. HOWEVER...THE CYCLONE
WILL LOCATED BE NORTH OF THE AREA OF HIGH OCEANIC HEAT CONTENT AND
THE UPWELLING COULD HALT THE INTENSIFICATION. 
 
  
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/2100Z 28.4N  85.8W   50 KT  60 MPH
 12H  25/0600Z 28.7N  85.5W   50 KT  60 MPH
 24H  25/1800Z 29.0N  85.5W   50 KT  60 MPH
 36H  26/0600Z 29.0N  85.5W   55 KT  65 MPH
 48H  26/1800Z 29.0N  85.5W   60 KT  70 MPH
 72H  27/1800Z 29.5N  85.5W   60 KT  70 MPH
 96H  28/1800Z 30.0N  85.5W   40 KT  45 MPH
120H  29/1800Z 30.5N  85.5W   30 KT  35 MPH...INLAND
 
$$
FORECASTER AVILA
 

WTNT44 KNHC 250258
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER   7
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
1000 PM CDT SUN JUN 24 2012
 
THE APPEARANCE OF DEBBY IN SATELLITE AND RADAR IMAGERY HAS DEGRADED
SIGNIFICANTLY THIS EVENING AS A SHARP MID-LEVEL DRY INTRUSION HAS
WORKED ITS WAY INTO THE CENTER OF THE CYCLONE AND ERODED ALL OF THE
INNER CORE DEEP CONVECTION. THE INITIAL INTENSITY IS BEING HELD AT
50 KT FOR THIS FORECAST PACKAGE BASED MAINLY ON CONTINUITY WITH THE
PREVIOUS ADVISORY AND THE RELATIVELY LOW CENTRAL PRESSURE OF 991 MB
REPORTED BY AN AIR FORCE RESERVE RECON AIRCRAFT THIS EVENING.

DEBBY HAS BEEN NEARLY STATIONARY SINCE THE LAST ADVISORY. BOTH 18Z
AND 00Z UPPER-AIR DATA INDICATE MID-LEVEL RIDGING HAS CONTINUED TO
BUILD ACROSS THE SOUTHEASTERN U.S. TO THE NORTH OF DEBBY...AND THIS
HAS LIKELY BEEN THE REASON FOR THE LACK OF ANY SIGNIFICANT MOTION
OVER THE PAST SEVERAL HOURS. ALL OF THE NHC MODEL GUIDANCE...EXCEPT
FOR THE GFS AND GFS-ENSEMBLE MODELS...INDICATE THIS BLOCKING PATTERN
ACROSS THE CENTRAL AND EASTERN U.S. SHOULD CONTINUE AS FAST-MOVING
SHORTWAVE TROUGHS PASS WELL TO THE NORTH OF DEBBY. THE RESULT
SHOULD BE THAT THE CYCLONE WILL MOVE LITTLE DURING THE NEXT COUPLE
OF DAYS...AND THEN ONLY DRIFT SLOWLY NORTHWARD AFTER THAT AS THE
RIDGE OVER THE SOUTHEASTERN U.S. GRADUALLY BREAKS DOWN. ALTHOUGH THE
GFS MODEL HAS BEEN VERY CONSISTENT WITH A FAST NORTHEASTWARD MOTION
ACROSS NORTH FLORIDA THE PAST FEW DAYS...THE LARGE SPRAWLING NATURE
OF THE CYCLONE AND THE BLOCKING RIDGE TO THE NORTH WOULD SUGGEST
THAT THE GFS MODEL MAY BE LIFTING OUT DEBBY TOO QUICKLY. THE
OFFICIAL FORECAST TRACK IS SIMILAR TO BUT SLIGHTLY LEFT OF THE
PREVIOUS ADVISORY TRACK...MAINLY DUE TO THE MORE WESTWARD INITIAL
POSITION.
 
DEBBY HAS FINALLY CONSOLIDATED ALL OF THE MULTIPLE SMALL SWIRLS INTO
A WELL-DEFINED LOW-LEVEL CIRCULATION CENTER. THE GLOBAL MODELS ARE
FORECASTING THE AFOREMENTIONED DEEP DRY SLOT TO GRADUALLY MOISTEN
UP OVER THE NEXT 48 HOURS AS DEEP MOISTURE AND INSTABILITY
CURRENTLY OVER THE FLORIDA PENINSULA ADVECTS WESTWARD INTO THE
INNER CORE. THE COMBINATION OF THESE TWO FEATURES MAY ALLOW FOR
SOME SLIGHT STRENGTHENING BEFORE DEBBY BEGINS TO INTERACT WITH LAND
OR COLD UPWELLING BENEATH THE CYCLONE OCCURS. THE OFFICIAL
INTENSITY FORECAST IS IDENTICAL TO THE PREVIOUS ADVISORY AND
FOLLOWS A BLEND OF THE SHIPS/LGEM STATISTICAL MODELS AND THE
HWRF/GFDL REGIONAL MODELS.

FORECAST POSITIONS AND MAX WINDS
 
INIT  25/0300Z 28.3N  85.9W   50 KT  60 MPH
 12H  25/1200Z 28.6N  85.8W   50 KT  60 MPH
 24H  26/0000Z 28.7N  85.8W   50 KT  60 MPH
 36H  26/1200Z 28.8N  85.8W   55 KT  65 MPH
 48H  27/0000Z 28.9N  85.8W   60 KT  70 MPH
 72H  28/0000Z 29.4N  85.8W   55 KT  65 MPH
 96H  29/0000Z 29.9N  85.8W   35 KT  40 MPH...NEAR COAST
120H  30/0000Z 30.4N  85.6W   30 KT  35 MPH...INLAND
 
$$
FORECASTER STEWART
 

WTNT44 KNHC 250838
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER   8
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
400 AM CDT MON JUN 25 2012
 
DEBBY HAS A HIGHLY UNIMPRESSIVE APPEARANCE ON SATELLITE IMAGERY.
ALTHOUGH RADAR DATA CONTINUE TO DEPICT SOME SHOWER ACTIVITY OVER
THE CIRCULATION...THESE SHOWERS ARE BEING PRODUCED BY SHALLOW
CONVECTION AS THE ENHANCED IR IMAGES DO NOT SHOW ANY SIGNIFICANT
AREAS OF COLD CLOUD TOPS.  AIRCRAFT DATA FROM SEVERAL HOURS AGO
ALONG WITH SYNOPTIC OBSERVATIONS INDICATE THAT THE MAXIMUM SURFACE
WINDS HAVE DECREASED...AND THE CURRENT INTENSITY IS SET AT 45 KT.
DEBBY IS LOCATED NORTH OF THE AREA OF MAXIMUM OCEANIC HEAT
CONTENT...BUT AS LONG AS THE CYCLONE REMAINS OVER WATER AND IS ABLE
TO REGENERATE SOME DEEP CONVECTION THERE IS A POTENTIAL FOR AT
LEAST SLIGHT RE-INTENSIFICATION.  THE CURRENT NHC INTENSITY
FORECAST IS A LITTLE LOWER THAN THE PREVIOUS ONES...BUT A LITTLE
HIGHER THAN MOST OF THE NUMERICAL GUIDANCE.
 
BEST GUESS AT INITIAL MOTION IS QUASI-STATIONARY.  DEBBY REMAINS IN
A COL REGION OF THE MID-TROPOSPHERIC STEERING FLOW BETWEEN TWO
ANTICYCLONES...AND IS LIKELY TO REMAIN SO FOR THE NEXT COUPLE OF
DAYS.  THEREFORE LITTLE MOTION IS ANTICIPATED DURING AT LEAST THE
FIRST HALF OF THE FORECAST PERIOD.  IN THE LONGER-TERM...THE TRACK
GUIDANCE CONTINUES TO BE ALL OVER THE PLACE...WITH SOME MODELS
TAKING DEBBY WEST AND NORTH OF ITS CURRENT POSITION AND OTHERS
MOVING EAST OR NORTHEAST AND ULTIMATELY INTO THE ATLANTIC.  THE
LATTER SCENARIO ASSUMES THAT DEBBY WILL EVENTUALLY BE INFLUENCED BY
A MID-TROPOSPHERIC TROUGH OVER THE NORTHEASTERN UNITED STATES. 
THIS SCENARIO SEEMS MORE LIKELY SINCE IT IS SUPPORTED BY BOTH THE
GFS AND THE ECMWF MODELS.  REGARDLESS OF WHICH SCENARIO PLAYS
OUT...THE CYCLONE DOES NOT SEEM TO BE GOING ANYWHERE ANYTIME SOON. 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  25/0900Z 28.6N  85.8W   45 KT  50 MPH
 12H  25/1800Z 28.8N  85.7W   45 KT  50 MPH
 24H  26/0600Z 28.9N  85.6W   50 KT  60 MPH
 36H  26/1800Z 29.0N  85.5W   50 KT  60 MPH
 48H  27/0600Z 29.2N  85.4W   55 KT  65 MPH
 72H  28/0600Z 29.4N  85.3W   55 KT  65 MPH
 96H  29/0600Z 29.7N  85.2W   45 KT  50 MPH...INLAND
120H  30/0600Z 30.2N  85.0W   30 KT  35 MPH...INLAND
 
$$
FORECASTER PASCH
 

WTNT44 KNHC 251451
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER   9
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
1000 AM CDT MON JUN 25 2012
 
THERE HAS BEEN NO SIGNIFICANT DEEP CONVECTION NEAR THE CENTER OF
DEBBY FOR OVER 12 HOURS. WHAT CONVECTION REMAINS IS PRIMARILY
LOCATED IN A FRAGMENTED BAND WELL EAST OF THE CENTER...AND
SOUNDINGS ALONG THE GULF COAST INDICATE THAT THE ENTRAINMENT OF DRY
MID-LEVEL AIR IS AFFECTING THE STORM. IN ADDITION...THE SLOW
MOVEMENT OF DEBBY HAS INDUCED OCEANIC UPWELLING AND COOLING
UNDERNEATH THE CYCLONE AND MAY HAVE CONTRIBUTED TO THE OBSERVED
WEAKENING. LATEST DATA FROM THE RECONNAISSANCE AIRCRAFT INDICATE
THAT THE MAXIMUM WINDS ARE NEAR 40 KT. WITH DRY AIR LURKING AND
WESTERLY SHEAR ON THE INCREASE OVER THE NEXT COUPLE DAYS...
SIGNIFICANT RE-INTENSIFICATION OF THE CYCLONE PRIOR TO LANDFALL
SEEMS UNLIKELY. THE NEW NHC FORECAST IS ADJUSTED DOWNWARD IN LINE
WITH CURRENT TRENDS AND THE LATEST INTENSITY GUIDANCE.
 
AIRCRAFT AND SATELLITE FIXES HAVE SHOWN LITTLE OVERALL MOVEMENT OVER
THE PAST 12 TO 18 HOURS... ALTHOUGH RECENT SATELLITE IMAGERY
INDICATES AN EAST-NORTHEASTWARD TO NORTHEASTWARD SHORT-TERM MOTION.
AT THE MOMENT...IT IS UNCLEAR WHETHER THE CURRENT MOTION REPRESENTS
A MEANDERING OR A MORE DECIDED MOTION. ON THE LARGE SCALE...DEBBY
IS TRAPPED IN A REGION OF WEAK STEERING IN BETWEEN A STRONG
MID-LEVEL RIDGE OVER THE PLAINS AND ONE OVER THE SUBTROPICAL
CENTRAL ATLANTIC. GLOBAL MODELS DEPICT AN AMPLIFYING TROUGH
OFFSHORE THE EASTERN SEABOARD CAUSING DEBBY TO MOVE GENERALLY
EASTWARD THROUGH THE FORECAST PERIOD...WITH THE CENTER EMERGING
OVER THE SOUTHWEST ATLANTIC BY DAY 5. THE ECMWF/GFS SOLUTIONS BEGIN
TO LIFT OUT THE WESTERN ATLANTIC TROUGH IN ABOUT 72 HOURS...WHICH
COULD LEAVE DEBBY IN WEAK STEERING CURRENT AGAIN AFTER THAT TIME.
SINCE YESTERDAY... THE GUIDANCE HAS COME INTO BETTER
AGREEMENT...WITH ONLY THE UKMET NOW SHOWING A WESTWARD MOTION. IN
ADDITION...THE LATEST GFS ENSEMBLE MEMBERS FAVOR AN EASTWARD MOTION
BY ABOUT A 3 TO 1 RATIO. THE NEW FORECAST TRACK REPRESENTS A
SUBSTANTIAL CHANGE FROM THE PREVIOUS ONE BUT IS STILL SLOWER THAN
THE MULTI-MODEL CONSENSUS IN THE SHORT TERM.
 

FORECAST POSITIONS AND MAX WINDS
 
INIT  25/1500Z 28.6N  85.2W   40 KT  45 MPH
 12H  26/0000Z 28.8N  85.1W   35 KT  40 MPH
 24H  26/1200Z 28.9N  84.9W   35 KT  40 MPH
 36H  27/0000Z 29.0N  84.7W   35 KT  40 MPH
 48H  27/1200Z 29.2N  84.4W   35 KT  40 MPH
 72H  28/1200Z 29.5N  83.5W   35 KT  40 MPH
 96H  29/1200Z 29.5N  82.5W   30 KT  35 MPH...INLAND
120H  30/1200Z 29.5N  81.0W   30 KT  35 MPH
 
$$
FORECASTER KIMBERLAIN/FRANKLIN
 

WTNT44 KNHC 252052
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER  10
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
400 PM CDT MON JUN 25 2012
 
SATELLITE IMAGERY INDICATES THAT DEBBY HAS CHANGED LITTLE IN
ORGANIZATION TODAY. THE CENTER OF THE CYCLONE IS A LITTLE HARDER TO
LOCATE...WITH AT LEAST A COUPLE OF SMALL VORTICES ROTATING AROUND A
MEAN CENTER. THERE HAD BEEN VIRTUALLY NO CONVECTION ASSOCIATED WITH
THE CENTER OF THE CYCLONE EITHER...BUT A BURST OF DEEP CONVECTION
HAS RECENTLY FORMED OVER LAND TO THE NORTH OF THE CENTER. EARLIER
AIRCRAFT DATA SHOWED PEAK FLIGHT-LEVEL WINDS OF 57 KT AT 850MB...
WITH MAXIMUM SFMR VALUES AROUND 40 KT. GIVEN THESE DATA AND THE
LACK OF STRUCTURAL CHANGES TO THE CYCLONE...THE INITIAL INTENSITY
REMAINS 40 KT.  THE CURRENT STRUCTURE...COMBINED WITH AN INCREASE
IN WESTERLY SHEAR AND ADDITIONAL DRY AIR POSSIBLY WRAPPING INTO THE
STORM CIRCULATION...WOULD SEEM TO PRECLUDE MUCH SHORT-TERM
RE-INTENSIFICATION OF DEBBY...AND THE SHIPS AND LGEM MODELS SHOW NO
APPRECIABLE CHANGE IN STRENGTH PRIOR TO LANDFALL. MARGINALLY
FAVORABLE ENVIRONMENTAL CONDITIONS COULD PROVIDE AN OPPORTUNITY FOR
RE-STRENGTHENING OVER THE WESTERN ATLANTIC AT THE END OF THE
FORECAST PERIOD.
 
A SMOOTHING OF RECENT AIRCRAFT AND SATELLITE FIXES YIELDS A SLOW
NORTHEASTWARD MOTION OF 040/04. LARGE-SCALE MODELS SHOW DEBBY
CONTINUING ON AN EAST-NORTHEASTWARD TO NORTHEASTWARD COURSE OVER
THE NEXT FEW DAYS IN RESPONSE TO AN AMPLIFYING TROUGH OFFSHORE OF
THE U.S. EAST COAST. AS THE WESTERN ATLANTIC TROUGH BEGINS TO LIFT
OUT IN 2-3 DAYS...DEBBY IS EXPECTED TO SLOW DOWN AND BE LEFT BEHIND
OVER THE SOUTHWESTERN ATLANTIC. WITH THE EXCEPTION OF THE GFS
ENSEMBLE MEMBERS...THE MODEL GUIDANCE IS IN BETTER AGREEMENT
OVERALL ON AN EASTWARD TRACK...ALTHOUGH SIGNIFICANT SPEED
DIFFERENCES REMAIN. THE GFS IS CONSIDERABLY SLOWER THAN THE MODEL
CONSENSUS...AND SHOWS DEBBY TAKING FIVE DAYS TO MOVE OFFSHORE THE
FLORIDA ATLANTIC COAST. INTERESTINGLY...THE ECMWF IS NOW ONE OF THE
FASTEST MODELS TO THE EAST. THE NHC OFFICIAL TRACK FORECAST IS NOT
AS FAST AS THE MULTI-MODEL CONSENSUS IN DEFERENCE TO CONTINUITY AND
THE GFS.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  25/2100Z 29.3N  85.1W   40 KT  45 MPH
 12H  26/0600Z 29.4N  84.9W   40 KT  45 MPH
 24H  26/1800Z 29.5N  84.7W   40 KT  45 MPH
 36H  27/0600Z 29.6N  84.4W   40 KT  45 MPH
 48H  27/1800Z 29.7N  83.8W   40 KT  45 MPH
 72H  28/1800Z 29.8N  82.5W   30 KT  35 MPH...INLAND
 96H  29/1800Z 29.8N  81.0W   30 KT  35 MPH
120H  30/1800Z 30.0N  79.0W   35 KT  40 MPH
 
$$
FORECASTER KIMBERLAIN/
 

WTNT44 KNHC 260300
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER  11
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
1000 PM CDT MON JUN 25 2012
 
AFTER AN INTENSE BURST OF DEEP CONVECTION NEAR AND NORTH OF THE
LOW-LEVEL CENTER THIS LATE AFTERNOON AND EVENING...THE CONVECTIVE
CLOUD SHIELD IS SHOWING SIGNS OF SLOWLY PULLING AWAY FROM CENTER OF
CIRCULATION DUE TO MODERATE TO STRONG SOUTHWESTERLY VERTICAL WIND
SHEAR. THE HIGHEST RELIABLE SFMR WINDS REPORTED BY AN AIR FORCE
RESERVE RECON AIRCRAFT THIS EVENING HAS BEEN 42 KT TO THE WEST AND
WELL SOUTHEAST OF THE CENTER...ALONG WITH 59-KT AND 56-KT
FLIGHT-LEVEL WINDS...RESPECTIVELY. ALTHOUGH THE TALLAHASSEE DOPPLER
WEATHER RADAR HAS BEEN INDICATING LARGE WINDS OF 60-65 VELOCITIES
BETWEEN 2000 AND 6500 FT IN SOME RATHER VIGOROUS CONVECTION...THOSE
CONDITIONS HAVE BEEN OVER LAND. THEREFORE...THE INITIAL INTENSITY
WILL REMAIN AT 40 KT.

THE MOTION ESTIMATE IS A SLOW DRIFT TO THE NORTHEAST OR 040/02 KT
OVER THE PAST 12 HOURS. THERE IS NO SIGNIFICANT CHANGE TO THE
PREVIOUS TRACK REASONING. UPPER-AIR DATA AT 18Z AND 00Z INDICATE 
DEBBY REMAINS TRAPPED IN A BLOCKING RIDGE PATTERN THAT EXTENDS
ACROSS THE SOUTHEASTERN U.S. AND INTO THE EASTERN GULF OF MEXICO
AND WESTERN ATLANTIC. THE RESULTANT WEAK STEERING FLOW SHOULD KEEP
DEBBY MOVING VERY SLOWLY NORTHEAST OR EASTWARD AT LESS THAN 5 KT
THROUGHOUT THE FORECAST PERIOD. IN FACT...DEBBY WILL LIKELY REMAIN
OVER THE NORTHEASTERN GULF OF MEXICO FOR AT LEAST THE NEXT 2 DAYS
BEFORE IT CREEPS SLOWLY ACROSS NORTH FLORIDA IN DAYS 3-4. IN THE
ABSENCE OF ANY LARGE-SCALE STEERING FLOW...THE LOW-LEVEL CENTER OF
DEBBY WILL CLOSELY FOLLOW ANY DEEP CONVECTION THAT DEVELOPS...WHICH
SHOULD REMAIN PRIMARILY TO NORTHEAST OF THE CENTER.  THE OFFICIAL
FORECAST TRACK IS SIMILAR TO THE PREVIOUS ADVISORY TRACK THROUGH
DAY 3...AND IS THEN A LITTLE NORTH OF THE PREVIOUS TRACK AND CLOSE
TO THE NHC MODEL CONSENSUS.

THE PRESENCE OF DRY MID-LEVEL AIR WRAPPING INTO THE WESTERN AND
SOUTHERN PORTION OF THE CIRCULATION...ALONG WITH SOUTHWESTERLY
VERTICAL WIND SHEAR OF 20-25 KT FOR THE NEXT 48 HOURS OR SO SHOULD
INHIBIT ANY SIGNIFICANT DEVELOPMENT WHILE DEBBY REMAINS OVER WATER.
THE SHEAR DECREASES SIGNIFICANTLY BY 72 HOURS AND BEYOND...BUT
DEBBY WILL BE OVER OR INTERACTING WITH LAND AT DAYS 3 AND 4...SO
THAT WILL PREVENT THE CYCLONE FROM TAKING ADVANTAGE OF THE
IMPROVING SHEAR CONDITIONS. BY DAY 5...HOWEVER...DEBBY IS EXPECTED
TO BE MOVING OVER THE WARMER WATERS OF THE GULFSTREAM...WHICH MAY
ALLOW FOR SOME MODEST STRENGTHENING TO OCCUR AFTER HAVING WEAKENED
OVER LAND. THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE
PREVIOUS ADVISORY AND CLOSELY FOLLOWS THE LGEM INTENSITY MODEL.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  26/0300Z 29.2N  85.1W   40 KT  45 MPH
 12H  26/1200Z 29.3N  84.9W   40 KT  45 MPH
 24H  27/0000Z 29.4N  84.6W   40 KT  45 MPH
 36H  27/1200Z 29.5N  84.2W   40 KT  45 MPH
 48H  28/0000Z 29.6N  83.6W   40 KT  45 MPH
 72H  29/0000Z 29.8N  82.3W   30 KT  35 MPH...INLAND
 96H  30/0000Z 30.1N  80.7W   35 KT  40 MPH...OVER WATER
120H  01/0000Z 30.8N  78.7W   40 KT  45 MPH
 
$$
FORECASTER STEWART
 

WTNT44 KNHC 232052
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER   1
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
400 PM CDT SAT JUN 23 2012
 
AIRCRAFT RECONNAISSANCE...SATELLITE...AND BUOY DATA INDICATE THAT
THE CIRCULATION ASSOCIATED WITH THE AREA OF LOW PRESSURE IN THE
GULF OF MEXICO HAS BECOME SUFFICIENTLY DEFINED TO CLASSIFY THIS
SYSTEM AS A TROPICAL STORM.  THE INITIAL INTENSITY IS BASED ON A
HIGHEST 1000-FT FLIGHT-LEVEL WIND OF 61 KT AND SFMR WINDS NEAR 45
KT.  THESE WINDS ARE ONLY OCCURRING TO THE EAST OF THE CENTER.
 
DEBBY IS MOVING SLOWLY NORTHWARD...OR 360 DEGREES AT 5 KT.  THE
CYCLONE IS IN A WEAK STEERING ENVIRONMENT BETWEEN TWO MID-LEVEL
RIDGES LOCATED OVER THE GREATER ANTILLES AND THE SOUTHERN UNITED
STATES...AND DEBBY IS NOT EXPECTED TO MOVE MUCH DURING THE NEXT
COUPLE OF DAYS.  THE TRACK GUIDANCE IS SPLIT IN TWO BRANCHES...WITH
THE GFS AND GFDL SHOWING AN EASTWARD MOTION ACROSS FLORIDA...AND
THE REST OF THE MODELS BRINGING DEBBY WESTWARD ACROSS THE NORTHERN
GULF TOWARDS TEXAS.  EVEN THOUGH THE DETERMINISTIC GFS SHOWS AN
EASTWARD TRACK...MORE THAN HALF OF THE GFS ENSEMBLE MEMBERS ARE IN
AGREEMENT WITH THE WESTWARD-MOVING MODELS...MAKING THE WESTWARD
SCENARIO SEEM MORE LIKELY.  IT IS IMPORTANT TO NOTE TOO THAT THE
ECMWF MODEL SHOWS A FASTER WESTWARD MOTION THAN INDICATED IN THE
NHC FORECAST...SO IT IS POSSIBLE THAT DEBBY COULD REACH THE COAST
EARLIER THAN INDICATED.
 
DEBBY IS CURRENTLY A SHEARED CYCLONE WITH NEARLY ALL OF THE DEEP
CONVECTION LOCATED IN A CURVED BAND TO THE EAST OF THE CENTER.
HOWEVER...AN UPPER-LEVEL LOW OVER THE NORTHWESTERN GULF OF MEXICO
IS FORECAST TO DIG SOUTHWESTWARD...WHICH WILL RESULT IN A DECREASE
OF VERTICAL SHEAR AFFECTING THE SYSTEM...AND A GREATER CHANCE OF
INTENSIFICATION OVER THE NEXT FEW DAYS.  BECAUSE THE OFFICIAL TRACK
FORECAST IS SO DIFFERENT FROM THE GFS SOLUTION...THE GFS FIELDS USED
BY THE SHIPS AND LGEM MODELS ARE NOT LIKELY TO BE REPRESENTATIVE OF
THE CONDITIONS ENCOUNTERED BY DEBBY.  THE NHC FORECAST THEREFORE
SHOWS MORE STRENGTHENING THAN INDICATED BY THE INTENSITY GUIDANCE.
 
DEBBY IS THE EARLIEST 4TH STORM IN THE HISTORICAL RECORDS...
SURPASSING HURRICANE DENNIS OF 2005...WHICH BECAME A TROPICAL STORM
ON JULY 5TH.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  23/2100Z 26.2N  87.6W   45 KT  50 MPH
 12H  24/0600Z 26.9N  87.8W   45 KT  50 MPH
 24H  24/1800Z 27.3N  88.1W   50 KT  60 MPH
 36H  25/0600Z 27.4N  88.5W   50 KT  60 MPH
 48H  25/1800Z 27.5N  89.5W   55 KT  65 MPH
 72H  26/1800Z 27.5N  91.5W   55 KT  65 MPH
 96H  27/1800Z 27.5N  93.5W   60 KT  70 MPH
120H  28/1800Z 27.5N  95.0W   60 KT  70 MPH
 
$$
FORECASTER BERG/AVILA
 

WTNT44 KNHC 240257
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER   2
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
1000 PM CDT SAT JUN 23 2012
 
DEBBY IS GRADUALLY SHOWING SIGNS OF IMPROVED ORGANIZATION AS THE
UPPER-LEVEL SHEAR SHIFTS FROM SOUTHWESTERLY TO MORE OF A SOUTHERLY
COMPONENT. SHIP ZCDJ2 LOCATED ABOUT 80 NMI EAST OF THE CENTER AND
NEAR NOAA BUOY 42003 REPORTED A PRESSURE OF 1001.6 MB AND 38 KT
WINDS AT 24/00Z. BASED ON THIS INFORMATION...THE CENTRAL PRESSURE
IS CONSERVATIVELY ESTIMATED TO BE 998 MB. AIRCRAFT RECONNAISSANCE
DATA AT 23/2020Z INDICATED 850 MB FLIGHT-LEVEL WINDS OF 61 KT IN
THE NORTHEAST QUADRANT...WHICH IS EQUAL TO ABOUT 49 KT SURFACE
WINDS. CONVECTION WAS SOMEWHAT MEAGER AT THAT...BUT SINCE THEN HAS
INCREASED RATHER MARKEDLY IN THAT AREA. THEREFORE THE INITIAL
INTENSITY ESTIMATE IS A SOLID 45 KT.

DEBBY HAS BEEN NEARLY STATIONARY DURING THE PAST 6 HOURS. MULTIPLE
LOW-LEVEL VORTICES HAVE BEEN OUT FROM UNDERNEATH THE EASTERN
SEMICIRCLE CONVECTIVE CLOUD MASS ABOUT A MEAN CENTER OF ROTATION OF
A LARGER GYRE...AND THE LOCATION OF THE LARGER STATIONARY GYRE IS
THE ADVISORY POSITION. ALTHOUGH THERE MAY BE SOME SLIGHT
NORTHEASTWARD MOTION DUE TO REDEVELOPMENT OF THE CENTER CLOSER TO
THE DEEP CONVECTION...THE GENERAL MOTION FOR THE NEXT 24 HOURS OR
SO SHOULD BE SLOWLY POLEWARD. THE LONGWAVE PATTERN ACROSS THE U.S.
HAS A DEEPENING TROUGH OFF THE WEST COAST...WHICH IS CREATING
DOWNSTREAM RIDGING ACROSS THE CENTRAL AND EASTERN UNITED STATES.
THIS INCREASED RIDGING IS REFLECTED BY 20-40 METER 500 MB HEIGHT
RISES AT 00Z ACROSS THE CENTRAL AND SOUTHERN PLAINS...AND EXTENDING
AS FAR EAST AS THE CAROLINA COASTS. THIS BLOCKING RIDGE PATTERN TO
THE NORTH OF DEBBY IS EXPECTED TO GRADUALLY TURN THE CYCLONE
WESTWARD ACROSS THE NORTH-CENTRAL GULF OF MEXICO BY 36-48
HOURS...WITH A CONTINUED WESTWARD MOTION ACROSS THE NORTHWESTERN
GULF AFTER THAT. ALL OF THE AVAILABLE NHC MODEL GUIDANCE...EXCEPT
FOR THE GFS AND GFS-ENSEMBLE MODELS...SUPPORTS THE GENERAL WESTWARD
MOTION SCENARIO. THE MAIN REASON THAT THE GFS MOVES DEBBY EASTWARD
ACROSS THE NORTHEASTERN GULF IS DUE TO IT HAVING A WEAKER AND MORE
VERTICALLY SHALLOW STORM DEPICTED IN THE MODEL. GIVEN THE EXPECTED
FAVORABLE UPPER-LEVEL FLOW PATTERN WITH WEAKER VERTICAL SHEAR
FORECAST TO DEVELOP AFTER 24 HOURS...A DEEPER AND MORE ROBUST
WESTWARD MOVING TROPICAL CYCLONE AS DEPICTED IN THE
ECMWF...UKMET... NOGAPS MODELS SEEMS A MORE REASONABLE SCENARIO.
THE OFFICIAL FORECAST TRACK IS JUST AN UPDATE OF THE PREVIOUS
ADVISORY TRACK.

MODERATE SOUTHWESTERLY VERTICAL WIND SHEAR IS EXPECTED TO GRADUALLY
GIVE WAY TO SOUTHERLY AND EVENTUALLY SOUTHEASTERLY WEAKER WIND
SHEAR BY 36-48 HOURS AS AN UPPER-LEVEL LOW NORTHWEST OF THE CYCLONE
MOVES SOUTHWESTWARD...WHICH ALLOWS DEBBY TO MOVE UNDERNEATH A 200
MB RIDGE AXIS. THE OFFICIAL INTENSITY FORECAST LEANS TOWARD THE
ECMWF MODEL...WHICH IS FORECASTING A HURRICANE CENTRAL PRESSURE BY
96 HOURS...AND IS ABOVE THE GFS-BASED SHIPS AND LGEM MODELS SINCE
THAT OUTPUT LIKELY DOES NOT REPRESENT THE ENVIRONMENTAL CONDITIONS
THAT DEBBY WILL ENCOUNTER. THE OFFICIAL INTENSITY FORECAST IS A
LITTLE HIGHER THAN THE PREVIOUS ADVISORY...AND BRINGS DEBBY TO
HURRICANE STRENGTH BY 72 HOURS.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/0300Z 26.3N  87.5W   45 KT  50 MPH
 12H  24/1200Z 26.7N  87.8W   50 KT  60 MPH
 24H  25/0000Z 27.0N  88.1W   50 KT  60 MPH
 36H  25/1200Z 27.1N  88.8W   55 KT  65 MPH
 48H  26/0000Z 27.2N  89.8W   60 KT  70 MPH
 72H  27/0000Z 27.2N  91.8W   65 KT  75 MPH
 96H  28/0000Z 27.2N  93.7W   70 KT  80 MPH
120H  29/0000Z 27.2N  95.2W   70 KT  80 MPH
 
$$
FORECASTER STEWART
 

WTNT44 KNHC 240837
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER   3
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
400 AM CDT SUN JUN 24 2012
 
THE CLOUD PATTERN OF THE TROPICAL STORM HAS NOT BECOME SIGNIFICANTLY
BETTER ORGANIZED OVER THE PAST FEW HOURS.  DEBBY HAS BEEN PRODUCING
VERY COLD-TOPPED DEEP CONVECTION BUT THESE THUNDERSTORMS...AND
LIKELY THE STRONGEST WINDS...ARE OCCURRING SOME 100 TO 150 MILES
NORTHEAST OF THE LOW-LEVEL CENTER.  THE CURRENT INTENSITY IS KEPT
AT 45 KT...WHICH IS IN AGREEMENT WITH DATA FROM AN ASCAT PASS
SEVERAL HOURS AGO.  NO CHANGE IS MADE TO THE PREVIOUS INTENSITY
FORECAST...HOWEVER THIS FORECAST IS BASED ON THE PREMISE THAT THE
VERTICAL SHEAR WILL DECREASE OVER THE NEXT FEW DAYS AND THE GLOBAL
MODELS ARE NOT UNANIMOUS ON THIS.  THE OFFICIAL WIND SPEED FORECAST
IS CLOSEST TO THE MOST RECENT HWRF GUIDANCE...AND IT SHOULD BE
NOTED THAT WE HAVE LIMITED SKILL IN PREDICTING TROPICAL CYCLONE
INTENSITY CHANGE. 

WITH INFRARED IMAGERY THE CENTER...ALTHOUGH PARTIALLY EXPOSED...HAS
BECOME A LITTLE MORE DIFFICULT TO LOCATE AND THE FIXES FROM TAFB
AND SAB ARE ABOUT 50 MILES APART.  MY BEST ESTIMATE OF INITIAL
MOTION IS SLOWLY NORTHWARD...OR 360/3.  THE TRACK FORECAST FOR THIS
STORM IS EXTREMELY CHALLENGING.  THE SYNOPTIC REASONING IN PREVIOUS
ADVISORIES WAS BASED ON A MID-LEVEL RIDGE BUILDING TO THE NORTH OF
THE TROPICAL CYCLONE...WHICH WOULD CAUSE DEBBY TO MOVE TOWARD THE
NORTHWEST GULF OF MEXICO COAST IN SEVERAL DAYS.  THAT TRACK
SCENARIO WAS SUPPORTED BY THE ECMWF MODEL...WHICH HAS BEEN THE
BEST-PERFORMING GUIDANCE OVER THE PAST FEW YEARS.  HOWEVER...THE
0000 RUN OF THAT MODEL HAS SHIFTED SUBSTANTIALLY TO THE NORTH AND
EAST OF THE PREVIOUS RUNS.  THE U.K. MET. OFFICE MODEL HAS ALSO
SHIFTED SIGNIFICANTLY TO THE RIGHT.  IN FACT...ONLY THE HWRF MODEL
IS CLOSE TO THE PREVIOUS OFFICIAL FORECASTS...AND EVEN IT IS TO THE
NORTH OF THEM.  THEREFORE AN UNUSUALLY LARGE RIGHTWARD ADJUSTMENT
TO THE NHC FORECAST IS REQUIRED...AND ADDITIONAL SHIFTS TO THE
NORTH AND EAST MAY BE NECESSARY IN SUBSEQUENT ADVISORY PACKAGES.

NEEDLESS TO SAY...THIS IS A LOW CONFIDENCE FORECAST.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/0900Z 27.3N  87.3W   45 KT  50 MPH
 12H  24/1800Z 27.5N  87.4W   50 KT  60 MPH
 24H  25/0600Z 27.9N  87.8W   50 KT  60 MPH
 36H  25/1800Z 28.2N  88.4W   55 KT  65 MPH
 48H  26/0600Z 28.3N  89.0W   60 KT  70 MPH
 72H  27/0600Z 28.5N  90.5W   65 KT  75 MPH
 96H  28/0600Z 28.5N  92.0W   70 KT  80 MPH
120H  29/0600Z 28.5N  93.5W   70 KT  80 MPH
 
$$
FORECASTER PASCH
 

WTNT44 KNHC 241159
TCDAT4
 
TROPICAL STORM DEBBY SPECIAL DISCUSSION NUMBER   4
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
700 AM CDT SUN JUN 24 2012
 
THE PURPOSE OF THIS SPECIAL ADVISORY IS TO ISSUE A TROPICAL STORM
WARNING FROM THE MISSISSIPPI ALABAMA BORDER EASTWARD TO THE
OCHOLOCKONEE RIVER. THIS IS BASED ON THE EXPANSION OF TROPICAL
STORM FORCE WINDS IN THE NORTHEAST QUADRANT. THERE HAVE BEEN NO
CHANGES TO THE FORECAST TRACK NOR INTENSITY.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/1200Z 27.5N  87.0W   50 KT  60 MPH
 12H  24/1800Z 27.5N  87.4W   50 KT  60 MPH
 24H  25/0600Z 27.9N  87.8W   50 KT  60 MPH
 36H  25/1800Z 28.2N  88.4W   55 KT  65 MPH
 48H  26/0600Z 28.3N  89.0W   60 KT  70 MPH
 72H  27/0600Z 28.5N  90.5W   65 KT  75 MPH
 96H  28/0600Z 28.5N  92.0W   70 KT  80 MPH
120H  29/0600Z 28.5N  93.5W   70 KT  80 MPH
 
$$
FORECASTER AVILA
 


WTNT44 KNHC 241458
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER   5
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
1000 AM CDT SUN JUN 24 2012
 
IT IS A VERY DIFFICULT AND HIGHLY UNCERTAIN FORECAST THIS MORNING.
DEBBY HAS BEEN MOVING VERY SLOWLY TOWARD THE NORTHEAST...040 AT 3
KNOTS...WHILE THE WIND RADII HAVE BEEN EXPANDING IN THE EASTERN
SEMICIRCLE.  THIS HAS PROMPTED ADDITIONAL TROPICAL STORM WARNINGS
AND WATCHES FOR PORTIONS OF THE FLORIDA COAST. 

DEBBY CONTINUES TO BE SHEARED WITH MOST OF THE THUNDERSTORM ACTIVITY
NORTH AND EAST OF THE CENTER.  THIS SHEAR IS EXPECTED TO CONTINUE
FOR THE NEXT DAY OR SO...ALTHOUGH SOME DECREASE IN THE SHEAR IS
POSSIBLE AFTER THAT...PARTICULARLY IF THE ECMWF VERIFIES.  THE
OFFICIAL FORECAST IS A LITTLE LESS AGGRESSIVE THAN THE PREVIOUS
FORECAST...BUT REMAINS ABOVE MOST OF THE EXPLICIT INTENSITY
GUIDANCE.   

THE TRACK FORECAST IS EVEN MORE COMPLEX. THE GFS INSISTS ON A TRACK
TOWARD THE NORTHEAST AS DEBBY BECOMES EMBEDDED WITHIN A LARGE
MID-LATITUDE TROUGH. HOWEVER...THE ECMWF AND THE HWRF BUILD A RIDGE
TO THE NORTH OF DEBBY AND FORECAST A WESTWARD TRACK.  GIVEN THE
WESTWARD TURN INHERITED FROM THE PREVIOUS FORECAST...AS WELL AS THE
HISTORICAL STRONG RECORD OF THE ECMWF...THE NEW OFFICIAL FORECAST
MOVES DEBBY INITIALLY A LITTLE BIT TO THE NORTHEAST TO REFLECT
CURRENT TRENDS BUT THEN TURNS THE CYCLONE BACK TOWARD THE WEST OR
WEST-NORTHWEST IN 24 TO 36 HOURS.  A MAJORITY OF THE GFS ENSEMBLE
MEMBERS NOW ARE CONSISTENT WITH THE DETERMINISTIC RUN...WHICH WAS
NOT THE CASE YESTERDAY...MAKING A STRONGER CASE FOR THE EASTWARD
SOLUTION.  WE MUST BE READY TO MAKE A CHANGE OF THE FORECAST TRACK
AT ANY TIME.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/1500Z 28.0N  86.2W   50 KT  60 MPH
 12H  25/0000Z 28.5N  85.8W   50 KT  60 MPH
 24H  25/1200Z 28.5N  85.8W   50 KT  60 MPH
 36H  26/0000Z 28.5N  86.2W   55 KT  65 MPH
 48H  26/1200Z 28.7N  87.0W   60 KT  70 MPH
 72H  27/1200Z 29.0N  88.4W   65 KT  75 MPH
 96H  28/1200Z 29.5N  90.5W   45 KT  50 MPH
120H  29/1200Z 30.0N  91.5W   30 KT  35 MPH
 
$$
FORECASTER AVILA
 

WTNT44 KNHC 242034
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER   6
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
400 PM CDT SUN JUN 24 2012
 
THERE HAS BEEN A SIGNIFICANT CHANGE IN THE FORECAST TRACK WITH THIS
ADVISORY. THE OFFICIAL FORECAST NO LONGER BRINGS DEBBY WESTWARD
ALONG THE NORTHERN GULF OF MEXICO AND INSTEAD KEEPS THE CYCLONE
MEANDERING OVER THE NORTHEASTERN GULF FOR THE NEXT 3 TO 4 DAYS.
THIS FORECAST IS A COMPROMISE BETWEEN THE CONSISTENT EASTWARD
SOLUTION PROVIDED BY THE GFS FOR THE PAST SEVERAL DAYS AND THE NEW
TWIST OF THE ECMWF. THE ECMWF MODEL...WHICH HAS BEEN
FORECASTING DEBBY TO MOVE WESTWARD ALONG THE GULF OF MEXICO... NOW
HAS THE CYCLONE MEANDERING FOR THE NEXT 3 DAYS OVER THE
NORTHEASTERN GULF. SINCE THESE TWO RELIABLE MODELS ARE IN
MARGINALLY BETTER AGREEMENT...I AM A LITTLE MORE CONFIDENT...BUT
NOT COMPLETELY...THAT DEBBY IS NOT GOING TO TURN WESTWARD OVER THE
GULF. HOWEVER...NEW OFFICIAL TRACK REMAINS A LOW-CONFIDENCE
FORECAST.
 
DEBBY IS A SPRAWLING SYSTEM...WITH MOST OF THE THUNDERSTORM ACTIVITY
IN A CURVED BAND WELL REMOVED FROM THE CENTER.  DATA FROM THE
RECONNAISSANCE PLANE A FEW HOURS AGO INDICATE THAT THE INITIAL
INTENSITY REMAINS 50 KNOTS. THE SHEAR IS NOT EXPECTED TO CHANGE
MUCH FOR THE NEXT DAY OR SO...BUT BECAUSE DEBBY IS FORECAST TO
REMAIN OVER WATER...THERE WILL BE SOME OPPORTUNITY FOR A SLIGHT
STRENGTHENING BEFORE THE CENTER MOVES INLAND. HOWEVER...THE CYCLONE
WILL LOCATED BE NORTH OF THE AREA OF HIGH OCEANIC HEAT CONTENT AND
THE UPWELLING COULD HALT THE INTENSIFICATION. 
 
  
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/2100Z 28.4N  85.8W   50 KT  60 MPH
 12H  25/0600Z 28.7N  85.5W   50 KT  60 MPH
 24H  25/1800Z 29.0N  85.5W   50 KT  60 MPH
 36H  26/0600Z 29.0N  85.5W   55 KT  65 MPH
 48H  26/1800Z 29.0N  85.5W   60 KT  70 MPH
 72H  27/1800Z 29.5N  85.5W   60 KT  70 MPH
 96H  28/1800Z 30.0N  85.5W   40 KT  45 MPH
120H  29/1800Z 30.5N  85.5W   30 KT  35 MPH...INLAND
 
$$
FORECASTER AVILA
 

WTNT44 KNHC 250258
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER   7
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
1000 PM CDT SUN JUN 24 2012
 
THE APPEARANCE OF DEBBY IN SATELLITE AND RADAR IMAGERY HAS DEGRADED
SIGNIFICANTLY THIS EVENING AS A SHARP MID-LEVEL DRY INTRUSION HAS
WORKED ITS WAY INTO THE CENTER OF THE CYCLONE AND ERODED ALL OF THE
INNER CORE DEEP CONVECTION. THE INITIAL INTENSITY IS BEING HELD AT
50 KT FOR THIS FORECAST PACKAGE BASED MAINLY ON CONTINUITY WITH THE
PREVIOUS ADVISORY AND THE RELATIVELY LOW CENTRAL PRESSURE OF 991 MB
REPORTED BY AN AIR FORCE RESERVE RECON AIRCRAFT THIS EVENING.

DEBBY HAS BEEN NEARLY STATIONARY SINCE THE LAST ADVISORY. BOTH 18Z
AND 00Z UPPER-AIR DATA INDICATE MID-LEVEL RIDGING HAS CONTINUED TO
BUILD ACROSS THE SOUTHEASTERN U.S. TO THE NORTH OF DEBBY...AND THIS
HAS LIKELY BEEN THE REASON FOR THE LACK OF ANY SIGNIFICANT MOTION
OVER THE PAST SEVERAL HOURS. ALL OF THE NHC MODEL GUIDANCE...EXCEPT
FOR THE GFS AND GFS-ENSEMBLE MODELS...INDICATE THIS BLOCKING PATTERN
ACROSS THE CENTRAL AND EASTERN U.S. SHOULD CONTINUE AS FAST-MOVING
SHORTWAVE TROUGHS PASS WELL TO THE NORTH OF DEBBY. THE RESULT
SHOULD BE THAT THE CYCLONE WILL MOVE LITTLE DURING THE NEXT COUPLE
OF DAYS...AND THEN ONLY DRIFT SLOWLY NORTHWARD AFTER THAT AS THE
RIDGE OVER THE SOUTHEASTERN U.S. GRADUALLY BREAKS DOWN. ALTHOUGH THE
GFS MODEL HAS BEEN VERY CONSISTENT WITH A FAST NORTHEASTWARD MOTION
ACROSS NORTH FLORIDA THE PAST FEW DAYS...THE LARGE SPRAWLING NATURE
OF THE CYCLONE AND THE BLOCKING RIDGE TO THE NORTH WOULD SUGGEST
THAT THE GFS MODEL MAY BE LIFTING OUT DEBBY TOO QUICKLY. THE
OFFICIAL FORECAST TRACK IS SIMILAR TO BUT SLIGHTLY LEFT OF THE
PREVIOUS ADVISORY TRACK...MAINLY DUE TO THE MORE WESTWARD INITIAL
POSITION.
 
DEBBY HAS FINALLY CONSOLIDATED ALL OF THE MULTIPLE SMALL SWIRLS INTO
A WELL-DEFINED LOW-LEVEL CIRCULATION CENTER. THE GLOBAL MODELS ARE
FORECASTING THE AFOREMENTIONED DEEP DRY SLOT TO GRADUALLY MOISTEN
UP OVER THE NEXT 48 HOURS AS DEEP MOISTURE AND INSTABILITY
CURRENTLY OVER THE FLORIDA PENINSULA ADVECTS WESTWARD INTO THE
INNER CORE. THE COMBINATION OF THESE TWO FEATURES MAY ALLOW FOR
SOME SLIGHT STRENGTHENING BEFORE DEBBY BEGINS TO INTERACT WITH LAND
OR COLD UPWELLING BENEATH THE CYCLONE OCCURS. THE OFFICIAL
INTENSITY FORECAST IS IDENTICAL TO THE PREVIOUS ADVISORY AND
FOLLOWS A BLEND OF THE SHIPS/LGEM STATISTICAL MODELS AND THE
HWRF/GFDL REGIONAL MODELS.

FORECAST POSITIONS AND MAX WINDS
 
INIT  25/0300Z 28.3N  85.9W   50 KT  60 MPH
 12H  25/1200Z 28.6N  85.8W   50 KT  60 MPH
 24H  26/0000Z 28.7N  85.8W   50 KT  60 MPH
 36H  26/1200Z 28.8N  85.8W   55 KT  65 MPH
 48H  27/0000Z 28.9N  85.8W   60 KT  70 MPH
 72H  28/0000Z 29.4N  85.8W   55 KT  65 MPH
 96H  29/0000Z 29.9N  85.8W   35 KT  40 MPH...NEAR COAST
120H  30/0000Z 30.4N  85.6W   30 KT  35 MPH...INLAND
 
$$
FORECASTER STEWART
 

WTNT44 KNHC 250838
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER   8
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
400 AM CDT MON JUN 25 2012
 
DEBBY HAS A HIGHLY UNIMPRESSIVE APPEARANCE ON SATELLITE IMAGERY.
ALTHOUGH RADAR DATA CONTINUE TO DEPICT SOME SHOWER ACTIVITY OVER
THE CIRCULATION...THESE SHOWERS ARE BEING PRODUCED BY SHALLOW
CONVECTION AS THE ENHANCED IR IMAGES DO NOT SHOW ANY SIGNIFICANT
AREAS OF COLD CLOUD TOPS.  AIRCRAFT DATA FROM SEVERAL HOURS AGO
ALONG WITH SYNOPTIC OBSERVATIONS INDICATE THAT THE MAXIMUM SURFACE
WINDS HAVE DECREASED...AND THE CURRENT INTENSITY IS SET AT 45 KT.
DEBBY IS LOCATED NORTH OF THE AREA OF MAXIMUM OCEANIC HEAT
CONTENT...BUT AS LONG AS THE CYCLONE REMAINS OVER WATER AND IS ABLE
TO REGENERATE SOME DEEP CONVECTION THERE IS A POTENTIAL FOR AT
LEAST SLIGHT RE-INTENSIFICATION.  THE CURRENT NHC INTENSITY
FORECAST IS A LITTLE LOWER THAN THE PREVIOUS ONES...BUT A LITTLE
HIGHER THAN MOST OF THE NUMERICAL GUIDANCE.
 
BEST GUESS AT INITIAL MOTION IS QUASI-STATIONARY.  DEBBY REMAINS IN
A COL REGION OF THE MID-TROPOSPHERIC STEERING FLOW BETWEEN TWO
ANTICYCLONES...AND IS LIKELY TO REMAIN SO FOR THE NEXT COUPLE OF
DAYS.  THEREFORE LITTLE MOTION IS ANTICIPATED DURING AT LEAST THE
FIRST HALF OF THE FORECAST PERIOD.  IN THE LONGER-TERM...THE TRACK
GUIDANCE CONTINUES TO BE ALL OVER THE PLACE...WITH SOME MODELS
TAKING DEBBY WEST AND NORTH OF ITS CURRENT POSITION AND OTHERS
MOVING EAST OR NORTHEAST AND ULTIMATELY INTO THE ATLANTIC.  THE
LATTER SCENARIO ASSUMES THAT DEBBY WILL EVENTUALLY BE INFLUENCED BY
A MID-TROPOSPHERIC TROUGH OVER THE NORTHEASTERN UNITED STATES. 
THIS SCENARIO SEEMS MORE LIKELY SINCE IT IS SUPPORTED BY BOTH THE
GFS AND THE ECMWF MODELS.  REGARDLESS OF WHICH SCENARIO PLAYS
OUT...THE CYCLONE DOES NOT SEEM TO BE GOING ANYWHERE ANYTIME SOON. 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  25/0900Z 28.6N  85.8W   45 KT  50 MPH
 12H  25/1800Z 28.8N  85.7W   45 KT  50 MPH
 24H  26/0600Z 28.9N  85.6W   50 KT  60 MPH
 36H  26/1800Z 29.0N  85.5W   50 KT  60 MPH
 48H  27/0600Z 29.2N  85.4W   55 KT  65 MPH
 72H  28/0600Z 29.4N  85.3W   55 KT  65 MPH
 96H  29/0600Z 29.7N  85.2W   45 KT  50 MPH...INLAND
120H  30/0600Z 30.2N  85.0W   30 KT  35 MPH...INLAND
 
$$
FORECASTER PASCH
 

WTNT44 KNHC 251451
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER   9
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
1000 AM CDT MON JUN 25 2012
 
THERE HAS BEEN NO SIGNIFICANT DEEP CONVECTION NEAR THE CENTER OF
DEBBY FOR OVER 12 HOURS. WHAT CONVECTION REMAINS IS PRIMARILY
LOCATED IN A FRAGMENTED BAND WELL EAST OF THE CENTER...AND
SOUNDINGS ALONG THE GULF COAST INDICATE THAT THE ENTRAINMENT OF DRY
MID-LEVEL AIR IS AFFECTING THE STORM. IN ADDITION...THE SLOW
MOVEMENT OF DEBBY HAS INDUCED OCEANIC UPWELLING AND COOLING
UNDERNEATH THE CYCLONE AND MAY HAVE CONTRIBUTED TO THE OBSERVED
WEAKENING. LATEST DATA FROM THE RECONNAISSANCE AIRCRAFT INDICATE
THAT THE MAXIMUM WINDS ARE NEAR 40 KT. WITH DRY AIR LURKING AND
WESTERLY SHEAR ON THE INCREASE OVER THE NEXT COUPLE DAYS...
SIGNIFICANT RE-INTENSIFICATION OF THE CYCLONE PRIOR TO LANDFALL
SEEMS UNLIKELY. THE NEW NHC FORECAST IS ADJUSTED DOWNWARD IN LINE
WITH CURRENT TRENDS AND THE LATEST INTENSITY GUIDANCE.
 
AIRCRAFT AND SATELLITE FIXES HAVE SHOWN LITTLE OVERALL MOVEMENT OVER
THE PAST 12 TO 18 HOURS... ALTHOUGH RECENT SATELLITE IMAGERY
INDICATES AN EAST-NORTHEASTWARD TO NORTHEASTWARD SHORT-TERM MOTION.
AT THE MOMENT...IT IS UNCLEAR WHETHER THE CURRENT MOTION REPRESENTS
A MEANDERING OR A MORE DECIDED MOTION. ON THE LARGE SCALE...DEBBY
IS TRAPPED IN A REGION OF WEAK STEERING IN BETWEEN A STRONG
MID-LEVEL RIDGE OVER THE PLAINS AND ONE OVER THE SUBTROPICAL
CENTRAL ATLANTIC. GLOBAL MODELS DEPICT AN AMPLIFYING TROUGH
OFFSHORE THE EASTERN SEABOARD CAUSING DEBBY TO MOVE GENERALLY
EASTWARD THROUGH THE FORECAST PERIOD...WITH THE CENTER EMERGING
OVER THE SOUTHWEST ATLANTIC BY DAY 5. THE ECMWF/GFS SOLUTIONS BEGIN
TO LIFT OUT THE WESTERN ATLANTIC TROUGH IN ABOUT 72 HOURS...WHICH
COULD LEAVE DEBBY IN WEAK STEERING CURRENT AGAIN AFTER THAT TIME.
SINCE YESTERDAY... THE GUIDANCE HAS COME INTO BETTER
AGREEMENT...WITH ONLY THE UKMET NOW SHOWING A WESTWARD MOTION. IN
ADDITION...THE LATEST GFS ENSEMBLE MEMBERS FAVOR AN EASTWARD MOTION
BY ABOUT A 3 TO 1 RATIO. THE NEW FORECAST TRACK REPRESENTS A
SUBSTANTIAL CHANGE FROM THE PREVIOUS ONE BUT IS STILL SLOWER THAN
THE MULTI-MODEL CONSENSUS IN THE SHORT TERM.
 

FORECAST POSITIONS AND MAX WINDS
 
INIT  25/1500Z 28.6N  85.2W   40 KT  45 MPH
 12H  26/0000Z 28.8N  85.1W   35 KT  40 MPH
 24H  26/1200Z 28.9N  84.9W   35 KT  40 MPH
 36H  27/0000Z 29.0N  84.7W   35 KT  40 MPH
 48H  27/1200Z 29.2N  84.4W   35 KT  40 MPH
 72H  28/1200Z 29.5N  83.5W   35 KT  40 MPH
 96H  29/1200Z 29.5N  82.5W   30 KT  35 MPH...INLAND
120H  30/1200Z 29.5N  81.0W   30 KT  35 MPH
 
$$
FORECASTER KIMBERLAIN/FRANKLIN
 


WTNT44 KNHC 252052
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER  10
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
400 PM CDT MON JUN 25 2012
 
SATELLITE IMAGERY INDICATES THAT DEBBY HAS CHANGED LITTLE IN
ORGANIZATION TODAY. THE CENTER OF THE CYCLONE IS A LITTLE HARDER TO
LOCATE...WITH AT LEAST A COUPLE OF SMALL VORTICES ROTATING AROUND A
MEAN CENTER. THERE HAD BEEN VIRTUALLY NO CONVECTION ASSOCIATED WITH
THE CENTER OF THE CYCLONE EITHER...BUT A BURST OF DEEP CONVECTION
HAS RECENTLY FORMED OVER LAND TO THE NORTH OF THE CENTER. EARLIER
AIRCRAFT DATA SHOWED PEAK FLIGHT-LEVEL WINDS OF 57 KT AT 850MB...
WITH MAXIMUM SFMR VALUES AROUND 40 KT. GIVEN THESE DATA AND THE
LACK OF STRUCTURAL CHANGES TO THE CYCLONE...THE INITIAL INTENSITY
REMAINS 40 KT.  THE CURRENT STRUCTURE...COMBINED WITH AN INCREASE
IN WESTERLY SHEAR AND ADDITIONAL DRY AIR POSSIBLY WRAPPING INTO THE
STORM CIRCULATION...WOULD SEEM TO PRECLUDE MUCH SHORT-TERM
RE-INTENSIFICATION OF DEBBY...AND THE SHIPS AND LGEM MODELS SHOW NO
APPRECIABLE CHANGE IN STRENGTH PRIOR TO LANDFALL. MARGINALLY
FAVORABLE ENVIRONMENTAL CONDITIONS COULD PROVIDE AN OPPORTUNITY FOR
RE-STRENGTHENING OVER THE WESTERN ATLANTIC AT THE END OF THE
FORECAST PERIOD.
 
A SMOOTHING OF RECENT AIRCRAFT AND SATELLITE FIXES YIELDS A SLOW
NORTHEASTWARD MOTION OF 040/04. LARGE-SCALE MODELS SHOW DEBBY
CONTINUING ON AN EAST-NORTHEASTWARD TO NORTHEASTWARD COURSE OVER
THE NEXT FEW DAYS IN RESPONSE TO AN AMPLIFYING TROUGH OFFSHORE OF
THE U.S. EAST COAST. AS THE WESTERN ATLANTIC TROUGH BEGINS TO LIFT
OUT IN 2-3 DAYS...DEBBY IS EXPECTED TO SLOW DOWN AND BE LEFT BEHIND
OVER THE SOUTHWESTERN ATLANTIC. WITH THE EXCEPTION OF THE GFS
ENSEMBLE MEMBERS...THE MODEL GUIDANCE IS IN BETTER AGREEMENT
OVERALL ON AN EASTWARD TRACK...ALTHOUGH SIGNIFICANT SPEED
DIFFERENCES REMAIN. THE GFS IS CONSIDERABLY SLOWER THAN THE MODEL
CONSENSUS...AND SHOWS DEBBY TAKING FIVE DAYS TO MOVE OFFSHORE THE
FLORIDA ATLANTIC COAST. INTERESTINGLY...THE ECMWF IS NOW ONE OF THE
FASTEST MODELS TO THE EAST. THE NHC OFFICIAL TRACK FORECAST IS NOT
AS FAST AS THE MULTI-MODEL CONSENSUS IN DEFERENCE TO CONTINUITY AND
THE GFS.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  25/2100Z 29.3N  85.1W   40 KT  45 MPH
 12H  26/0600Z 29.4N  84.9W   40 KT  45 MPH
 24H  26/1800Z 29.5N  84.7W   40 KT  45 MPH
 36H  27/0600Z 29.6N  84.4W   40 KT  45 MPH
 48H  27/1800Z 29.7N  83.8W   40 KT  45 MPH
 72H  28/1800Z 29.8N  82.5W   30 KT  35 MPH...INLAND
 96H  29/1800Z 29.8N  81.0W   30 KT  35 MPH
120H  30/1800Z 30.0N  79.0W   35 KT  40 MPH
 
$$
FORECASTER KIMBERLAIN/
 

WTNT44 KNHC 260300
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER  11
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
1000 PM CDT MON JUN 25 2012
 
AFTER AN INTENSE BURST OF DEEP CONVECTION NEAR AND NORTH OF THE
LOW-LEVEL CENTER THIS LATE AFTERNOON AND EVENING...THE CONVECTIVE
CLOUD SHIELD IS SHOWING SIGNS OF SLOWLY PULLING AWAY FROM CENTER OF
CIRCULATION DUE TO MODERATE TO STRONG SOUTHWESTERLY VERTICAL WIND
SHEAR. THE HIGHEST RELIABLE SFMR WINDS REPORTED BY AN AIR FORCE
RESERVE RECON AIRCRAFT THIS EVENING HAS BEEN 42 KT TO THE WEST AND
WELL SOUTHEAST OF THE CENTER...ALONG WITH 59-KT AND 56-KT
FLIGHT-LEVEL WINDS...RESPECTIVELY. ALTHOUGH THE TALLAHASSEE DOPPLER
WEATHER RADAR HAS BEEN INDICATING LARGE WINDS OF 60-65 VELOCITIES
BETWEEN 2000 AND 6500 FT IN SOME RATHER VIGOROUS CONVECTION...THOSE
CONDITIONS HAVE BEEN OVER LAND. THEREFORE...THE INITIAL INTENSITY
WILL REMAIN AT 40 KT.

THE MOTION ESTIMATE IS A SLOW DRIFT TO THE NORTHEAST OR 040/02 KT
OVER THE PAST 12 HOURS. THERE IS NO SIGNIFICANT CHANGE TO THE
PREVIOUS TRACK REASONING. UPPER-AIR DATA AT 18Z AND 00Z INDICATE 
DEBBY REMAINS TRAPPED IN A BLOCKING RIDGE PATTERN THAT EXTENDS
ACROSS THE SOUTHEASTERN U.S. AND INTO THE EASTERN GULF OF MEXICO
AND WESTERN ATLANTIC. THE RESULTANT WEAK STEERING FLOW SHOULD KEEP
DEBBY MOVING VERY SLOWLY NORTHEAST OR EASTWARD AT LESS THAN 5 KT
THROUGHOUT THE FORECAST PERIOD. IN FACT...DEBBY WILL LIKELY REMAIN
OVER THE NORTHEASTERN GULF OF MEXICO FOR AT LEAST THE NEXT 2 DAYS
BEFORE IT CREEPS SLOWLY ACROSS NORTH FLORIDA IN DAYS 3-4. IN THE
ABSENCE OF ANY LARGE-SCALE STEERING FLOW...THE LOW-LEVEL CENTER OF
DEBBY WILL CLOSELY FOLLOW ANY DEEP CONVECTION THAT DEVELOPS...WHICH
SHOULD REMAIN PRIMARILY TO NORTHEAST OF THE CENTER.  THE OFFICIAL
FORECAST TRACK IS SIMILAR TO THE PREVIOUS ADVISORY TRACK THROUGH
DAY 3...AND IS THEN A LITTLE NORTH OF THE PREVIOUS TRACK AND CLOSE
TO THE NHC MODEL CONSENSUS.

THE PRESENCE OF DRY MID-LEVEL AIR WRAPPING INTO THE WESTERN AND
SOUTHERN PORTION OF THE CIRCULATION...ALONG WITH SOUTHWESTERLY
VERTICAL WIND SHEAR OF 20-25 KT FOR THE NEXT 48 HOURS OR SO SHOULD
INHIBIT ANY SIGNIFICANT DEVELOPMENT WHILE DEBBY REMAINS OVER WATER.
THE SHEAR DECREASES SIGNIFICANTLY BY 72 HOURS AND BEYOND...BUT
DEBBY WILL BE OVER OR INTERACTING WITH LAND AT DAYS 3 AND 4...SO
THAT WILL PREVENT THE CYCLONE FROM TAKING ADVANTAGE OF THE
IMPROVING SHEAR CONDITIONS. BY DAY 5...HOWEVER...DEBBY IS EXPECTED
TO BE MOVING OVER THE WARMER WATERS OF THE GULFSTREAM...WHICH MAY
ALLOW FOR SOME MODEST STRENGTHENING TO OCCUR AFTER HAVING WEAKENED
OVER LAND. THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE
PREVIOUS ADVISORY AND CLOSELY FOLLOWS THE LGEM INTENSITY MODEL.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  26/0300Z 29.2N  85.1W   40 KT  45 MPH
 12H  26/1200Z 29.3N  84.9W   40 KT  45 MPH
 24H  27/0000Z 29.4N  84.6W   40 KT  45 MPH
 36H  27/1200Z 29.5N  84.2W   40 KT  45 MPH
 48H  28/0000Z 29.6N  83.6W   40 KT  45 MPH
 72H  29/0000Z 29.8N  82.3W   30 KT  35 MPH...INLAND
 96H  30/0000Z 30.1N  80.7W   35 KT  40 MPH...OVER WATER
120H  01/0000Z 30.8N  78.7W   40 KT  45 MPH
 
$$
FORECASTER STEWART
 

WTNT44 KNHC 232052
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER   1
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
400 PM CDT SAT JUN 23 2012
 
AIRCRAFT RECONNAISSANCE...SATELLITE...AND BUOY DATA INDICATE THAT
THE CIRCULATION ASSOCIATED WITH THE AREA OF LOW PRESSURE IN THE
GULF OF MEXICO HAS BECOME SUFFICIENTLY DEFINED TO CLASSIFY THIS
SYSTEM AS A TROPICAL STORM.  THE INITIAL INTENSITY IS BASED ON A
HIGHEST 1000-FT FLIGHT-LEVEL WIND OF 61 KT AND SFMR WINDS NEAR 45
KT.  THESE WINDS ARE ONLY OCCURRING TO THE EAST OF THE CENTER.
 
DEBBY IS MOVING SLOWLY NORTHWARD...OR 360 DEGREES AT 5 KT.  THE
CYCLONE IS IN A WEAK STEERING ENVIRONMENT BETWEEN TWO MID-LEVEL
RIDGES LOCATED OVER THE GREATER ANTILLES AND THE SOUTHERN UNITED
STATES...AND DEBBY IS NOT EXPECTED TO MOVE MUCH DURING THE NEXT
COUPLE OF DAYS.  THE TRACK GUIDANCE IS SPLIT IN TWO BRANCHES...WITH
THE GFS AND GFDL SHOWING AN EASTWARD MOTION ACROSS FLORIDA...AND
THE REST OF THE MODELS BRINGING DEBBY WESTWARD ACROSS THE NORTHERN
GULF TOWARDS TEXAS.  EVEN THOUGH THE DETERMINISTIC GFS SHOWS AN
EASTWARD TRACK...MORE THAN HALF OF THE GFS ENSEMBLE MEMBERS ARE IN
AGREEMENT WITH THE WESTWARD-MOVING MODELS...MAKING THE WESTWARD
SCENARIO SEEM MORE LIKELY.  IT IS IMPORTANT TO NOTE TOO THAT THE
ECMWF MODEL SHOWS A FASTER WESTWARD MOTION THAN INDICATED IN THE
NHC FORECAST...SO IT IS POSSIBLE THAT DEBBY COULD REACH THE COAST
EARLIER THAN INDICATED.
 
DEBBY IS CURRENTLY A SHEARED CYCLONE WITH NEARLY ALL OF THE DEEP
CONVECTION LOCATED IN A CURVED BAND TO THE EAST OF THE CENTER.
HOWEVER...AN UPPER-LEVEL LOW OVER THE NORTHWESTERN GULF OF MEXICO
IS FORECAST TO DIG SOUTHWESTWARD...WHICH WILL RESULT IN A DECREASE
OF VERTICAL SHEAR AFFECTING THE SYSTEM...AND A GREATER CHANCE OF
INTENSIFICATION OVER THE NEXT FEW DAYS.  BECAUSE THE OFFICIAL TRACK
FORECAST IS SO DIFFERENT FROM THE GFS SOLUTION...THE GFS FIELDS USED
BY THE SHIPS AND LGEM MODELS ARE NOT LIKELY TO BE REPRESENTATIVE OF
THE CONDITIONS ENCOUNTERED BY DEBBY.  THE NHC FORECAST THEREFORE
SHOWS MORE STRENGTHENING THAN INDICATED BY THE INTENSITY GUIDANCE.
 
DEBBY IS THE EARLIEST 4TH STORM IN THE HISTORICAL RECORDS...
SURPASSING HURRICANE DENNIS OF 2005...WHICH BECAME A TROPICAL STORM
ON JULY 5TH.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  23/2100Z 26.2N  87.6W   45 KT  50 MPH
 12H  24/0600Z 26.9N  87.8W   45 KT  50 MPH
 24H  24/1800Z 27.3N  88.1W   50 KT  60 MPH
 36H  25/0600Z 27.4N  88.5W   50 KT  60 MPH
 48H  25/1800Z 27.5N  89.5W   55 KT  65 MPH
 72H  26/1800Z 27.5N  91.5W   55 KT  65 MPH
 96H  27/1800Z 27.5N  93.5W   60 KT  70 MPH
120H  28/1800Z 27.5N  95.0W   60 KT  70 MPH
 
$$
FORECASTER BERG/AVILA
 

WTNT44 KNHC 240257
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER   2
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
1000 PM CDT SAT JUN 23 2012
 
DEBBY IS GRADUALLY SHOWING SIGNS OF IMPROVED ORGANIZATION AS THE
UPPER-LEVEL SHEAR SHIFTS FROM SOUTHWESTERLY TO MORE OF A SOUTHERLY
COMPONENT. SHIP ZCDJ2 LOCATED ABOUT 80 NMI EAST OF THE CENTER AND
NEAR NOAA BUOY 42003 REPORTED A PRESSURE OF 1001.6 MB AND 38 KT
WINDS AT 24/00Z. BASED ON THIS INFORMATION...THE CENTRAL PRESSURE
IS CONSERVATIVELY ESTIMATED TO BE 998 MB. AIRCRAFT RECONNAISSANCE
DATA AT 23/2020Z INDICATED 850 MB FLIGHT-LEVEL WINDS OF 61 KT IN
THE NORTHEAST QUADRANT...WHICH IS EQUAL TO ABOUT 49 KT SURFACE
WINDS. CONVECTION WAS SOMEWHAT MEAGER AT THAT...BUT SINCE THEN HAS
INCREASED RATHER MARKEDLY IN THAT AREA. THEREFORE THE INITIAL
INTENSITY ESTIMATE IS A SOLID 45 KT.

DEBBY HAS BEEN NEARLY STATIONARY DURING THE PAST 6 HOURS. MULTIPLE
LOW-LEVEL VORTICES HAVE BEEN OUT FROM UNDERNEATH THE EASTERN
SEMICIRCLE CONVECTIVE CLOUD MASS ABOUT A MEAN CENTER OF ROTATION OF
A LARGER GYRE...AND THE LOCATION OF THE LARGER STATIONARY GYRE IS
THE ADVISORY POSITION. ALTHOUGH THERE MAY BE SOME SLIGHT
NORTHEASTWARD MOTION DUE TO REDEVELOPMENT OF THE CENTER CLOSER TO
THE DEEP CONVECTION...THE GENERAL MOTION FOR THE NEXT 24 HOURS OR
SO SHOULD BE SLOWLY POLEWARD. THE LONGWAVE PATTERN ACROSS THE U.S.
HAS A DEEPENING TROUGH OFF THE WEST COAST...WHICH IS CREATING
DOWNSTREAM RIDGING ACROSS THE CENTRAL AND EASTERN UNITED STATES.
THIS INCREASED RIDGING IS REFLECTED BY 20-40 METER 500 MB HEIGHT
RISES AT 00Z ACROSS THE CENTRAL AND SOUTHERN PLAINS...AND EXTENDING
AS FAR EAST AS THE CAROLINA COASTS. THIS BLOCKING RIDGE PATTERN TO
THE NORTH OF DEBBY IS EXPECTED TO GRADUALLY TURN THE CYCLONE
WESTWARD ACROSS THE NORTH-CENTRAL GULF OF MEXICO BY 36-48
HOURS...WITH A CONTINUED WESTWARD MOTION ACROSS THE NORTHWESTERN
GULF AFTER THAT. ALL OF THE AVAILABLE NHC MODEL GUIDANCE...EXCEPT
FOR THE GFS AND GFS-ENSEMBLE MODELS...SUPPORTS THE GENERAL WESTWARD
MOTION SCENARIO. THE MAIN REASON THAT THE GFS MOVES DEBBY EASTWARD
ACROSS THE NORTHEASTERN GULF IS DUE TO IT HAVING A WEAKER AND MORE
VERTICALLY SHALLOW STORM DEPICTED IN THE MODEL. GIVEN THE EXPECTED
FAVORABLE UPPER-LEVEL FLOW PATTERN WITH WEAKER VERTICAL SHEAR
FORECAST TO DEVELOP AFTER 24 HOURS...A DEEPER AND MORE ROBUST
WESTWARD MOVING TROPICAL CYCLONE AS DEPICTED IN THE
ECMWF...UKMET... NOGAPS MODELS SEEMS A MORE REASONABLE SCENARIO.
THE OFFICIAL FORECAST TRACK IS JUST AN UPDATE OF THE PREVIOUS
ADVISORY TRACK.

MODERATE SOUTHWESTERLY VERTICAL WIND SHEAR IS EXPECTED TO GRADUALLY
GIVE WAY TO SOUTHERLY AND EVENTUALLY SOUTHEASTERLY WEAKER WIND
SHEAR BY 36-48 HOURS AS AN UPPER-LEVEL LOW NORTHWEST OF THE CYCLONE
MOVES SOUTHWESTWARD...WHICH ALLOWS DEBBY TO MOVE UNDERNEATH A 200
MB RIDGE AXIS. THE OFFICIAL INTENSITY FORECAST LEANS TOWARD THE
ECMWF MODEL...WHICH IS FORECASTING A HURRICANE CENTRAL PRESSURE BY
96 HOURS...AND IS ABOVE THE GFS-BASED SHIPS AND LGEM MODELS SINCE
THAT OUTPUT LIKELY DOES NOT REPRESENT THE ENVIRONMENTAL CONDITIONS
THAT DEBBY WILL ENCOUNTER. THE OFFICIAL INTENSITY FORECAST IS A
LITTLE HIGHER THAN THE PREVIOUS ADVISORY...AND BRINGS DEBBY TO
HURRICANE STRENGTH BY 72 HOURS.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/0300Z 26.3N  87.5W   45 KT  50 MPH
 12H  24/1200Z 26.7N  87.8W   50 KT  60 MPH
 24H  25/0000Z 27.0N  88.1W   50 KT  60 MPH
 36H  25/1200Z 27.1N  88.8W   55 KT  65 MPH
 48H  26/0000Z 27.2N  89.8W   60 KT  70 MPH
 72H  27/0000Z 27.2N  91.8W   65 KT  75 MPH
 96H  28/0000Z 27.2N  93.7W   70 KT  80 MPH
120H  29/0000Z 27.2N  95.2W   70 KT  80 MPH
 
$$
FORECASTER STEWART
 

WTNT44 KNHC 240837
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER   3
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
400 AM CDT SUN JUN 24 2012
 
THE CLOUD PATTERN OF THE TROPICAL STORM HAS NOT BECOME SIGNIFICANTLY
BETTER ORGANIZED OVER THE PAST FEW HOURS.  DEBBY HAS BEEN PRODUCING
VERY COLD-TOPPED DEEP CONVECTION BUT THESE THUNDERSTORMS...AND
LIKELY THE STRONGEST WINDS...ARE OCCURRING SOME 100 TO 150 MILES
NORTHEAST OF THE LOW-LEVEL CENTER.  THE CURRENT INTENSITY IS KEPT
AT 45 KT...WHICH IS IN AGREEMENT WITH DATA FROM AN ASCAT PASS
SEVERAL HOURS AGO.  NO CHANGE IS MADE TO THE PREVIOUS INTENSITY
FORECAST...HOWEVER THIS FORECAST IS BASED ON THE PREMISE THAT THE
VERTICAL SHEAR WILL DECREASE OVER THE NEXT FEW DAYS AND THE GLOBAL
MODELS ARE NOT UNANIMOUS ON THIS.  THE OFFICIAL WIND SPEED FORECAST
IS CLOSEST TO THE MOST RECENT HWRF GUIDANCE...AND IT SHOULD BE
NOTED THAT WE HAVE LIMITED SKILL IN PREDICTING TROPICAL CYCLONE
INTENSITY CHANGE. 

WITH INFRARED IMAGERY THE CENTER...ALTHOUGH PARTIALLY EXPOSED...HAS
BECOME A LITTLE MORE DIFFICULT TO LOCATE AND THE FIXES FROM TAFB
AND SAB ARE ABOUT 50 MILES APART.  MY BEST ESTIMATE OF INITIAL
MOTION IS SLOWLY NORTHWARD...OR 360/3.  THE TRACK FORECAST FOR THIS
STORM IS EXTREMELY CHALLENGING.  THE SYNOPTIC REASONING IN PREVIOUS
ADVISORIES WAS BASED ON A MID-LEVEL RIDGE BUILDING TO THE NORTH OF
THE TROPICAL CYCLONE...WHICH WOULD CAUSE DEBBY TO MOVE TOWARD THE
NORTHWEST GULF OF MEXICO COAST IN SEVERAL DAYS.  THAT TRACK
SCENARIO WAS SUPPORTED BY THE ECMWF MODEL...WHICH HAS BEEN THE
BEST-PERFORMING GUIDANCE OVER THE PAST FEW YEARS.  HOWEVER...THE
0000 RUN OF THAT MODEL HAS SHIFTED SUBSTANTIALLY TO THE NORTH AND
EAST OF THE PREVIOUS RUNS.  THE U.K. MET. OFFICE MODEL HAS ALSO
SHIFTED SIGNIFICANTLY TO THE RIGHT.  IN FACT...ONLY THE HWRF MODEL
IS CLOSE TO THE PREVIOUS OFFICIAL FORECASTS...AND EVEN IT IS TO THE
NORTH OF THEM.  THEREFORE AN UNUSUALLY LARGE RIGHTWARD ADJUSTMENT
TO THE NHC FORECAST IS REQUIRED...AND ADDITIONAL SHIFTS TO THE
NORTH AND EAST MAY BE NECESSARY IN SUBSEQUENT ADVISORY PACKAGES.

NEEDLESS TO SAY...THIS IS A LOW CONFIDENCE FORECAST.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/0900Z 27.3N  87.3W   45 KT  50 MPH
 12H  24/1800Z 27.5N  87.4W   50 KT  60 MPH
 24H  25/0600Z 27.9N  87.8W   50 KT  60 MPH
 36H  25/1800Z 28.2N  88.4W   55 KT  65 MPH
 48H  26/0600Z 28.3N  89.0W   60 KT  70 MPH
 72H  27/0600Z 28.5N  90.5W   65 KT  75 MPH
 96H  28/0600Z 28.5N  92.0W   70 KT  80 MPH
120H  29/0600Z 28.5N  93.5W   70 KT  80 MPH
 
$$
FORECASTER PASCH
 

WTNT44 KNHC 241159
TCDAT4
 
TROPICAL STORM DEBBY SPECIAL DISCUSSION NUMBER   4
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
700 AM CDT SUN JUN 24 2012
 
THE PURPOSE OF THIS SPECIAL ADVISORY IS TO ISSUE A TROPICAL STORM
WARNING FROM THE MISSISSIPPI ALABAMA BORDER EASTWARD TO THE
OCHOLOCKONEE RIVER. THIS IS BASED ON THE EXPANSION OF TROPICAL
STORM FORCE WINDS IN THE NORTHEAST QUADRANT. THERE HAVE BEEN NO
CHANGES TO THE FORECAST TRACK NOR INTENSITY.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/1200Z 27.5N  87.0W   50 KT  60 MPH
 12H  24/1800Z 27.5N  87.4W   50 KT  60 MPH
 24H  25/0600Z 27.9N  87.8W   50 KT  60 MPH
 36H  25/1800Z 28.2N  88.4W   55 KT  65 MPH
 48H  26/0600Z 28.3N  89.0W   60 KT  70 MPH
 72H  27/0600Z 28.5N  90.5W   65 KT  75 MPH
 96H  28/0600Z 28.5N  92.0W   70 KT  80 MPH
120H  29/0600Z 28.5N  93.5W   70 KT  80 MPH
 
$$
FORECASTER AVILA
 


WTNT44 KNHC 241458
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER   5
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
1000 AM CDT SUN JUN 24 2012
 
IT IS A VERY DIFFICULT AND HIGHLY UNCERTAIN FORECAST THIS MORNING.
DEBBY HAS BEEN MOVING VERY SLOWLY TOWARD THE NORTHEAST...040 AT 3
KNOTS...WHILE THE WIND RADII HAVE BEEN EXPANDING IN THE EASTERN
SEMICIRCLE.  THIS HAS PROMPTED ADDITIONAL TROPICAL STORM WARNINGS
AND WATCHES FOR PORTIONS OF THE FLORIDA COAST. 

DEBBY CONTINUES TO BE SHEARED WITH MOST OF THE THUNDERSTORM ACTIVITY
NORTH AND EAST OF THE CENTER.  THIS SHEAR IS EXPECTED TO CONTINUE
FOR THE NEXT DAY OR SO...ALTHOUGH SOME DECREASE IN THE SHEAR IS
POSSIBLE AFTER THAT...PARTICULARLY IF THE ECMWF VERIFIES.  THE
OFFICIAL FORECAST IS A LITTLE LESS AGGRESSIVE THAN THE PREVIOUS
FORECAST...BUT REMAINS ABOVE MOST OF THE EXPLICIT INTENSITY
GUIDANCE.   

THE TRACK FORECAST IS EVEN MORE COMPLEX. THE GFS INSISTS ON A TRACK
TOWARD THE NORTHEAST AS DEBBY BECOMES EMBEDDED WITHIN A LARGE
MID-LATITUDE TROUGH. HOWEVER...THE ECMWF AND THE HWRF BUILD A RIDGE
TO THE NORTH OF DEBBY AND FORECAST A WESTWARD TRACK.  GIVEN THE
WESTWARD TURN INHERITED FROM THE PREVIOUS FORECAST...AS WELL AS THE
HISTORICAL STRONG RECORD OF THE ECMWF...THE NEW OFFICIAL FORECAST
MOVES DEBBY INITIALLY A LITTLE BIT TO THE NORTHEAST TO REFLECT
CURRENT TRENDS BUT THEN TURNS THE CYCLONE BACK TOWARD THE WEST OR
WEST-NORTHWEST IN 24 TO 36 HOURS.  A MAJORITY OF THE GFS ENSEMBLE
MEMBERS NOW ARE CONSISTENT WITH THE DETERMINISTIC RUN...WHICH WAS
NOT THE CASE YESTERDAY...MAKING A STRONGER CASE FOR THE EASTWARD
SOLUTION.  WE MUST BE READY TO MAKE A CHANGE OF THE FORECAST TRACK
AT ANY TIME.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/1500Z 28.0N  86.2W   50 KT  60 MPH
 12H  25/0000Z 28.5N  85.8W   50 KT  60 MPH
 24H  25/1200Z 28.5N  85.8W   50 KT  60 MPH
 36H  26/0000Z 28.5N  86.2W   55 KT  65 MPH
 48H  26/1200Z 28.7N  87.0W   60 KT  70 MPH
 72H  27/1200Z 29.0N  88.4W   65 KT  75 MPH
 96H  28/1200Z 29.5N  90.5W   45 KT  50 MPH
120H  29/1200Z 30.0N  91.5W   30 KT  35 MPH
 
$$
FORECASTER AVILA
 

WTNT44 KNHC 242034
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER   6
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
400 PM CDT SUN JUN 24 2012
 
THERE HAS BEEN A SIGNIFICANT CHANGE IN THE FORECAST TRACK WITH THIS
ADVISORY. THE OFFICIAL FORECAST NO LONGER BRINGS DEBBY WESTWARD
ALONG THE NORTHERN GULF OF MEXICO AND INSTEAD KEEPS THE CYCLONE
MEANDERING OVER THE NORTHEASTERN GULF FOR THE NEXT 3 TO 4 DAYS.
THIS FORECAST IS A COMPROMISE BETWEEN THE CONSISTENT EASTWARD
SOLUTION PROVIDED BY THE GFS FOR THE PAST SEVERAL DAYS AND THE NEW
TWIST OF THE ECMWF. THE ECMWF MODEL...WHICH HAS BEEN
FORECASTING DEBBY TO MOVE WESTWARD ALONG THE GULF OF MEXICO... NOW
HAS THE CYCLONE MEANDERING FOR THE NEXT 3 DAYS OVER THE
NORTHEASTERN GULF. SINCE THESE TWO RELIABLE MODELS ARE IN
MARGINALLY BETTER AGREEMENT...I AM A LITTLE MORE CONFIDENT...BUT
NOT COMPLETELY...THAT DEBBY IS NOT GOING TO TURN WESTWARD OVER THE
GULF. HOWEVER...NEW OFFICIAL TRACK REMAINS A LOW-CONFIDENCE
FORECAST.
 
DEBBY IS A SPRAWLING SYSTEM...WITH MOST OF THE THUNDERSTORM ACTIVITY
IN A CURVED BAND WELL REMOVED FROM THE CENTER.  DATA FROM THE
RECONNAISSANCE PLANE A FEW HOURS AGO INDICATE THAT THE INITIAL
INTENSITY REMAINS 50 KNOTS. THE SHEAR IS NOT EXPECTED TO CHANGE
MUCH FOR THE NEXT DAY OR SO...BUT BECAUSE DEBBY IS FORECAST TO
REMAIN OVER WATER...THERE WILL BE SOME OPPORTUNITY FOR A SLIGHT
STRENGTHENING BEFORE THE CENTER MOVES INLAND. HOWEVER...THE CYCLONE
WILL LOCATED BE NORTH OF THE AREA OF HIGH OCEANIC HEAT CONTENT AND
THE UPWELLING COULD HALT THE INTENSIFICATION. 
 
  
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/2100Z 28.4N  85.8W   50 KT  60 MPH
 12H  25/0600Z 28.7N  85.5W   50 KT  60 MPH
 24H  25/1800Z 29.0N  85.5W   50 KT  60 MPH
 36H  26/0600Z 29.0N  85.5W   55 KT  65 MPH
 48H  26/1800Z 29.0N  85.5W   60 KT  70 MPH
 72H  27/1800Z 29.5N  85.5W   60 KT  70 MPH
 96H  28/1800Z 30.0N  85.5W   40 KT  45 MPH
120H  29/1800Z 30.5N  85.5W   30 KT  35 MPH...INLAND
 
$$
FORECASTER AVILA
 

WTNT44 KNHC 250258
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER   7
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
1000 PM CDT SUN JUN 24 2012
 
THE APPEARANCE OF DEBBY IN SATELLITE AND RADAR IMAGERY HAS DEGRADED
SIGNIFICANTLY THIS EVENING AS A SHARP MID-LEVEL DRY INTRUSION HAS
WORKED ITS WAY INTO THE CENTER OF THE CYCLONE AND ERODED ALL OF THE
INNER CORE DEEP CONVECTION. THE INITIAL INTENSITY IS BEING HELD AT
50 KT FOR THIS FORECAST PACKAGE BASED MAINLY ON CONTINUITY WITH THE
PREVIOUS ADVISORY AND THE RELATIVELY LOW CENTRAL PRESSURE OF 991 MB
REPORTED BY AN AIR FORCE RESERVE RECON AIRCRAFT THIS EVENING.

DEBBY HAS BEEN NEARLY STATIONARY SINCE THE LAST ADVISORY. BOTH 18Z
AND 00Z UPPER-AIR DATA INDICATE MID-LEVEL RIDGING HAS CONTINUED TO
BUILD ACROSS THE SOUTHEASTERN U.S. TO THE NORTH OF DEBBY...AND THIS
HAS LIKELY BEEN THE REASON FOR THE LACK OF ANY SIGNIFICANT MOTION
OVER THE PAST SEVERAL HOURS. ALL OF THE NHC MODEL GUIDANCE...EXCEPT
FOR THE GFS AND GFS-ENSEMBLE MODELS...INDICATE THIS BLOCKING PATTERN
ACROSS THE CENTRAL AND EASTERN U.S. SHOULD CONTINUE AS FAST-MOVING
SHORTWAVE TROUGHS PASS WELL TO THE NORTH OF DEBBY. THE RESULT
SHOULD BE THAT THE CYCLONE WILL MOVE LITTLE DURING THE NEXT COUPLE
OF DAYS...AND THEN ONLY DRIFT SLOWLY NORTHWARD AFTER THAT AS THE
RIDGE OVER THE SOUTHEASTERN U.S. GRADUALLY BREAKS DOWN. ALTHOUGH THE
GFS MODEL HAS BEEN VERY CONSISTENT WITH A FAST NORTHEASTWARD MOTION
ACROSS NORTH FLORIDA THE PAST FEW DAYS...THE LARGE SPRAWLING NATURE
OF THE CYCLONE AND THE BLOCKING RIDGE TO THE NORTH WOULD SUGGEST
THAT THE GFS MODEL MAY BE LIFTING OUT DEBBY TOO QUICKLY. THE
OFFICIAL FORECAST TRACK IS SIMILAR TO BUT SLIGHTLY LEFT OF THE
PREVIOUS ADVISORY TRACK...MAINLY DUE TO THE MORE WESTWARD INITIAL
POSITION.
 
DEBBY HAS FINALLY CONSOLIDATED ALL OF THE MULTIPLE SMALL SWIRLS INTO
A WELL-DEFINED LOW-LEVEL CIRCULATION CENTER. THE GLOBAL MODELS ARE
FORECASTING THE AFOREMENTIONED DEEP DRY SLOT TO GRADUALLY MOISTEN
UP OVER THE NEXT 48 HOURS AS DEEP MOISTURE AND INSTABILITY
CURRENTLY OVER THE FLORIDA PENINSULA ADVECTS WESTWARD INTO THE
INNER CORE. THE COMBINATION OF THESE TWO FEATURES MAY ALLOW FOR
SOME SLIGHT STRENGTHENING BEFORE DEBBY BEGINS TO INTERACT WITH LAND
OR COLD UPWELLING BENEATH THE CYCLONE OCCURS. THE OFFICIAL
INTENSITY FORECAST IS IDENTICAL TO THE PREVIOUS ADVISORY AND
FOLLOWS A BLEND OF THE SHIPS/LGEM STATISTICAL MODELS AND THE
HWRF/GFDL REGIONAL MODELS.

FORECAST POSITIONS AND MAX WINDS
 
INIT  25/0300Z 28.3N  85.9W   50 KT  60 MPH
 12H  25/1200Z 28.6N  85.8W   50 KT  60 MPH
 24H  26/0000Z 28.7N  85.8W   50 KT  60 MPH
 36H  26/1200Z 28.8N  85.8W   55 KT  65 MPH
 48H  27/0000Z 28.9N  85.8W   60 KT  70 MPH
 72H  28/0000Z 29.4N  85.8W   55 KT  65 MPH
 96H  29/0000Z 29.9N  85.8W   35 KT  40 MPH...NEAR COAST
120H  30/0000Z 30.4N  85.6W   30 KT  35 MPH...INLAND
 
$$
FORECASTER STEWART
 

WTNT44 KNHC 250838
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER   8
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
400 AM CDT MON JUN 25 2012
 
DEBBY HAS A HIGHLY UNIMPRESSIVE APPEARANCE ON SATELLITE IMAGERY.
ALTHOUGH RADAR DATA CONTINUE TO DEPICT SOME SHOWER ACTIVITY OVER
THE CIRCULATION...THESE SHOWERS ARE BEING PRODUCED BY SHALLOW
CONVECTION AS THE ENHANCED IR IMAGES DO NOT SHOW ANY SIGNIFICANT
AREAS OF COLD CLOUD TOPS.  AIRCRAFT DATA FROM SEVERAL HOURS AGO
ALONG WITH SYNOPTIC OBSERVATIONS INDICATE THAT THE MAXIMUM SURFACE
WINDS HAVE DECREASED...AND THE CURRENT INTENSITY IS SET AT 45 KT.
DEBBY IS LOCATED NORTH OF THE AREA OF MAXIMUM OCEANIC HEAT
CONTENT...BUT AS LONG AS THE CYCLONE REMAINS OVER WATER AND IS ABLE
TO REGENERATE SOME DEEP CONVECTION THERE IS A POTENTIAL FOR AT
LEAST SLIGHT RE-INTENSIFICATION.  THE CURRENT NHC INTENSITY
FORECAST IS A LITTLE LOWER THAN THE PREVIOUS ONES...BUT A LITTLE
HIGHER THAN MOST OF THE NUMERICAL GUIDANCE.
 
BEST GUESS AT INITIAL MOTION IS QUASI-STATIONARY.  DEBBY REMAINS IN
A COL REGION OF THE MID-TROPOSPHERIC STEERING FLOW BETWEEN TWO
ANTICYCLONES...AND IS LIKELY TO REMAIN SO FOR THE NEXT COUPLE OF
DAYS.  THEREFORE LITTLE MOTION IS ANTICIPATED DURING AT LEAST THE
FIRST HALF OF THE FORECAST PERIOD.  IN THE LONGER-TERM...THE TRACK
GUIDANCE CONTINUES TO BE ALL OVER THE PLACE...WITH SOME MODELS
TAKING DEBBY WEST AND NORTH OF ITS CURRENT POSITION AND OTHERS
MOVING EAST OR NORTHEAST AND ULTIMATELY INTO THE ATLANTIC.  THE
LATTER SCENARIO ASSUMES THAT DEBBY WILL EVENTUALLY BE INFLUENCED BY
A MID-TROPOSPHERIC TROUGH OVER THE NORTHEASTERN UNITED STATES. 
THIS SCENARIO SEEMS MORE LIKELY SINCE IT IS SUPPORTED BY BOTH THE
GFS AND THE ECMWF MODELS.  REGARDLESS OF WHICH SCENARIO PLAYS
OUT...THE CYCLONE DOES NOT SEEM TO BE GOING ANYWHERE ANYTIME SOON. 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  25/0900Z 28.6N  85.8W   45 KT  50 MPH
 12H  25/1800Z 28.8N  85.7W   45 KT  50 MPH
 24H  26/0600Z 28.9N  85.6W   50 KT  60 MPH
 36H  26/1800Z 29.0N  85.5W   50 KT  60 MPH
 48H  27/0600Z 29.2N  85.4W   55 KT  65 MPH
 72H  28/0600Z 29.4N  85.3W   55 KT  65 MPH
 96H  29/0600Z 29.7N  85.2W   45 KT  50 MPH...INLAND
120H  30/0600Z 30.2N  85.0W   30 KT  35 MPH...INLAND
 
$$
FORECASTER PASCH
 

WTNT44 KNHC 251451
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER   9
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
1000 AM CDT MON JUN 25 2012
 
THERE HAS BEEN NO SIGNIFICANT DEEP CONVECTION NEAR THE CENTER OF
DEBBY FOR OVER 12 HOURS. WHAT CONVECTION REMAINS IS PRIMARILY
LOCATED IN A FRAGMENTED BAND WELL EAST OF THE CENTER...AND
SOUNDINGS ALONG THE GULF COAST INDICATE THAT THE ENTRAINMENT OF DRY
MID-LEVEL AIR IS AFFECTING THE STORM. IN ADDITION...THE SLOW
MOVEMENT OF DEBBY HAS INDUCED OCEANIC UPWELLING AND COOLING
UNDERNEATH THE CYCLONE AND MAY HAVE CONTRIBUTED TO THE OBSERVED
WEAKENING. LATEST DATA FROM THE RECONNAISSANCE AIRCRAFT INDICATE
THAT THE MAXIMUM WINDS ARE NEAR 40 KT. WITH DRY AIR LURKING AND
WESTERLY SHEAR ON THE INCREASE OVER THE NEXT COUPLE DAYS...
SIGNIFICANT RE-INTENSIFICATION OF THE CYCLONE PRIOR TO LANDFALL
SEEMS UNLIKELY. THE NEW NHC FORECAST IS ADJUSTED DOWNWARD IN LINE
WITH CURRENT TRENDS AND THE LATEST INTENSITY GUIDANCE.
 
AIRCRAFT AND SATELLITE FIXES HAVE SHOWN LITTLE OVERALL MOVEMENT OVER
THE PAST 12 TO 18 HOURS... ALTHOUGH RECENT SATELLITE IMAGERY
INDICATES AN EAST-NORTHEASTWARD TO NORTHEASTWARD SHORT-TERM MOTION.
AT THE MOMENT...IT IS UNCLEAR WHETHER THE CURRENT MOTION REPRESENTS
A MEANDERING OR A MORE DECIDED MOTION. ON THE LARGE SCALE...DEBBY
IS TRAPPED IN A REGION OF WEAK STEERING IN BETWEEN A STRONG
MID-LEVEL RIDGE OVER THE PLAINS AND ONE OVER THE SUBTROPICAL
CENTRAL ATLANTIC. GLOBAL MODELS DEPICT AN AMPLIFYING TROUGH
OFFSHORE THE EASTERN SEABOARD CAUSING DEBBY TO MOVE GENERALLY
EASTWARD THROUGH THE FORECAST PERIOD...WITH THE CENTER EMERGING
OVER THE SOUTHWEST ATLANTIC BY DAY 5. THE ECMWF/GFS SOLUTIONS BEGIN
TO LIFT OUT THE WESTERN ATLANTIC TROUGH IN ABOUT 72 HOURS...WHICH
COULD LEAVE DEBBY IN WEAK STEERING CURRENT AGAIN AFTER THAT TIME.
SINCE YESTERDAY... THE GUIDANCE HAS COME INTO BETTER
AGREEMENT...WITH ONLY THE UKMET NOW SHOWING A WESTWARD MOTION. IN
ADDITION...THE LATEST GFS ENSEMBLE MEMBERS FAVOR AN EASTWARD MOTION
BY ABOUT A 3 TO 1 RATIO. THE NEW FORECAST TRACK REPRESENTS A
SUBSTANTIAL CHANGE FROM THE PREVIOUS ONE BUT IS STILL SLOWER THAN
THE MULTI-MODEL CONSENSUS IN THE SHORT TERM.
 

FORECAST POSITIONS AND MAX WINDS
 
INIT  25/1500Z 28.6N  85.2W   40 KT  45 MPH
 12H  26/0000Z 28.8N  85.1W   35 KT  40 MPH
 24H  26/1200Z 28.9N  84.9W   35 KT  40 MPH
 36H  27/0000Z 29.0N  84.7W   35 KT  40 MPH
 48H  27/1200Z 29.2N  84.4W   35 KT  40 MPH
 72H  28/1200Z 29.5N  83.5W   35 KT  40 MPH
 96H  29/1200Z 29.5N  82.5W   30 KT  35 MPH...INLAND
120H  30/1200Z 29.5N  81.0W   30 KT  35 MPH
 
$$
FORECASTER KIMBERLAIN/FRANKLIN
 


WTNT44 KNHC 252052
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER  10
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
400 PM CDT MON JUN 25 2012
 
SATELLITE IMAGERY INDICATES THAT DEBBY HAS CHANGED LITTLE IN
ORGANIZATION TODAY. THE CENTER OF THE CYCLONE IS A LITTLE HARDER TO
LOCATE...WITH AT LEAST A COUPLE OF SMALL VORTICES ROTATING AROUND A
MEAN CENTER. THERE HAD BEEN VIRTUALLY NO CONVECTION ASSOCIATED WITH
THE CENTER OF THE CYCLONE EITHER...BUT A BURST OF DEEP CONVECTION
HAS RECENTLY FORMED OVER LAND TO THE NORTH OF THE CENTER. EARLIER
AIRCRAFT DATA SHOWED PEAK FLIGHT-LEVEL WINDS OF 57 KT AT 850MB...
WITH MAXIMUM SFMR VALUES AROUND 40 KT. GIVEN THESE DATA AND THE
LACK OF STRUCTURAL CHANGES TO THE CYCLONE...THE INITIAL INTENSITY
REMAINS 40 KT.  THE CURRENT STRUCTURE...COMBINED WITH AN INCREASE
IN WESTERLY SHEAR AND ADDITIONAL DRY AIR POSSIBLY WRAPPING INTO THE
STORM CIRCULATION...WOULD SEEM TO PRECLUDE MUCH SHORT-TERM
RE-INTENSIFICATION OF DEBBY...AND THE SHIPS AND LGEM MODELS SHOW NO
APPRECIABLE CHANGE IN STRENGTH PRIOR TO LANDFALL. MARGINALLY
FAVORABLE ENVIRONMENTAL CONDITIONS COULD PROVIDE AN OPPORTUNITY FOR
RE-STRENGTHENING OVER THE WESTERN ATLANTIC AT THE END OF THE
FORECAST PERIOD.
 
A SMOOTHING OF RECENT AIRCRAFT AND SATELLITE FIXES YIELDS A SLOW
NORTHEASTWARD MOTION OF 040/04. LARGE-SCALE MODELS SHOW DEBBY
CONTINUING ON AN EAST-NORTHEASTWARD TO NORTHEASTWARD COURSE OVER
THE NEXT FEW DAYS IN RESPONSE TO AN AMPLIFYING TROUGH OFFSHORE OF
THE U.S. EAST COAST. AS THE WESTERN ATLANTIC TROUGH BEGINS TO LIFT
OUT IN 2-3 DAYS...DEBBY IS EXPECTED TO SLOW DOWN AND BE LEFT BEHIND
OVER THE SOUTHWESTERN ATLANTIC. WITH THE EXCEPTION OF THE GFS
ENSEMBLE MEMBERS...THE MODEL GUIDANCE IS IN BETTER AGREEMENT
OVERALL ON AN EASTWARD TRACK...ALTHOUGH SIGNIFICANT SPEED
DIFFERENCES REMAIN. THE GFS IS CONSIDERABLY SLOWER THAN THE MODEL
CONSENSUS...AND SHOWS DEBBY TAKING FIVE DAYS TO MOVE OFFSHORE THE
FLORIDA ATLANTIC COAST. INTERESTINGLY...THE ECMWF IS NOW ONE OF THE
FASTEST MODELS TO THE EAST. THE NHC OFFICIAL TRACK FORECAST IS NOT
AS FAST AS THE MULTI-MODEL CONSENSUS IN DEFERENCE TO CONTINUITY AND
THE GFS.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  25/2100Z 29.3N  85.1W   40 KT  45 MPH
 12H  26/0600Z 29.4N  84.9W   40 KT  45 MPH
 24H  26/1800Z 29.5N  84.7W   40 KT  45 MPH
 36H  27/0600Z 29.6N  84.4W   40 KT  45 MPH
 48H  27/1800Z 29.7N  83.8W   40 KT  45 MPH
 72H  28/1800Z 29.8N  82.5W   30 KT  35 MPH...INLAND
 96H  29/1800Z 29.8N  81.0W   30 KT  35 MPH
120H  30/1800Z 30.0N  79.0W   35 KT  40 MPH
 
$$
FORECASTER KIMBERLAIN/
 

WTNT44 KNHC 260300
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER  11
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
1000 PM CDT MON JUN 25 2012
 
AFTER AN INTENSE BURST OF DEEP CONVECTION NEAR AND NORTH OF THE
LOW-LEVEL CENTER THIS LATE AFTERNOON AND EVENING...THE CONVECTIVE
CLOUD SHIELD IS SHOWING SIGNS OF SLOWLY PULLING AWAY FROM CENTER OF
CIRCULATION DUE TO MODERATE TO STRONG SOUTHWESTERLY VERTICAL WIND
SHEAR. THE HIGHEST RELIABLE SFMR WINDS REPORTED BY AN AIR FORCE
RESERVE RECON AIRCRAFT THIS EVENING HAS BEEN 42 KT TO THE WEST AND
WELL SOUTHEAST OF THE CENTER...ALONG WITH 59-KT AND 56-KT
FLIGHT-LEVEL WINDS...RESPECTIVELY. ALTHOUGH THE TALLAHASSEE DOPPLER
WEATHER RADAR HAS BEEN INDICATING LARGE WINDS OF 60-65 VELOCITIES
BETWEEN 2000 AND 6500 FT IN SOME RATHER VIGOROUS CONVECTION...THOSE
CONDITIONS HAVE BEEN OVER LAND. THEREFORE...THE INITIAL INTENSITY
WILL REMAIN AT 40 KT.

THE MOTION ESTIMATE IS A SLOW DRIFT TO THE NORTHEAST OR 040/02 KT
OVER THE PAST 12 HOURS. THERE IS NO SIGNIFICANT CHANGE TO THE
PREVIOUS TRACK REASONING. UPPER-AIR DATA AT 18Z AND 00Z INDICATE 
DEBBY REMAINS TRAPPED IN A BLOCKING RIDGE PATTERN THAT EXTENDS
ACROSS THE SOUTHEASTERN U.S. AND INTO THE EASTERN GULF OF MEXICO
AND WESTERN ATLANTIC. THE RESULTANT WEAK STEERING FLOW SHOULD KEEP
DEBBY MOVING VERY SLOWLY NORTHEAST OR EASTWARD AT LESS THAN 5 KT
THROUGHOUT THE FORECAST PERIOD. IN FACT...DEBBY WILL LIKELY REMAIN
OVER THE NORTHEASTERN GULF OF MEXICO FOR AT LEAST THE NEXT 2 DAYS
BEFORE IT CREEPS SLOWLY ACROSS NORTH FLORIDA IN DAYS 3-4. IN THE
ABSENCE OF ANY LARGE-SCALE STEERING FLOW...THE LOW-LEVEL CENTER OF
DEBBY WILL CLOSELY FOLLOW ANY DEEP CONVECTION THAT DEVELOPS...WHICH
SHOULD REMAIN PRIMARILY TO NORTHEAST OF THE CENTER.  THE OFFICIAL
FORECAST TRACK IS SIMILAR TO THE PREVIOUS ADVISORY TRACK THROUGH
DAY 3...AND IS THEN A LITTLE NORTH OF THE PREVIOUS TRACK AND CLOSE
TO THE NHC MODEL CONSENSUS.

THE PRESENCE OF DRY MID-LEVEL AIR WRAPPING INTO THE WESTERN AND
SOUTHERN PORTION OF THE CIRCULATION...ALONG WITH SOUTHWESTERLY
VERTICAL WIND SHEAR OF 20-25 KT FOR THE NEXT 48 HOURS OR SO SHOULD
INHIBIT ANY SIGNIFICANT DEVELOPMENT WHILE DEBBY REMAINS OVER WATER.
THE SHEAR DECREASES SIGNIFICANTLY BY 72 HOURS AND BEYOND...BUT
DEBBY WILL BE OVER OR INTERACTING WITH LAND AT DAYS 3 AND 4...SO
THAT WILL PREVENT THE CYCLONE FROM TAKING ADVANTAGE OF THE
IMPROVING SHEAR CONDITIONS. BY DAY 5...HOWEVER...DEBBY IS EXPECTED
TO BE MOVING OVER THE WARMER WATERS OF THE GULFSTREAM...WHICH MAY
ALLOW FOR SOME MODEST STRENGTHENING TO OCCUR AFTER HAVING WEAKENED
OVER LAND. THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE
PREVIOUS ADVISORY AND CLOSELY FOLLOWS THE LGEM INTENSITY MODEL.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  26/0300Z 29.2N  85.1W   40 KT  45 MPH
 12H  26/1200Z 29.3N  84.9W   40 KT  45 MPH
 24H  27/0000Z 29.4N  84.6W   40 KT  45 MPH
 36H  27/1200Z 29.5N  84.2W   40 KT  45 MPH
 48H  28/0000Z 29.6N  83.6W   40 KT  45 MPH
 72H  29/0000Z 29.8N  82.3W   30 KT  35 MPH...INLAND
 96H  30/0000Z 30.1N  80.7W   35 KT  40 MPH...OVER WATER
120H  01/0000Z 30.8N  78.7W   40 KT  45 MPH
 
$$
FORECASTER STEWART
 

WTNT44 KNHC 260841
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER  12
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
500 AM EDT TUE JUN 26 2012
 
DEBBY REMAINS A SHEARED TROPICAL STORM WITH MOST OF THE DEEP
CONVECTION OVER NORTHERN FLORIDA AND SOUTHEASTERN GEORGIA...I.E.
DISPLACED WELL TO THE NORTHEAST OF THE CENTER.  IN SPITE OF ITS
DISORGANIZED APPEARANCE...OBSERVATIONS FROM A C-MAN STATION NEAR
APALACHICOLA AND AN ASCAT OVERPASS INDICATE THAT THE CYCLONE IS
MAINTAINING AN INTENSITY OF ABOUT 40 KT.  GIVEN THE MARGINAL
ATMOSPHERIC AND OCEANIC ENVIRONMENT FOR THE NEXT COUPLE OF
DAYS...NO SIGNIFICANT CHANGE IN STRENGTH IS LIKELY UNTIL THE CENTER
MOVES OVER LAND.  DEBBY IS LIKELY TO WEAKEN IF AND WHEN IT MOVES
OVER LAND AND...BASED ON THIS OFFICIAL FORECAST...IT COULD BECOME A
DEPRESSION IN A COUPLE OF DAYS.  ASSUMING THAT THE CYCLONE WILL
EMERGE OVER THE ATLANTIC...SOME RE-INTENSIFICATION IS EXPECTED.
THE OFFICIAL INTENSITY FORECAST IN THE 3 TO 5 DAY TIME RANGE IS
CLOSE TO THE MODEL CONSENSUS...BUT COULD BE CONSERVATIVE GIVEN THE
POTENTIAL INFLUENCE OF THE GULF STREAM.
 
SURFACE SYNOPTIC DATA AND RADAR IMAGERY SUGGEST THAT DEBBY HAS
TURNED TOWARD THE EAST OVER THE PAST FEW HOURS.  THE INITIAL MOTION
ESTIMATE IS 090/3...AS THE STORM IS APPARENTLY BEGINNING TO RESPOND
TO A MID-LEVEL TROUGH OVER THE EASTERN UNITED STATES.   SOME OF THE
DYNAMICAL MODEL GUIDANCE...IN PARTICULAR THE TYPICALLY
BEST-PERFORMING GFS AND ECMWF GLOBAL MODELS...ARE NOW TAKING DEBBY
SIGNIFICANTLY FASTER TO THE EAST AND NORTHEAST OVER THE FORECAST
PERIOD.  IT IS WORTH NOTING THAT THE TRACK FORECASTS FROM THESE TWO
MODELS HAVE NOW COME INTO RATHER CLOSE AGREEMENT.  THE U.K. MET.
OFFICE GLOBAL MODEL IS BY THE FAR THE FASTEST AND SHOWS THE CYCLONE
NEAR THE CANADIAN MARITIMES IN 4 DAYS OR LESS.  WHEREAS THE LATTER
SCENARIO SEEMS UNREALISTIC...THE OVERALL CHANGE IN THE GUIDANCE
SUPPORTS A FASTER TRACK ACROSS FLORIDA AND INTO THE ATLANTIC THAN
THE PREVIOUS NHC PREDICTIONS.  THE NEW OFFICIAL FORECAST TRACK LIES
BETWEEN THE PREVIOUS NHC TRACK AND THE ECMWF AND GFS SOLUTIONS.
  
FORECAST POSITIONS AND MAX WINDS
 
INIT  26/0900Z 29.0N  84.5W   40 KT  45 MPH
 12H  26/1800Z 29.0N  84.2W   40 KT  45 MPH
 24H  27/0600Z 29.0N  83.8W   40 KT  45 MPH
 36H  27/1800Z 29.1N  83.1W   40 KT  45 MPH
 48H  28/0600Z 29.3N  82.2W   30 KT  35 MPH...INLAND
 72H  29/0600Z 29.9N  80.4W   35 KT  40 MPH
 96H  30/0600Z 30.5N  78.5W   40 KT  45 MPH
120H  01/0600Z 31.5N  76.5W   45 KT  50 MPH
 
$$
FORECASTER PASCH
 

WTNT44 KNHC 261452
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER  13
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
1100 AM EDT TUE JUN 26 2012
 
DEEP CONVECTION HAS BECOME SHEARED AWAY FROM THE CENTER OF DEBBY
AGAIN...WITH THE NEAREST SHOWER ACTIVITY OVER NORTHERN FLORIDA. AN
AMPLIFYING TROUGH OVER THE NORTHEASTERN STATES IS RESPONSIBLE FOR
AN INCREASE IN WESTERLY SHEAR TO 20-25 KT...WELL PREDICTED EARLIER
BY DYNAMICAL MODELS. THE CLOUD LINES IN THE CYCLONE CORE ARE NOT
WELL DEFINED...AND THE CIRCULATION IS BECOMING SLIGHTLY ELONGATED
FROM SOUTHWEST TO NORTHEAST. AIRCRAFT DATA SUGGEST THAT DEBBY IS
WEAKENING...WITH PEAK FLIGHT-LEVEL WINDS OF 51 KT AT 850MB AND
MAXIMUM BIAS-CORRECTED SFMR OBSERVATIONS OF AROUND 30 KT. A
DROPSONDE ABOUT 80 NM SOUTHEAST OF THE CENTER REPORTED SURFACE
WINDS OF 33 KT. BASED ON THESE DATA...THE INITIAL INTENSITY IS
ESTIMATED TO BE 35 KT. DRY AIR CONTINUES TO WRAP AROUND CIRCULATION
OF DEBBY...WITH ADDITIONAL DRY AIR FORECAST BY THE MODELS TO ADVECT
TOWARD THE STORM IN THE NEXT DAY OR SO. DEBBY IS EXPECTED TO WEAKEN
TO A DEPRESSION WHILE THE CENTER MOVES ACROSS FLORIDA...IF NOT
BEFORE. LATER IN THE FORECAST PERIOD...A LESSENING OF THE SHEAR AND
A NEW SUPPLY OF WARM WATER COULD ALLOW DEBBY TO RESTRENGTHEN.
 
AIRCRAFT FIXES AND RADAR IMAGERY INDICATE THAT DEBBY IS DRIFTING
EASTWARD...WITH THE INITIAL MOTION ESTIMATE 090/03.  THE
LARGE-SCALE MODELS ARE IN GOOD AGREEMENT THAT A LONGWAVE TROUGH
DIGGING ALONG 70W WILL HAVE ENOUGH AMPLITUDE TO CARRY DEBBY ACROSS
NORTH-CENTRAL FLORIDA DURING THE NEXT 24-48 HOURS.  EVEN THOUGH THE
WESTERN ATLANTIC TROUGH LIFTS OUT IN ABOUT 2-3 DAYS...AN ABSENCE
OF RIDGING ACROSS THIS REGION MAKES DEBBY SUSCEPTIBLE TO THE
MID-LATITUDE WESTERLY FLOW...AND THE CYCLONE IS NOW EXPECTED TO
CONTINUE MOVING NORTHEASTWARD THROUGH THE FORECAST PERIOD.  THE
GUIDANCE...INCLUDING THE THE 06Z GFS ENSEMBLE MEMBERS...ARE IN
BETTER AGREEMENT ON A FASTER MOTION.  THE LATEST OFFICIAL FORECAST
IS FASTER THAN THE PREVIOUS ONE BUT STILL SLOWER THAN THE BULK OF
THE GUIDANCE.
  
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  26/1500Z 28.9N  84.2W   35 KT  40 MPH
 12H  27/0000Z 28.9N  83.9W   35 KT  40 MPH
 24H  27/1200Z 29.1N  82.9W   35 KT  40 MPH
 36H  28/0000Z 29.3N  81.7W   30 KT  35 MPH...INLAND
 48H  28/1200Z 29.6N  80.0W   30 KT  35 MPH
 72H  29/1200Z 30.3N  77.5W   35 KT  40 MPH
 96H  30/1200Z 31.5N  74.5W   40 KT  45 MPH
120H  01/1200Z 33.5N  72.0W   45 KT  50 MPH
 
$$
FORECASTER KIMBERLAIN/FRANKLIN
 

WTNT44 KNHC 262059
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER  14
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
500 PM EDT TUE JUN 26 2012
 
AN AIR FORCE MISSION THAT ENDED EARLY THIS AFTERNOON MEASURED
BIAS-CORRECTED SFMR WINDS JUST BELOW TROPICAL STORM STRENGTH. BASED
ON THOSE DATA...IT IS ASSUMED THAT THERE ARE STILL A FEW SPOTS OF
TROPICAL-STORM-FORCE WINDS REMAINING IN BANDS TO THE SOUTHEAST OF
THE CENTER. IN THE FACE OF STRONG WESTERLY VERTICAL WIND
SHEAR...DEBBY IS GENERATING ONLY LIMITED DEEP CONVECTION TO THE
NORTHEAST OF THE CENTER OVER NORTHERN FLORIDA...AND HAS LESS THAN A
FULLY TROPICAL APPEARANCE. THE CYCLONE IS ALSO BEING OVERTAKEN BY A
LARGE REGION OF DRY AIR OVER THE SOUTHERN UNITED STATES AND GULF OF
MEXICO. THE PASSAGE OF DEBBY OVER LAND...IN ADDITION TO THE
NEGATIVE FACTORS CITED ABOVE...WILL LIKELY CAUSE DEBBY TO WEAKEN TO
A DEPRESSION WITHIN 12 HOURS. AFTER THE CENTER EMERGES OVER THE
WESTERN ATLANTIC...SUBSTANTIALLY LOWER SHEAR AND WARMER WATERS
FAVOR SOME RE-INTENSIFICATION OF THE CYCLONE LATER IN THE FORECAST
PERIOD. THE NEW NHC FORECAST IS CLOSE TO THE SHIPS/LGEM GUIDANCE
AND IS BASICALLY AN UPDATE OF THE PREVIOUS ONE.
 
AS ADVERTISED BY DYNAMICAL MODELS...DEBBY IS MOVING FASTER TOWARD
THE EAST-NORTHEAST AND THE INITIAL MOTION ESTIMATE IS 070/05. THE
INCREASE IN FORWARD SPEED IS RELATED TO AN INCREASING WESTERLY MID-
TO UPPER-TROPOSPHERIC FLOW ASSOCIATED WITH AN UNUSUALLY DEEP
LONGWAVE TROUGH DIGGING OFFSHORE THE ATLANTIC SEABOARD. THE GFS
BRIEFLY SLOWS THE CYCLONE MOTION IN THE FIRST 12-24 HOURS OF THE
FORECAST...AND PERHAPS AS A RESULT THE WESTERN ATLANTIC TROUGH
FAILS TO CAPTURE DEBBY AS STRONGLY AS SHOWN BY THE ECMWF AND UKMET.
THE NEW NHC FORECAST IS FASTER THAN THE PREVIOUS ONE BUT IS NOT AS
QUICK AS THE ECMWF/UKMET/MULTI-MODEL CONSENSUS...BOTH BECAUSE OF
CONTINUITY AND RESPECT FOR THE GFS.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  26/2100Z 29.5N  83.4W   35 KT  40 MPH...ON THE COAST
 12H  27/0600Z 29.5N  82.5W   30 KT  35 MPH...INLAND
 24H  27/1800Z 29.7N  81.4W   30 KT  35 MPH...INLAND
 36H  28/0600Z 30.0N  79.7W   30 KT  35 MPH...OVER WATER
 48H  28/1800Z 30.3N  77.7W   35 KT  40 MPH
 72H  29/1800Z 31.4N  74.1W   35 KT  40 MPH
 96H  30/1800Z 33.5N  71.0W   40 KT  45 MPH
120H  01/1800Z 36.6N  66.0W   45 KT  50 MPH
 
$$
FORECASTER KIMBERLAIN/FRANKLIN
 

WTNT44 KNHC 270301
TCDAT4
 
TROPICAL DEPRESSION DEBBY DISCUSSION NUMBER  15
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
1100 PM EDT TUE JUN 26 2012

THE CENTER OF DEBBY MADE LANDFALL IN THE FLORIDA BIG BEND
REGION AT AROUND 2100 UTC.  SINCE THAT TIME...THE CENTER HAS TURNED
SOUTHEASTWARD...POSSIBLY DUE TO INTERACTION WITH A GUST FRONT FROM
THE MOST RECENT CONVECTIVE BURST AND A MESOSCALE VORTICITY CENTER
OVER NORTHEASTERN FLORIDA.  THE CIRCULATION HAS ALSO BECOME
ELONGATED WITH THE CENTRAL PRESSURE RISING TO AROUND 1000 MB.  THE
INITIAL INTENSITY OF 30 KT IS BASED ON COASTAL OBSERVATIONS AND THE
CHANCE THAT SOME STRONGER WINDS MAY EXIST OVER THE WATER.

THE INITIAL MOTION IS 125/6.  A DEEP-LAYER TROUGH IS NORTH AND
NORTHEAST OF DEBBY...AND AN ASSOCIATED SURFACE FRONTAL ZONE EXTENDS
FROM SOUTHERN GEORGIA EAST-NORTHEASTWARD INTO THE ATLANTIC.  WHILE
THE LARGE-SCALE MODELS FORECAST THESE FEATURES TO WEAKEN DURING THE
NEXT 72 HR...THEY AGREE THAT THERE WILL BE ENOUGH WESTERLY STEERING
FLOW TO ALLOW THE CENTER TO CROSS FLORIDA AND REACH THE ATLANTIC
DURING THE NEXT 24 HR OR SO.  THE MODELS DIVERGE AFTER THAT.  THE
NOGAPS AND CANADIAN MODELS SHOW THE CENTER STALLING OFF THE U. S.
COAST...WHILE THE GFS...UKMET...ECMWF...GFDL...AND HWRF MOVE IT
EAST-NORTHEASTWARD INTO THE ATLANTIC AT VARYING SPEEDS.  THE
FORECAST TRACK GOES WITH THE LATTER SCENARIO.  THE NEW FORECAST IS
ADJUSTED SOUTH OF THE PREVIOUS TRACK BASED ON THE INITIAL POSITION
AND MOTION...AND IS A BIT FASTER.  IT SHOULD BE NOTED THAT
ADDITIONAL ADJUSTMENTS TO THE TRACK FORECAST MAY BE NECESSARY IF
THE CENTER RE-FORMS WHILE CROSSING FLORIDA.

DEBBY IS CURRENTLY EXPERIENCING MODERATE VERTICAL WIND SHEAR...DRY
AIR ENTRAINMENT...AND LAND INTERACTION.  THIS COMBINATION SHOULD
PERSIST UNTIL THE CENTER REACHES THE ATLANTIC.  IN 36-48 HR...THE
GFS...UKMET...AND ECMWF FORECAST AN UPPER-LEVEL TROUGH TO INTERACT
WITH THE CYCLONE...WHICH COULD REDUCE THE SHEAR AND PROVIDE
FAVORABLE UPPER-LEVEL DIVERGENCE.  HOWEVER...DEEP-LAYER DRY AIR
SHOULD STILL BE NEAR DEBBY AT THAT TIME...WHICH COULD PREVENT THE
MORE FAVORABLE DYNAMICS FROM STRENGTHENING THE SYSTEM.  THUS...THE
NEW INTENSITY FORECAST IS ALMOST IDENTICAL TO THE PREVIOUS
FORECAST.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  27/0300Z 29.0N  82.8W   30 KT  35 MPH
 12H  27/1200Z 29.3N  81.7W   30 KT  35 MPH...INLAND
 24H  28/0000Z 29.7N  80.0W   30 KT  35 MPH...OVER WATER
 36H  28/1200Z 30.3N  77.8W   30 KT  35 MPH
 48H  29/0000Z 30.7N  75.6W   35 KT  40 MPH
 72H  30/0000Z 32.0N  72.5W   40 KT  45 MPH
 96H  01/0000Z 35.0N  69.0W   45 KT  50 MPH
120H  02/0000Z 39.0N  62.0W   45 KT  50 MPH
 
$$
FORECASTER BEVEN
 

WTNT44 KNHC 270832
TCDAT4
 
TROPICAL DEPRESSION DEBBY DISCUSSION NUMBER  16
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
500 AM EDT WED JUN 27 2012
 
SATELLITE...RADAR AND SURFACE OBSERVATIONS INDICATE THAT THE
CIRCULATION OF DEBBY IS INCREASINGLY BECOMING ELONGATED. THE CENTER
IS DIFFICULT TO LOCATE GIVEN THE LACK OF ORGANIZATION...BUT THE AREA
OF MINIMUM PRESSURE HAS BEEN MOVING EAST-NORTHEASTWARD OR 075
DEGREES AT 9 KNOTS ACROSS NORTH-CENTRAL FLORIDA. MOST OF THE DEEP
CONVECTION IS IN A FRONTAL-TYPE BAND EXTENDING NORTHEASTWARD FROM
FLORIDA ACROSS THE ADJACENT ATLANTIC.  THE MAXIMUM WINDS ARE STILL
PROBABLY 30 KNOTS IN A FEW SQUALLS MAINLY OVER WATER. 

NONE OF THE INTENSITY GUIDANCE SHOW A SIGNIFICANT INCREASE IN
STRENGTH...AND IN FACT...BOTH THE GFS AND THE ECMWF SUGGEST
WEAKENING IN THE 00 UTC RUN. THE OFFICIAL FORECAST KEEPS DEBBY AS A
TROPICAL DEPRESSION AND ALLOWS SOME SLIGHT STRENGTHENING BEYOND 3
DAYS.

DEBBY IS EMBEDDED IN WESTERLY FLOW WITHIN THE BASE OF A MID-LATITUDE
TROUGH...AND IT SHOULD CONTINUE TO MOVE TOWARD THE EAST-NORTHEAST OR
NORTHEAST AS INDICATED BY GLOBAL MODELS. THE OFFICIAL FORECAST IS
IN BETWEEN THE GFS AND ECMWF MODELS.
  
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  27/0900Z 29.6N  81.0W   30 KT  35 MPH...OVER WATER
 12H  27/1800Z 30.0N  79.4W   30 KT  35 MPH
 24H  28/0600Z 30.5N  76.5W   30 KT  35 MPH
 36H  28/1800Z 31.0N  73.0W   30 KT  35 MPH
 48H  29/0600Z 32.0N  70.5W   30 KT  35 MPH
 72H  30/0600Z 35.0N  66.5W   35 KT  40 MPH
 96H  01/0600Z 38.0N  62.0W   40 KT  45 MPH
120H  02/0600Z 45.5N  50.0W   40 KT  45 MPH
 
$$
FORECASTER AVILA
 

WTNT44 KNHC 271438
TCDAT4
 
TROPICAL DEPRESSION DEBBY DISCUSSION NUMBER  17
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
1100 AM EDT WED JUN 27 2012
 
DEBBY IS STRUGGLING TO SURVIVE AS A TROPICAL CYCLONE. OCCASIONAL
BURSTS OF CONVECTION CONTINUE TO FORM NEAR THE CENTER...BUT ARE
IMMEDIATELY BEING PUSHED TO THE EAST BY STRONG WESTERLY SHEAR. IN
FACT...AT 12Z...THE CONVECTION WAS TOO DISORGANIZED TO WARRANT A
DVORAK CLASSIFICATION. THE LOW-LEVEL CENTER HAS BECOME INCREASINGLY
DISTORTED...WITH AN ELONGATED NORTHEAST-TO-SOUTHWEST APPEARANCE. A
LOW-LEVEL BAROCLINIC ZONE IS ALSO IMPINGING ON THE CYCLONE BUT HAS
NOT YET BECOME INVOLVED WITH THE CIRCULATION CENTER. BUOY REPORTS
NEAR THE CENTER SHOW 1-MINUTE WINDS OF AROUND 25 KT. IT IS ASSUMED
THAT STRONGER WINDS ARE OCCURING IN THE CONVECTION TO THE EAST...SO
THE INITIAL INTENSITY IS KEPT AT 30 KT.

SATELLITE...RADAR...AND SYNOPTIC DATA INDICATE THAT THE CENTER OF
DEBBY MOVED INTO THE WESTERN ATLANTIC AROUND 8Z. USING THESE DATA
SOURCES...THE INITIAL MOTION ESTIMATE IS 085/09. ALTHOUGH A DEEP
TROUGH OVER THE WESTERN ATLANTIC WILL BE IN THE PROCESS OF LIFTING
OUT OVER THE NEXT COUPLE OF DAYS...GLOBAL MODELS SHOW IT HAVING
SUFFICIENT AMPLITUDE TO DRAW DEBBY EAST-NORTHEASTWARD. HAVING
GAINED ENOUGH LATITUDE...STRONGER MID-LATITUDE WESTERLY FLOW SHOULD
THEN CAUSE DEBBY TO ACCELERATE NORTHEASTWARD FOR THE REMAINDER OF
THE FORECAST PERIOD. THE ECMWF/GFS/UKMET ARE IN GOOD AGREEMENT ON
THIS SCENARIO...BUT THE REGIONAL DYNAMICAL MODELS SHOW DEBBY BEING
LEFT BEHIND BY THE WESTERN ATLANTIC TROUGH. ASSUMING THAT DEBBY
REMAINS A DISTINCT ENTITY...THE FORMER CAMP OF MODELS FAVORS THIS
SCENARIO AND SO DOES THIS OFFICIAL FORECAST.

ALTHOUGH THERE SHOULD BE A RELATIVE DECREASE IN THE SHEAR OVER THE
CYCLONE AFTER 24 HOURS...DEBBY WILL REMAIN SURROUNDED BY A LARGE
POOL OF VERY DRY AND STABLE AIR OVER THE WESTERN ATLANTIC EVEN
AFTER THE FRONTAL BOUNDARY RETREATS. THESE FACTORS SHOULD TEMPER
ANY SIGNIFICANT RE-INTENSIFICATION. THE SHIPS/LGEM GENERALLY AGREE
WITH THIS IDEA...NO LONGER SHOWING MUCH STRENGTHENING. IT SHOULD BE
NOTED THAT THE GFS SHOWS DEBBY LOSING ORGANIZATION DURING THE NEXT
48 HOURS AND BECOMING AN OPEN WAVE OVER THE CENTRAL ATLANTIC. IN
THE FACE OF THESE NEGATIVE ENVIRONMENTAL FACTORS...THERE IS A
POSSIBILITY THAT DEBBY WILL DISSIPATE SOON.
  
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  27/1500Z 29.7N  79.8W   30 KT  35 MPH
 12H  28/0000Z 30.1N  77.5W   30 KT  35 MPH
 24H  28/1200Z 30.5N  74.8W   30 KT  35 MPH
 36H  29/0000Z 31.3N  71.8W   30 KT  35 MPH
 48H  29/1200Z 32.3N  69.5W   30 KT  35 MPH
 72H  30/1200Z 35.5N  65.3W   30 KT  35 MPH
 96H  01/1200Z 40.0N  60.0W   35 KT  40 MPH
120H  02/1200Z 46.0N  48.0W   35 KT  40 MPH
 
$$
FORECASTER KIMBERLAIN
 

