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TROPICAL DEPRESSION FOURTEEN DISCUSSION NUMBER   5
NATIONAL WEATHER SERVICE MIAMI FL
11 AM EDT TUE OCT 15 2002
 
TROPICAL DEPRESSION FOURTEEN HAS CHANGED LITTLE DURING THE PAST 12 
TO 18 HOURS WHILE DRIFTING/MEANDERING SLOWLY TO THE NORTHEAST. THE 
LAST REPORT FROM A RECONNAISSANCE AIRCRAFT INDICATE THAT THE  
HIGHEST FLIGHTL-LEVEL WINDS WERE 35 KT AND THE CENTRAL PRESSURE WAS 
STILL 1004 MB...SO THE INITIAL INTENSITY IS HELD AT 30 KT. THE 
UPPER-LEVEL OUTFLOW PATTERN IS STILL QUITE IMPRESSIVE...EXCEPT THAT 
THE LOW-LEVEL CENTER REMAINS SHEARED AT LEAST 120 NMI WEST OF THE 
UPPER-LEVEL ANTICYCLONE.
 
THERE IS CONSIDERABLE UNCERTAINTY IN THE INITIAL MOTION ESTIMATE... 
BUT A 12 HOUR TREND YIELDS ABOUT 045/04. THE GLOBAL MODEL GUIDANCE 
HAS BEEN LESS THAN STERLING THE PAST 24 HOURS...WITH ALL THE MODELS 
YESTERDAY AGREEING ON THE DEPRESSION BEING EAST OF HAVANA AT THIS 
TIME. THE MODELS HAVE NOT HANDLED WELL THE STRENGTH AND LOCATION OF 
THE 850 AND 700 MB RIDGE LOCATED NORTH OF THE GREATER ANTILLES THAT 
EXTENDS AS FAR WEST AS CENTRAL CUBA...BASED ON RECENT 12Z UPPER-AIR 
DATA. DUE TO THE STRENGTH AND WESTWARD EXTENT OF THIS LOW-LEVEL 
RIDGE...I HAVE SHIFTED THE FORECAST TRACK SLIGHTLY TO THE EAST AND A 
LITTLE SLOWER THAN THE PREVIOUS FORECAST THROUGH 36 HOURS AND THEN 
BRING IT BACK ON TRACK AFTER THAT. THERE IS A TIGHT PACKING OF THE 
NHC MODEL GUIDANCE ON TAKING THE DEPRESSION QUICKLY TO THE NORTHEAST 
ACROSS CENTRAL CUBA IN 12 HOURS AND ACROSS THE CENTRAL BAHAMAS IN 24 
HOURS. HOWEVER...THERE HAS BEEN SIMILAR STRONG AGREEMENT FOR THE 
PAST 24 HOURS...AND THE DEPRESSION IS STILL DEEP IN THE CARIBBEAN 
SEA. TIMING OF THE EROSION OF THE LOW-LEVEL RIDGE IS TRICKY AT BEST. 
THE STRONG SHORTWAVE TROUGH OVER THE NORTHEAST GULF OF MEXICO THAT 
WAS SUPPOSED TO HAVE ALREADY PICKED UP THE TROPICAL CYCLONE IS 
BEGINNING TO LIFT OUT TO THE NORTHEAST BASED ON LATEST WATER VAPOR 
TRENDS AND 12Z UPPER-AIR DATA. MY BEST GUESS IS THAT THE NEXT 
STRONGER UPSTREAM TROUGH OVER THE NORTHERN AND CENTRAL PLAINS WILL 
HAVE TO DROP DOWN INTO THE MEAN LONGWAVE TROUGH AND LIFT OUT THE 
DEPRESSION. UNFORTUNATELY...THAT MAY NOT OCCUR FOR ANOTHER 24 HOURS 
WHICH WOULD LEAVE TD 14 STILL MEANDERING OVER THE NORTHWEST 
CARIBBEAN FOR ANOTHER 12 TO 18 HOURS. THE OFFICIAL TRACK IS CLOSE TO 
THE UKMET-GFS-NOGAPS-GFDL CONSENSUS FOR DIRECTION...BUT SIMILAR TO 
THE SLOWER GFS ENSEMBLE MEAN MODEL FOR SPEED.

THE DEPRESSION COULD STILL STRENGTHEN INTO A TROPICAL STORM GIVEN 
THAT IT IS OVER 29C WATER AND CONVECTIVE BANDING FEATURES HAVE BEEN 
IMPROVING THIS MORNING. STRENGTHENING AFTER 36 HOURS IS EXPECTED TO 
RESULT FROM BAROCLINIC ENERGY SOURCES AS THE CYCLONE COMES UNDER THE 
INFLUENCE OF A STRONG NEGATIVELY-TILTED UPPER-LEVEL TROUGH. RAPID 
TRANSITION INTO AN EXTRATROPICAL LOW NORTHEAST OF THE BAHAMAS SHOULD 
OCCUR AS A RESULT OF THIS MID-LATITUDE INTERACTION.
 
FORECASTER STEWART
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     15/1500Z 17.9N  82.7W    30 KTS
12HR VT     16/0000Z 19.3N  81.3W    35 KTS
24HR VT     16/1200Z 21.7N  79.2W    40 KTS
36HR VT     17/0000Z 24.6N  76.7W    45 KTS
48HR VT     17/1200Z 29.5N  72.3W    50 KTS...EXTRATROPICAL
72HR VT     18/1200Z 40.0N  63.0W    50 KTS...EXTRATROPICAL
 
 
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