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TROPICAL DEPRESSION ELEVEN DISCUSSION NUMBER   2
NATIONAL WEATHER SERVICE MIAMI FL
11 PM EDT THU OCT 04 2001
 
AFTER FINDING A POORLY-DEFINED CIRCULATION CENTER LATE THIS
AFTERNOON...SUBSEQUENT ATTEMPTS TO CLOSE OFF A CENTER BY THE
AIRCRAFT WERE UNSUCCESSFUL.  NEITHER HAVE THERE BEEN ANY RECENT
SURFACE OBSERVATIONS TO SUGGEST THAT THE SYSTEM HAS A DEFINITE
CLOSED SURFACE CIRCULATION.  FURTHERMORE...A QUIKSCAT PASS AT 2216Z
SHOWED AN OPEN WAVE.  HOWEVER...SINCE THE SYSTEM HAS MAINTAINED A
DECENT SATELLITE PRESENTATION...WITH GOOD OUTFLOW AND ABUNDANT DEEP
CONVECTION NEAR THE CENTER OR WAVE AXIS...WE WILL GIVE THE
DEPRESSION THE BENEFIT OF THE DOUBT UNTIL AT LEAST FIRST LIGHT
TOMORROW.  

SURFACE AND RECON OBS SUGGEST THAT THE INITIAL MOTION IS 
UNCHANGED...290/16.  THE KEY SYNOPTIC PLAYER IN THE NEAR TERM IS THE 
UPPER-LEVEL CUTOFF LOW TO THE WEST OF THE CYCLONE.  WATER VAPOR 
IMAGERY INDICATES THAT THIS LOW IS MOVING TO THE WEST BUT NOT AS 
FAST AS THE DEPRESSION...AND RECENT IMAGES SUGGEST THAT THE 
CIRCULATION AROUND THE UPPER LOW IS BEGINNING TO IMPINGE ON THE 
OUTFLOW FROM THE DEPRESSION.  ASSUMING THAT THERE IS A TROPICAL 
CYCLONE TOMORROW...IT WILL PROBABLY BE DEFLECTED A LITTLE TO THE 
RIGHT OF ITS PRESENT HEADING OVER THE NEXT 24 TO 36 HOURS.   THIS IS 
REFLECTED IN THE NOGAPS AND PARTICULARLY IN THE AVN SOLUTION...AND 
TO SOME EXTENT IN THE OFFICIAL FORECAST...WHICH IS A SHADE NORTH OF 
THE PREVIOUS ADVISORY.

THE INTENSITY FORECAST IS DIFFICULT.  ONE POSSIBILITY IS THAT THE
DEPRESSION WILL WEAKEN TO AN OPEN WAVE...IF IT HAS NOT DONE SO
ALREADY.  THIS IS THE UNANIMOUS VIEW OF THE GLOBAL MODELS.  THE
SHIPS MODEL...OUR BEST INTENSITY GUIDANCE ON AVERAGE...BRINGS THE
SYSTEM TO 78 KT IN 72 HOURS...IMPLICITLY MINIMIZING THE IMPACT OF
THE UPPER LOW.  THE GFDL IS IN BETWEEN...AND SHOWS LITTLE CHANGE IN
STRENGTH WHILE THE DEPRESSION INTERACTS WITH THE UPPER LOW.  THE
OFFICIAL FORECAST IS CLOSE TO THIS LAST SCENARIO.

FORECASTER FRANKLIN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     05/0300Z 13.7N  62.2W    30 KTS
12HR VT     05/1200Z 14.6N  64.5W    30 KTS
24HR VT     06/0000Z 15.8N  67.1W    35 KTS
36HR VT     06/1200Z 16.9N  69.5W    45 KTS
48HR VT     07/0000Z 17.5N  72.0W    50 KTS
72HR VT     08/0000Z 18.5N  76.5W    50 KTS
 
 
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