HOME	ARCHIVES	FORECASTS	IMAGERY	ABOUT TPC	RECONNAISSANCE

ZCZC MIATCDAT5 ALL
TTAA00 KNHC DDHHMM
TROPICAL DEPRESSION TEN DISCUSSION NUMBER   7
NATIONAL WEATHER SERVICE MIAMI FL
5 PM EDT TUE SEP 17 2002
 
THE DEPRESSION REMAINS POORLY ORGANIZED THIS AFTERNOON...WITH RECON
REPORTS CONTINUING TO INDICATE A BROAD ELONGATED CENTER SOUTH AND
WEST OF THE DEEP CONVECTION.  PEAK FLIGHT-LEVEL WINDS WERE ABOUT 40
KT.  THE AIRCRAFT ALSO SPENT SOME TIME IN THE DEEP CONVECTION EAST
OF THE CENTER TO SEE IF THERE WAS A SURFACE REFLECTION BELOW THE
MID-LEVEL TURNING THAT WAS EVIDENT THERE.  THERE WAS NONE.  
HOWEVER...IN THE LAST HOUR OR SO RECON FIXED A CENTER CLOSER TO THE 
NEW CONVECTION JUST SOUTH OF JAMAICA...NORTHEAST OF THE PREVIOUS 
ONE.  THIS MAY PRESAGE THE BEGINNING OF AN ORGANIZATION TREND.
 
THE MOTION HAS SLOWED SOME...AND IS NOW ESTIMATED TO BE 285/5.  THE
PRIMARY STEERING FACTORS ARE A MID-LEVEL RIDGE RUNNING EAST/WEST
ACROSS FLORIDA...AND THE MID-TO UPPER LEVEL LOW THAT EXTENDS FROM
THE NORTHWESTERN CARIBBEAN SOUTHWESTWARD ACROSS CENTRAL AMERICA.
OVER THE NEXT THREE DAYS...THE RIDGE WILL BUILD OR SLIDE EASTWARD
WHILE THE UPPER LOW MOVES WESTWARD OR SOUTHWESTWARD WHILE A NEW
TROUGH ENTERS THE WESTERN GULF OF MEXICO.  THIS PATTERN FAVORS A
NORTHWESTERLY TRACK THROUGH MOST OF THE FORECAST PERIOD WITH A
NORTHWARD TURN AT THE END.  THERE IS NOW A GOOD CONSENSUS AMONG THE
GFDL...UKMET...CANADIAN...AND NOGAPS ON A PATH OVER WEST-CENTRAL
CUBA...ALBEIT WITH DIFFERENT SPEEDS THAT WILL HAVE SIGNIFICANT
IMPACT ON THE TRACK BEYOND 72 HOURS.  THE OFFICIAL FORECAST IS JUST
A LITTLE TO THE RIGHT OF THE PREVIOUS ADVISORY.  THE AVN DOES NOT
APPEAR TO HANDLE THE LOW-LEVEL VORTEX WELL.  THE NOAA GULFSTREAM-IV
JET IS CURRENTLY SAMPLING THE ENVIRONMENT OF THE DEPRESSION...AND
THESE DATA WILL GET INTO THE 00Z RUNS OF THE GLOBAL MODELS.

WATER VAPOR IMAGERY CONTINUES TO SHOW AN IMPROVING UPPER-LEVEL 
ENVIRONMENT...AS THE FLOW IS TURNING FROM SOUTHWESTERLY TO 
SOUTHEASTERLY AHEAD OF THE TROPICAL CYCLONE.  THE OUTFLOW PATTERN IS 
IMPROVING AS WELL.  THE INTENSITY GUIDANCE IS VERY AGGRESSIVE...WITH 
SHIPS BRINGING THE DEPRESSION TO 81 KT IN 72 HR.  AN EXPERIMENTAL 
VERSION OF SHIPS...THAT INCLUDES THE EFFECTS OF UPPER OCEAN HEAT 
CONTENT...TAKES THE SYSTEM TO 98 KT.  THE GFDL IS DOING ITS USUAL 
THING...INTENSITY-WISE...BUT IN THIS CASE IT MIGHT BE RIGHT.  I HAVE 
INCREASED THE INTENSITY FORECAST FROM THE PREVIOUS ADVISORY...BUT 
WOULD LIKE TO SEE JUST A LITTLE MORE ORGANIZATION FROM THE CYCLONE 
BEFORE CALLING FOR SO MUCH STRENGTHENING.  HOWEVER...MY GUT FEELING 
IS THAT SUBSEQUENT INTENSITY FORECASTS WILL BE RATHER HIGHER THAN 
THIS ONE.
 
FORECASTER FRANKLIN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     17/2100Z 16.3N  77.6W    30 KTS
12HR VT     18/0600Z 16.7N  78.6W    35 KTS
24HR VT     18/1800Z 17.6N  80.0W    45 KTS
36HR VT     19/0600Z 18.7N  81.4W    55 KTS
48HR VT     19/1800Z 20.0N  83.0W    65 KTS
72HR VT     20/1800Z 23.5N  84.5W    70 KTS
 
 
NNNN