WTNT45 KNHC 020915
TCDAT5
TROPICAL DEPRESSION TEN DISCUSSION NUMBER   1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL102008
500 AM EDT TUE SEP 02 2008

SATELLITE IMAGERY INDICATES THE LARGE TROPICAL DISTURBANCE JUST
SOUTH OF THE CAPE VERDE ISLANDS HAS DEVELOPED ENOUGH CONVECTIVE
CURVED BAND FEATURES TO BE CLASSIFIED AS TROPICAL DEPRESSION TEN.
SATELLITE INTENSITY ESTIMATES ARE T2.0/30 KT AND T2.5/35 KT FROM
TAFB AND SAB...RESPECTIVELY.

THE INITIAL MOTION ESTIMATE IS 275/14. THE DEPRESSION IS EXPECTED TO
MOVE IN A WEST TO WEST-NORTHWESTWARD MOTION FOR THE NEXT 24 HOURS
OR SO...AND THEN TURN MORE WEST-NORTHWESTWARD AND SLOW A LITTLE BIT
AS THE CYCLONE MOVES INTO A WEAKNESS IN THE SUBTROPICAL RIDGE TO
THE NORTH. THE MID/UPPER-LEVEL TROUGH THAT IS EXPECTED TO WEAKEN
THE RIDGE BETWEEN 30N-40 LONGITUDE IS FORECAST BY MOST OF THE
GLOBAL MODELS TO WEAKEN AND LIFT OUT TO THE NORTHEAST BY 72-96
HOURS...WHICH WILL ALLOW THE RIDGE TO SLOWLY BUILD BACK IN AND TURN
THE CYCLONE MORE WESTWARD BY DAYS 4 AND 5. THE OFFICIAL FORECAST IS
SIMILAR TO BUT TO THE SOUTH OF THE NHC MODEL CONSENSUS TO ACCOUNT
FOR WHAT APPEARS TO BE A POLEWARD BIAS BY THE GFDL AND HWRF MODELS.

THE CYCLONE IS EXPECTED TO STEADILY INTENSIFY FOR THE NEXT 24 HOURS
OR SO DUE TO A VERY FAVORABLE UPPER-LEVEL FLOW REGIME. HOWEVER...BY
36-48 HOURS...ALL OF THE MODELS SUGGEST THAT SOUTHERLY VERTICAL
SHEAR OF 20-30 KT WILL DEVELOP...WHICH COULD DISRUPT OR EVEN HALT
THE STRENGTHENING PROCESS. SOME OF THE MODELS LIKE THE GFS
COMPLETELY DISSIPATE THE CYCLONE...WHICH SEEMS UNREASONABLE AT THIS
TIME GIVEN THE LARGE CIRCULATION ENVELOPE NOTED IN SATELLITE
IMAGERY. THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE SHIPS
MODEL THROUGH 48 HOURS...AND THEN HIGHER AT 96 AND 120 HOURS DUE TO
THE CYCLONE FORECAST TO REMAIN SOUTH OF 20N LATITUDE OVER WARMER
WATER AND UNDER LESS SHEAR THAN THE SHIPS MODEL IS DEPICTING.

FORECAST POSITIONS AND MAX WINDS

INITIAL      02/0900Z 12.4N  23.9W    30 KT
12HR VT     02/1800Z 12.9N  25.9W    40 KT
24HR VT     03/0600Z 13.6N  28.7W    50 KT
36HR VT     03/1800Z 14.5N  31.1W    50 KT
48HR VT     04/0600Z 15.4N  33.3W    55 KT
72HR VT     05/0600Z 17.5N  38.0W    60 KT
96HR VT     06/0600Z 19.0N  41.5W    65 KT
120HR VT     07/0600Z 20.0N  46.0W    70 KT

$$
FORECASTER STEWART




