025
WTNT45 KNHC 191207
TCDAT5
TROPICAL STORM TAMMY SPECIAL DISCUSSION NUMBER 4
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202023
800 AM AST THU OCT 19 2023
A NOAA HURRICANE HUNTER AIRCRAFT INVESTIGATING TAMMY HAS FOUND THAT
THE SYSTEM HAS STRENGTHENED OVERNIGHT. THE PLANE HAS MEASURED PEAK
700-MB FLIGHT LEVEL WINDS OF 49 KT AND SEVERAL SFMR WINDS OF 50 KT
IN BOTH THE NORTHEAST AND NORTHERN QUADRANTS OF THE STORM.
THEREFORE, THE INITIAL INTENSITY HAS BEEN RAISED TO 50 KT. THE
INTENSITY FORECAST CALLS FOR GRADUAL STRENGTHENING DURING THE NEXT
FEW DAYS WHILE TAMMY MOVES OVER WARM SSTS AND REMAINS WITHIN AN
ENVIRONMENT OF LOW TO MODERATE VERTICAL WIND SHEAR. ADDITIONAL
UPDATES TO THE INTENSITY FORECAST MAY BE REQUIRED LATER THIS
MORNING.
KEY MESSAGES:
1. TROPICAL STORM CONDITIONS ARE POSSIBLE ACROSS PORTIONS OF THE
LESSER ANTILLES BEGINNING ON FRIDAY, WHERE TROPICAL STORM
WATCHES ARE CURRENTLY IN EFFECT. ADDITIONAL WATCHES AND WARNINGS
WILL LIKELY BE REQUIRED LATER TODAY.
2. HEAVY RAINS FROM TAMMY WILL BEGIN TO AFFECT THE NORTHERN
WINDWARD AND LEEWARD ISLANDS ON FRIDAY, SPREADING INTO THE BRITISH
AND U.S. VIRGIN ISLANDS AND PUERTO RICO OVER THE WEEKEND. THIS
RAINFALL MAY PRODUCE ISOLATED FLASH AND URBAN FLOODING, ALONG WITH
ISOLATED MUDSLIDES IN AREAS OF HIGHER TERRAIN.
FORECAST POSITIONS AND MAX WINDS
INIT 19/1200Z 13.5N 55.1W 50 KT 60 MPH
12H 19/1800Z 13.9N 56.4W 50 KT 60 MPH
24H 20/0600Z 14.5N 58.2W 55 KT 65 MPH
36H 20/1800Z 15.5N 60.0W 55 KT 65 MPH
48H 21/0600Z 16.8N 61.3W 60 KT 70 MPH
60H 21/1800Z 18.4N 62.4W 65 KT 75 MPH
72H 22/0600Z 19.9N 63.1W 65 KT 75 MPH
96H 23/0600Z 23.3N 63.0W 70 KT 80 MPH
120H 24/0600Z 27.2N 59.5W 70 KT 80 MPH
FORECASTER BROWN
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