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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