Hurricane Tammy Forecast Discussion Number 26

By | October 24, 2023

WTNT45 KNHC 242041

Hurricane Tammy Discussion Number  26
NWS National Hurricane Center Miami FL       AL202023
500 PM AST Tue Oct 24 2023

There have not been many changes in the satellite appearance of 
Tammy since the previous advisory.  Bursts of convection continue to 
wrap around the estimated surface center.  An AMSR2 microwave 
satellite pass at 1657 UTC showed a closed low-level circulation. 
While a couple of ASCAT passes showed surface winds less than 
hurricane strength, the resolution of the instrument likely cannot 
capture the peak winds in Tammy's small inner core.  The initial 
intensity is held at 65 kt, closest to the TAFB satellite intensity 
estimate, though this could be generous.

Simulated satellite imagery suggests Tammy could strengthen slightly 
within a day or so when the hurricane enters a region of enhanced 
upper-level divergence.  Beyond this time frame, strong 
southwesterly shear, dry mid-level relative humidities, and cooling 
sea surface temperatures should cause Tammy to steadily weaken.  
Global models now indicate the hurricane should transition into a 
gale-force extratropical cyclone by 48 h, and this is reflected in 
the official intensity prediction.

Tammy is moving to the northeast at about 7 kt.  A mid-latitude 
trough should turn the hurricane north-northeastward and northward 
in a day or so.  By Thursday, Tammy should bend to the northwest and 
slow down within the light steering currents between two ridges.  A 
gradual westward turn is expected by the end of the forecast period. 
The latest NHC track prediction is slightly to the south of the 
previous advisory, and forward speed in the long-term forecast has 
been slowed. 


INIT  24/2100Z 24.6N  61.7W   65 KT  75 MPH
 12H  25/0600Z 25.6N  60.7W   70 KT  80 MPH
 24H  25/1800Z 27.5N  59.6W   70 KT  80 MPH
 36H  26/0600Z 29.2N  59.4W   65 KT  75 MPH
 48H  26/1800Z 30.4N  60.3W   55 KT  65 MPH...POST-TROP/EXTRATROP
 60H  27/0600Z 31.1N  61.2W   50 KT  60 MPH...POST-TROP/EXTRATROP
 72H  27/1800Z 31.6N  62.2W   50 KT  60 MPH...POST-TROP/EXTRATROP
 96H  28/1800Z 32.0N  63.4W   45 KT  50 MPH...POST-TROP/EXTRATROP
120H  29/1800Z 32.0N  64.4W   40 KT  45 MPH...POST-TROP/EXTRATROP

Forecaster Bucci

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