Official Discussion issued by the National Hurricane Center

Tammy (AL202023) DATA RELEASED: 10/27/2023 3:00:00 PM UTC

Copy of official data

Tropical Storm Tammy Discussion Number  33
NWS National Hurricane Center Miami FL       AL202023
1100 AM AST Fri Oct 27 2023

Tammy appears to have become separate from the frontal zone in 
which it was formerly embedded.  Satellite imagery shows that 
moderately deep convection has developed in a fairly symmetrical 
pattern near the center, and there are also convective bands 
surrounding the center.  This change in structure indicates that 
the system has evolved back into a tropical cyclone, so advisories 
are being re-initiated on Tammy.  Extrapolation of earlier 
scatterometer data suggest that the current intensity is around 55 

Over the next few days, the atmospheric and oceanic environment 
for Tammy should result in gradual weakening.  The cyclone is 
currently over marginal SSTs, and westerly vertical wind shear is 
likely to increase.  Later in the forecast period, Tammy will 
probably move over slightly warmer waters, but dry air and strong 
shear will likely cause continued weakening.  The official 
intensity forecast is on the high side of the model guidance and 
shows the cyclone weakening to a depression in 5 days, although 
given the environment this may occur sooner.

The storm is drifting slowly northwestward, with a motion near 
320/3 kt.  Tammy should turn eastward in 12 to 24 hours under the 
influence of mid-level westerly flow on the north side of a 
subtropical ridge.  Later in the forecast period, the system is 
expected to turn southeastward and southward on the eastern side of 
a subtropical anticyclone and west of a broad trough over the 
eastern Atlantic.  The official forecast is similar to, but 
somewhat slower than, the model consensus prediction and roughly in 
the middle of the track guidance suite.

Gusty winds are expected in Bermuda through tonight, and a gale 
warning is in effect for that island.


INIT  27/1500Z 32.2N  61.1W   55 KT  65 MPH
12H  28/0000Z 32.4N  61.3W   55 KT  65 MPH
24H  28/1200Z 32.7N  59.9W   50 KT  60 MPH
36H  29/0000Z 32.5N  57.5W   45 KT  50 MPH
48H  29/1200Z 32.0N  54.5W   45 KT  50 MPH
60H  30/0000Z 30.7N  51.4W   40 KT  45 MPH
72H  30/1200Z 29.0N  50.0W   40 KT  45 MPH
96H  31/1200Z 27.5N  50.0W   35 KT  40 MPH
120H  01/1200Z 28.0N  51.0W   30 KT  35 MPH

Forecaster Pasch