Official Discussion issued by the National Hurricane Center

Tammy (AL202023) DATA RELEASED: 10/27/2023 9:00:00 PM UTC

Copy of official data

Tropical Storm Tammy Discussion Number  34
NWS National Hurricane Center Miami FL       AL202023
500 PM AST Fri Oct 27 2023

Tammy's cloud pattern hasn't changed much on satellite images since 
earlier today.  There has been some cooling of the convective cloud 
tops to about -60 deg C near the center of circulation along with a 
few banding features.  There is limited upper-level outflow to the 
south and east of the system.  The current intensity is held at 55 
kt in agreement with an objective ADT Dvorak estimate from UW-CIMSS.

Tammy is currently situated over SSTs of around 25 deg C in a 
marginally moist mid-level air mass.  The dynamical guidance 
indicates a significant increase in vertical wind shear during the 
next day or so.  This should cause a gradual weakening trend to 
commence soon.  Later in the forecast period, although the ocean 
waters under Tammy should get a little warmer, strong shear and 
substantially drier air should cause continued weakening.  The 
official intensity forecast is above most of the model guidance, so 
Tammy could weaken to a depression sooner than shown here.

Tammy is currently moving slowly northwestward at about 320/3 
kt.  The cyclone should soon turn to an eastward track and move 
along the northern side of a subtropical ridge for a couple of 
days.  Later in the forecast period, Tammy is expected to turn 
southward and move along the eastern side of a mid-level high.  The 
official track forecast lies between the simple and corrected 
dynamical model consensus solutions.


INIT  27/2100Z 32.5N  61.4W   55 KT  65 MPH
12H  28/0600Z 32.7N  60.8W   50 KT  60 MPH
24H  28/1800Z 32.7N  59.0W   50 KT  60 MPH
36H  29/0600Z 32.3N  56.2W   45 KT  50 MPH
48H  29/1800Z 31.2N  53.4W   40 KT  45 MPH
60H  30/0600Z 30.0N  51.5W   35 KT  40 MPH
72H  30/1800Z 28.5N  51.0W   30 KT  35 MPH
96H  31/1800Z 28.0N  51.4W   25 KT  30 MPH
120H  01/1800Z 27.5N  52.0W   25 KT  30 MPH

Forecaster Pasch