####018002592####
WTNT45 KNHC 280236

TCDAT5

 

Tropical Storm Tammy Discussion Number  35

NWS National Hurricane Center Miami FL       AL202023

1100 PM AST Fri Oct 27 2023

 

Strong southwesterly shear is taking a toll on Tammy tonight. Its 

limited convection is confined to the northeastern portion of its 

circulation, which is partially exposed in proxy-visible satellite 

images. This shear has resulted in the vortex becoming vertically 

tilted, with the mid-level center displaced to the northeast of the 

low-level center in recent AMSR2 passive microwave images. Based on 

these structural changes and the decreasing satellite intensity 

estimates from TAFB and UW-CIMSS, the initial intensity is lowered 

to 50 kt. 

 

The deep-layer shear is expected to persist over Tammy during the 

next few days, which should result in weakening while the storm 

moves over marginal SSTs. While the forecast track does bring the 

center of Tammy over warmer waters by early next week, the much 

drier and more convergent upper-level environment should make it 

difficult for Tammy to sustain organized convection. In fact, GFS 

and ECMWF model-simulated satellite data indicate Tammy could be 

completely devoid of convection within the next 2-3 days. The 

updated NHC forecast is lower than the previous one, following the 

latest IVCN and HCCA aids. Post-tropical remnant low status is shown 

in 72 h, although this could occur even sooner than forecast.

 

The long-term motion of Tammy is north-northwestward (335/4 kt), but 

recent satellite images indicate the cyclone is now turning 

northward as anticipated. A faster eastward to southeastward motion 

is forecast over the weekend as Tammy moves around the northern and 

eastern sides of a mid-level ridge. Then, the weakening cyclone is 

forecast to slow down and turn southward on Monday as the ridge 

becomes positioned to its west. No major changes were made to the 

NHC track forecast, which still lies between the simple and 

corrected consensus aids.

 

 

FORECAST POSITIONS AND MAX WINDS

 

INIT  28/0300Z 32.7N  61.3W   50 KT  60 MPH

 12H  28/1200Z 32.9N  60.3W   45 KT  50 MPH

 24H  29/0000Z 32.6N  57.9W   40 KT  45 MPH

 36H  29/1200Z 31.9N  55.0W   40 KT  45 MPH

 48H  30/0000Z 30.5N  52.7W   35 KT  40 MPH

 60H  30/1200Z 29.1N  51.6W   30 KT  35 MPH

 72H  31/0000Z 28.2N  51.6W   25 KT  30 MPH...POST-TROP/REMNT LOW

 96H  01/0000Z 28.1N  52.2W   20 KT  25 MPH...POST-TROP/REMNT LOW

120H  02/0000Z...DISSIPATED

 

$$

Forecaster Reinhart