Tropical Cyclone Discussion

687
WTNT41 KNHC 211452
TCDAT1
 
Tropical Storm Fay Discussion Number   9
NWS National Hurricane Center Miami FL       AL062026
300 PM GMT Mon Sep 21 2026

Fay continues to be affected by strong west-northwesterly vertical 
wind shear.  Practically all of the deep convection is confined to 
a band of showers and thunderstorms located well to the 
east of the well-defined low-level center.  Using a blend of 
subjective and objective intensity estimates, the advisory 
intensity is reduced to 45 kt.

Global model simulations show a strong upper-level trough shifting 
eastward from Fay during the next day or two.  This evolution would 
allow for some relaxation of the shear, and this is also indicated 
by the Decay SHIPS model.  However, the model guidance also 
indicates that the system is likely to encounter a drier low- to 
mid-level air mass, which should inhibit re-strengthening.  
Simulated satellite imagery from the ECMWF output shows Fay's deep 
convection mostly dissipated during the next few days.  Therefore 
the official forecast, like the previous one, shows the cyclone 
degenerating into a remnant low by 48 hours.

Fay is now moving southward at around 4 kt, along the eastern side 
of a mid-level high.  Over the next several days, the cyclone 
is expected turn southwestward to west-southwestward and move 
around the southeastern and southern periphery of the high.  This 
should keep the system over the open Atlantic through dissipation 
later in the week.  Not much change has been made to the previous 
NHC track forecast, which remains in good agreement with the Google 
DeepMind ensemble mean and corrected model consensus, HCCA.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  21/1500Z 33.3N  32.0W   45 KT  50 MPH
 12H  22/0000Z 32.6N  32.5W   40 KT  45 MPH
 24H  22/1200Z 31.6N  33.9W   40 KT  45 MPH
 36H  23/0000Z 30.7N  35.6W   35 KT  40 MPH
 48H  23/1200Z 30.0N  37.4W   30 KT  35 MPH...POST-TROP/REMNT LOW
 60H  24/0000Z 29.4N  39.2W   30 KT  35 MPH...POST-TROP/REMNT LOW
 72H  24/1200Z 29.3N  40.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  25/1200Z 29.3N  43.1W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  26/1200Z...DISSIPATED