####018002782####
WTNT44 KNHC 110836

TCDAT4

 

Tropical Storm Sean Discussion Number   2

NWS National Hurricane Center Miami FL       AL192023

500 AM AST Wed Oct 11 2023



Satellite images indicate that deep convection has increased near 

the center of the cyclone, with some curved banding features 

located both north and south of the center.  Subjective and 

objective Dvorak estimates from TAFB/SAB/UW-CIMSS range from 30-47 

kt, and a conservative blend of this data gives an initial wind 

speed of 35 kt for this advisory.  Thus Tropical Storm Sean has 

formed, the 19th named storm in this busy 2023 Atlantic season.  



Sean could intensify a bit more during the next day or so before 

increasing southerly shear affects the core of the cyclone.  Some 

hints of this shear can already be seen in cirrus cloud motions from 

convective activity northwest of the tropical cyclone. Thereafter, 

moderate-to-strong shear is expected to generally cancel out the 

enhancing effects of a relatively moist and unstable environment, 

leading to little net change for a few days.  By the end of the 

week, while the shear could weaken, global models are generally 

showing an influx of drier mid-level air along with upper-level 

convergence, which would typically weaken any associated deep 

convection.  Many of the regional hurricane models, however, 

actually show some strengthening at long range, but they have been 

inconsistent at that time frame.  The NHC forecast leans more on 

the global models for now, similar to the previous forecast and the 

model consensus, and continues to show Sean becoming a remnant low 

on day 5.



The storm is moving west-northwestward at about 11 kt.   A mid-level 

ridge located to the northeast of the cyclone should steer Sean 

west-northwestward to northwestward through Friday. Very late in the 

forecast period, a bend back toward the west-northwest is 

anticipated as the cyclone weakens and is steered by the low-level 

trade wind flow.  The new NHC track forecast is adjusted a bit west 

of the last one at longer range, between the model-consensus and 

corrected-consensus aids, which favors the weaker track aids on the 

left side of the guidance envelope.

 

 

FORECAST POSITIONS AND MAX WINDS

 

INIT  11/0900Z 10.3N  33.1W   35 KT  40 MPH

 12H  11/1800Z 10.7N  34.8W   40 KT  45 MPH

 24H  12/0600Z 11.2N  36.5W   40 KT  45 MPH

 36H  12/1800Z 11.8N  38.0W   40 KT  45 MPH

 48H  13/0600Z 12.6N  39.5W   40 KT  45 MPH

 60H  13/1800Z 13.5N  40.8W   40 KT  45 MPH

 72H  14/0600Z 14.5N  42.0W   35 KT  40 MPH

 96H  15/0600Z 16.7N  44.6W   35 KT  40 MPH

120H  16/0600Z 18.0N  47.0W   30 KT  35 MPH...POST-TROP/REMNT LOW

 

$$

Forecaster Blake