Tropical Storm Sean Forecast Discussion Number 11

By | October 13, 2023

WTNT44 KNHC 131442

Tropical Storm Sean Discussion Number  11
NWS National Hurricane Center Miami FL       AL192023
1100 AM AST Fri Oct 13 2023

Sean's structure and overall satellite appearance have begun to 
degrade. Deep convection associated with the tropical storm is 
limited in both strength and coverage as a result of dry surrounding 
air and continued westerly wind shear, and has decreased noticeably 
in the last few hours. Recent intensity estimates range from about 
25 to 45 kt, but are generally lower than they were for the previous 
advisory. The initial intensity is therefore lowered to 35 kt for 
this advisory.

Continued gradual weakening is expected for the next several days as 
Sean moves through a stable environment. Simulated satellite output 
from several models suggests that Sean may continue to produce 
occasional bursts of convection for another day or two, but these 
should become less organized in time. This should cause Sean to 
become a post-tropical remnant low by Sunday, but recent trends 
suggest this could happen much sooner. Sean's wind's should 
gradually decrease as its convection wanes, and it is forecast to 
open into a trough by Monday.

The tropical storm has continued to move west-northwestward for the 
last few hours. A turn northwestward is forecasted by every 
available dynamical model and is expected to begin at any time, but 
since Sean hasn't turned yet, the NHC track forecast had to be 
adjusted westward again with this advisory. Otherwise, no 
significant changes were made to the forecast reasoning, with the 
models in good agreement on Sean's track for the next few days until 
it dissipates.


INIT  13/1500Z 14.6N  41.7W   35 KT  40 MPH
 12H  14/0000Z 15.3N  42.6W   35 KT  40 MPH
 24H  14/1200Z 16.6N  44.0W   30 KT  35 MPH
 36H  15/0000Z 17.5N  45.0W   30 KT  35 MPH
 48H  15/1200Z 18.1N  46.1W   25 KT  30 MPH...POST-TROP/REMNT LOW
 60H  16/0000Z 18.6N  47.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  16/1200Z...DISSIPATED

Forecaster D. Zelinsky

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