Tropical Storm Sean Forecast Discussion Number 12

By | October 13, 2023

WTNT44 KNHC 132038

Tropical Storm Sean Discussion Number  12
NWS National Hurricane Center Miami FL       AL192023
500 PM AST Fri Oct 13 2023

Sean's satellite appearance continues to deteriorate this afternoon. 
Convection has waned with warming cloud tops to the east of the 
exposed low-level center. Sean is noticeably struggling with drier 
air impacting the system and the continued westerly wind shear. Any 
convection that tries to develop near the center is sheared off and 
dissipates. Satellite intensity estimates this afternoon range from 
25 to 40 kt. The initial intensity is held at 35 kt for this 
advisory, but this could be generous given the waning convection the 
last several hours.

As Sean moves through the drier and more stable airmass, further 
weakening is anticipated. Simulated satellite from the ECMWF and GFS 
depict that Sean may have occasional burst of convection the next 
day or so, but will continue to become less organized. This should 
cause Sean to become a post-tropical remnant low this weekend. 
However, recent trends suggest this could occur as early as 
tomorrow. The NHC intensity forecast is similar to the previous 
advisory, near the consensus intensity aids. 

The tropical storm has continued to move west-northwestward today, 
around 290 at 10 kt. A turn northwestward has been forecast to occur 
today, but the center has continued west-northwestward, which has 
resulted in a westward shift of the NHC forecast track. The forecast 
still calls for the northwestward motion to begin later this evening 
and continue over the next day or so. As Sean becomes a remnant low 
and further weakens, the system will turn more west-northwestward 
again and dissipate into an open trough in a few days.


INIT  13/2100Z 14.9N  42.5W   35 KT  40 MPH
 12H  14/0600Z 15.8N  43.6W   30 KT  35 MPH
 24H  14/1800Z 16.9N  44.7W   30 KT  35 MPH
 36H  15/0600Z 17.7N  45.8W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  15/1800Z 18.4N  47.2W   25 KT  30 MPH...POST-TROP/REMNT LOW
 60H  16/0600Z 18.8N  48.7W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  16/1800Z...DISSIPATED

Forecaster Kelly

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