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Tropical Depression Sean Discussion Number  17
NWS National Hurricane Center Miami FL       AL192023
1100 PM AST Sat Oct 14 2023
 
Deep convection continues to burst near Sean's center, and as a 
result, Dvorak estimates from TAFB and SAB remain T2.0/30 kt.  In 
addition, a recent ASCAT-B pass showed winds a little over 25 kt, 
and all these estimates support maintaining Sean as a 30-kt 
tropical depression.  With relatively low vertical shear, warm sea 
surface temperatures of 28-29 degrees Celsius, and an unstable 
atmosphere, the environment is just conducive enough for additional 
bursts of convection.  The biggest limiting factor is a lack of 
mid-level moisture, with relative humidities running about 50 
percent.  Consequently, the convection is likely to become less 
persistent and less organized, and global models indicate that 
Sean's small circulation should open up into a trough over the next 
day or two.  The NHC forecast shows Sean degenerating into a remnant 
low in 24 hours and then dissipating by 48 hours, but it's also 
possible that the system remains a tropical depression right up 
until it opens up into a trough.

Sean continues to move northwestward, or 305/7 kt.  As it becomes a 
weaker system, the depression is expected to become increasingly 
steered by lower-level ridging.  As a result, Sean is expected to 
turn west-northwestward overnight and then westward by early Monday, 
just before or as it degenerates into a trough.  The NHC track 
forecast is very close to the previous prediction and the latest 
TVCA multi-model consensus.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  15/0300Z 16.9N  45.5W   30 KT  35 MPH
 12H  15/1200Z 17.3N  46.6W   30 KT  35 MPH
 24H  16/0000Z 17.7N  48.4W   25 KT  30 MPH...POST-TROP/REMNT LOW
 36H  16/1200Z 18.1N  50.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  17/0000Z...DISSIPATED
 
$$
Forecaster Berg
 
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