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Tropical Storm Sean Discussion Number   3
NWS National Hurricane Center Miami FL       AL192023
1100 AM AST Wed Oct 11 2023
 
This morning, satellite imagery depicts Sean as a rather
disorganized tropical storm, with some convective bursting occurring
to the northwest and southeast of its elongated center. Subjective
satellite intensity estimates from SAB and TAFB are a consensus
T2.5/35 kt, and thus the initial intensity is held at 35 kt.  An
ASCAT-C pass at around 12 UTC suggested that this wind speed value
could be a little generous.
 
The intensity is forecast to remain at 35 kt over the first 12 h as
the storm already appears embedded in an environment of moderate
wind shear. Thereafter, there may be an opportunity for Sean to
intensify slightly as it moves into a region of lower wind shear
before the current mid-level moisture begin to decrease. By the
weekend, the storm is forecast to gradually weaken due to dry air
entrainment, and is predicted to become a remnant low by the end of
the forecast period. This intensity forecast is in the middle of
the guidance envelope for the majority of the forecast period.
 
Sean continues to move west-northwestward at about 11 kt, and is
expected to continue moving in this general direction over the next
day or two. After 48 hours, the storm will begin to turn more to the
northwest and decrease in forward speed as it moves along the
southwestern portion of a mid-level ridge to its northeast. By this
weekend, a turn back to the west-northwest or west is anticipated as
a low- to mid-level ridge re-establishes itself to the north of Sean
and it becomes a more shallow cyclone. The NHC track forecast is
similar to the previous one and close to the HCCA track guidance.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  11/1500Z 10.9N  34.4W   35 KT  40 MPH
 12H  12/0000Z 11.2N  35.8W   35 KT  40 MPH
 24H  12/1200Z 11.7N  37.4W   40 KT  45 MPH
 36H  13/0000Z 12.4N  38.9W   40 KT  45 MPH
 48H  13/1200Z 13.1N  40.5W   40 KT  45 MPH
 60H  14/0000Z 14.1N  41.9W   40 KT  45 MPH
 72H  14/1200Z 15.1N  43.0W   35 KT  40 MPH
 96H  15/1200Z 16.8N  45.3W   35 KT  40 MPH
120H  16/1200Z 18.1N  48.9W   30 KT  35 MPH...POST-TROP/REMNT LOW
 
$$
Forecaster Camposano/Cangialosi
 
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