Tropical Depression Sean Forecast Discussion Number 18

By | October 15, 2023

WTNT44 KNHC 150837

Tropical Depression Sean Discussion Number  18
NWS National Hurricane Center Miami FL       AL192023
500 AM AST Sun Oct 15 2023

Deep convection associated with Sean has dissipated overnight, and 
within the past hour or so the circulation center has become easier 
to pinpoint as the mid- and high-level clouds that were obscuring 
it have thinned.  The latest Dvorak Current Intensity (CI) numbers 
from both TAFB and SAB are T2.0/30 kt but the Data-T numbers have 
fallen even more.  Based on the Dvorak CI numbers Sean's initial 
intensity is held at 30 kt, but this could be generous.

Although Sean is located within an area of relatively low vertical
wind shear and over warm waters, a surrounding dry mid-level
environment is expected to cause weakening during the next day or
so.  The system may continue to produce intermittent bursts of
convection, but these are likely to become less persistent and even
less organized than they have been over the past day or so.  As a
result, the NHC forecast now calls for Sean to degenerate into a
remnant low as soon as today.  An alternate scenario is that Sean
continues to produce enough organized convection to remain a
tropical depression until the small circulation opens up into a
trough in a day or so.

Sean appears to have turned west-northwestward. As the cyclone
weakens and becomes increasingly vertically shallow, its motion is
forecast to bend westward within the low-level steering flow. The
NHC track is similar to the previous advisory and is near the
middle of the latest guidance envelope.


INIT  15/0900Z 17.4N  46.2W   30 KT  35 MPH
 12H  15/1800Z 17.7N  47.3W   25 KT  30 MPH...POST-TROP/REMNT LOW
 24H  16/0600Z 18.0N  49.4W   25 KT  30 MPH...POST-TROP/REMNT LOW
 36H  16/1800Z 18.1N  51.7W   20 KT  25 MPH...POST-TROP/REMNT LOW
 48H  17/0600Z...DISSIPATED

Forecaster Brown

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