####018002282####
WTNT44 KNHC 120834

TCDAT4

 

Tropical Depression Sean Discussion Number   6

NWS National Hurricane Center Miami FL       AL192023

500 AM AST Thu Oct 12 2023

 

Sean remains a sheared, poorly organized tropical cyclone. Recent 

AMSR2 passive microwave images show the surface circulation lies 

well to the west of the associated deep convection. The lackluster 

satellite presentation of Sean has resulted in decreasing subjective 

Dvorak data-T numbers from TAFB and SAB, which supports keeping the 

system a tropical depression. The initial intensity is held at 30 

kt, consistent with the ASCAT data from yesterday evening. 

 

The depression is moving west-northwestward at 300/10 kt. A weak 

low- to mid-level ridge to the north and northeast of Sean should 

steer the cyclone to the west-northwest and northwest through early 

next week. A slight rightward adjustment was made to the NHC track 

forecast to reflect the latest multi-model consensus trends. But 

otherwise, the updated forecast is similar to the previous 

prediction. 



Moderate to strong westerly shear is expected to persist over the 

depression for the next day or two. By the time the shear relents, 

simulated satellite images from the GFS and ECMWF models suggest 

that Sean could struggle to sustain organized convection near its 

center within a drier and more convergent upper-level environment. 

While small intensity fluctuations cannot be ruled out during the 

next couple of days, the NHC intensity forecast follows the HCCA and 

IVCN aids and keeps Sean a depression through 60 h. Sean is forecast 

to degenerate to a post-tropical remnant low soon thereafter and 

dissipate to a trough by day 4, although this could occur even 

sooner if the cyclone remains poorly organized.

 

 

FORECAST POSITIONS AND MAX WINDS

 

INIT  12/0900Z 12.5N  36.7W   30 KT  35 MPH

 12H  12/1800Z 13.0N  38.0W   30 KT  35 MPH

 24H  13/0600Z 13.8N  39.6W   30 KT  35 MPH

 36H  13/1800Z 14.8N  41.2W   30 KT  35 MPH

 48H  14/0600Z 16.0N  42.6W   30 KT  35 MPH

 60H  14/1800Z 17.3N  43.9W   25 KT  30 MPH

 72H  15/0600Z 18.2N  45.0W   25 KT  30 MPH...POST-TROP/REMNT LOW

 96H  16/0600Z...DISSIPATED

 

$$

Forecaster Reinhart