####018002701####
WTNT44 KNHC 122033

TCDAT4

 

Tropical Storm Sean Discussion Number   8

NWS National Hurricane Center Miami FL       AL192023

500 PM AST Thu Oct 12 2023

 

Sean remains fairly disorganized on satellite imagery this 

afternoon. The low-level center is still exposed, however there has 

been a recent burst of convection closer to the center. Subjective 

Dvorak intensity estimates have increased since the previous cycle, 

with final-T numbers of T2.5/T2.0 from TAFB and SAB, respectively. 

These estimates are in fairly good agreement with the scatterometer 

data from earlier. Therefore, the initial intensity for this 

advisory is held at 35 kt.

 

The tropical storm is moving at a slightly faster northwestward 

motion at 310/10 kt, gaining a little more latitude since this 

morning. A weak ridge to the northeast of the system will continue 

to steer Sean northwestward to west-northwestward throughout the 

forecast period. Model guidance remains in fairly good agreement 

with this scenario. There was a slight shift to the right in the 

short-term center positions to account for the slightly faster 

northwestward motion.  Otherwise, the track forecast is similar to 

the previous and lies near the consensus aids.

 

Westerly vertical wind shear is expected to persist over the system 

for the next day or so, before decreasing along Sean's forecast 

track.  However, the system will be moving into an area with drier 

mid-level RH values, a more stable environment, and a less favorable 

upper-level wind pattern. Simulated satellite imagery from the GFS 

and ECMWF models suggest that Sean could struggle to produce 

organized convection in the coming days. While small intensity 

fluctuations are possible, the NHC intensity forecast remains near 

the HCCA and IVCN consensus aids, keeping Sean a tropical storm for 

the next day or so, then weakening it back into a depression. 

Afterwards, the system is forecast to degenerate into a 

post-tropical remnant low as it becomes devoid of convection, and 

dissipate into a trough by day 4. Although, some global models 

depict that these transitions could occur even sooner than forecast.

 

 

FORECAST POSITIONS AND MAX WINDS

 

INIT  12/2100Z 13.8N  38.2W   35 KT  40 MPH

 12H  13/0600Z 14.5N  39.5W   35 KT  40 MPH

 24H  13/1800Z 15.5N  41.2W   35 KT  40 MPH

 36H  14/0600Z 16.8N  42.6W   30 KT  35 MPH

 48H  14/1800Z 18.0N  43.8W   30 KT  35 MPH

 60H  15/0600Z 19.0N  44.8W   25 KT  30 MPH...POST-TROP/REMNT LOW

 72H  15/1800Z 19.9N  45.9W   25 KT  30 MPH...POST-TROP/REMNT LOW

 96H  16/1800Z...DISSIPATED

 

$$

Forecaster Kelly