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| #1157085 (Received by flhurricane at: 4:35 PM 12.Oct.2023) 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 |
