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| #1155150 (Received by flhurricane at: 10:40 PM 29.Sep.2023) TCDAT3 Tropical Storm Rina Discussion Number 7 NWS National Hurricane Center Miami FL AL182023 1100 PM AST Fri Sep 29 2023 Rina continues to produce persistent but poorly organized shower and thunderstorm activity well to the east of its exposed surface center. Despite the apparent lack of organization, a pair of ASCAT passes near 00Z revealed that Rina`s wind field was both slightly larger and stronger than previously estimated. Both ASCAT passes showed a large swath of winds of 40-45 kt east and northeast of Rina`s center. Based on this new information, the intensity of Rina has been increased to 45 kt. Both ASCAT passes had slightly higher winds in the deep convection that were flagged as marginal for rain contamination, so they weren`t considered as representative. That said, its possible 45 kt could be slightly conservative. With SHIPS-analyzed 850-200 mb shear higher than 40 kt for the next 24 h, its very unlikely Rina will become any better organized than it is now. Nearly all of the dynamical models forecast that Rina will dissipate in the next 24 to 48 h. Based on the structure information provided by ASCAT, it appears unlikely that the tropical storm will dissipate that quickly. Therefore the the NHC official forecast is a little more conservative, but still shows Rina slowly weakening, close to the intensity consensus. It is worth noting that the vortex tracker associated with a few models flipped to Philippe beyond 72 h and the tracks are therefore not representative of the actual model forecast. Rina is heading northwestward near 10 kt. The combination of Tropical Storm Philippe to its west-southwest and a subtropical ridge to the northeast should keep Rina on this general heading for a couple of days. The NHC track forecast is near the center of the guidance envelope, between the simple and corrected consensus aids. FORECAST POSITIONS AND MAX WINDS INIT 30/0300Z 20.4N 48.8W 45 KT 50 MPH 12H 30/1200Z 21.1N 50.2W 45 KT 50 MPH 24H 01/0000Z 22.2N 51.9W 40 KT 45 MPH 36H 01/1200Z 23.3N 53.7W 35 KT 40 MPH 48H 02/0000Z 24.8N 55.6W 30 KT 35 MPH...POST-TROP/REMNT LOW 60H 02/1200Z 26.7N 56.8W 30 KT 35 MPH...POST-TROP/REMNT LOW 72H 03/0000Z...DISSIPATED $$ Forecaster D. Zelinsky |
