978 WTNT42 KNHC 030232 TCDAT2 Subtropical Storm Patty Discussion Number 4 NWS National Hurricane Center Miami FL AL172024 300 AM GMT Sun Nov 03 2024 The convective structure of Patty has changed some over the past several hours as the center passes just south of the central Azores. While the cloud tops have cooled, the convection is now mainly to the northeast of the center, and the overall cloud pattern is elongated south-to-north. The system remains embedded in a deep-layer cold air mass, with surface temperatures in the Azores currently below 20C. Satellite intensity estimates have decreased a little due to the decreased convective symmetry, and this is the basis for lowering the initial intensity to 50 kt. Patty is expected to weaken over the next few days as the parent upper-level low decays to an open trough, leaving the storm in stronger shear. While this happens, it should also move into a drier and more stable airmass. This combination is expected to cause the convection to dissipate by 36 h, with the storm becoming a post-tropical low at that time. The latest global model guidance suggests that the remnant low is likely to decay to a trough by 72 h, so the new intensity forecast now calls for dissipation by then. The initial motion is now 095/17 kt. The mid-latitude westerly flow is expected to steer the cyclone eastward for 12-24 h, followed by an east-northeastward motion. The models remain in fairly good agreement, and the forecast track is again near the middle of the guidance envelope. Key Messages: 1. Tropical storm conditions are expected in the Azores through the weekend, where Tropical Storm Warnings are in effect. 2. Locally heavy rains are possible across the Azores through the weekend. FORECAST POSITIONS AND MAX WINDS INIT 03/0300Z 37.9N 27.8W 50 KT 60 MPH 12H 03/1200Z 37.6N 24.7W 45 KT 50 MPH 24H 04/0000Z 37.6N 20.8W 45 KT 50 MPH 36H 04/1200Z 38.5N 16.6W 40 KT 45 MPH...POST-TROPICAL 48H 05/0000Z 40.1N 12.7W 35 KT 40 MPH...POST-TROPICAL 60H 05/1200Z 41.6N 9.5W 30 KT 35 MPH...POST-TROP/REMNT LOW 72H 06/0000Z...DISSIPATED $$ Forecaster Beven