Subtropical Storm Patty Forecast Discussion Number 2
Issued at 300 PM GMT Sat Nov 02 2024 000 WTNT42 KNHC 021436 TCDAT2 Subtropical Storm Patty Discussion Number 2 NWS National Hurricane Center Miami FL AL172024 300 PM GMT Sat Nov 02 2024 Patty has strengthened over the past several hours. Satellite images continue to show the system maintaining a tight core with a ring of cold cloud tops surrounding the center. On a larger scale, however, the storm has a considerable amount of cool and dry air wrapping around the core and it is co-located with an upper-level low. These mixed tropical and extratropical characteristics are supportive of maintaining Patty's subtropical status. ASCAT data from a few hours ago showed peak winds near 50 kt in the southwestern quadrant, and given potential undersampling due to the instrument's resolution, the initial wind speed is increased to 55 kt. The wind radii have also been adjusted based on the ASCAT data. Patty is likely near its peak intensity as it currently lies in a region of instability beneath its parent upper-level low and in relatively low vertical wind shear. However, the models show the upper-level feature weakening, resulting in more stable conditions and increasing westerly vertical wind shear. These environmental factors should cause steady weakening and lead to post-tropical transition by Sunday night. The low is expected to dissipate in 3 to 4 days. The NHC intensity forecast is above the previous in the short term due to the higher initial intensity. The subtropical storm is accelerating southeastward, and the latest initial motion estimate is 130/11 kt. A faster eastward motion is expected to begin soon, taking the storm near or just south of the Azores tonight and Sunday. An east-northeastward motion is expected after that toward western Europe. The models are in fairly good agreement, and this forecast lies near the middle of the guidance envelope. Key Messages: 1. Tropical storm conditions are expected in the Azores tonight and Sunday. 2. Locally heavy rains are possible across the Azores through Sunday. FORECAST POSITIONS AND MAX WINDS INIT 02/1500Z 39.0N 32.4W 55 KT 65 MPH 12H 03/0000Z 38.2N 29.5W 50 KT 60 MPH 24H 03/1200Z 37.8N 25.7W 45 KT 50 MPH 36H 04/0000Z 37.8N 21.6W 40 KT 45 MPH...POST-TROPICAL 48H 04/1200Z 38.7N 17.3W 35 KT 40 MPH...POST-TROPICAL 60H 05/0000Z 40.0N 13.4W 30 KT 35 MPH...POST-TROP/REMNT LOW 72H 05/1200Z 41.6N 10.1W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 06/1200Z...DISSIPATED $$ Forecaster Cangialosi
Issued at 300 PM GMT Sat Nov 02 2024
000 WTNT42 KNHC 021436 TCDAT2 Subtropical Storm Patty Discussion Number 2 NWS National Hurricane Center Miami FL AL172024 300 PM GMT Sat Nov 02 2024 Patty has strengthened over the past several hours. Satellite images continue to show the system maintaining a tight core with a ring of cold cloud tops surrounding the center. On a larger scale, however, the storm has a considerable amount of cool and dry air wrapping around the core and it is co-located with an upper-level low. These mixed tropical and extratropical characteristics are supportive of maintaining Patty's subtropical status. ASCAT data from a few hours ago showed peak winds near 50 kt in the southwestern quadrant, and given potential undersampling due to the instrument's resolution, the initial wind speed is increased to 55 kt. The wind radii have also been adjusted based on the ASCAT data. Patty is likely near its peak intensity as it currently lies in a region of instability beneath its parent upper-level low and in relatively low vertical wind shear. However, the models show the upper-level feature weakening, resulting in more stable conditions and increasing westerly vertical wind shear. These environmental factors should cause steady weakening and lead to post-tropical transition by Sunday night. The low is expected to dissipate in 3 to 4 days. The NHC intensity forecast is above the previous in the short term due to the higher initial intensity. The subtropical storm is accelerating southeastward, and the latest initial motion estimate is 130/11 kt. A faster eastward motion is expected to begin soon, taking the storm near or just south of the Azores tonight and Sunday. An east-northeastward motion is expected after that toward western Europe. The models are in fairly good agreement, and this forecast lies near the middle of the guidance envelope. Key Messages: 1. Tropical storm conditions are expected in the Azores tonight and Sunday. 2. Locally heavy rains are possible across the Azores through Sunday. FORECAST POSITIONS AND MAX WINDS INIT 02/1500Z 39.0N 32.4W 55 KT 65 MPH 12H 03/0000Z 38.2N 29.5W 50 KT 60 MPH 24H 03/1200Z 37.8N 25.7W 45 KT 50 MPH 36H 04/0000Z 37.8N 21.6W 40 KT 45 MPH...POST-TROPICAL 48H 04/1200Z 38.7N 17.3W 35 KT 40 MPH...POST-TROPICAL 60H 05/0000Z 40.0N 13.4W 30 KT 35 MPH...POST-TROP/REMNT LOW 72H 05/1200Z 41.6N 10.1W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 06/1200Z...DISSIPATED $$ Forecaster Cangialosi
