Issued at 500 PM AST Wed Oct 01 2025
000 WTNT44 KNHC 012045 TCDAT4 Hurricane Imelda Discussion Number 21 NWS National Hurricane Center Miami FL AL092025 500 PM AST Wed Oct 01 2025 Visible satellite images and scatterometer data show that Imelda is beginning to interact with a nearby front that is impinging on the northern portion of the hurricane's circulation. Partial ASCAT-B and -C passes over Imelda reveal that the large wind field is becoming asymmetric, with the strongest winds occurring over the western semicircle of the hurricane. In addition, some structural changes were reported by the Air Force Reserve Hurricane Hunters on their final pass through Imelda. The eyewall had taken an elliptical shape and was open to the northeast, unlike the closed circular eyewall that was reported earlier this morning. The last center dropsonde indicated the minimum pressure was still around 966 mb. Based on their peak 700-mb flight-level winds of 93 kt, the initial intensity is held at 85 kt. Another Air Force Reserve Hurricane Hunter aircraft is currently en route to investigate the storm. Tropical storm conditions, especially in gusts, are already being reported on Bermuda. Imelda continues moving east-northwestward (070 deg) at around 19 kt, with the center expected to pass over or just south of Bermuda and bring hurricane-force conditions to the island late tonight into early Thursday. Although the system is moving quickly, the wind field is growing and becoming asymmetric due to the early stages of extratropical transition. As a result, the strongest winds may occur early Thursday morning after the center has passed Bermuda. The GFS and ECMWF indicate some strengthening could occur in the near term due to baroclinic interaction, and this is reflected in the NHC intensity forecast. After Imelda clears Bermuda and becomes fully extratropical, most models show the cyclone turning northeastward by late Thursday or Friday within the flow between a deep-layer trough over the western Atlantic and a narrow subtropical ridge to the east. This portion of the track forecast remains challenging. There is still significant model spread, mostly related to whether the cyclone becomes fully captured by the trough. The GFS remains a major outlier among the rest of the global guidance, and the updated NHC track forecast continues to trend closer to a blend of the ECMWF and Google DeepMind solutions. Beyond 24 h, steady weakening is forecast while the extratropical low moves deeper into the mid-latitudes and gradually fills while becoming stretched out along the front. KEY MESSAGES: 1. Imelda is expected to bring damaging hurricane-force winds and large and damaging waves to Bermuda when it passes near or over the island late tonight into early Thursday. Significant hurricane-force gusts are likely across Bermuda even after the center passes. 2. Heavy rainfall could cause flash flooding across Bermuda tonight into Thursday. 3. Swells and high surf from Imelda are expected to produce dangerous marine conditions and rip currents along much of the East Coast of the United States and the western Atlantic during the next several days. FORECAST POSITIONS AND MAX WINDS INIT 01/2100Z 31.6N 67.9W 85 KT 100 MPH 12H 02/0600Z 32.3N 64.1W 90 KT 105 MPH 24H 02/1800Z 33.2N 58.7W 80 KT 90 MPH...POST-TROP/EXTRATROP 36H 03/0600Z 34.8N 53.8W 70 KT 80 MPH...POST-TROP/EXTRATROP 48H 03/1800Z 37.2N 51.1W 65 KT 75 MPH...POST-TROP/EXTRATROP 60H 04/0600Z 39.5N 49.7W 60 KT 70 MPH...POST-TROP/EXTRATROP 72H 04/1800Z 42.4N 46.9W 55 KT 65 MPH...POST-TROP/EXTRATROP 96H 05/1800Z 47.5N 38.0W 45 KT 50 MPH...POST-TROP/EXTRATROP 120H 06/1800Z 49.5N 32.0W 40 KT 45 MPH...POST-TROP/EXTRATROP $$ Forecaster Reinhart
