Issued at 500 AM EDT Thu Aug 21 2025
000 WTNT45 KNHC 210846 TCDAT5 Hurricane Erin Discussion Number 40 NWS National Hurricane Center Miami FL AL052025 500 AM EDT Thu Aug 21 2025 Erin's satellite presentation currently shows the low-level center embedded beneath a 90 n mi-wide Central Dense Overcast. Outer convective bands extend a couple of hundred miles away from the center, but there has recently been some erosion of the clouds within the southwestern part of the circulation, which likely signals an increase in shear. On the last transect through the storm, the Air Force Reserve Hurricane Hunters measured 700-mb flight-level winds of 100 kt, and found that the central pressure had risen to 945 mb. The current intensity is estimated to be 90 kt, although it should be noted that some of the satellite intensity estimates are lower. Erin has made its closest approach to the North Carolina coast and is now moving north-northeastward (020 degrees) at 15 kt. There is no change in the forecast reasoning of the future track. Erin should continue to accelerate and turn east-northeastward by Friday as it becomes increasingly embedded within the mid-latitude westerlies. The new NHC track forecast is a bit faster than the previous prediction, showing Erin racing across the north Atlantic with a peak forward speed of about 35 kt in 72 hours. The prospects for strengthening appear to be coming to a close, particularly with the atmosphere becoming more stable and shear increasing during the next 12-24 hours. Only slow weakening is forecast during the next 36 hours, but steady weakening is likely after that time. Erin's transition to a post-tropical cyclone has been moved up to 60 hours in the official forecast, but some of the latest guidance indicate it could happen as soon as 36-48 hours from now. The global models, including the GFS and ECMWF, are also trending toward keeping the post-tropical cyclone big and strong while it moves across the north Atlantic, and the NHC wind radii and intensity forecasts have been adjusted upward accordingly. KEY MESSAGES: 1. Erin will continue to produce life-threatening surf and rip currents along the beaches of the Bahamas, much of the east coast of the U.S., Bermuda, and Atlantic Canada during the next several days. Beachgoers in those areas should follow advice from lifeguards, local authorities, and beach warning flags. 2. Storm surge flooding and tropical storm conditions will continue on the North Carolina Outer Banks today. The storm surge will be accompanied by large waves, leading to significant beach erosion and overwash, making some roads impassible. 3. Tropical storm conditions are expected today along the Virginia coast. Wind gusts to tropical storm force are likely along portions of the remainder of the U.S. Mid-Atlantic and southern New England coasts today through early Friday. 4. Tropical storm conditions are possible on Bermuda this afternoon through early Friday. Gusts to gale force are possible along the coast of Nova Scotia on Friday and the Avalon Peninsula of Newfoundland on Saturday. FORECAST POSITIONS AND MAX WINDS INIT 21/0900Z 34.2N 72.1W 90 KT 105 MPH 12H 21/1800Z 35.8N 70.3W 90 KT 105 MPH 24H 22/0600Z 37.8N 66.7W 85 KT 100 MPH 36H 22/1800Z 39.6N 62.1W 85 KT 100 MPH 48H 23/0600Z 41.4N 56.2W 75 KT 85 MPH 60H 23/1800Z 43.6N 48.7W 65 KT 75 MPH...POST-TROP/EXTRATROP 72H 24/0600Z 46.7N 40.2W 60 KT 70 MPH...POST-TROP/EXTRATROP 96H 25/0600Z 53.0N 26.7W 55 KT 65 MPH...POST-TROP/EXTRATROP 120H 26/0600Z 56.8N 21.7W 45 KT 50 MPH...POST-TROP/EXTRATROP $$ Forecaster Berg