Issued at 500 AM EDT Mon Aug 18 2025
000 WTNT45 KNHC 180836 TCDAT5 Hurricane Erin Discussion Number 28 NWS National Hurricane Center Miami FL AL052025 500 AM EDT Mon Aug 18 2025 Erin is growing in size, as predicted. Data from the Air Force Hurricane Hunters and ASCAT passes from a few hours ago showed that the hurricane- and tropical-storm-force winds now extend up to 70 n mi and 200 n mi from the eye, respectively. The eye of the hurricane has also grown and is now about 30 n mi in diameter, and there is some evidence of mesovorticies within it. There is also some indication that Erin again has concentric eyewalls as the Hurricane Hunters reported a double wind maximum in their last pass. The initial intensity remains 115 kt based on a combination of the earlier aircraft data and current satellite estimates. Erin's outer rainbands are affecting the southeast Bahamas and the Turks and Caicos Islands, and those locations will likely continue to experience tropical storm conditions for several more hours. The hurricane has wobbled to the left over the past 6 hours, but a longer-term motion is still west-northwestward at 11 kt. Erin is still forecast to gradually turn northward later today and Tuesday as it moves into a weakness within the subtropical ridge. This motion should take the core of the hurricane roughly midway between Bermuda and the east coast of the U.S. on Wednesday and Thursday. After that time, an approaching trough should cause Erin to accelerate northeastward over the northern Atlantic. The NHC track forecast has been nudged to the left of the previous one to be closer to the various consensus models. Deep convection has been increasing in intensity and symmetry, and it seems likely that Erin will strengthen today. The intensification is likely to end by tonight due to some increase in shear and a broadening of the inner core wind field. Slow weakening seems likely beginning Tuesday, but it should be emphasized that Erin is expected to remain a powerful hurricane through the week. The NHC intensity forecast is above the models in the short term, but falls near the middle of the guidance after that. Based on an evaluation of storm sizes of major hurricanes over the past couple of decades in the subtropics, Erin is around the 80th percentile. Erin's wind field is expected to keep growing over the next few days. The expanding wind field will result in rough ocean conditions over much of the western Atlantic. It should be noted that the 34- and 50-kt wind speed probabilities beyond 36 hours in the text and graphical products are likely underestimating the risk of those winds occurring. This is because the forecast wind field of Erin is considerably larger than average compared to the wind field used to derive the wind speed probability product. KEY MESSAGES: 1. Bands of heavy rainfall are expected today over portions of Hispaniola and through Tuesday for the Turks and Caicos and portions of the southeast and central Bahamas. Flash and urban flooding are possible. 2. Tropical storm conditions are expected in the Turks and Caicos Islands and in the southeast Bahamas today. Tropical storm conditions are possible in portions of the central Bahamas late today through Tuesday. 3. Erin is expected 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. 4. Interests along the Outer Banks of North Carolina and Bermuda should monitor the progress of Erin as there is a risk of strong winds associated with the outer rainbands during the middle part of the week. FORECAST POSITIONS AND MAX WINDS INIT 18/0900Z 22.8N 70.2W 115 KT 130 MPH 12H 18/1800Z 23.6N 71.2W 125 KT 145 MPH 24H 19/0600Z 25.0N 72.2W 115 KT 130 MPH 36H 19/1800Z 26.6N 72.9W 110 KT 125 MPH 48H 20/0600Z 28.6N 73.4W 105 KT 120 MPH 60H 20/1800Z 30.7N 73.4W 100 KT 115 MPH 72H 21/0600Z 32.9N 72.2W 95 KT 110 MPH 96H 22/0600Z 37.2N 66.1W 85 KT 100 MPH 120H 23/0600Z 41.6N 56.0W 75 KT 85 MPH $$ Forecaster Cangialosi