Issued at 500 PM AST Wed Aug 13 2025
500 WTNT45 KNHC 132034 TCDAT5 Tropical Storm Erin Discussion Number 10 NWS National Hurricane Center Miami FL AL052025 500 PM AST Wed Aug 13 2025 Convection has become more concentrated near the center of Erin during the past few hours, although the storm still has a somewhat ragged overall appearance. Satellite intensity estimates have increased a little since the last advisory and are now in the 35-50 kt range. Based on these trends, the initial intensity is increased to 45 kt. Erin remains in an area of marginal sea surface temperatures and moisture and this should continue for another 12 h or so. After that, the forecast track takes the system over warmer SSTs that increase to 29-30C by the end of the forecast period. In addition, the cyclone is currently in a favorable low- to moderate-shear environment, and this is likely to continue for the next 72 h or so. This evolution should allow Erin to significantly intensify, with the cyclone forecast to become a hurricane by 36 h and a major hurricane by 96 hr. After 72-96 h, Erin may encounter increased northwesterly shear as it tracks to the northeast of a large upper-level anticyclone forecast to form near Hispaniola and the southeastern Bahamas. Although it is unclear how much shear Erin will encounter, the intensity guidance suggests at least a lower rate of intensification at that time. The new intensity forecast is adjusted upward somewhat from the previous forecast through 72 h based on current trends and the intensity consensus. The initial motion is now 270/15 kt. A low- to mid-level ridge north of Erin should steer the cyclone westward for the next 12 h or so, followed by a generally west-northwestward motion through 96 h. After that time, a developing break in the ridge near the southeastern coast of the United States should lead to a northwestward motion. The track guidance is still in fairly good agreement, and the official forecast remains on the southern side of the guidance envelope between the HCCA corrected consensus and the other consensus models. However, the guidance envelope has shifted a little westward since the last advisory, and the new forecast track is also a little west of the previous track. Users are reminded that NHC track forecasts have an average error of 150 to 215 miles at days 4 and 5, and future adjustments to the forecast are still possible. It should be noted that the directional spread becomes very large in both the deterministic and ensemble track guidance at long range. Therefore, there is a greater than normal uncertainty about what impacts Erin may bring to portions of the Bahamas, the east coast of the United States, and Bermuda. KEY MESSAGES: 1. Locally heavy rainfall, high surf and rip currents, and tropical-storm force winds could occur in portions of the northern Leeward Islands, the Virgin Islands, and Puerto Rico this weekend as the core of Erin passes north of those islands. Interests in these areas should continue to monitor the progress of Erin. 2. While there is still uncertainty in what impacts might occur in portions of the Bahamas, the east coast of the United States, and Bermuda next week, the risk of dangerous surf and rip currents across the western Atlantic basin next week is increasing. As we approach the climatological peak of the hurricane season, this is an opportune time to ensure your preparedness plans are in place. FORECAST POSITIONS AND MAX WINDS INIT 13/2100Z 16.3N 45.0W 45 KT 50 MPH 12H 14/0600Z 16.3N 47.2W 50 KT 60 MPH 24H 14/1800Z 16.9N 50.1W 55 KT 65 MPH 36H 15/0600Z 17.6N 53.0W 65 KT 75 MPH 48H 15/1800Z 18.4N 55.9W 75 KT 85 MPH 60H 16/0600Z 19.3N 58.8W 85 KT 100 MPH 72H 16/1800Z 20.2N 61.4W 95 KT 110 MPH 96H 17/1800Z 22.2N 65.8W 100 KT 115 MPH 120H 18/1800Z 24.8N 68.2W 105 KT 120 MPH $$ Forecaster Beven