Issued at 1100 PM AST Tue Aug 12 2025
817 WTNT45 KNHC 130238 TCDAT5 Tropical Storm Erin Discussion Number 7 NWS National Hurricane Center Miami FL AL052025 1100 PM AST Tue Aug 12 2025 Deep convection has returned near Erin this evening, though it appears to mostly be west of the center. An ASCAT pass from a few hours ago showed maximum winds of about the same magnitude as the earlier data, 35-40 kt, though it did display a larger area of tropical-storm-force winds. With no significant change in the satellite intensity estimates, the initial wind speed remains 40 kt. The environment around Erin gradually gets more conducive for strengthening during the next day or so, including a slow rise in SSTs and instability. By late Thursday, SSTs rise above 28C with continued light or moderate shear. This evolution should promote slow intensification in the near-term, followed by quick intensification in a couple of days, especially if Erin continues to have a small core. The new NHC intensity forecast is similar to the previous one, but a little higher to follow the latest corrected consensus guidance. Beyond 96 hours, the global models all suggest that shear will increase, so the wind speed is leveled off at that point. Erin continues to move quickly south-of-due-west (260/17) due to strong low- to mid-level ridging located to the north over the central and eastern Atlantic. Model guidance has trended a bit southward in the near-term, so the first day or so of the forecast has been adjusted equatorward. In a couple of days, a weakening of that ridge is anticipated, which should cause Erin to begin moving west-northwestward by Friday. There are no significant changes to the long-range NHC forecast, and note that the 18Z GFS appeared to be a significant outlier and was mostly disregarded in this package. The new forecast remains along the southern part of the guidance envelope, lying closest to the HFIP Corrected Consensus (HCCA) and Google Deep Mind (GDM) models. Keep in mind that NHC track forecasts have an average error of 120-180 n mi (150-215 statute miles) at days 4 and 5, and future adjustments in the forecast are still possible. KEY MESSAGES: 1. Erin could move close enough to the northern Leeward Islands, Virgin Islands, and Puerto Rico over the weekend to produce some impacts on those islands. However, the magnitude of those impacts is still not known, and interests there should continue to monitor the progress of this storm. 2. There is even greater uncertainty in what impacts might occur in portions of the Greater Antilles, the Bahamas, the east coast of the United States, and Bermuda next week. 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 13/0300Z 16.7N 40.1W 40 KT 45 MPH 12H 13/1200Z 16.3N 42.6W 45 KT 50 MPH 24H 14/0000Z 16.2N 45.5W 45 KT 50 MPH 36H 14/1200Z 16.6N 48.4W 50 KT 60 MPH 48H 15/0000Z 17.3N 51.4W 60 KT 70 MPH 60H 15/1200Z 18.1N 54.6W 75 KT 85 MPH 72H 16/0000Z 18.9N 57.5W 85 KT 100 MPH 96H 17/0000Z 20.5N 62.6W 100 KT 115 MPH 120H 18/0000Z 22.5N 66.5W 100 KT 115 MPH $$ Forecaster Blake