Issued at 500 AM AST Fri Aug 15 2025
000 WTNT45 KNHC 150843 TCDAT5 Tropical Storm Erin Discussion Number 16 NWS National Hurricane Center Miami FL AL052025 500 AM AST Fri Aug 15 2025 Erin has struggled to become better organized tonight, as the system is still trying to establish an inner core. Convection has diminished over the low-level center in recent hours due to some dry air entrainment. The Air Force Reserve Hurricane Hunters have been investigating the system this morning and found maximum flight-level winds of 52 kt. Recent infrared satellite imagery depicts a deep convective band becoming established in the southern semi-circle although flight-level aircraft data found little wind within that band. Objective satellite intensity estimates range from 55 to 67 kt. Given the latest recon data and satellite estimates, the intensity is held at a potentially generous 60 kt. A NOAA P-3 hurricane hunter aircraft is en route to investigate the system, and hopefully Tail Doppler Radar data will be able to better assess the structure of the system. Erin is moving west-northwestward at an estimated motion of 285/15 kt. A subtropical ridge to the north will continue to steer the system west-northwestward into the weekend. A weakness in the ridge is forecast to develop early next week, and this will result in the system gradually turning northwestward then northward by the end of the forecast period. The guidance is in fairly good agreement through about 60-72 hours. After 72 hours, there are some differences in the forward speed and cross-track spread with the turn toward the north. The regional hurricane models lie along the western edge of the guidance envelope with the GFS and Google DeepMind models remaining on the eastern edge of the guidance. The latest NHC forecast is similar to the previous one in the short term, and was nudged slightly west beyond day 3 closer to some of the simple consensus aids. There is still uncertainty about what impacts Erin may bring to portions of the Bahamas, the east coast of the United States, and Bermuda in the long range. The storm is in a favorable environment for strengthening, and it will likely intensify once the inner core becomes more organized. Sea surface temperatures have warmed to about 28C and should continue to warm to near 30C along the forecast track, with a slight decrease in shear expected over the next day or so. Although SHIPS guidance depicts a slight increase in shear later this weekend, the upper-level wind pattern becomes a little more favorable with increasing mid-level RH values. The NHC forecast is similar to the previous with a steady rate of strengthening and lies near the consensus aids, with Erin forecast to become a hurricane later today, and a major hurricane late this weekend. Some of the hurricane regional models and the Florida State Superensemble depict a higher peak intensity than the current NHC forecast. Regardless of the details, Erin will be a large and powerful hurricane over the southwestern Atlantic Ocean this weekend. KEY MESSAGES: 1. Heavy rainfall across the northernmost Leeward Islands, the U.S. and British Virgin Islands, as well as southern and eastern Puerto Rico, may lead to isolated flash and urban flooding, along with landslides or mudslides this weekend into early next week. 2. Tropical storm conditions are possible for portions of the northern Leeward Islands, where Tropical Storm Watches are in effect, beginning on Saturday as the core of Erin passes north of those islands. Tropical storm conditions could also occur in portions of the Virgin Islands and Puerto Rico later in the weekend, and additional watches may be required later today. 3. 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 continues to increase. FORECAST POSITIONS AND MAX WINDS INIT 15/0900Z 17.8N 54.4W 60 KT 70 MPH 12H 15/1800Z 18.4N 56.9W 70 KT 80 MPH 24H 16/0600Z 19.3N 59.9W 80 KT 90 MPH 36H 16/1800Z 20.1N 62.5W 90 KT 105 MPH 48H 17/0600Z 21.0N 64.8W 100 KT 115 MPH 60H 17/1800Z 22.2N 66.9W 110 KT 125 MPH 72H 18/0600Z 23.2N 68.5W 115 KT 130 MPH 96H 19/0600Z 25.5N 70.5W 110 KT 125 MPH 120H 20/0600Z 28.9N 71.4W 105 KT 120 MPH $$ Forecaster Kelly