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| #1246161 (Received by flhurricane at: 4:45 PM 26.Sep.2025) TCDAT4 Potential Tropical Cyclone Nine Discussion Number 1 NWS National Hurricane Center Miami FL AL092025 500 PM EDT Fri Sep 26 2025 Visible satellite images and surface observations suggest that Invest 94L is gradually organizing and beginning to develop a low-level circulation near eastern Cuba with estimated maximum winds of about 30 kt. Although the system does not meet the criteria of a tropical cyclone currently, it is expected to become one during the next day or so. In addition, the system is likely to bring tropical storm conditions to portions of the central and northwestern Bahamas this weekend and potential impacts to portions of the southeast U.S. early next week. Therefore, NHC is now initiating Potential Tropical Cyclone advisories for this disturbance. The system has been moving west-northwestward at about 8 kt during the past 12 to 24 hours. However, this motion is expected to change as the disturbance is forecast to turn northward in southerly flow between a large-scale trough over the eastern U.S. and a subtropical ridge over the central-western Atlantic. This track should take the system across the central and northwestern Bahamas over the weekend. The models are in good agreement through that time period, but they diverge significantly early next week when the synoptic pattern becomes complicated. If the system moves on the fast side of the guidance, it will likely be more influenced by the U.S. trough that is expected to cut off. In that scenario, the disturbance would move inland over the southeast U.S. early next week. Conversely, if the system moves on the slow side of the guidance, Humberto's circulation will cause the steering currents to collapse, resulting in this system stalling near the southeast coast or drifting eastward. The NHC track forecast lies roughly between these scenarios, in best agreement with EMXI, but confidence is very low in the days 4 and 5 positions. Strengthening is likely to be slow in the short term due to the current land interaction and some southerly shear. However, gradual intensification seems like a good bet this weekend and on Monday while the system tracks over the Gulf Stream and within a diffluent upper-level wind pattern. The NHC intensity forecast lies close to the hurricane regional and consensus models and shows the system reaching hurricane strength early next week. It should be emphasized that the long-range intensity forecast depends largely on where the system is and the degree of land interaction at those periods, and therefore, is of low confidence. Given the higher-than-usual uncertainty in the forecast track and intensity of the system, NOAA Hurricane Hunter aircraft have been collecting data over the western Atlantic since yesterday, and additional upper-air launches are occurring. This data collection will continue through the weekend to help improve the model guidance for this system. KEY MESSAGES: 1. The disturbance is forecast to become a tropical storm this weekend and bring tropical storm conditions to portions of the central and northwestern Bahamas, where Tropical Storm Warnings and Watches, respectively, have been issued. Rainfall associated with this system will impact eastern Cuba, Hispaniola, Jamaica, and the Bahamas through the weekend. 2. There is an increasing threat of heavy rainfall early next week from coastal Georgia through the Carolinas and into the southern Mid-Atlantic states, which could cause flash, urban, and river flooding. 3. The system is expected to be at or near hurricane intensity when it approaches the southeast U.S. coast early next week, where there is a risk of storm surge and wind impacts. Residents in that area should monitor updates to the forecast and ensure they have their hurricane plan in place. FORECAST POSITIONS AND MAX WINDS INIT 26/2100Z 20.9N 74.6W 30 KT 35 MPH...POTENTIAL TROP CYCLONE 12H 27/0600Z 21.7N 75.3W 30 KT 35 MPH...POTENTIAL TROP CYCLONE 24H 27/1800Z 22.7N 75.8W 30 KT 35 MPH...TROPICAL CYCLONE 36H 28/0600Z 24.1N 76.4W 35 KT 40 MPH 48H 28/1800Z 25.6N 76.9W 45 KT 50 MPH 60H 29/0600Z 27.4N 77.3W 55 KT 65 MPH 72H 29/1800Z 29.7N 78.0W 65 KT 75 MPH 96H 30/1800Z 31.8N 78.9W 65 KT 75 MPH 120H 01/1800Z 32.3N 79.3W 60 KT 70 MPH $$ Forecaster Cangialosi |
