|
Show Selection: |
| #1246360 (Received by flhurricane at: 5:00 AM 28.Sep.2025) TCDAT4 Tropical Depression Nine Discussion Number 7 NWS National Hurricane Center Miami FL AL092025 500 AM EDT Sun Sep 28 2025 The depression has been slowly becoming more organized overnight. The minimum central pressure has fallen to 1003 mb, and satellite images are indicating that a tighter circulation has formed along with increasing deep convection. The initial intensity is held at 30 kt per the latest aircraft flight-level winds, but this system will probably become a tropical storm soon. The initial motion is a bit faster to the north-northwest, or 345/6 kt. This general motion with a turn towards the north is anticipated during the next couple of days while the system moves between an upper trough over the southeastern United States and the subtropical ridge. Beyond that time, models are generally faster and more offshore of the United States with the eventual track of the tropical cyclone, following the trend of the past few cycles, due to it missing the upper trough and eventually following Hurricane Humberto more out to sea. While it is too early to feel extremely confident, almost all of the reliable ensembles now keep the system offshore of the southeastern United States, though some impacts are still anticipated. The latest NHC forecast is shifted to the south and east, but is not nearly as far to the southeast as the latest consensus models due to continuity constraints. Now that a better-defined core has formed, gradual intensification is anticipated for the next couple of days while the system remains in a warm water but moderate shear environment. The intensity forecast is similar to the previous one through the first couple days of the forecast. Afterwards, the intensity forecast is slightly raised as the system could find itself in a lower shear environment while still over warm waters. By the end of the forecast, interaction with a frontal boundary is likely to cause some weakening, along with extratropical transition. This is a low confidence forecast at long range given the recent large track changes. KEY MESSAGES: 1. The depression is expected to strengthen and bring tropical storm conditions to portions of the central and northwestern Bahamas through tonight. Tropical storm conditions are also possible along portions of the east coast of central Florida beginning Monday, where a Tropical Storm Watch is in effect. 2. Rainfall associated with Tropical Depression Nine will continue to impact eastern Cuba and the Bahamas through Tuesday, which will likely produce flash and urban flooding. Mudslides are possible in the higher terrain. Heavy rainfall across the coastal Carolinas could cause flash, urban, and river flooding into Wednesday morning. 3. There is still a risk of heavy rainfall, wind and high surf impacts for the southeast U.S. coast even if the center remains offshore. Residents should closely monitor the latest forecast updates and ensure that they have their hurricane plan in place. FORECAST POSITIONS AND MAX WINDS INIT 28/0900Z 23.0N 77.2W 30 KT 35 MPH 12H 28/1800Z 24.1N 77.4W 40 KT 45 MPH 24H 29/0600Z 25.7N 77.6W 50 KT 60 MPH 36H 29/1800Z 27.4N 77.8W 60 KT 70 MPH 48H 30/0600Z 28.8N 77.8W 65 KT 75 MPH 60H 30/1800Z 29.5N 77.4W 70 KT 80 MPH 72H 01/0600Z 29.9N 75.5W 70 KT 80 MPH 96H 02/0600Z 30.6N 72.1W 75 KT 85 MPH 120H 03/0600Z 31.7N 66.4W 65 KT 75 MPH...POST-TROP/EXTRATROP $$ Forecaster Blake |
