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| #1200653 (Received by flhurricane at: 4:45 PM 27.Sep.2024) TCPAT4 BULLETIN Post-Tropical Cyclone Helene Advisory Number 18 NWS National Hurricane Center Miami FL AL092024 400 PM CDT Fri Sep 27 2024 ...HELENE STILL PRODUCING CATASTROPHIC FLOODING OVER PORTIONS OF THE SOUTHERN APPALACHIANS AND TENNESSEE VALLEY... ...FUTURE ADVISORIES WILL BE ISSUED BY THE WEATHER PREDICTION CENTER... SUMMARY OF 400 PM CDT...2100 UTC...INFORMATION ---------------------------------------------- LOCATION...37.5N 85.5W ABOUT 50 MI...80 KM SSE OF LOUISVILLE KENTUCKY MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H PRESENT MOVEMENT...NNW OR 330 DEGREES AT 17 MPH...28 KM/H MINIMUM CENTRAL PRESSURE...984 MB...29.06 INCHES WATCHES AND WARNINGS -------------------- There are no coastal watches or warnings in effect. For storm information specific to your area, please monitor products issued by your local National Weather Service forecast office. DISCUSSION AND OUTLOOK ---------------------- At 400 PM CDT (2100 UTC), the center of Post-Tropical Cyclone Helene was located near latitude 37.5 North, longitude 85.5 West. The post-tropical cyclone is moving toward the north-northwest near 17 mph (28 km/h). A slowdown in forward speed is expected, and the system is forecast to stall over the Tennessee Valley late tonight and through the weekend. Maximum sustained winds are near 35 mph (55 km/h) with higher gusts. Continued weakening is expected during the next couple of days. The estimated minimum central pressure is 984 mb (29.06 inches). HAZARDS AFFECTING LAND ---------------------- Key Messages for Helene can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDAT4 and WMO header WTNT44 KNHC and on the web at hurricanes.gov/text/MIATCDAT4.shtml RAINFALL: Over portions of the central and southern Appalachians, Helene is expected to produce additional rainfall amounts of 1 to 2 inches leading to widespread total rainfall accumulations of 6 to 12 inches, with isolated totals exceeding 20 inches. This rainfall will result in catastrophic and potentially life-threatening flash and urban flooding, along with record level river flooding in many instances. Numerous significant landslides are expected in steep terrain across the southern Appalachians. Elsewhere, 1 to 3 inches of rainfall is expected across portions of the Ohio Valley through Sunday evening. For a complete depiction of forecast rainfall associated with Tropical Storm Helene, please see the National Weather Service Storm Total Rainfall Graphic, available at hurricanes.gov/graphics_at4.shtml?rainqpf and the Flash Flood Risk graphic at hurricanes.gov/graphics_at4.shtml?ero. For a list of rainfall observations (and wind reports) associated this storm, see the companion storm summary at WBCSCCNS4 with the WMO header ACUS44 KWBC or at the following link: www.wpc.ncep.noaa.gov/discussions/nfdscc4.html. TORNADOES: Isolated tornadoes are possible this afternoon and evening over southern Virginia and northeast North Carolina. SURF: Swells generated by Helene will affect the coasts of Georgia and the Carolinas during the next day or so. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. NEXT ADVISORY ------------- This is the last public advisory issued by the National Hurricane Center on Helene. Future information on this system can be found in Public Advisories issued by the Weather Prediction Center beginning at 1000 PM CDT, under AWIPS header TCPAT4, WMO header WTNT34 KWNH, and on the web at www.hurricanes.gov. Rainfall forecasts for the United States can always be found at https://www.wpc.ncep.noaa.gov/qpf/qpf2.shtml and outlooks of flash flood risks can be found at https://www.wpc.ncep.noaa.gov/qpf/excessive_rainfall_outlook_ero.php . $$ Forecaster Cangialosi |
