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| #1200497 (Received by flhurricane at: 1:57 AM 27.Sep.2024) TCPAT4 BULLETIN Hurricane Helene Intermediate Advisory Number 15A NWS National Hurricane Center Miami FL AL092024 200 AM EDT Fri Sep 27 2024 ...HELENE WEAKENING AS IT MOVES QUICKLY NORTH-NORTHEASTWARD NEAR VALDOSTA GEORGIA... ...LIFE-THREATENING STORM SURGE, WINDS, AND HEAVY RAINS CONTINUE... SUMMARY OF 200 AM EDT...0600 UTC...INFORMATION ---------------------------------------------- LOCATION...31.2N 83.3W ABOUT 30 MI...50 KM N OF VALDOSTA GEORGIA ABOUT 85 MI...135 KM NE OF TALLAHASSEE FLORIDA MAXIMUM SUSTAINED WINDS...90 MPH...145 KM/H PRESENT MOVEMENT...NNE OR 15 DEGREES AT 26 MPH...42 KM/H MINIMUM CENTRAL PRESSURE...955 MB...28.20 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: The Tropical Storm Warning has been discontinued for the Florida Keys, including the Dry Tortugas. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Storm Surge Warning is in effect for... * Mexico Beach eastward and southward to Flamingo * Tampa Bay * Charlotte Harbor A Hurricane Warning is in effect for... * Anclote River to Mexico Beach A Hurricane Watch is in effect for... * Englewood to Anclote River, including Tampa Bay A Tropical Storm Warning is in effect for... * Flamingo to Anclote River, including Tampa Bay * West of Mexico Beach to the Okaloosa/Walton County Line * Flamingo northward to Little River Inlet * Lake Okeechobee A Storm Surge Warning means there is a danger of life-threatening inundation, from rising water moving inland from the coastline. For a depiction of areas at risk, please see the National Weather Service Storm Surge Watch/Warning Graphic, available at hurricanes.gov. This is a life-threatening situation. Persons located within these areas should take all necessary actions to protect life and property from rising water and the potential for other dangerous conditions. Promptly follow evacuation and other instructions from local officials. A Hurricane Warning means that hurricane conditions are expected somewhere within the warning area. A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area. A Hurricane Watch means that hurricane conditions are possible within the watch area. For storm information specific to your area in the United States, including possible inland watches and warnings, please monitor products issued by your local National Weather Service forecast office. DISCUSSION AND OUTLOOK ---------------------- At 200 AM EDT (0600 UTC), the center of Hurricane Helene was located near latitude 31.2 North, longitude 83.3 West. Helene is moving toward the north-northeast near 26 mph (42 km/h). A turn toward the north is expected overnight, taking the center over central and northern Georgia this morning. After that, Helene is expected to turn northwestward and slow down over the Tennessee Valley later today and Saturday. Maximum sustained winds have decreased to near near 90 mph (145 km/h) with higher gusts. Continued weakening is expected, but the fast forward speed will allow strong, damaging winds, especially in gusts, to penetrate well inland across the southeastern United States, including over the higher terrain of the southern Appalachians. Hurricane-force winds extend outward up to 30 miles (50 km) from the center and tropical-storm-force winds extend outward up to 310 miles (500 km), mainly to the east of the center. A automated station at Grassy Pond, Georgia, just south of Valdosta, recently reported a wind gust of 96 mph (154 km/h). On the Atlantic coast of Georgia, Savannah International Airport recently reported a wind gust of 75 mph (120 km/h.) The minimum central pressure based on surface observations in the Valdosta area is 955 mb (28.20 inches). A NOAA National Ocean Service tide gauge located on Cedar Key recently reported a water level of 9.30 feet above mean higher high water. 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 STORM SURGE: The combination of a life-threatening storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline. The water could reach the following heights above ground somewhere in the indicated areas if the peak surge occurs at the time of high tide... Carrabelle, FL to Suwannee River, FL...15-20 ft Apalachicola, FL to Carrabelle, FL...10-15 ft Suwannee River, FL to Chassahowitzka, FL...10-15 ft Chassahowitzka, FL to Anclote River, FL...8-12 ft Indian Pass, FL to Apalachicola, FL...6-10 ft Anclote River, FL to Middle of Longboat Key, FL...5-8 ft Tampa Bay...5-8 ft Middle of Longboat Key, FL to Englewood, FL...4-7 ft East of Mexico Beach, FL to Indian Pass, FL...3-5 ft Englewood, FL to Flamingo, FL...3-5 ft Charlotte Harbor...3-5 ft The deepest water will occur along the immediate coast near and to the east of the landfall location, where the surge will be accompanied by large and dangerous waves. Surge-related flooding depends on the relative timing of the surge and the tidal cycle, and can vary greatly over short distances. For information specific to your area, please see products issued by your local National Weather Service forecast office. For a complete depiction of areas at risk of storm surge inundation, please see the National Weather Service Peak Storm Surge Graphic, available at hurricanes.gov/graphics_at4.shtml?peakSurge. WIND: Hurricane conditions are occurring within the hurricane warning area. When the eye passes over, people are reminded to not venture out into the relative calm, as hazardous winds will increase very quickly when the eye passes. Tropical storm conditions are occurring from southern Florida to southeastern Georgia, and these conditions will continue spreading northward across the tropical storm warning areas in the Southeastern U.S. through today. Strong, damaging winds, especially in gusts, will likely penetrate as far inland as the higher terrain of the southern Appalachians. RAINFALL: Over portions of the Southeastern U.S. into the Southern Appalachians, Helene is expected to produce total rain accumulations of 6 to 12 inches, with isolated totals around 20 inches. This rainfall will likely result in catastrophic and potentially life-threatening flash and urban flooding, along with significant river flooding. Numerous significant landslides are expected in steep terrain across the southern Appalachians. For a complete depiction of forecast rainfall associated with Hurricane 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: The risk for several tornadoes continues tonight through this morning over parts of north/central Florida, Georgia, South Carolina, and southern North Carolina. The tornado risk will persist today across the Carolinas and southern Virginia. SURF: Swells generated by Helene will affect much of Florida and the coasts of Georgia and the Carolinas during the next couple of days. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. NEXT ADVISORY ------------- Next complete advisory at 500 AM EDT. Next Tropical Cyclone Update at 300 and 400 AM EDT. $$ Forecaster Beven |
