000 WTNT31 KNHC 111451 TCPAT1 BULLETIN Tropical Storm Irma Advisory Number 50 NWS National Hurricane Center Miami FL AL112017 1100 AM EDT Mon Sep 11 2017 ...IRMA GRADUALLY WEAKENING WHILE MOVING OVER NORTHERN FLORIDA ... SUMMARY OF 1100 AM EDT...1500 UTC...INFORMATION ----------------------------------------------- LOCATION...30.3N 83.1W ABOUT 70 MI...115 KM E OF TALLAHASSEE FLORIDA ABOUT 85 MI...135 KM N OF CEDAR KEY FLORIDA MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H PRESENT MOVEMENT...NNW OR 340 DEGREES AT 17 MPH...28 KM/H MINIMUM CENTRAL PRESSURE...975 MB...28.80 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: The Storm Surge Warning has been discontinued from Bonita Beach southward. The Tropical Storm Warning has been discontinued for Lake Okeechobee. The Tropical Storm Warning has been discontinued from the Volusia/Brevard County line southward. The Tropical Storm Warning has been discontinued south of Anclote River. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Storm Surge Warning is in effect for... * South Santee River southward to the Flagler/Volusia County line * North of Bonita Beach to the Ochlockonee River * Tampa Bay A Tropical Storm Warning is in effect for... * Anclote River to the Okaloosa/Walton County Line * North of the Volusia/Brevard County line to the South Santee River A Storm Surge Warning means there is a danger of life-threatening inundation, from rising water moving inland from the coastline, during the next 36 hours in the indicated locations. 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. Interests elsewhere in the southeastern United States should monitor the progress of Irma. 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 48-HOUR OUTLOOK ------------------------------ At 1100 AM EDT (1500 UTC), the center of Tropical Storm Irma was located near latitude 30.3 North, longitude 83.1 West. Irma is moving toward the north-northwest near 17 mph (28 km/h), and this motion is expected to continue through Tuesday. On the forecast track, the center of Irma will move into southwestern Georgia later today, and move into eastern Alabama Tuesday morning. Maximum sustained winds have decreased to near 65 mph (100 km/h) with higher gusts. Continued slow weakening is forecast, and Irma is likely to become a tropical depression on Tuesday. Irma remains a large tropical cyclone. Tropical-storm-force winds extend outward up to 415 miles (665 km) from the center. A 60 mph (96 km/h) sustained wind and a 69 mph (111 km/h) gust was recently reported at the National Data Buoy Center C-MAN station in St. Augustine. The estimated minimum central pressure is 975 mb (28.80 inches). HAZARDS AFFECTING LAND ---------------------- STORM SURGE: The combination of a dangerous 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 is expected to reach the following HEIGHTS ABOVE GROUND if the peak surge occurs at the time of high tide... Clearwater Beach to Ochlockonee River...4 t 6 ft Anna Maria Island to Clearwater, including Tampa Bay...2 to 4 ft Captiva to Anna Maria Island...3 to 5 ft Bonita Beach to Captiva...2 to 4 ft South Santee River to Fernandina Beach...4 to 6 ft Fernandina Beach to Flagler/Volusia County line, including the St. Johns River...3 to 5 ft The deepest water will occur along the immediate coast in areas of onshore winds, where the surge will be accompanied by large and destructive 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. WIND: Tropical storm conditions will continue across portions of the central and northern Florida peninsula and southern Georgia. Tropical storm conditions are spreading into the eastern Florida Panhandle. Tropical storm conditions are also expected to spread northward across the remainder of the warning area through today. Rainfall: Irma is expected to produce the following rain accumulations through Wednesday: Northern Florida peninsula and southern Georgia: additional 3 to 6 inches with storm total amounts of 8 to 15 inches. Central Georgia, eastern Alabama and southern South Carolina: 3 to inches, isolated 10 inches. Central Florida Panhandle, western Alabama, northern Mississippi, southern Tennessee, northern Georgia, northern South Carolina and western North Carolina: 2 to 4 inches. The precipitation threat for most of the Florida peninsula, except for the northernmost portions, has diminished. Scattered showers are expected to produce additional rainfall amounts of less than an inch across most of the Florida peninsula during Monday. TORNADOES: A few tornadoes are possible today and tonight near the Georgia and South Carolina coasts. SURF: Swells generated by Irma are affecting the southeast coast of the United States. These swells are likely to cause life- threatening surf and rip current conditions. Please consult products from your local weather office. NEXT ADVISORY ------------- Next intermediate advisory at 200 PM EDT. Next complete advisory at 500 PM EDT. $$ Forecaster Pasch