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| #1016487 (Received by flhurricane at: 4:41 PM 13.Sep.2020) TCPAT4 BULLETIN Tropical Storm Sally Advisory Number 9 NWS National Hurricane Center Miami FL AL192020 400 PM CDT Sun Sep 13 2020 ...SALLY FORECAST TO BECOME A HURRICANE ON MONDAY... ...LIFE-THREATENING STORM SURGE, HURRICANE-FORCE WINDS, AND HEAVY RAINFALL EXPECTED ALONG PORTIONS OF THE NORTHERN GULF COAST STARTING ON MONDAY... SUMMARY OF 400 PM CDT...2100 UTC...INFORMATION ---------------------------------------------- LOCATION...27.8N 85.9W ABOUT 165 MI...265 KM S OF PANAMA CITY FLORIDA ABOUT 215 MI...345 KM ESE OF THE MOUTH OF THE MISSISSIPPI RIVER MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H PRESENT MOVEMENT...WNW OR 295 DEGREES AT 9 MPH...15 KM/H MINIMUM CENTRAL PRESSURE...996 MB...29.41 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: None SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Storm Surge Warning is in effect for... * Port Fourchon Louisiana to the Mississippi/Alabama Border * Lake Pontchartrain, Lake Maurepas, and Lake Borgne A Hurricane Warning is in effect for... * Morgan City Louisiana to Ocean Springs Mississippi * Lake Pontchartrain and Lake Maurepas including metropolitan New Orleans A Storm Surge Watch is in effect for... * Mississippi/Alabama Border to the Alabama/Florida Border A Hurricane Watch is in effect for... * East of Ocean Springs to the Alabama/Florida Border A Tropical Storm Warning is in effect for... * East of Ocean Springs to Indian Pass * Intracoastal City Louisiana to west of Morgan City A Tropical Storm Watch is in effect for... * Indian Pass to Ochlockonee River Florida 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. A Hurricane Warning means that hurricane conditions are expected somewhere within the warning area. A warning is typically issued 36 hours before the anticipated first occurrence of tropical-storm-force winds, conditions that make outside preparations difficult or dangerous. Preparations to protect life and property should be rushed to completion. A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area within 36 hours. A Storm Surge Watch means there is a possibility of life- threatening inundation, from rising water moving inland from the coastline, in the indicated locations during the next 48 hours. For a depiction of areas at risk, please see the National Weather Service Storm Surge Watch/Warning Graphic, available at hurricanes.gov. A Hurricane Watch means that hurricane conditions are possible within the watch area. A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, in this case within 12 to 24 hours. For storm information specific to your area, including possible inland watches and warnings, please monitor products issued by your local National Weather Service forecast office. DISCUSSION AND OUTLOOK ---------------------- At 400 PM CDT (2100 UTC), the center of Tropical Storm Sally was located near latitude 27.8 North, longitude 85.9 West. Sally is moving toward the west-northwest near 9 mph (15 km/h), and this motion is expected to continue through tonight. A slower west- northwestward motion is expected Monday and Monday night, followed by a further decrease in forward speed and a turn to the northwest Monday night and Tuesday. On the forecast track, the center of Sally will move over the north-central Gulf of Mexico tonight and Monday, and approach the north-central Gulf Coast within the hurricane warning area late Monday and Monday night. Sally is expected to move slowly northward near the southeastern Louisiana or Mississippi coasts through Tuesday. Maximum sustained winds are near 60 mph (95 km/h) with higher gusts. Strengthening is expected over the next day or so, and Sally is forecast to become a hurricane on Monday, with some additional strengthening possible before the center nears the northern Gulf Coast. Tropical-storm-force winds extend outward up to 125 miles (205 km) primarily to the east of the center. The latest minimum central pressure estimated from data from a NOAA reconnaissance aircraft is 996 mb (29.41 inches). HAZARDS AFFECTING LAND ---------------------- Key messages for Sally can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDAT4 and WMO header WTNT44 KNHC, and on the web at www.hurricanes.gov/text/MIATCDAT4.shtml 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 could reach the following heights above ground somewhere in the indicated areas if the peak surge occurs at the time of high tide... Mouth of the Mississippi River to Ocean Springs, MS including Lake Borgne...7-11 ft Port Fourchon, LA to Mouth of the Mississippi River...4-7 ft Ocean Springs, MS to MS/AL Border...4-7 ft Lake Pontchartrain and Lake Maurepas...4-6 ft MS/AL Border to AL/FL Border including Mobile Bay...2-4 ft AL/FL Border to Chassahowitzka, FL including Pensacola Bay, Choctawhatchee Bay, and Saint Andrew Bay...1-3 ft Burns Point, LA to Port Fourchon, LA...1-3 ft Overtopping of local levees outside of the Hurricane and Storm Damage Risk Reduction System is possible where local inundation values may be higher than those shown above. The deepest water will occur along the immediate coast in areas of onshore winds, where the surge will be accompanied by large and damaging 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: Hurricane conditions are expected within the hurricane warning area starting late Monday. Tropical storm conditions are possible within the watch area tonight, and are expected within the warning area beginning Monday. RAINFALL: Sally is expected to be a slow moving system resulting in significant flash flooding for the central Gulf Coast Monday into Wednesday. Sally is expected to produce rainfall of 8 to 16 inches with isolated amounts of 24 inches over portions of the central Gulf Coast from the western Florida Panhandle to southeast Louisiana from Monday through the middle of the week. This rainfall will likely result in new widespread minor to isolated major flooding on area rivers. Sally is forecast to move inland early Wednesday and track into the Southeast with rainfall of 5 to 10 inches possible across much of inland Mississippi and Alabama. Flash and urban flooding is possible, as well as widespread minor to moderate flooding on some rivers in Mississippi and Alabama. Further heavy rain is then anticipated across portions of Tennessee, northern Georgia and western North Carolina. Flash, urban, and minor river flooding is possible across this region. Outer bands of Sally are expected to produce additional rainfall of 1 to 3 inches across central and northern Florida through Monday. This rainfall may produce flash and urban flooding and prolong high flows and ongoing minor flooding on rivers across central Florida. TORNADOES: The risk of isolated tornadoes will begin to increase Monday afternoon and evening over parts of the western Florida Panhandle, southern Alabama, southern Mississippi, and southeast Louisiana. SURF: Swells from Sally are affecting the west coast of the Florida peninsula, the coast of the Florida Panhandle, and will be spreading northwestward along the northern Gulf coast through Monday. 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 700 PM CDT. Next complete advisory at 1000 PM CDT. $$ Forecaster Brown |