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| #1016582 (Received by flhurricane at: 4:53 AM 14.Sep.2020) TCPAT4 BULLETIN Tropical Storm Sally Advisory Number 11 NWS National Hurricane Center Miami FL AL192020 400 AM CDT Mon Sep 14 2020 ...OUTER RAIN BANDS APPROACHING THE NORTHERN GULF COAST... ...SALLY LIKELY TO PRODUCE LIFE-THREATENING STORM SURGE, HURRICANE-FORCE WINDS, AND FLASH FLOODING ALONG PORTIONS OF THE NORTHERN GULF COAST STARTING LATE TODAY... SUMMARY OF 400 AM CDT...0900 UTC...INFORMATION ---------------------------------------------- LOCATION...28.3N 87.3W ABOUT 120 MI...195 KM ESE OF THE MOUTH OF THE MISSISSIPPI RIVER ABOUT 175 MI...280 KM SE OF BILOXI MISSISSIPPI MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H PRESENT MOVEMENT...WNW OR 285 DEGREES AT 9 MPH...15 KM/H MINIMUM CENTRAL PRESSURE...996 MB...29.42 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 Alabama/Florida Border * Lake Pontchartrain, Lake Maurepas, and Lake Borgne * Mobile Bay A Hurricane Warning is in effect for... * Morgan City Louisiana to the Mississippi/Alabama Border * Lake Pontchartrain and Lake Maurepas including metropolitan New Orleans A Tropical Storm Warning is in effect for... * Mississippi/Alabama Border to Indian Pass Florida * Intracoastal City Louisiana to west of Morgan City A Hurricane Watch is in effect for... * Mississippi/Alabama Border to the Alabama/Florida Border 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. 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 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. 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 AM CDT (0900 UTC), the center of Tropical Storm Sally was located near latitude 28.3 North, longitude 87.3 West. Sally is moving toward the west-northwest near 9 mph (15 km/h). This general motion is expected today, followed by a decrease in forward speed and a turn to the northwest tonight and a northward turn sometime on Tuesday. On the forecast track, the center of Sally will move over the north-central Gulf of Mexico today, and approach southeastern Louisiana this afternoon, and make landfall in the hurricane warning area on Tuesday. Afterward, Sally is expected to move slowly north-northeastward near the northern Gulf Coast through Wednesday. 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 by tonight, with additional strengthening possible before the center crosses the northern Gulf Coast. Tropical-storm-force winds extend outward up to 125 miles (205 km) from the center. The estimated minimum central pressure based on dropsonde data from the NOAA Hurricane Hunters is 996 mb (29.42 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 including Lake Borgne...7-11 ft Ocean Springs to MS/AL Border...5-8 ft MS/AL Border to AL/FL Border including Mobile Bay...4-6 ft Lake Pontchartrain and Lake Maurepas...4-6 ft Port Fourchon to Mouth of the Mississippi River...3-5 ft AL/FL Border to Navarre including Pensacola Bay...2-4 ft Navarre to Chassahowitzka including Choctawhatchee Bay and Saint Andrew Bay...1-3 ft Burns Point to Port Fourchon...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 today. Tropical storm conditions are possible within the watch area during the next few hours, and are expected within the warning area beginning this morning. RAINFALL: Sally is expected to be a slow-moving system as it approaches land producing 8 to 16 inches of rainfall with isolated amounts of 24 inches over portions of the central Gulf Coast from the western Florida Panhandle to far southeast Louisiana through the middle of the week. Life-threatening flash flooding is possible. In addition, this rainfall will likely lead to widespread minor to isolated major flooding on area rivers. Sally is forecast to turn inland early Wednesday and track into the Southeast with rainfall of 6 to 12 inches possible across portions of inland southeast Mississippi and Alabama. Significant flash and urban flooding is likely, as well as widespread minor to moderate flooding on some rivers. Further heavy rain is then anticipated across portions of eastern Tennessee, northern Georgia and western North Carolina Thursday into Friday. 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 the Florida peninsula today. This rainfall may produce flash and urban flooding and prolong high flows and ongoing minor flooding on rivers across central Florida. TORNADOES: A tornado or two may occur this afternoon through Tuesday over coastal areas of the Florida Panhandle, Mississippi, Alabama, and extreme southeastern Louisiana. SURF: Swells from Sally are affecting the west coast of the Florida peninsula westward through the coast of Alabama, and will be spreading northwestward along the northern Gulf coast through today. 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 AM CDT. Next complete advisory at 1000 AM CDT. $$ Forecaster Blake |