Summary for Hurricane Ida (AT4/AL092021)
ActuCyclone
28 août 2021
000 WTNT34 KNHC 280552 TCPAT4 BULLETIN Hurricane Ida Intermediate Advisory Number 7A NWS National Hurricane Center Miami FL AL092021 200 AM EDT Sat Aug 28 2021 ...IDA MOVING ACROSS THE SOUTHEASTERN GULF OF MEXICO... ...FORECAST TO RAPIDLY INTENSIFY BEFORE REACHING THE NORTHERN GULF COAST... SUMMARY OF 200 AM EDT...0600 UTC...INFORMATION ---------------------------------------------- LOCATION...23.5N 84.7W ABOUT 150 MI...240 KM WNW OF HAVANA CUBA ABOUT 560 MI...900 KM SE OF NEW ORLEANS LOUISIANA MAXIMUM SUSTAINED WINDS...80 MPH...130 KM/H PRESENT MOVEMENT...NW OR 320 DEGREES AT 15 MPH...24 KM/H MINIMUM CENTRAL PRESSURE...987 MB...29.15 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: None. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Storm Surge Warning is in effect for... * East of Rockefeller Wildlife Refuge Louisiana to the Mississippi/Alabama border * Vermilion Bay, Lake Borgne, Lake Pontchartrain, and Lake Maurepas A Hurricane Warning is in effect for... * Cuban provinces of Pinar del Rio and Artemisa, and the Isle of Youth * Intracoastal City Louisiana to the Mouth of the Pearl River * Lake Pontchartrain, Lake Maurepas, and Metropolitan New Orleans A Storm Surge Watch is in effect for... * Sabine Pass to Rockefeller Wildlife Refuge Louisiana * Mobile Bay A Hurricane Watch is in effect for... * Cameron Louisiana to west of Intracoastal City Louisiana * Mouth of the Pearl River to the Mississippi/Alabama border A Tropical Storm Warning is in effect for... * Cuban provinces of Matanzas, Mayabeque, and Havana * Cameron Louisiana to west of Intracoastal City Louisiana * Mouth of the Pearl River to the Mississippi/Alabama border A Tropical Storm Watch is in effect for... * Mississippi/Alabama border to the Alabama/Florida border 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. A Hurricane Watch means that hurricane conditions are possible within the watch area. A watch is typically issued 48 hours before the anticipated first occurrence of tropical-storm-force winds, conditions that make outside preparations difficult or dangerous. A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, generally within 48 hours. Interests elsewhere along the northern U.S. Gulf coast should monitor the progress of this system. Interests in the Dry Tortugas should also monitor the progress of Ida. 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. For storm information specific to your area outside of the United States, please monitor products issued by your national meteorological service. DISCUSSION AND OUTLOOK ---------------------- At 200 AM EDT (0600 UTC), the center of Hurricane Ida was located near latitude 23.5 North, longitude 84.7 West. Ida is moving toward the northwest near 15 mph (24 km/h) and this general motion should continue until Ida reaches the northern Gulf coast on Sunday. A slower northward motion is forecast after Ida moves inland. On the forecast track, the center of Ida will move over the southeastern Gulf of Mexico today and over the north central Gulf of Mexico on Sunday. Ida is then expected to make landfall along the U.S. northern Gulf coast within the hurricane warning area by late Sunday. Reports from an Air Force Reserve Hurricane Hunter aircraft indicate that maximum sustained winds are near 80 mph (130 km/h) with higher gusts. Rapid strengthening is forecast during the next day or two, and Ida is expected to be an extremely dangerous major hurricane when it approaches the northern Gulf coast on Sunday. Hurricane-force winds extend outward up to 25 miles (35 km) from the center and tropical-storm-force winds extend outward up to 115 miles (185 km). The minimum central pressure estimated from the Hurricane Hunter aircraft data is 987 mb (29.15 inches). HAZARDS AFFECTING LAND ---------------------- Key messages for Ida can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDAT4, WMO header WTNT44 KNHC, and on the web at hurricanes.gov/graphics_at4.shtml?key_messages. STORM SURGE: A dangerous storm surge will raise water levels by as much as 4 to 6 feet above normal tide levels in areas of onshore winds along the immediate coast of the Isle of Youth and near and to the east of where the center crosses the coast of western Cuba. Near the coast, the surge will be accompanied by large and destructive waves. 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... Morgan City, LA to Mouth of the Mississippi River...10-15 ft Mouth of the Mississippi River to Ocean Springs, MS including Lake Borgne...7-11 ft Intracoastal City, LA to Morgan City, LA including Vermilion Bay...6-9 ft Ocean Springs, MS to MS/AL border...4-7 ft Lake Pontchartrain...4-7 ft Lake Maurepas...3-5 ft Pecan Island, LA to Intracoastal City, LA...3-5 ft MS/AL border to AL/FL border including Mobile Bay...2-4 ft Sabine Pass to Pecan Island, LA...2-4 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 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. WIND: Hurricane and tropical storm conditions are occuring over the Isle of Youth and portions of western Cuba, and these winds will continue for a few more hours. Hurricane conditions are expected in the hurricane warning area along the northern Gulf coast beginning Sunday with tropical storm conditions expected to begin by late Saturday night or early Sunday morning. RAINFALL: Ida is expected to produce total rainfall accumulations of 5 to 10 inches with isolated maximum amounts of 15 inches across western Cuba, including the Isle of Youth. These rainfall amounts may produce life-threatening flash floods and mudslides. As Ida approaches the central Gulf Coast Sunday afternoon, total rainfall accumulations of 8 to 16 inches with isolated maximum amounts of 20 inches are possible across southeast Louisiana and southern Mississippi through Monday. This is likely to result in considerable flash and riverine flooding impacts. Ida is forecast to turn northeast as it moves inland later Monday, with rainfall totals of 4 to 8 inches possible from northeastern Louisiana and central Mississippi into the Tennessee Valley. This is likely to result in flash and riverine flooding impacts. SURF: Swells generated by Ida will continue to affect western Cuba through Saturday morning. Swells will begin reaching portions of the northern Gulf coast Saturday night or early Sunday. 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. $$ Forecaster Beven