108  WTNT34 KNHC 290552 TCPAT4  BULLETIN Hurricane Ida Intermediate Advisory Number 11A NWS National Hurricane Center Miami FL       AL092021 100 AM CDT Sun Aug 29 2021  ...AIR FORCE HURRICANE HUNTER AIRCRAFT FINDS IDA HAS STRENGTHENED  INTO A MAJOR HURRICANE... ...LIFE-THREATENING STORM SURGE, POTENTIALLY CATASTROPHIC WIND DAMAGE, AND FLOODING RAINFALL EXPECTED TO IMPACT THE NORTHERN GULF COAST BEGINNING THIS MORNING...   SUMMARY OF 100 AM CDT...0600 UTC...INFORMATION ---------------------------------------------- LOCATION...27.6N 88.7W ABOUT 105 MI...170 KM SSE OF THE MOUTH OF THE MISSISSIPPI RIVER ABOUT 185 MI...295 KM SE OF HOUMA LOUISIANA MAXIMUM SUSTAINED WINDS...115 MPH...185 KM/H PRESENT MOVEMENT...NW OR 320 DEGREES AT 15 MPH...24 KM/H MINIMUM CENTRAL PRESSURE...955 MB...28.20 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 Alabama/Florida border * Vermilion Bay, Lake Borgne, Lake Pontchartrain, Lake Maurepas, and Mobile Bay  A Hurricane Warning is in effect for... * Intracoastal City Louisiana to the Mouth of the Pearl River * Lake Pontchartrain, Lake Maurepas, and Metropolitan New Orleans  A Tropical Storm Warning is in effect for... * Cameron Louisiana to west of Intracoastal City Louisiana * Mouth of the Pearl River 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 within the next 6 to 12 hours.    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, in this case within the  next 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 100 AM CDT (0600 UTC), the center of the eye of Hurricane Ida was  located by an Air Force Reserve Hurricane Hunter aircraft and NOAA  Doppler weather radars near latitude 27.6 North, longitude 88.7  West. Ida is moving toward the northwest near 15 mph (24 km/h), and  this general motion should continue through tonight and early  Monday, followed by a slower northward motion on Monday afternoon.   A northeastward turn is forecast by Monday night.  On the forecast  track, the center of Ida will continue moving across the  north-central Gulf of Mexico this morning, and make landfall along  the coast of Louisiana within the hurricane warning area this  afternoon or evening. Ida is then forecast to move well inland over  portions of Louisiana and western Mississippi on Monday and Monday  night.  Maximum sustained winds are near 115 mph (185 km/h) with higher gusts.  Ida is now a category 3 hurricane on the Saffir-Simpson  Hurricane Wind Scale. Rapid strengthening is forecast to continue  during the next 12 hours or so, and Ida is expected to be an  extremely dangerous major hurricane when it makes landfall along the  Louisiana coast this afternoon. Rapid weakening is expected after  landfall.  Hurricane-force winds extend outward up to 40 miles (65 km) from the center and tropical-storm-force winds extend outward up to 140 miles (220 km).  The minimum central pressure measured by an Air Force Hurricane  Hunter aircraft is 955 mb (28.20 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:  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 Burns Point, LA to Morgan City, LA...6-9 ft Lake Pontchartrain...5-8 ft Ocean Springs, MS to MS/AL border...4-7 ft Intracoastal City, LA to Burns Point, LA including Vermilion Bay...4-6 ft Lake Maurepas...4-6 ft Pecan Island, LA to Intracoastal City, LA...2-4 ft MS/AL border to AL/FL border including Mobile Bay...2-4 ft Sabine Pass to Pecan Island, 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 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 conditions are expected in the Hurricane Warning area along the Louisiana coast beginning by late morning with  tropical storm conditions expected to begin by early this morning.   These conditions will spread inland over portions of Louisiana and  Mississippi tonight and Monday.  RAINFALL:   Heavy rainfall from Ida will begin to impact the  Louisiana later this morning, spreading northeast into the Lower  Mississippi Valley by later today into Monday.  Total rainfall  accumulations of 8 to 16 inches with isolated maximum amounts of 20  inches are possible across southeast Louisiana into southern  Mississippi through Monday. This is likely to result in  life-threatening flash and urban flooding and significant riverine  flooding impacts.  Elsewhere across eastern Louisiana, Mississippi, far southwestern Alabama and the Middle Tennessee Valley -- considerable flash and riverine flooding impacts are likely on Monday and Tuesday, with rainfall totals of 4 to 8 inches possible. Rainfall from Ida will begin to affect the Ohio Valley by mid-week, resulting in flash and riverine flooding impacts.  TORNADOES:  Tornadoes will be possible today into Monday across eastern Louisiana, Mississippi, central and southern Alabama, and the Florida Panhandle.  SURF:  Swells are beginning to reach the northern Gulf coast and will continue to affect that area 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 complete advisory at 400 AM CDT.  Hourly Tropical Cyclone Updates will begin at 200 AM CDT.  These  can be found under WMO header WTNT64 KNHC and under AWIPS header  MIATCUAT4.  $$ Forecaster Stewart