| Track: https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/?cone#contents Satellite Floater: https://www.star.nesdis.noaa.gov/GOES/floater.php?stormid=AL102023 https://rammb-data.cira.colostate.edu/tc_realtime/storm.asp?storm_identifier=al102023 Southeast US Satellite: https://www.star.nesdis.noaa.gov/GOES/sector_band.php?sat=G16§or=se&band=13&length=24 Radar: https://www.sfwmd.gov/weather-radar/current-weather-conditions/west-central-florida/large-scale-loop Hurricane Idalia Discussion Number 13 NWS National Hurricane Center Miami FL AL102023 500 PM EDT Tue Aug 29 2023 The first stages of an eye have been taking shape in visible satellite imagery. The hurricane has a relatively small Central Dense Overcast and a prominent band of deep convection extending over the eastern semicircle, reaching across the Florida peninsula southward across western Cuba. An Air Force Reserve Hurricane Hunter aircraft just measured a peak 700-mb flight-level wind of 91 kt with the pressure falling to 972 mb. The initial intensity is therefore set at 85 kt. Idalia is moving faster toward the north, or 360/14 kt, between a mid-level trough over the northwestern Gulf of Mexico and a subtropical ridge over the Greater Antilles. Idalia is expected to continue moving northward and turn north-northeastward as it approaches the Big Bend region of Florida during the next 12-24 hours. There is very little spread among the track guidance, and the NHC official forecast has been placed very close to the HCCA and TVCX consensus aids during the first 24 hours. This has resulted in a westward shift of about 20-25 n mi compared to the previous forecast, although it should be stressed that additional shifts to the track will be possible until the center reaches land. After landfall, Idalia is expected to turn toward the northeast and then east, moving near or along the coast of Georgia and the Carolinas in 36-48 hours. Uncertainty in the track forecast is still quite large after 48 hours, with many of the global models turning Idalia southward, while some of the regional hurricane models still show the storm moving out to sea. As a result, the official track forecast continues to show slow motion on days 4 and 5. The 12-hour intensity forecast shows a 100-kt major hurricane. It is imperative to realize that Idalia is expected to continue strengthening beyond that time, possibly close to the 110 kt shown in the previous forecast, before the center reaches land. Weakening is expected after landfall, but due to the system's expected fast motion, it is possible that Idalia could maintain hurricane intensity as it moves across southern Georgia and approaches the coasts of Georgia and South Carolina. After Idalia's center moves offshore over the western Atlantic, strong shear is likely to limit re-intensification, and the official forecast essentially flatlines the intensity on days 2-5. KEY MESSAGES: 1. Catastrophic impacts from storm surge inundation of 10 to 15 feet above ground level and destructive waves are expected somewhere between Aucilla River and Yankeetown, Florida. Life-threatening storm surge inundation is likely elsewhere along portions of the Florida Gulf Coast where a Storm Surge Warning is in effect. Residents in these areas should follow any advice given by local officials. 2. There is the potential for destructive life-threatening winds where the core of Idalia moves onshore in the Big Bend region of Florida, with hurricane conditions expected elsewhere in portions of the Hurricane Warning area along the Florida Gulf Coast. Strong winds will also spread inland across portions of northern Florida and southern Georgia near the track of the center of Idalia where Hurricane Warnings are in effect. Residents in these areas should be prepared for long-duration power outages. Damaging hurricane-force winds are possible in portions of eastern Georgia and southeastern South Carolina where Hurricane Watches are in effect. 3. Areas of flash, urban, and moderate river flooding, with locally considerable impacts, are expected across the Florida Big Bend, central Georgia and South Carolina, through eastern North Carolina later tonight into Thursday. FORECAST POSITIONS AND MAX WINDS INIT 29/2100Z 26.1N 84.8W 85 KT 100 MPH 12H 30/0600Z 28.3N 84.5W 100 KT 115 MPH 24H 30/1800Z 31.0N 82.9W 75 KT 85 MPH...INLAND 36H 31/0600Z 32.9N 80.2W 50 KT 60 MPH...INLAND 48H 31/1800Z 33.9N 77.1W 45 KT 50 MPH...OVER WATER 60H 01/0600Z 33.8N 74.2W 45 KT 50 MPH 72H 01/1800Z 33.3N 71.8W 45 KT 50 MPH 96H 02/1800Z 32.3N 69.6W 45 KT 50 MPH 120H 03/1800Z 31.7N 69.0W 45 KT 50 MPH $$ Forecaster Berg Hurricane Idalia Advisory Number 13 NWS National Hurricane Center Miami FL AL102023 500 PM EDT Tue Aug 29 2023 ...IDALIA NOW A CATEGORY 2 HURRICANE... ...LIFE-THREATENING STORM SURGE AND HURRICANE CONDITIONS EXPECTED ALONG PORTIONS OF THE GULF COAST OF FLORIDA TONIGHT AND WEDNESDAY... SUMMARY OF 500 PM EDT...2100 UTC...INFORMATION ---------------------------------------------- LOCATION...26.1N 84.8W ABOUT 195 MI...310 KM SW OF TAMPA FLORIDA ABOUT 300 MI...480 KM S OF TALLAHASSEE FLORIDA MAXIMUM SUSTAINED WINDS...100 MPH...155 KM/H PRESENT MOVEMENT...N OR 360 DEGREES AT 16 MPH...26 KM/H MINIMUM CENTRAL PRESSURE...972 MB...28.71 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: A Hurricane Watch has been issued from the mouth of the St. Mary's River northward to Edisto Beach. A Storm Surge Watch has been issued from Beaufort Inlet to Drum Inlet, North Carolina, as well as the Neuse and Pamlico Rivers. A Tropical Storm Warning has been issued from South Santee River northward to Surf City, North Carolina. A Tropical Storm Watch has been issued north of Surf City to the North Carolina/Virginia border, including Pamlico and Albemarle Sounds. The Hurricane Watch from Englewood to the Middle of Longboat Key has been discontinued. The Storm Surge Watch has been discontinued south of Bonita Beach, Florida. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Storm Surge Warning is in effect for... * Englewood northward to Indian Pass, including Tampa Bay A Hurricane Warning is in effect for... * Middle of Longboat Key northward to Indian Pass, including Tampa Bay A Tropical Storm Warning is in effect for... * Dry Tortugas Florida * Chokoloskee northward to the Middle of Longboat Key * West of Indian Pass to Mexico Beach * Sebastian Inlet Florida to South Santee River South Carolina A Storm Surge Watch is in effect for... * Bonita Beach northward to Englewood, including Charlotte Harbour * Mouth of the St. Mary's River to South Santee River South Carolina * Beaufort Inlet to Drum Inlet North Carolina * Neuse and Pamlico Rivers North Carolina A Hurricane Watch is in effect for... * Mouth of the St. Mary's River to Edisto Beach South Carolina A Tropical Storm Watch is in effect for... * Lower Florida Keys west of the west end of the Seven Mile Bridge * North of Surf City North Carolina to the North Carolina/Virginia border * Pamlico and Albemarle Sounds 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 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 Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area. 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, generally within 48 hours. Additional warnings will likely be required tonight or on Wednesday. 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 OUTLOOK ---------------------- At 500 PM EDT (2100 UTC), the center of Hurricane Idalia was located near latitude 26.1 North, longitude 84.8 West. Idalia is moving toward the north near 16 mph (26 km/h). A northward to north-northeastward motion is expected through tonight, with Idalia's center forecast to reach the Big Bend coast of Florida on Wednesday morning. After landfall, the center of Idalia is forecast to turn toward the northeast and east, moving near or along the coasts of Georgia, South Carolina, and North Carolina late Wednesday and Thursday. Data from an Air Force Reserve Hurricane Hunter aircraft indicate that maximum sustained winds have increased to near 100 mph (155 km/h) with higher gusts. Additional strengthening is forecast, and Idalia is expected to become a major hurricane tonight before it reaches the Big Bend coast of Florida. Idalia is likely to still be a hurricane while moving across southern Georgia, and possibly when it reaches the coast of Georgia or southern South Carolina on Wednesday. Hurricane-force winds extend outward up to 25 miles (35 km) from the center and tropical-storm-force winds extend outward up to 160 miles (260 km). The minimum central pressure based on reconnaissance data is 972 mb (28.71 inches). HAZARDS AFFECTING LAND ---------------------- Key messages for Idalia can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDAT5 and WMO header WTNT45 KNHC, and on the web at hurricanes.gov/text/MIATCDAT5.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... Aucilla River, FL to Yankeetown, FL...10-15 ft Yankeetown to Chassahowitzka, FL...7-11 ft Ochlockonee River, FL to Aucilla River, FL...7-11 ft Chassahowitzka, FL to Anclote River, FL...6-9 ft Anclote River, FL to Middle of Longboat Key, FL...4-6 ft Tampa Bay...4-7 ft Carrabelle, FL to Ochlockonee River, FL...4-7 ft Middle of Longboat Key, FL to Englewood, FL...3-5 ft Englewood, FL to Bonita Beach, FL...2-4 ft Charlotte Harbor...2-4 ft Indian Pass, FL to Carrabelle, FL...3-5 ft Mouth of the St. Mary's River to South Santee, SC...2-4 ft Beaufort Inlet to Drum Inlet, NC...2-4 ft Pamlico and Neuse Rivers...2-4 ft South of Bonita Beach to Chokoloskee, FL...1-3 ft South Santee, SC to Beaufort Inlet, NC...1-3 ft Drum Inlet to Duck, NC...1-3 ft Chokoloskee, FL to East Cape Sable, FL...1-3 ft Flagler/Volusia County Line, FL to Mouth of St. Mary's River...1-3 ft Indian Pass to Mexico Beach...1 to 3 ft. Florida Keys...1-2 ft The deepest water will occur along the immediate coast in areas of onshore winds, 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 within the hurricane warning area in Florida by tonight or early Wednesday, with tropical storm conditions beginning soon. Tropical storm conditions are occurring in the Dry Tortugas and are possible within the Lower Florida Keys. Tropical storm conditions will begin within the tropical storm warning area along the Florida Gulf coast and the Florida west coast soon. Hurricane conditions are possible within the hurricane watch area along the coasts of Georgia and South Carolina Wednesday and Wednesday night. Tropical storm conditions are expected to begin on Wednesday in the warning area along the east coast of Florida, Georgia, and South Carolina, and spread into North Carolina Wednesday night and Thursday. Tropical storm conditions are possible within the watch area in North Carolina by Thursday. RAINFALL: Idalia is expected to produce the following rainfall amounts: Western Cuba: 4 to 7 inches, with isolated higher totals of 10 inches. Portions of the west coast of Florida, the Florida Panhandle, southeast Georgia and the eastern Carolinas: 4 to 8 inches from Tuesday into Thursday. Isolated higher totals of 12 inches are possible, primarily near landfall in northern Florida. This rainfall may lead to flash and urban flooding, and landslides across western Cuba. Areas of flash and urban flooding, some of which may be locally significant, are expected across portions of the west coast of Florida, the Florida Panhandle, and southern Georgia Tuesday into Wednesday, spreading into portions of the eastern Carolinas Wednesday into Thursday. SURF: Swells generated by Idalia are affecting the southwestern coast of Florida and will spread northward and westward to the north-central Gulf coast through Wednesday. Swells affecting portions of the southern coast of Cuba will subside tonight. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. TORNADOES: A few tornadoes will be possible along the west central Florida coast through tonight. The tornado threat will also spread northward into the Florida Big Bend tonight, and toward southeast Georgia and the coastal Carolinas Wednesday. NEXT ADVISORY ------------- Next intermediate advisory at 800 PM EDT. Next complete advisory at 1100 PM EDT. $$ Forecaster Berg |