| in a few minutes I am going to park just outside my front entrance to the neighborhood and just drive away from the water as it comes up. I'm going to turn off my power before leaving. Hurricane Idalia Discussion Number 15 NWS National Hurricane Center Miami FL AL102023 500 AM EDT Wed Aug 30 2023 Idalia continues to undergo rapid intensification. Maximum flight-level winds were 123 kt, with believable SFMR values of 115 kt. Satellite images show a small eye surrounded by very cold clouds tops, especially in the western quadrant. The initial wind speed is set to 115 kt, making Idalia an extremely dangerous category 4 hurricane. The hurricane still has a few hours left to intensify before it makes landfall. The biggest change to the intensity forecast is to increase the wind speeds over southeastern Georgia and South Carolina as the rapid motion and track close to the coast is expected to keep the system near hurricane strength for longer. Thus a Hurricane Warning has been issued for a portion of those coasts, and the Hurricane Watch is extended northeastward. After the hurricane moves offshore, the wind field on the northwestern side near eastern North Carolina is expected to be enhanced by a cold front, and the Tropical Storm Watch has been upgraded to a Tropical Storm Warning in that area. The long-range intensity forecast is quite uncertain with Idalia taking on some hybrid characteristics due to a baroclinc trough. No changes were made at this time, and the forecast remains close to the consensus. Idalia is moving faster toward the north-northeast or 025/16 kt. After landfall, Idalia is expected to move near or along the coast of Georgia and the Carolinas in 24-36 hours. Uncertainty in the track forecast beyond 48 hours remains quite large, and the latest guidance is significantly faster. The new forecast is adjusted toward the consensus, but could be too slow at long range. KEY MESSAGES: 1. Catastrophic impacts from storm surge inundation of 12 to 16 feet above ground level and destructive waves are expected somewhere between the Wakulla/Jefferson County line 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. Destructive life-threatening winds will occur 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 likely in portions of eastern Georgia and southeastern South Carolina where Hurricane Warnings are now in effect. 3. Areas of flash, urban, and moderate river flooding, with considerable impacts, are expected from the Florida Big Ben through, central Georgia and South Carolina, through eastern North Carolina into Thursday. FORECAST POSITIONS AND MAX WINDS INIT 30/0900Z 29.1N 84.1W 115 KT 130 MPH 12H 30/1800Z 31.0N 82.7W 85 KT 100 MPH...INLAND 24H 31/0600Z 33.1N 79.6W 60 KT 70 MPH...INLAND 36H 31/1800Z 33.8N 76.1W 50 KT 60 MPH...OVER WATER 48H 01/0600Z 33.3N 72.7W 50 KT 60 MPH 60H 01/1800Z 32.4N 70.7W 45 KT 50 MPH 72H 02/0600Z 31.5N 69.5W 45 KT 50 MPH 96H 03/0600Z 30.7N 68.0W 45 KT 50 MPH 120H 04/0600Z 30.5N 66.0W 45 KT 50 MPH $$ Forecaster Blake Hurricane Idalia Advisory Number 15 NWS National Hurricane Center Miami FL AL102023 500 AM EDT Wed Aug 30 2023 ...IDALIA RAPIDLY INTENSIFIES INTO A CATEGORY 4 HURRICANE... ...CATASTROPHIC STORM SURGE AND DESTRUCTIVE WINDS ARE NEARING THE FLORIDA BIG BEND REGION... SUMMARY OF 500 AM EDT...0900 UTC...INFORMATION ---------------------------------------------- LOCATION...29.1N 84.1W ABOUT 60 MI...95 KM W OF CEDAR KEY FLORIDA ABOUT 90 MI...145 KM S OF TALLAHASSEE FLORIDA MAXIMUM SUSTAINED WINDS...130 MPH...215 KM/H PRESENT MOVEMENT...NNE OR 25 DEGREES AT 18 MPH...30 KM/H MINIMUM CENTRAL PRESSURE...940 MB...27.76 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: A Hurricane Warning has been issued for the east coast of the United States from Altamaha Sound Georgia to Edisto Beach South Carolina. A Storm Surge Warning has been issued from St. Catherine's Sound to South Santee River. A Hurricane Watch has been issued from Edisto Beach South Carolina to South Santee River South Carolina. A Tropical Storm Warning has been issued from North of Surf City North Carolina to the North Carolina/Virginia border, and Pamlico and Albemarle Sounds. The Tropical Storm Warning for the west coast of Florida from Bonita Beach southward is discontinued. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Storm Surge Warning is in effect for... * Englewood northward to Indian Pass, including Tampa Bay * St. Catherine's Sound to South Santee River 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... * Chokoloskee northward to the Middle of Longboat Key * West of Indian Pass to Mexico Beach * Sebastian Inlet Florida to Surf City North 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 St. Catherine's Sound Georgia * 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 Altamaha Sound * Edisto Beach to South Santee River 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. Additional warnings could be required later today. 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 500 AM EDT (0900 UTC), the eye of Hurricane Idalia was located by Tallahassee radar near latitude 29.1 North, longitude 84.1 West. Idalia is moving toward the north-northeast near 18 mph (30 km/h). A north-northeastward motion is expected through the morning, with Idalia's center forecast to reach the Big Bend coast of Florida this morning. After landfall, Idalia is forecast to turn toward the northeast and east-northeast, moving near or along the coasts of Georgia, South Carolina, and North Carolina late today and Thursday. Hurricane Hunter aircraft data indicate that maximum sustained winds have increased to near 130 mph (215 km/h) with higher gusts. Idalia is a category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale. Idalia could continue to strengthen before it reaches the Big Bend coast of Florida in a few hours. While Idalia should weaken after landfall, it is likely to still be a hurricane while moving across southern Georgia, and near the coast of Georgia or southern South Carolina late today. Idalia should emerge off the southeastern United States coast early on Thursday and move eastward through late week. Hurricane-force winds extend outward up to 25 miles (35 km) from the center and tropical-storm-force winds extend outward up to 175 miles (280 km). The estimated minimum central pressure is 940 mb (27.76 inches) based on aircraft data. 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 storm surge and 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... Wakulla/Jefferson County, FL to Yankeetown, FL...12-16 ft Ochlockonee River, FL to Wakulla/Jefferson County, FL...8-12 ft Yankeetown, FL to Chassahowitzka, FL...7-11 ft Chassahowitzka, FL to Anclote River, FL...6-9 ft Carrabelle, FL to Ochlockonee River, FL...5-8 ft Anclote River, FL to Middle of Longboat Key, FL...4-6 ft Tampa Bay...4-6 ft Indian Pass, FL to Carrabelle, FL...3-5 ft Middle of Longboat Key, FL to Englewood, FL...3-5 ft Saint Catherines Sound, GA to South Santee River, SC...3-5 ft Englewood, FL to Bonita Beach, FL...2-4 ft Beaufort Inlet, NC to Ocracoke Inlet, NC...2-4 ft Mouth of the St. Mary's River to Saint Catherines Sound, GA...2-4 ft Charlotte Harbor...2-4 ft Neuse and Bay Rivers...2-4 ft Pamlico and Pungo Rivers...2-4 ft Flagler/Volusia County Line, FL to Mouth of the St. Mary's River...1-3 ft Mexico Beach, FL to Indian Pass, FL...1-3 ft Bonita Beach, FL to East Cape Sable, FL...1-3 ft South Santee River, SC to Beaufort Inlet, NC...1-3 ft Ocracoke Inlet, NC to Duck, NC...1-3 ft The deepest water will occur along the immediate coast near and to the right of the center, where the surge will be accompanied by large and destructive 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 soon, with tropical storm conditions spreading northward and westward through this morning. Tropical storm conditions will continue within the tropical storm warning area along the Florida Gulf and west coasts. Hurricane conditions are expected in the Hurricane Warning area along the coasts of Georgia and South Carolina later today and tonight. Hurricane conditions are possible in the Hurricane Watch area along the coasts of Georgia and South Carolina later today and tonight. Tropical storm conditions are expected to begin later today in the warning area along the east coast of Florida, Georgia, and South Carolina, and spread into North Carolina tonight and Thursday. RAINFALL: Idalia is expected to produce a swath of 4 to 8 inches of rainfall with isolated maxima up to 12 inches from the Florida Big Bend through central Georgia and South Carolina, and through eastern North Carolina into Thursday. These rainfall amounts will lead to areas of flash, urban, and moderate river flooding, with considerable impacts. 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 today. 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 are possible this morning across west-central and northern Florida into southeast Georgia, with the tornado risk shifting toward the coastal Carolinas this afternoon and tonight. NEXT ADVISORY ------------- Next intermediate advisory at 800 AM EDT. Next complete advisory at 1100 AM EDT. $$ Forecaster Blake |