24 Hours Until Landfall; Irma Shifts; West Coast Florida Bullseye
September 9, 2017
Hurricane Irma will roar through the state of Florida this weekend with destructive impacts, including wind damage, storm surge, heavy rain and possible tornadoes.
Irma Satellite Tracking. NOAA
- Hurricane Irma is now hammering parts of Cuba as a Category 3 hurricane.
- Hurricane and storm surge warnings have been extended northward in parts of Florida.
- Irma is expected to make a direct hit to Florida Sunday as a major hurricane.
- A potentially devastating storm surge will swamp parts of southwest Florida Sunday.
- Destructive winds will then race up the Florida Peninsula.
Hurricane Irma, currently hammering the north coast of Cuba, is now less than 24 hours from a potentially catastrophic Category 4 hurricane strike on Florida, the state's strongest hurricane strike since Charley 13 years ago.
Life-threatening and historic storm surge is possible in parts of South Florida, according to the National Weather Service.
A storm surge warning has also been issued from the Volusia/Brevard County Line around the peninsula to Suwanee River, including the Florida Keys and Tampa Bay. A storm surge watch is in effect from north of the Volusia/Brevard County line to the Isle of Palms, South Carolina on the east coast and on the west coast from north of the Suwannee River to Ochlockonee River.
In addition, hurricane and tropical storm watches and warnings have been issued.
Hurricane warnings now extend as far north as Fernandina Beach on the Atlantic side, and up to Aucilla River on the Gulf side. Included in the hurricane warnings are the Florida Keys, Naples, Ft. Myers, the Tampa/St. Petersburg metro, Miami, and West Palm Beach.
Hurricane warnings also continue in the northwest Bahamas and a part of the north coast of Cuba. Hurricane warnings mean either hurricane conditions are occurring, or are expected to occur within 36 hours.
A hurricane watch is also in effect for the Georgia coast northward to Edisto Beach, South Carolina, as well as from Aucilla River to Indian Pass along the Gulf of Mexico coast. A watch means hurricane conditions are possible within 48 hours.
Hurricane Irma continues to move closer to Florida. National Weather Service
Projected Path and Intensity
Irma may take advantage of deep, warm water in the Florida Straits and reintensify before striking Florida with Category 4 intensity Sunday.
At this intensity, small deviations in wind speed intensity will not significantly change impacts. A direct hit will be devastating.
Here's a general overview of the timing for impacts from Irma.
Potential Impact Timing
- Bahamas: Improvement in the central Bahamas Saturday; Tropical storm or hurricane conditions in parts of the northwest Bahamas at least through Sunday night
- Cuba: Hurricane conditions along north-central Cuba coast Saturday; conditions improving Sunday
- Florida: Tropical storm conditions in the Keys by Sat. afternoon; hurricane-force winds may arrive in South Florida and the Florida Keys by Saturday night; hurricane conditions spread north up the peninsula Sunday through early Monday; improvement Monday from south to north
- Georgia-Carolinas: Late Sunday-Monday, possibly lingering into early Tuesday in some areas
South Florida Forecast, Impacts
According to the latest National Hurricane Center's forecast, the center of Irma will pass over the Florida Keys Sunday morning, then track toward the southwest Florida coast Sunday afternoon.
The following life-threatening water-level rises (storm surge) are possible in South Florida Sunday, according to the National Hurricane Center, if they occur at high tide:
- Southwestern Florida from Cape Sable to Captiva: 10 to 15 feet
- Captiva to Ana Maria Island: 6 to 10 feet
- Card Sound Bridge through Cape Sable, including the Florida Keys: 5 to 10 feet
- Ana Maria Island to Clearwater Beach, including Tampa Bay: 5 to 8 feet
- North Miami Beach to Card Sound Bridge, including Biscayne Bay: 4 to 6 feet
- North of Miami Beach: 2 to 4 feet
PLEASE evacuate as instructed by local emergency managers if you're in an area where storm surge is forecast. Water (storm surge, rainfall flooding) is what claims the large majority of lives in hurricanes.
— NWS Key West (@NWSKeyWest) September 9, 2017
Irma's wind field is large. Hurricane-force winds extend outward up to 70 miles from the center, and tropical-storm-force winds extend outward up to 195 miles. These winds will expand eastward across the entire peninsula.
Depending on the exact track of Irma, locations in the hurricane warning in central and southern Florida could see devastating to catastrophic impacts, including structural damage and widespread power and communication outages from high winds. The National Weather Service said that areas in the hurricane warning could be uninhabitable for weeks or months.
If that wasn't enough, up to 25 inches of rain is possible. Here are the latest rainfall forecasts from the National Hurricane Center and Weather Prediction Center:
- The Florida Keys: 10 to 20 inches, with isolated 25 inch totals
- Florida peninsula: 8 to 15 inches, with isolated 20 inch totals
Yet, another threat will be for isolated tornadoes, especially to the north and east of where the center passes.
North Florida Forecast, Impacts
Irma's center is expected to track up the Florida west coast Sunday into Monday.
Dangerous water-level rises (storm surge) are also possible in North Florida early next week, according to the National Hurricane Center, if they occur at high tide:
- Clearwater Beach to Ochlockonee River: 4 to 6 feet
- Fernandina Beach to North Miami Beach: 2 to 4 feet
Significant inland wind damage and rainfall flooding could occur in parts of northern Florida, given Irma's large size.
Locally heavy rainfall is expected, with up to 20 inches possible, based on the latest rainfall forecasts from the National Hurricane Center and Weather Prediction Center:
- Florida peninsula: 8 to 15 inches, with isolated 20 inch totals
- Eastern Florida Panhandle: 3 to 6 inches, with isolated 8 inch totals
Georgia, Carolinas Forecast, Impacts
The center of Irma is then expected to track into Georgia Monday night into Tuesday.
Dangerous water-level rises (storm surge) of 4 to 6 feet are also possible from Isle of Palms, South Carolina to Fernandina Beach, Florida according to the National Hurricane Center, if they occur at high tide.
Significant inland wind damage and rainfall flooding could occur in parts of Georgia and the Carolinas, as well.
A forecast model developed by Seth Guikema (University of Michigan), Steven Quiring (Ohio State University) and Brent McRoberts (Texas A&M) predicted 1 to 2 million customers could be without power from Florida to east Tennessee from Irma's widespread winds.
Dangerous surf and coastal flooding will likely exist throughout the southeastern U.S. coastline even well away from Irma's center this weekend into early next week.
In fact, the National Weather Service in Charleston, South Carolina, says that record tide levels, topping those during Hurricane Matthew, are possible at Ft. Pulaski, Georgia and storm surge at Charleston Harbor Monday could top that seen from Matthew, exceeded only by Hurricane Hugo in 1989.
Heavy rainfall may is expected to spread across the Southeast. Here are the latest rainfall forecasts from the National Hurricane Center and Weather Prediction Center:
- Southeast Georgia: 8 to 15 inches, with isolated 20 inch totals
- Rest of eastern Georgia, western South Carolina, western North Carolina: 4 to 8 inches
- Western Georgia, eastern and northern Alabama, southern Tennessee: 2 to 5 inches
Isolated tornadoes will be a concern into early next week.
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