Current Snapshot

The Pacific Disaster Center’s (PDC Global) Thursday, September 26, 2024, Tropical Cyclone Activity Report for the Atlantic Ocean, the Caribbean Sea, and the Gulf of Mexico

CURRENT TROPICAL CYCLONES:

Tropical Cyclone 09L (Helene)…located about 255 miles southwest of Tampa, Florida

Tropical Cyclone 10L (Issac)…located about 820 miles east-northeast of Bermuda

>>> Eastern and Central Tropical Atlantic:

Invest 98L

Shower and thunderstorm activity associated with an area of low pressure located several hundred miles west of the Cabo Verde Islands has become more organized during the past several hours. Environmental conditions appear conducive for continued development of this system, and a tropical depression could form as soon as later today while it moves generally westward to west-northwestward near 15 mph today and tomorrow. The system is then forecast to slow down and turn northward late Friday and Saturday.

* Formation chance through 48 hours…high…80 percent
* Formation chance through 7 days…high…90 percent

Tropical Cyclone 09L (Helene)

HELENE STRENGTHENING AND EXPECTED TO MAKE LANDFALL IN THE FLORIDA BIG BEND THIS EVENING AS A MAJOR HURRICANE…PREPARATIONS TO PROTECT LIFE AND PROPERTY SHOULD BE RUSHED TO COMPLETION

According to the NHC Advisory number 13

Helene is moving toward the north-northeast near 14 mph (22 km/h). A
significant increase in forward speed is expected during the next 24 hours. On the forecast track, Helene will make landfall in the Florida Big Bend region this evening. After landfall, Helene is expected to turn northwestward and slow down over the Tennessee Valley on Friday and Saturday.

Maximum sustained winds have increased to near 105 mph (165 km/h) with higher gusts. Additional strengthening is forecast, and Helene is expected to be a major hurricane when it reaches the Florida Big Bend coast this evening. Weakening is expected after landfall, but Helene’s fast forward speed will allow strong, damaging winds, especially in gusts, to penetrate well inland across the southeastern United States, including over the higher terrain of the southern Appalachians.

Helene is a very large hurricane. Hurricane-force winds extend outward up to 60 miles (95 km) from the center and tropical-storm-force winds extend outward up to 345 miles (555 km).

HAZARDS AFFECTING LAND

RAINFALL: Hurricane Helene is expected to produce total rain accumulations of 4 to 8 inches over western Cuba. This rainfall brings a risk of considerable flooding.

Over portions of the Southeastern U.S. into the Southern Appalachians, Helene is expected to produce total rain accumulations of 6 to 12 inches, with isolated totals around 20 inches. This rainfall will likely result in catastrophic and potentially life-threatening flash and urban flooding, along with significant river flooding. Numerous significant landslides are expected in steep terrain across the southern Appalachians.

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…

Carrabelle, FL to Suwannee River, FL…15-20 ft
Apalachicola, FL to Carrabelle, FL…10-15 ft
Suwannee River, FL to Chassahowitzka, FL…10-15 ft
Chassahowitzka, FL to Anclote River, FL…8-12 ft
Indian Pass, FL to Apalachicola, FL…6-10 ft
Anclote River, FL to Middle of Longboat Key, FL…5-8 ft
Tampa Bay…5-8 ft
Middle of Longboat Key, FL to Englewood, FL…4-7 ft
East of Mexico Beach, FL to Indian Pass, FL…3-5 ft
Englewood, FL to Flamingo, FL…3-5 ft
Charlotte Harbor…3-5 ft

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.

WIND: Hurricane conditions are expected within the U.S. hurricane warning area late today. Tropical storm conditions have already begun in the Florida Keys and portions of south Florida, and these conditions are expected to spread northward across the tropical storm warning areas in the southeastern U.S. through early Friday. Strong, damaging winds, especially in gusts, will likely penetrate as far inland as the higher terrain of the southern Appalachians.

Tropical storm conditions are expected over portions of the warning area in western Cuba during the next couple of hours.

SURF: Swells generated by Helene will affect much of Florida and the coasts of Georgia and the Carolinas during the next couple of days. Swells will also continue across portions of Cuba and the Yucatan Peninsula through tonight.

TORNADOES: The risk for several tornadoes will gradually increase today through tonight. The greatest threat is expected from parts of northern Florida into southeast Georgia, the Midlands and Low Country of South Carolina, and southern North Carolina.

Tropical Cyclone 10L (Issac)

ISAAC FORECAST TO STRENGTHEN OVER THE NORTH ATLANTIC DURING THE NEXT COUPLE OF DAYS

According to the NHC Advisory number 3

Isaac is moving toward the east near 12 mph (19 km/h). A turn toward the east-northeast or northeast is expected by the weekend, along with a slight increase in forward speed.

Maximum sustained winds are near 50 mph (85 km/h) with higher gusts. Strengthening is forecast, and Isaac is expected reach or be near hurricane strength by late Friday or early Saturday.

Tropical-storm-force winds extend outward up to 70 miles (110 km) from the center.

HAZARDS AFFECTING LAND

SURF: Swells generated by Isaac and a large wind fetch from a deep-layer trough are affecting portions of the coast of Bermuda and could spread into the Azores by this weekend.