Hurricane Isaías has been downgraded to category 1 in the 14th advisory from the National Hurricane Center (NHC), issued at 11:00 p.m. Miami time on Friday, with maximum sustained winds of 90 mph (150 km/h) and gusts of up to 105 knots as it moved over the northwest part of Florida toward Alabama.
The weakening occurred hours after the system made landfall near Destin, Florida as a Category 2 hurricane. According to the technical discussion of advisory 14, the strong vertical wind shear degraded the cyclone's structure after it moved inland, leading the NHC to downgrade the initial intensity from 90 to 80 knots for this bulletin.
However, the downgrade does not mean the end of danger. The NHC warned that "sustained surface winds associated with Isaias will weaken rapidly now that the system is inland, but damaging gusts are expected well inland throughout Saturday, especially in higher elevation areas."
In notice 14, the center of the system was located about 75 km northeast of Pensacola and 100 km northwest of Panama City, moving north at 20 mph (31 km/h).
The NHC forecasts that Isaías will become a post-tropical system within the next 12 hours as it moves northward across Alabama, but it clarified that this transition will not put an end to destructive inland gusts.
To provide context for the current intensity: the Saffir-Simpson scale categorizes hurricanes as Category 1 with winds ranging from 74 to 95 mph, enough to cause numerous power outages and turn loose objects into projectiles.
With this notice, the NHC canceled several coastal warnings: the Hurricane Warning west of the Mississippi/Alabama border, the Tropical Storm Warning west of Ocean Springs (Mississippi), the Storm Surge Warning west of Dauphin Island (Alabama), and the Storm Surge Watch east of the Suwannee River (Florida).
However, there are still alerts of greater severity.
The Coastal Flood Warning remains in effect from Dauphin Island to the Suwannee River, an area designated by the NHC as a "life-threatening situation."
A Hurricane Warning also remains in effect from the Mississippi/Alabama border to the county line between Bay and Gulf in Florida, and a Tropical Storm Warning is in effect from that line to the Aucilla River.
The storm surge could flood normally dry areas with heights of between three and five feet (0.9 to 1.5 meters) from Dauphin Island to the Aucilla River, and from two to four feet in Mobile Bay and between the Aucilla River and the Suwannee, provided that the peak surge coincides with high tide.
Among the other active risks, the NHC forecasts four to eight inches of rainfall in southern Alabama, the Florida Panhandle, and the Big Bend, with local totals reaching up to 15 inches in some bands; a risk of tornadoes overnight in the Panhandle and northern Florida extending into southern Georgia, which will spread into Georgia and the Carolinas on Saturday; and a possibility of landslides in the southern Appalachians.
The NHC forecast positions the system as post-tropical over Alabama by noon UTC on Saturday, with winds at 60 mph, and indicates that it will dissipate by Monday, October 12, at 12:00 UTC.
The NHC summarized the central message for areas still under Hurricane Warning: "Residents in these areas should have a safe shelter to weather the storm and prepare for long-duration power outages."
Related videos:
Filed under: