Isaias Now a Hurricane - Reduce Flooding

9/8/26 – At 4 am CDT today, the National Hurricane Center (NHC) issued an advisory stating that Tropical Storm Isaias had intensified into a hurricane overnight. NHC expects winds to increase to near major hurricane status in the next 24 hours and says the storm will produce life-threatening surge up to 7-feet high across the northern Gulf Coast from the mouth of the Mississippi to the Florida panhandle.

Isaias is now moving toward the east-northeast near 9 mph and should turn toward the northeast later today followed by a turn northward on Friday. NHC expects landfall along the U.S. northern Gulf Coast late Friday or early Saturday.

A dropsonde launched from an Air Force Reserve hurricane hunter found average winds of 76 kt – the basis for upgrading Isaias to a hurricane at 0330 UTC.

Environmental Factors Affecting Forecast

Since that time, Isaias has continued to intensify, but with some northward tilt with height, likely due to moderate westerly vertical wind shear that continues to hinder circulation. However, circulation has increased since yesterday.

Aircraft fixes indicate that Isaias continues to maintain an east-northeastward heading. The most critical steering features:

A subtropical ridge centered east of the Bahamas
A mid-level trough along the northern Gulf coast
Low pressure digging in from the Rocky Mountains.

The net effect:

Isaias should make a left turn to the northeast and the north over the next 24-48 hours.
NHC

The forecast has not changed appreciably though models continue to disagree over the exact track (east or west) after the turn to the north. The storm should become post-tropical over the Tennessee Valley.

The intensity forecast remains difficult. Isaias is fighting around 20 kt of westerly vertical wind shear, and an eyewall keeps coming and going.

*Infrared image of circulation at 5 AM CDT*

Other favorable environmental factors for further intensification include 30 C sea-surface temperatures and abundant moisture. Shear should not increase appreciably for the next 24 hours. In fact, the hurricane has intensified despite shear. So NHC expects significant intensification in the short-term. making Isaias just shy of major hurricane intensity in 24 hours.

However, in the final 12-24 hours before Isaias makes landfall on the north Gulf coast, vertical wind shear should ramp up to 40-50 kt. This will likely impart some weakening. At the same time, the hurricane’s wind field may become broader.

Regardless, NHC expects Isaias to remain a dangerous hurricane through landfall with gusty winds extended well inland.

Key Messages from NHC

Key Messages:

1. Isaias should strengthen and become a strong hurricane when it approaches the northern Gulf Coast on Friday. A life-threatening storm surge is expected along a portion of the northern Gulf Coast,and a Storm Surge Warning remains in effect from the Mouth of the Mississippi River to Steinhatchee, Florida. Residents in the warning area should follow advice given by local officials and evacuate if told to do so.

2. Damaging hurricane force-winds will extend across the Florida Panhandle, southern Alabama, and southern Mississippi. A Hurricane Warning remains in effect from Ocean Springs, Mississippi to the Bay/Gulf County Line, Florida. Residents there should prepare for extended power outages.

3. Isaias will bring areas of heavy rainfall to the central U.S. Gulf coast and much of the Southeast Friday into the weekend. Flash and urban flooding, along with isolated river flooding, will be possible.