Isaias Expected to Rapidly Strengthen Before Striking the Gulf Coast

Is it really happening? Forecasters are growing increasingly certain that the first hurricane of the Atlantic season is about to form. Here is a look at when and where this storm is forecast to make landfall.

Tropical Storm Isaias Forecast to Become First Hurricane of the Atlantic Season

Tropical Depression 9 formed in the Gulf on Tuesday, evolving into Tropical Storm Isaias on Wednesday. This system is now expected to become the first hurricane of the Atlantic season as it churns closer to the U.S. central Gulf Coast region. 

As of the latest update from the National Hurricane Center (NHC), Isaias is packing maximum sustained winds of 45 mph. The storm is moving to the east-northeast at a speed of 8 mph, heading closer to the U.S. from its point of origin in the Bay of Campeche.

Should the forecast come to fruition, Isaias will go down in history as the latest first hurricane to ever form in the Atlantic in over 100 years of record-keeping. Water temperatures in the Gulf are hovering in the 80s, currently well over the threshold needed to support tropical development.

The latest forecast models from the NHC have the storm strengthening into a Category 2 hurricane before making landfall along the Gulf Coast late Friday or early Saturday.  Isaias is expected to dodge the strongest wind shear in the Gulf, fueling its intensification just as a dip in the jet stream pulls the storm closer to the U.S. coastline.

Hurricane Watch in Effect for Long Stretch of Gulf Coast

A hurricane watch has been issued for a zone from Bay St. Louis, Mississippi, to Indian Pass, Florida. In addition, a storm surge watch is in effect stretching from the mouth of the Mississippi River in Louisiana east to Yankeetown, Florida.

Winds will begin to pick up speed near the center of the storm in the coming days. Forecasters are warning that the large swells generated by this storm will present hazardous conditions to small watercraft in the central Gulf. These swells will eventually reach the coastal waters and beaches along the Gulf Coast, increasing the threat of rip currents.

Gusty conditions and rain will increase as the storm nears the north-central portion of the Gulf Coast. As of early Wednesday, the storm is forecast to make landfall at some point between southeastern Louisiana and the western edge of the Florida Panhandle.

Rain intensity will increase in the zone north of the center. Widespread rainfall totals of 1 to 4 inches are likely across much of the southeastern U.S. Isolated pockets of 8 to 12 inches are possible in the area just to the east of landfall, as this is where the heaviest rain bands associated with tropical events tend to set up.

The strongest winds are expected to whip up near and just east of where the storm eventually comes ashore.  Winds of 100 to 120 mph are expected near the eye of the storm. This is also where the highest risk of coastal storm surge flooding will develop.

Broader tropical storm-force winds hitting 40 to 60 mph are expected across a large swath of the Southeast, particularly in the central portions of the Gulf Coast and to the north into Tennessee. Isaias will also raise the threat of severe thunderstorms capable of generating tornadoes and waterspouts.

While the worst of the severe storms will erupt near and east of the eye, the threat of stormy conditions will stretch for hundreds of miles out from the center. The dip in the jet stream and the associated high-pressure circulation will work together to lift the storm's impact as far north as the Ohio Valley by the end of the weekend.

Whatever is left of Isaias is forecast to make a turn to the east, sending the remnants across the Appalachians and off the coast of the mid-Atlantic by early next week. Isaias is likely to weaken to a tropical rainstorm by the time it reaches the Appalachians. However, the rugged terrain in this region makes it more vulnerable to localized flash flooding.

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