Gulf Coast braces for 1st significant impact of 2021 hurricane season

Less than three weeks into the season, the Gulf Coast of the United States was bracing for its first significant impact of the 2021 Atlantic hurricane season.

Tropical storm warnings were plastered along the coast from southwestern Louisiana to the far western Florida panhandle on Friday, and residents took their cue to dock their boats and prepare their homes for flooding.

Tropical storm conditions arrived Friday as rough waters were pushed toward the coastline, well in advance of the storm's landfall along the coast expected in the early hours of Saturday. Precipitation from the system moved into New Orleans and other areas along the central Gulf Coast on Friday morning.

The system, which the National Hurricane Center (NHC) dubbed Potential Tropical Cyclone Three late Thursday afternoon, is expected to make landfall along the Louisiana coastline early Saturday morning. Prior to that, it is possible the system could strengthen into Tropical Storm Claudette. However, AccuWeather forecasters say the potential tropical cyclone is running out of time to earn a name.

As of very early Saturday morning, the system was moving over the western Gulf of Mexico to the north at 10 mph, and had sustained winds of 45 mph. Winds were above the tropical storm threshold of 39 mph, but the storm had still not yet developed a closed circulation. According to the NHC, the weather system was 40 miles south of Morgan City, Louisiana.

AccuWeather meteorologists warn that not only will this be a bad Father's Day weekend for outdoor plans in parts of the southeastern United States, but some communities are likely to be hit with torrential rain, flooding, gusty winds and even severe thunderstorms.

Louisiana Gov. John Bel Edwards issued a state of emergency declaration Thursday ahead of any tropical storm conditions. The declaration of a state of emergency allows the use of state resources to provide storm response aid.

AccuWeather forecasters have rated the budding cyclone a 1 on the AccuWeather RealImpact™ Scale for Hurricanes due primarily from the projection of flooding rainfall.

"The system continued to struggle with dry air and disruptive winds (wind shear) on Friday, preventing it from developing a closed circulation at its center," AccuWeather Meteorologist Mary Gilbert explained. "The system will still have a slim chance at becoming a tropical or subtropical storm into Saturday morning as long as it remains over the waters of the Gulf of Mexico."

A subtropical storm has both tropical and non-tropical features and its winds are spread out over a larger area than a fully tropical storm.

This radar snapshot, taken on Friday evening, June 18, 2021, shows heavy rain and thunderstorms over the central Gulf coast. (AccuWeather)

While the storm tried develop a clearly defined center on Friday, tropical storm conditions began to batter an approximately 300-mile stretch of the central Gulf coast. Near tropical storm conditions will continue to spread hundreds of miles inland over the Southern states this weekend.

A tropical storm warning is in effect from just east of Morgan City, Louisiana, to the Okaloosa/Walton County line in the Florida Panhandle. The New Orleans metropolitan area is covered under the warning as well.

The system's quick forward motion limited its duration spent over the 80-degree-Fahrenheit waters in the Gulf of Mexico. AccuWeather forecasters say a system stronger than a low-end tropical storm is highly unlikely due to that factor. However, even a low-end tropical storm can pose risks to lives and property. T

his particular storm has a high risk of unleashing torrential rain that can trigger major street and highway flooding, as well as significant rises on rivers from Louisiana to the Florida Panhandle and as far inland as the Interstate 20 corridor of Louisiana, Mississippi, Alabama, Georgia and perhaps South Carolina.

"AccuWeather meteorologists have been and continue to warn about a large swath of 6-12 inches of rain with an AccuWeather Local StormMax™ of 20 inches from the storm," AccuWeather Senior Meteorologist Rob Miller said.

The steady forward motion and relative weakness of the system should prevent a repeat of the 30-40 inches of rain that fell from storms such as Florence from 2018, which peaked as a Category 4 hurricane prior to making landfall in North Carolina. Florence unleashed historic flooding in parts of the Carolinas.

With the potential rainfall of 1-2 inches per hour over a several-hour period, including in such cities as New Orleans, Biloxi, Mississippi, and Mobile, Alabama, street flooding is likely. New Orleans is situated several feet below sea level and rainfall of this magnitude can overwhelm storm water pumps for a time.

Since a hurricane is not expected to roll ashore, major coastal flooding is not anticipated. "Minor coastal flooding with a storm surge of 1-3 feet, especially at times of high tide, is likely from southeastern Louisiana through the Florida Panhandle, which can lead to periodic inundation of low-lying coastal roads through Saturday," Miller said.

Frequent and strong rip currents with powerful surf are forecast along much of the central Gulf Coast through at least Saturday. Forecasters and officials are urging bathers and boaters to stay out of the water in the region.

"The strongest sustained winds of 40-60 mph with an AccuWeather Local StormMax™ of 70 mph are anticipated over southeastern Louisiana, southern Mississippi, southern Alabama and the western part of the Florida Panhandle," Miller said.

At this force, trees can topple and minor property damage and power outages can occur. This zone also has a somewhat elevated risk of brief, isolated tornadoes and waterspouts.

Farther to the north and east, weaker winds are in store, but a large zone of heavy rain and locally severe thunderstorms are expected. As the weekend progresses, a broad zone of 25- to 40-mph sustained winds and locally stronger gusts can occur along the I-10 and I-20 corridors from Louisiana to Georgia and South Carolina. Incidents of flooding and sporadic power outages can occur in this zone. In communities that are hit by severe thunderstorms, more significant damage and power outages can occur.

Those with outdoor plans this Father's Day weekend either at home, camping or at the beach may want to consider alternatives in much of the Southeastern states this weekend due to anticipated stormy conditions. For those venturing out regardless, access to the latest weather information, including the ability to receive severe weather bulletins, is essential. Severe weather warnings are disseminated via the free AccuWeather app.

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Because the storm is projected to take a curved path toward the northeast once it moves inland over the southeastern U.S. and also due in part to the presence of dry air on the western side of the storm, flooding rainfall is forecast to spare Texas and parts of western Louisiana. However, a couple of sporadic downpours may still affect these locations.

There is a chance for the system to re-organize as it emerges off the Atlantic coast and moves over the warm waters of the Gulf Stream early next week.

"Since it will move into a zone of strong wind shear off the Atlantic coast, development may be limited, just as it was over the Gulf of Mexico," AccuWeather Hurricane Expert Dan Kottlowski said.

A southward dip in the jet stream early next week is likely to prevent the storm from swinging inland in the Northeast.

"If this system had time to become a much stronger over the Gulf it would have a greater chance to re-strengthen in the west Atlantic, but it's barely going to become a storm in the Gulf and should have a poor circulation to start with again over the Atlantic," Kottlowski explained.

The feature with its rain and gusty winds is likely to be swept quickly to the north-northeast on Tuesday, near or just off the mid-Atlantic and New England coasts ahead of an approaching cool front, which will be triggering showers and thunderstorms.

AccuWeather will continue to provide updates on this storm, other systems, extreme western U.S. heat and severe weather potential through the Father's Day weekend.

Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier, Spectrum, FuboTV, Philo, and Verizon Fios.