An outbreak of severe weather that began as thunderstorms with large hail over the southern Plains Tuesday night and expanded through all modes of severe weather into Wednesday night over the South will continue to press eastward and reach the Atlantic coast on Thursday.
The severe weather at midweek turned deadly as over two dozen preliminary tornadoes were spawned in Oklahoma, Texas and Louisiana. Madill, Oklahoma, sustained significant damage from one of the deadly tornadoes, and AccuWeather National Reporter Bill Wadell was on the scene shortly after the tornado struck.
The violent weather will shift eastward across the Southern states during Thursday and Thursday evening.
A tornado watch was in effect for southern Alabama, northwestern Florida, eastern Louisiana and parts of eastern Mississippi Thursday morning. Farther north, parts of central Mississippi and Alabama were under a flash flood watch.
“Once again, all forms of severe weather can occur with the event ranging from damaging wind gusts and hail to frequent lightning strikes and tornadoes into Thursday evening,” according to AccuWeather Meteorologist Brett Edwards
Those sheltering at home or the few on the road should closely monitor the weather situation and be alert for rapidly changing conditions.
AccuWeather continues to offer free severe weather service to medical facilities as there are many communities with outdoor testing facilities set up.
There is some question as to the number of tornadoes that may occur during Thursday afternoon and evening as storms that erupt or slice through early on may disturb the atmosphere and inhibit a warm flow of moisture from the Gulf of Mexico enough to prevent supercell thunderstorms from forming on a mass scale during the afternoon hours.
In lieu of perfect tornado-forming conditions, smaller, less-intense tornadoes can still occur and pose significant risk to lives and property over the Southeastern states and even farther north toward evening in the lower part of the mid-Atlantic coast.
Assuming a busy atmosphere strewn with clouds and numerous showers and heavy, gusty thunderstorms, the potential for a few isolated tornadoes to spin up will exist. In some cases, these can be concealed by low clouds over the landscape, wrapped in rain and perhaps occurring after dark.
A few long-lived, strong tornadoes are a possibility in the strongest storms. Regardless of the number and intensity of tornadoes from this situation, there remains a significant risk to lives and property in the region. Even strong wind gusts can send large trees crashing into homes, onto vehicles and passers-by.
During Thursday, the area from southeastern Louisiana, northward to middle Tennessee and eastward to part of northern Florida and the central portions of Georgia and the Carolinas will be at risk for severe thunderstorms, including isolated tornadoes.
As drier air sweeps eastward during Thursday afternoon, the threat is likely to end by the late-day hours from the southern Appalachians to the western part of the Florida Panhandle on west.
During Thursday evening and perhaps past dark, the risk of severe thunderstorms, including tornadoes, is likely to extend from eastern North Carolina to the northern part of the Florida Peninsula.
Another ongoing aspect with the severe weather outbreak will continue to be heavy rainfall and the risk of flooding. Many streams and rivers continue to run near or above flood stage in the lower part of the Mississippi Valley and in part of the Southeast.
The additional 1-2 inches of rain with an AccuWeather Local StormMax™ of 4 inches from this storm system alone can be enough to not only produce flash, urban and small stream flooding but push some river levels that are already above flood stage even higher. This is especially the case along the Interstate 10 and 20 corridors.
The risk of severe weather uprisings and outbreaks will continue in the weeks ahead across the South. However, one potential round of severe weather could be more limited and disjointed Friday into this weekend.
A stream of warm, moist air from the Gulf of Mexico may be lacking with the next round of thunderstorms. This could limit the intensity of the individual storms.
The track of the parent storm system may also be farther north. Even though this may increase the risk of severe weather over portions of the Ohio Valley, the air may be cool enough and the sky cloudy enough to cap the intensity of the storm and may produce a more general area of rain and embedded thunderstorms instead.
That farther north track could also be a sign of a subtle change in the weather pattern that shifts some of the frequency of severe weather away from the I-10 and I-20 corridors of the South but brings more frequent rounds of thunderstorms and possible severe weather from portions of the central Plains to the Tennessee and Ohio valleys and perhaps the mid-Atlantic region.
In any event, rounds of thunderstorms will continue over the South every few days with some northward expansion of thunderstorms, including severe weather, likely in the coming weeks.