Severe storms will return to the South Friday into Saturday as a new storm system develops in the Southern Plains and tracks toward the Mid-Atlantic before moving off the coast Saturday night. This storm will allow for the formation of strong storms, which may deliver damaging winds, large hail, and a few tornadoes.
The tornado threat will be the greatest on Friday. This is due to the surface winds coming out of the south while strong winds associated with the low-level jet come out of southwest. Winds at the jet stream level will be coming out of the west, so that change in direction as altitude increases will allow for the risk of tornadoes. The strongest of the jet stream winds will be over the Northern Tier of the US, however, so that will limit the potential for a tornado outbreak and widespread damaging winds. There will also be moderate to high CAPE values, or instability, which will allow for the thunderstorms to grow and intensify, allowing for hail to form. The greatest instability will be in eastern Texas. The last two ingredients needed for severe weather are heat and humidity, both of which will be present. Temperatures will be in the 70s and 80s and dew points will mainly be in the 70s.
So where will the severe weather occur on Friday? Eastern Texas and Oklahoma, southern and central Arkansas, all of Louisiana and Mississippi, most of Alabama, and the western Florida Panhandle are all at risk for the strong to damaging storms. The storm threat may begin early as heavy rain and thunderstorms develops at around sunrise, spanning from much of Oklahoma through Arkansas. Scattered showers and storms are also expected in the Tennessee Valley. These storms will slowly move south and east ahead of a cold front. Due to the slow-movement of these storms, flash flooding is possible. The best chance for this threat will be in portions of the Lower and Mid-Mississippi River Valleys. Now as we get into the afternoon, the line of strong storms will move into northern Alabama and Mississippi, southern Arkansas, northern Louisiana, and northeastern Texas. It is these areas that have the greatest risk for severe storms as the instability and heat maximizes, providing the storms with as much energy as possible given the environmental conditions. Meanwhile to the north and east, it will be a light rain that impacts the Tennessee Valley. Then overnight, the severe weather threat will continue as storms near the Gulf Coast. By the pre-dawn hours of Saturday morning, storms will impact southeastern Texas, southern Louisiana, Mississippi, and Alabama. The western Florida Panhandle and northern Georgia may also deal with stronger storms.
Now on Saturday, the threat will continue to shift to the east. The tornado threat won’t be as great. The strongest of the jet stream winds will be to the north of where the thunderstorms will impact, and those jet stream winds will be coming out of the southwest, the same direction as the low-level jet and surface winds. Therefore, the threat is the greatest for damaging winds and medium-sized hail. There also won’t be much instability, so that will limit the potential of these storms.
The central Gulf Coast through the Carolina coast will be at risk for these severe storms on Saturday. Now let’s talk timing: scattered showers and storms are expected in the morning across eastern Texas, much of Arkansas, Louisiana, Mississippi, Alabama, Georgia, South Carolina, and the western Florida Panhandle. A steadier rain is expected in North Carolina. Then in the afternoon and evening, the weather will gradually clear out of the Southern Plains, Tennessee Valley, and the central Gulf Coast as storms primarily affect northern Florida, much of Georgia, and the Carolinas. By early-Sunday morning, all of the precipitation will move offshore, thus ending the risk for severe weather with this storm system.
Localized areas in the Lower-Mississippi River Valley may receive over 3 inches of rain, which coincides with where the best risk for flooding is. Otherwise, the general South and Southeast regions will receive between 0.5 and 1.5 inches of rainfall between Friday and Sunday.