An active weather pattern is setting up across the South through early next week with rounds of showers moving through the region. There is also the first significant threat for severe thunderstorms, especially on Monday into Tuesday. Based on our forecast graphics below on where severe weather is possible, notice how it coincides with the climatologically favorable zone for severe storms this time of the year, as shown on the map to the left.
On Sunday, there is a very large region at risk for severe weather. This threat spans from the central Plains in Kansas southward through northeast Texas and the ArkLaTex, and into the Gulf Coast states, as shown on the graphic below. The best chance for these strong storms will be from the Red River Valley through the Gulf Coast. This is where the best atmospheric dynamics will be found to produce this severe weather. It’s this region where dew points will be in the 60s and 70s, which indicates a moist environment needed for severe storms. Temperatures will also be in the 70s and 80s, so it will be warm enough for the development of storms. In terms of instability, it will be low to moderate at the Gulf Coast; the best instability will be back in Texas. This is where we think the most powerful storms will develop. These storms will pose the risk for several tornadoes, damaging winds of up to 70 mph, and large hail.
Now on Monday, this may be the most active day for severe weather so far this year with many tornadoes possible along with damaging winds and large hail in portions of the Southeast. A tornado outbreak is appearing likely, which means that at least 20 tornadoes occur. What also makes this threat especially dangerous is that the threat will go into Monday night, so make sure you have the weather alerts set on your phone. This threat includes Mississippi, Alabama, Georgia, Florida Panhandle, South Carolina, and Tennessee. We’re going to be tracking a Colorado Low tracking from the Rocky Mountains and racing toward the Carolina coast. Now while the set up for severe weather is not perfect, the ingredients are definitely there to produce dangerous storms. In the northern areas of the severe weather outlook, instability will be lacking but there will be plenty of shear. The question is whether the storms will be able to overcome that low instability and be able to produce tornadoes. Meanwhile to the south closer to the coast, instability will be high but shear will be marginal.
Now let’s talk timing: a large batch of showers and embedded thunderstorms will be impacting the Carolinas from Sunday’s disturbance while scattered showers and storms impact the rest of the Southeast. Most of that clutter will clear offshore by the afternoon, although it may stall at the Carolina coast. Meanwhile back toward the west at the Mid-Mississippi Valley, our low pressure will be arriving, bringing rain and storms into the western Ohio and Tennessee Valleys. The cold front associated with the low pressure will begin to spark the development of a broken line of strong storms moving eastward primarily through the Tennessee Valley. Ahead of this line, however, is where supercell thunderstorms may develop near the Southern Appalachians, Georgia, and South Carolina. It’s these supercells that have the best chance for producing tornadoes. Then overnight, the threat for severe weather will mainly impact Georgia and South Carolina.
On Monday, the risk for severe storms will shift to the south, affecting the northern Florida Peninsula. This includes cities like Jacksonville, Gainesville, Tampa, and Orlando. Large hail, damaging winds, and tornadoes are all threats with these storms. A secondary storm developing over the Southern Appalachians will spark the development of a squall line over the Gulf of Mexico and that line will move into the Florida Panhandle.
Through Monday, portions of the Southeast is expected to receive up to two to three inches, which could lead to isolated flooding.