Unseasonal warmth persist through Saturday, severe weather threat exists for Southeast US

By: Lead Forecaster Daniel Crawley

Good Thursday morning to everyone. Yesterday was quite warm across the Western Carolinas with temperatures in the 70’s. That was a result of a ridge of high pressure located to our south pumping in southwest winds aloft.

The current warm airmass in place will now be introduced by a strong upper trough that will be moving from west-to-east across the country over the next few days. The combination of a strong jet with increase moisture and instability will result in severe weather across the Southeast US.

The Storm Prediction Center is highlighting the Mid-South and Gulf Coast Region on Friday for a Slight Risk (Level 2 of 5) of severe weather as one piece of energy helps promote low pressure development across the Southern Plains moving northeast. The risk for damaging winds and some tornadoes exist on Friday along the eastern edge of the moisture plume. Places like Eastern Louisiana and across Mississippi and northeast into Western Alabama stands the best chance of seeing an isolated tornado.

As we get to Friday night and especially Saturday, the front will shift east and moisture will be riding into the Southern Appalachians from the southwest. The SPC has issued a Day 3 Marginal Risk (Level 1 of 5) from the Gulf Coast up through the Southern Appalachians. A secondary area of low pressure at the surface will assist in keeping a severe weather threat going in these regions.

One the bigger differences on Saturday verses Friday will be potentially more limited amounts of surface instability once you get toward the Western Carolinas. There will be a cluster of thunderstorms on-going first thing Saturday morning across Northern Alabama and Georgia, The question is: What will the atmospheric setup be like further east during the afternoon hours of Saturday? We should learn more about that over the next 24 hours as short range guidance get a better handle on the setup.

The one thing that looks more certain is that strong southwest winds will push a good slug of moisture into the Western Carolinas for Friday and Saturday. This kind of setup really benefits the Southern Mountains and Escarpment region, towns like Murphy, Franklin, Cherokee, Brevard could get anywhere from 2-3 inches of rain through Saturday evening. Once you get into the French Broad River Valley (Asheville) and up the Continental Divide, amounts lower into the 1-2 inch range.

For our coverage area, Polk, Rutherford, McDowell, Western half of Burke and Caldwell counties should benefit the most. There could ultimately be a sharp cutoff in precipitation amounts once you get just off the Blue Ridge, especially if surface instability is not able to establish itself during the afternoon hours of Saturday.