April 19, 2020

Another Dangerous Severe Weather Outbreak Is Possible In The Southeast On Sunday


Another severe weather outbreak is possible in the southeast on Sunday, affecting many of the same areas hit by severe weather just last weekend. A moderate risk for severe weather is in effect from Louisiana to Georgia, but just about everyone in the region is at risk for dangerous storms on Sunday and Sunday night. All modes of severe weather are possible, including the risk for strong, long-track tornadoes.

Source: Tropical Tidbits


A low-pressure system will move across the southeast during the day on Sunday. Thunderstorms will fire across the risk areas as the low pushes east through the day. Strong instability and wind shear will allow the storms to grow severe. The above model image for Sunday afternoon shows winds at the 850 mb level (about 5,000 feet or so), showing the low-level jet that will allow some storms to grow into supercells and pose a significant tornado threat.



This map looks similar to last weekend's severe weather threat The Storm Prediction Center paints a threat for severe thunderstorms across most of the southeast, with the greatest threat centered on Louisiana, Mississippi, Alabama, and Georgia. A moderate risk for severe weather covers many of the same areas that were under the greatest risk last week; this Sunday's threat covers a greater area, from northern Louisiana to central Georgia.

Storms will ramp up in a hurry during the afternoon and continue east through the nighttime hours. This is going to be another sleepless night for folks in Georgia and parts of the Carolinas.

Forecasters will refine these forecasts with updated information through the day on Sunday. Beware the sharp cutoff on the northern edge of the risk areas; it wouldn't take much of a shift to bump the threat for dangerous storms a few dozen miles to the north.

The most serious threat is tornadoes. The greatest threat for tornadoes exists in and around the moderate risk area, but any severe thunderstorms in the region have the potential to produce tornadoes. Remember that these percentages seem rather low, but we're talking the probability of tornadoes—the red shading means there's a 15% probability of a tornado within 25 miles of any point in the shaded area. The black hatching indicates the risk for strong, long-track tornadoes.



While tornadoes grab all the attention, there's a threat of large hail and damaging winds with any of the storms that form across the risk areas on Sunday. The strongest storms could produce hail the size of golf balls or larger.

There's also a significant wind threat on the eastern portion of the risk area in Alabama and Georgia. Storms will eventually coalesce into one or more squall lines capable of producing intense straight-line winds of 70+ MPH. This is a heavily wooded area, so communities are susceptible to widespread tree damage if a well-organized line can get going. It's a good idea to make a mental note of large trees or limbs hanging over your home and avoid those rooms when storms are on the way.

One caveat, like always, is that storm mode will determine who sees which hazards. Discrete thunderstorms will have the best opportunity to take advantage of the strong wind shear and live up to their full potential. That's what happened last week in Mississippi, where a big, messy cluster of storms to the north produced extensive wind damage while storms farther south had free rein to produce intense tornadoes.

As I pointed out last week, never count on the forecast flopping. Be prepared for the worst and hope for the best. Keep an eye on the radar and make sure you have multiple ways to receive severe weather warnings. Check that emergency alerts are activated in your phone's settings. Don't rely on tornado sirens for tornado warnings—sirens are outdoor warning systems that aren't designed to be heard indoors, and these aging systems prone to failure due to glitches, power outages, and high winds simply drowning them out.

Oh...one more thing. If you follow plenty of weather folks on social media, you might see chatter throughout the day on Sunday that the Storm Prediction Center might (or should, depending on their point of view) upgrade some areas to a high risk, or a full 5/5 on the scale used to measure the threat for severe weather. Don't worry about the difference between a moderate risk and a high risk. Some of the worst severe weather days have occurred during moderate risks. No matter how you phrase it, Sunday could be another significant severe weather day in the southeast and anyone in the region should be glued to the weather until the threat clears out.


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I graduated from the University of South Alabama in 2014 with a degree in political science and a minor in meteorology. I ran Gawker's The Vane for two years and I've contributed to Mental Floss, Forbes, Popular Science, and the Washington Post's Capital Weather Gang. I also teamed up with Outdoor Life to write a book called The Extreme Weather Survival Manual, which came out in October 2015.

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