Severe weather outbreak strikes South on Easter with damaging winds and tornadoes

For Easter Sunday, straight-line wind gusts of up to 70 mph are expected to rage as storms target the Gulf Coastal states, while ingredients could come together to produce "several strong tornadoes," according to the Storm Prediction Center. The severe weather threat continues overnight, with more dangerous thunderstorms, including a tornado threat, eyeing parts of the East Coast on Monday.

The stretch of dangerous weather kicked off Saturday as hail larger than softballs pummeled Del Rio, Texas - the first sign of a volatile atmosphere teeming with instability. A number of rotating supercell thunderstorms towered high above West Texas and Hill Country, even bringing an early-morning tornado scare just north of Austin.

The outbreak's timing on Easter Sunday presents a trifecta of communication challenges that make raising awareness even more difficult. Besides landing on a holiday weekend, the outbreak falls during the height of the coronavirus pandemic that's shaken many communities.

Some have shuttered community storm shelters due to concerns about the virus spreading, adding an additional hurdle to those eager to get out of harm's way. Some experts have weighed in, arguing in favor of prioritizing seeking shelter, with the American Meteorological Society even chiming in with a forceful statement late last week.

- Sunday

Areas at risk: The greatest chance for severe weather on Sunday will be across southeast Arkansas, northern Louisiana, Mississippi, Alabama and northern Georgia. The Storm Prediction Center has delineated these areas within a "moderate risk" for severe weather, denoting a level 4 out of 5 on their severe weather risk scale.

That translates to widespread severe thunderstorm activity, with all storm hazards in the offing.

Places like Birmingham and Tuscaloosa, Alabama, are located within this region - along with Jackson, Mississippi, and Alexandria, Louisiana. Surrounding the moderate category is a region of enhanced risk, blanketing the map from eastern Oklahoma and Texas as far east as the Interstate 95 corridor in Georgia. Little Rock, Mobile, Nashville and even Atlanta are included within the enhanced category - a level 3 out of 5 risk.

Hazards: Multiple rounds of storms are expected to form and rage across the South on Sunday and Sunday night. The most widespread hazard may be damaging winds, with some gusts topping 70 mph - particularly as a complex of thunderstorms barrels across northern Mississippi, northwest Alabama and Tennessee on Sunday afternoon. Additional storms will form across the region, sparing few from at least some impacts.

Tornadoes are likely as well, with a risk of "several strong tornadoes," according to the Storm Prediction Center. Any intense, long-track tornadoes would be most likely with individual rotating supercell thunderstorms, but it's unclear to what extent those will form. Destructive hail could accompany a few of the storms.

Timeline: Storms in Arkansas will move northeastward and begin to fizzle as they outrun the warm air pooling over the South. At the same time, the slug of heavy thunderstorm activity in Texas Sunday morning will intensify as it surges east in response to daytime heating, likely blossoming into bands of severe thunderstorms by late morning into midday. Those will likely bring a damaging wind threat north of Interstate 20 in Mississippi and Alabama, as well as Tennessee.

By early to mid afternoon, additional thunderstorms will develop farther to the south, across northern Louisiana and Mississippi. These could produce tornadoes along with damaging winds and large hail. The magnitude of the tornado risk depends on the particular structure of thunderstorms that evolve, which remains uncertain as of Sunday morning. Those storms will also move east, with heavy rain and storms blossoming in its wake.

Storms will congeal into a larger line capable of damaging winds and scattered tornadoes tonight as they shift eastward, making for a concerning setup in the Mid-Atlantic and Carolinas on Monday.

There is also a moderate risk of flash flooding in northern Mississippi, Alabama, north Georgia, Tennessee and the Carolina Piedmont as repeated rounds of storms move across the same areas that saw an exceptionally wet spring.

Uncertainty: Among the greatest wild cards in the forecast is the threat for strong tornadoes on Sunday. While many of the ingredients for strong tornadoes are there - including a warm, humid air mass and a change of wind speed and direction with height - getting them to form is dependent in part on the type of thunderstorms that materialize.

To get strong tornadoes, separate supercell thunderstorms are often required. Supercells are discrete, rotating thunderstorms that manage to tap into the atmosphere's full fury without being affected by neighboring storms.

It's safe to say that Easter will feature at least several tornadoes, with the potential for a higher-end event. But it's not yet clear how all the ingredients will come together to produce particular types of severe thunderstorms, since the presence of them isn't sufficient to cause a widespread tornado outbreak.

- Monday

Areas at risk: Much of the Mid-Atlantic and Southeast could be in the crosshairs of a continued severe weather onslaught, with the potential for an additional day of tornado and high wind risks. The greatest threat for severe storms and tornadoes will exist from coastal Georgia and South Carolina northward into Virginia, where the Storm Prediction Center has designated an enhanced risk - level 3 out of 5. That risk also calls for the threat of "significant" severe weather, including strong tornadoes. Richmond, Raleigh, Columbia and Savannah fall into this "enhanced" category.

A level 2 out of 5 slight risk trails south to Florida and reaches north all the way to the Pennsylvania-New York border.

Hazards: Once again, tornadoes will be possible - particularly in northern North Carolina and adjacent Virginia, where the latest computer model guidance hints that a strong tornado can't be ruled out. Scattered damaging winds, perhaps gusting above 65 mph, are possible in storms as well.

Even outside of any storms, wind gusts in excess of 50 to 60 mph will overspread most of the Mid-Atlantic into New England as the cold front pushes eastward, raising the concern for power outages. Wind gusts to 70 mph are anticipated along Long Island and in coastal New England, for example, and high winds may eventually cover a wide swath from New York to Boston and into northern areas as well.

Timeline: Leftover strong to severe thunderstorms will be ongoing overnight Sunday into early Monday morning in the Southeast. These will intensify once again while riding over the Appalachians on Monday as new forms storm as well. These will affect Georgia and the Carolinas in particular around midday in all but eastern areas.

A secondary band of storms could form in Virginia along the cold front around lunchtime into the early afternoon hours, with an enhanced risk of tornadoes and damaging winds. The Washington, D.C., and Baltimore metro areas have the potential to be affected by this line of severe weather.

Gusty thunderstorms are possible as far north as New Jersey and the tri-state area on Monday afternoon.

- The setup

The severe weather risk stems from a potent upper-level low, consisting in part of a lobe of cold air and atmospheric spin in the upper levels of the atmosphere diving across the South. It's brewing an amped-up atmosphere favoring pockets of rapidly-rising air that can give rise to dangerous thunderstorms.

The upper level low has been nurturing a surface disturbance that brings together the classic ingredients needed for a severe weather outbreak - strong southerly surface winds to truck in Gulf of Mexico heat and moisture, an impending dry air mass to trigger thunderstorm growth, and an impressive low-level jet stream.

Aiding this severe weather event are anomalously warm waters in the Gulf of Mexico, which is leading to more water vapor, and hence fuel, for thunderstorms to work with.

That jet stream is dipping far to the south and curling back northward around the low, with winds screaming north less than a mile above the ground at greater than highway speeds. Those strong low-level winds, coupled with a change of wind speed and direction with height, will help foster rotating thunderstorms.

- The bottom line

It's important to have a severe weather plan and review it with your family before severe weather strikes, and to act quickly to take shelter in the event warnings are issued.

In areas where community shelters are open, the American Meteorological Society recommends that you "not let the virus prevent you from seeking shelter." It's a good idea to check ahead of time to ensure your desired shelter location is open, and, if need be, alter your plans accordingly.

Other steps you can take in light of the severe weather threat include:

- Charge your NOAA weather radio.

- Call vulnerable neighbors, relatives and loved ones to talk over their severe weather plan - or inform them of the threat if they may be unaware.

- Have multiple ways to be informed of severe weather warnings. This can include disabling "do not disturb" on your phone, and ensuring you are able to receive wireless emergency alerts.

Tornado season is upon us in the Lower 48, a time when the annual clash of air masses punctuates spring with rounds of severe weather. It's a danger that can be lessened with steps to take whenever Mother Nature unleashes its worst.