Days of storms expected in central and southern states, continuing relentless season

A classic Great Plains severe weather outbreak — complete with large to giant hail and tornadoes — is likely on Thursday, kicking off a dayslong bout of severe weather that could stretch all the way to the Appalachians. Multiple days of rotating supercell thunderstorms are likely, with storms transforming into windy squall lines that could race hundreds of miles every night. Widespread strong winds are likely.

On Thursday, the risk begins over the High Plains, extending east toward Oklahoma and the Red River Valley in North Texas overnight. By Friday, a swath from the Plains to Tennessee and Kentucky could see severe storms. Similar risks are expected on Saturday and Sunday.

In the transition month of June, ample heat and humidity can fuel large-scale thunderstorm complexes that travel long distances. Sometimes, there are corridors in the atmosphere, like “storm highways” where conditions are ripe for developing systems. That’s what seems to be happening over the Mid-South this week, setting up the possibility of severe storms for two or three consecutive days.

On Thursday, the greatest risk for dangerous weather will extend from West Texas and eastern New Mexico into southern Colorado, southwest Kansas and the Oklahoma Panhandle. That’s where a dryline will be present — the leading edge of bone dry air from the Desert Southwest will impinge on Gulf moisture to the east. The clash brews nasty thunderstorms.

While severe weather is possible virtually anywhere in the risk area, there are two zones with greater tornado potential.

One is in southeast Colorado and southwest Kansas, particularly between Springfield, Lamar and Campo in Colorado and Ulysses and Syracuse in Kansas. This region is closest to the low-pressure center, which is replete spin. Surface temperatures won’t be as warm, so storms won’t grow quite as tall — meaning hail probably won’t grow much larger than limes. But all that extra spin will help storms rotate, which means tornadoes will be possible.

Farther south, a few storms were already ongoing across West Texas and the southern Panhandle to start the day. Those storms were exhaling cooler air, which was pooling along an “outflow boundary.” That’s the leading edge of storm exhaust. Any ongoing storms were expected to dissipate, just leaving behind that boundary — which was set to become a focus for afternoon storms. Several severe thunderstorms will likely blossom in eastern New Mexico and West Texas, and any of them could gobble up extra low-level spin along that boundary and rotate — producing softball-size hail and tornadoes.

The only wild card with the southern risk area is whether a cap — a lid of warm, dry air a mile above the ground — could suppress surface air from rising and forming storms.

By 9 p.m. Central time, it’s possible that thunderstorms merge into one or more windy complexes. The most likely location for damaging winds would be in northern Oklahoma.

On Friday, another leftover exhaust boundary will probably be present somewhere in West Texas, potentially triggering a rotating supercell thunderstorm or two. The tornado risk will be decrease a bit because warm temperatures at the atmosphere’s mid levels might cap surface air, inhibiting it from rising. Still, damaging gusts and large hail are possible.

Additional isolated rotating storms are possible all the way north into southeast Colorado, where again an isolated tornado will be possible.

But one or more storm complexes with damaging winds will also be a concern — perhaps as far east as Kentucky and Tennessee. A severe (Level 2 out of 5) weather risk has been drawn by the National Weather Service Storm Prediction Center, and includes Oklahoma City; Little Rock; Springfield, Missouri; Memphis; Nashville; Huntsville, Alabama; Louisville; and even the Appalachian Foothills northwest of Atlanta.

The main concern there would be damaging winds to 60 mph, though an isolated tornado can’t be ruled out.

One or more windy storm complexes will ride a warm front eastward, surfing the northern edge of ultra-humid air present along the Gulf Coast. This storm highway will span from Oklahoma City and Dallas east to the Southeast Coast on Saturday — with the area of risk drawn by the Storm Prediction Center stretching to Charleston, South Carolina.

The zone to watch also includes Little Rock, Memphis, Nashville, Atlanta, Birmingham and Jackson, Mississippi. Once again, damaging gusts are the primary concern.

Beyond Saturday, it’s difficult to offer specifics on the forecast, but there are indications that severe weather potential may linger in the coastal plain of the Carolinas.

Another area of severe weather risk may materialize in West Texas or the Oklahoma Panhandle, with wind and hail being the main concerns.

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More than 1,000 tornadoes this year

There have now been more than 1,000 reported tornadoes across the United States this year, according to the Storm Prediction Center. The 1,051 tornadoes reported from Jan. 1 through June 4 ranks as the fourth-highest number since 2010 and is about 30% higher than the average number of around 800.

Texas has had the most tornadoes with 110, followed by Missouri, 107; Illinois, 105; Mississippi, 100; Alabama, 66; Indiana, 58; Arkansas, 53; and Kentucky, 46.

Three dozen contiguous states have reported a tornado this year.