Storms could bring more tornadoes, flooding to central U.S.

A multiday stretch of severe weather — including the potential for tornadoes and locally significant flooding — is expected over the central United States ahead of the weekend. Strong to severe storms could stretch from the southern Plains to the Great Lakes — just the start of a very active pattern that will carry into May.

The storms are set to begin Thursday over the Corn Belt, where hail the size of golf balls is possible. Areas from the Great Lakes to Texas could see storms on Friday with wind and hail, and another batch of storms will brew from Texas to the Tennessee Valley on Saturday.

But the severe weather crescendos into Easter Sunday, when northeastern Texas; the Ark-La-Tex region, which includes southwestern Arkansas, northwestern Louisiana and northeastern Texas; the Ozarks and parts of the mid-Mississippi Valley will be at risk. Significant severe weather, including the chance for tornadoes and excessive rainfall with flash flooding, is expected.

That zone has dealt with multiple high-end tornado outbreaks and rainfall totals of up to 18 inches over the past five weeks, and it will once again be deluged. By early next week, parts of eastern Oklahoma, northwestern Arkansas and southern Missouri could be closing in on 4 to 6 more inches of rain.

Additional rains are expected to exacerbate any ongoing flood issues, and the ground is already saturated.

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Thursday’s risk

An organizing surface low-pressure system will move east from Kansas and southern Nebraska. Ahead of it, southerly winds will pump warm, moist gulf air northward. This will juice up the atmosphere in eastern Nebraska, Iowa and northern Missouri, providing thunderstorm fuel.

Even before the main event occurs, “appetizer storms” could bubble up as moisture increases. These storms may bring small hail late Wednesday into early Thursday, but the main event occurs Thursday afternoon. From Omaha eastward into southwestern and south-central Iowa, a couple of severe thunderstorms could produce damaging wind and large hail, perhaps up to the size of golf balls or hen eggs.

Any tornado threat would be relegated to southwestern Iowa near or south of Interstate 80. It’s unclear whether there will be enough moisture to support an isolated tornado. If moisture is delayed or the lower atmosphere is a bit too dry, storms would have higher bases — mitigating any tornado threat.

There could also be a zone of scattered hail-producing storms north of the warm front in northern Iowa, southern Minnesota and southwestern Wisconsin.

In Kansas and western Missouri, an isolated storm is possible, but a cap of warm air at the mid-levels will mostly suppress storm development. Storms are more likely near the low-pressure center, where conditions known as forcing, which provide some oomph, can kick up storms.

Friday’s risk

Low pressure moving toward the Great Lakes will drag a cold front east. Ahead of it, warm, humid gulf air will be in place. Scattered thunderstorms will blossom along the front as air masses clash. The zone to watch is from Detroit to Chicago southwestward to Kansas City, Missouri; Oklahoma City; and northwest of Dallas.

It’s likely that these storms will become clusters with predominantly damaging gusts and some hail. That’s because mid-level winds are parallel to the front. Since storms won’t be pushed off the boundary, they will grow along the front. That’s why clusters are probable — individual cells merge and become clumped together.

Tornadoes aren’t especially likely on Friday, because storms will struggle to rotate. Instead, a few storm clusters might produce damaging winds to 60 mph and hail the size of half dollars. Locally heavy rainfall is also possible.

Saturday’s storms

On Saturday, the zone to watch sags just a little bit farther southeast with the cold front.

Developing low pressure over Central and West Texas will gradually strengthen. Warm, humid air ahead of it will spread over much of Texas and Oklahoma, making for thunderstorm fuel. The battle-zone dry air west and humid air east will brew scattered thunderstorms.

For the storms over Central Texas, damaging gusts to 60 mph and large hail bigger than quarters are the main concerns. An isolated tornado can’t be ruled out.

Farther north, moisture will pool along a frontal boundary draped from near Wichita Falls, Texas, to Oklahoma City to Tulsa. That will make for downpours that repeatedly drench the same areas. Saturday will mark the beginning of a heavy rain/possible flood event.

As the forecast becomes clearer in the coming days, the placement of these conditions is subject to change. There is an increasing risk of heavy rain and flash flooding — but it remains unclear where the heaviest zone of rain will be.

Potentially significant storm event on Sunday

It’s still five days out, but there are signs that ingredients may be coming together for a round of severe weather — perhaps significant — over portions of the southern Plains, Ozarks and/or Texarkana region.

A bowling ball of strong low pressure will be sweeping overhead, which may drive a fierce dip in the jet stream. That roaring jet stream will blow over the warm, humid air tugged north ahead of the low. The result will be thunderstorms that blossom in the warm sector. These storms will grow tall and can be affected by the jet stream. Some will produce damaging gusts. Others will probably spin and could present a tornado risk.

Robust gulf moisture will also set the stage for heavy rain. Widespread totals of 3 to 5 inches can be expected over 36 hours from south-central Oklahoma through western Arkansas and southern Missouri.

The jet stream will also foster divergence, or the spreading of air aloft. As air in the upper atmosphere pulls apart, it makes a void that pulls warm, humid air upward. That boosts rainfall rates and intensity.

It’s too early to offer specifics, but ultimately an impactful weather event could be shaping up for an area that has already dealt with so much — both from severe weather and flooding. Lots of folks will be observing the Easter holiday, but that doesn’t mean it’s safe to let your guard down.