Severe storms, tornadoes are serious threat in central U.S. through weekend
Seemingly nonstop severe thunderstorms and tornadoes have been tearing through the Plains and Midwest for the past four weeks, and it looks like one final week of extreme weather is on the way before weather patterns simmer down a bit.
Severe storms are probable Friday and into the holiday weekend from Texas to the Ohio Valley, and could include the risk of damaging winds, large hail and more tornadoes.
Saturday’s threat looks to be substantial, and could affect hard-hit areas in Oklahoma that have faced three tornado outbreaks in as many weeks.
Kansas could be in play too, and strong tornadoes are a real possibility. The tornado potential and threat of hurricane-force winds will shift into the Mississippi Valley on Sunday.
Even the Mid-Atlantic might see dangerous storms on Memorial Day.
Since April 26, severe weather has been a nonstop staple of forecasts, and the U.S. is running far above average for its year-to-date tornado count. At least 705 tornadoes have occurred, the sixth most on record dating to 1950.
More than half of days in April and May so far have featured at least a Level 3 out of 5 risk of severe weather, according to the National Weather Service Storm Prediction Center.
Tuesday’s storms produced a devastating tornado outbreak in southwest Iowa. The strongest tornado, which lofted debris to 40,000 feet, tore through the town of Greenfield, killing four people. A female driver was killed in Corning, just to the southwest, when her vehicle was tossed off the road. Another suspected tornado hit Temple, Texas, on Wednesday, damaging homes and businesses. Cloud tops reached 65,000 to 70,000 feet, all but extinguishing daylight.
Thursday’s storm risk
Storms could form along a sprawling swath of the central states from Texas to Minnesota as a storm system enters the region.
A Level 3 risk covers central and southeast Nebraska, extreme southwest Iowa and north-central Kansas. Omaha, Lincoln and Grand Island in Nebraska are in the zone. A Level 2 risk encompasses the majority of the remainder of the Plains, including Fargo, North Dakota; Aberdeen and Sioux Falls in South Dakota; Des Moines, Iowa; Kansas City, Missouri; Wichita, Kansas; Oklahoma City; Dallas; and Little Rock, Arkansas.
How storms may evolve
The main concern will be for isolated to widely scattered rotating thunderstorms or supercells to form along a “dryline” during the afternoon and evening. That’s where dry air from the Desert Southwest meets Gulf moisture to the east. The dryline will extend from northwest Kansas all the way to Mexico. Storms will also form along a cold front in western Nebraska and the Dakotas.
The main hazard will be large, destructive hail, perhaps up to the size of baseballs, on the southern Plains. A tornado risk will also extend into northwest Texas, western Oklahoma, western Kansas and western-central Nebraska. Storms in Oklahoma may not fade until after midnight.
In Nebraska, storms will congeal into a mesoscale convective system – basically a large cluster of thunderstorms. The storms will push east into the night with an increasing risk of damaging straight-line winds.
Friday
Thursday’s storm system will shift east, affecting areas from northeast Texas to southern Michigan. A Level 2 risk extends from Chicago to Waco, Texas. Included in the zone are Springfield, Illinois; St. Louis; Jackson and Memphis in Tennessee; Little Rock; and Dallas.
A cold front will push east across the risk area. One or more thunderstorm complexes might be ongoing in the Corn Belt in the morning. Those will intensify in the afternoon, with additional storms forming to the south along the remainder of the front. Damaging winds and large hail will be the main concerns, especially in southwest Arkansas and Texas.
Saturday
The storm threat will become especially serious over the weekend, starting Saturday, as an intense disturbance ejects into the Plains.
A Level 3 risk is up for southern and central Kansas, central and eastern Oklahoma and extreme northern Texas. It includes Wichita Falls, Texas; Oklahoma City, Moore, Norman and Tulsa in Oklahoma; and Wichita and Salina in Kansas.
A Level 2 risk surrounds that, and includes Dallas, Little Rock and Kansas City.
The approaching disturbance will allow supercells to form along a dryline in the southern Plains during the afternoon, with an attendant risk for destructive winds, large to giant hail and tornadoes, perhaps strong.
By late evening, storms may merge into one or more quasilinear convective systems – essentially squall lines with embedded areas of spin – as they move east. They could produce widespread damaging gusts and give rise to quick-hitting tornadoes.
Sunday
The danger of serious storms will shift eastward Sunday, reaching the Ozarks and Mississippi River Valley.
A Level 3 risk has been drawn for Nashville, Tennessee; St. Louis; Louisville, Kentucky; and Evansville, Indiana. A Level 2 risk broadly covers areas from Chicago to Little Rock and east into extreme northern Alabama and Georgia
.