SIOUX FALLS, S.D. (KELO.com) — Thunderstorms that can pack high winds and flash flooding are forecast to strike areas from the central and northern Plains to the Upper Midwest Wednesday, AccuWeather meteorologists say.
While a major outbreak of severe weather is not expected, the setup has the potential to hit some communities hard with damaging winds that could produce power outages from portions of northeastern Nebraska to southeastern Minnesota and central Wisconsin.
“The combination of a potent wave of energy at the jet stream level, combined with moisture, which has been absent much of this summer, is expected to help set off the storms,” AccuWeather Meteorologist Matt Benz said.
A small but focused southward dip in the jet stream is forecast to interact with a frontal zone in just the right way to set off thunderstorms that can evolve into one or more large complexes of severe weather from Wednesday afternoon to Wednesday night.
“Damaging winds are likely to be the main concern with any strong thunderstorm, and there can be some isolated flash flooding as well,” Benz said. Straight-line wind gusts could reach an AccuWeather Local StormMax
of 80 mph
As is the case with any severe thunderstorms, there is a remote chance of an isolated tornado. A few of the stronger storms may also produce hail.
“Even if there is some flooding, a large portion of this region desperately needs the rain,” Benz said.
At this time, it appears that areas from Omaha, Nebraska, to Des Moines, Iowa, Minneapolis and Madison, Wisconsin, are most likely to be in the zone of severe weather during Wednesday afternoon and evening.
Soil conditions vary tremendously over the north-central United States. Some areas over the Ohio and Mississippi valleys are considered to be sufficiently moist, while areas over the northern Plains and Upper Midwest are dealing with severe to exceptional drought, according to data from the United States Drought Monitor.
The middle of July can be a make or break time for crops, such as corn, in the region. A sufficient dose of rain in the next few days can help nurse a struggling crop through much of the summer.
Sioux City, Iowa, has only received about 40% of its normal rainfall since June 1 with only 2.13 inches of rain being recorded in the region as of July 12. On average, Sioux City receives 5.26 inches of rain from June 1 through July 12. When combined with high soil evaporation rates in the summer, the region could greatly benefit from a dose of soaking rain.
There is the potential for 1-2 inches of rain to fall with locally higher amounts from portions of Nebraska to parts of Iowa, southern Minnesota and central Wisconsin. Rainfall of this magnitude, even if most of it fell within a couple of hours, could be beneficial. However, AccuWeather forecasters caution that it may also result in a flash flood threat.
Cities such as Chicago and Milwaukee have been on the northwestern outer edge of showers and thunderstorms that have riddled much of the Great Lakes and Ohio Valley since late last week.
There is a better chance for Chicago and Milwaukee to have some heavy, gusty storms Thursday as the cold front portion of the storm system pushes into the very warm and humid air.
In the wake of the storms, a push of slightly cooler and less humid air is forecast to settle southeastward in a large swath of the central U.S. late this week. Highs from the middle 80s to the lower 90s F will be replaced with highs in the upper 70s to the middle 80s.
( AccuWeather senior meteorologist, contributed this report.)
