Two separate rounds of severe weather, including the threat of tornadoes, will erupt and put tens of millions at risk across the Plains and Mississippi Valley this weekend. AccuWeather forecasters expect some of the strongest and most damaging storms to develop after dark, which will add to the danger.

Thunderstorms will have far-reaching effects with the potential for locally heavy and gusty storms to ignite as far north as the Canada border this weekend and along the Atlantic Seaboard by early next week.

Two storm systems will act as the triggers for severe weather as they swing east from the Rockies and track northeastward over the central United States this weekend. A dramatic clash in chilly air to the north and warm air to the south will aid in the development of severe thunderstorms as a strong jet stream overhead provides vigor to the volatile weather setup.

One key ingredient that is needed to fuel severe thunderstorms and tornadoes is moist air from the Gulf of Mexico, and that may not be in place until Saturday evening over portions of the central Plains.

"We have plenty of wind energy and we have the warmth for isolated severe thunderstorms to probably compensate for a lack of very moist air on Saturday afternoon and evening," AccuWeather Chief On-Air Meteorologist Bernie Rayno said, adding that, "The greatest risk with the brief thunderstorms during the first round of severe weather this weekend will be from damaging wind gusts, but there is the potential for a few isolated tornadoes as well."

The risk of severe thunderstorms on Saturday afternoon will begin to ramp up from eastern Iowa to northeastern Kansas but will likely reach its peak across Iowa and northern and central Missouri early Saturday evening. Major cities at risk for severe thunderstorms, including an isolated tornado, on Saturday include Kansas City, Missouri; Des Moines, Iowa; and Omaha, Nebraska.

Due to the strengthening nature of the storm system, there is the potential for heavy, gusty thunderstorms to last well into the nighttime hours as they advance through portions of Illinois, Wisconsin, Indiana, southeastern Minnesota and Michigan. At the very least, some people may be awakened in the middle of the night or prior to daybreak on Sunday due to thunder, lightning and downpours in Chicago, Milwaukee, Minneapolis, South Bend, Indiana, and Grand Rapids, Michigan. Motorists may want to avoid parking under trees for the night, where limbs could break in the gusty winds.

As the first storm shifts across Canada on Sunday, the second storm will advance across the southern Plains.

"All facets of severe weather are possible with the setup on Sunday, ranging from damaging wind gusts and isolated tornadoes to large hail and flooding downpours," AccuWeather Senior Meteorologist Tony Zortman said.

However, just like the setup from the day before, not all of the ingredients for severe weather may come together at the same time and could limit the magnitude of the event.

Most of the jet stream energy will not swing into the primary severe weather threat area until Sunday night after prime heating from the daytime hours has subsided. The energy will also aim to the west of the zone with the richest moisture from the Gulf of Mexico, AccuWeather Meteorologist Jake Sojda explained.

The majority of storms are likely to wait until late Sunday or Sunday evening to erupt, but severe weather hazards may continue well into Sunday night over portions of the southern Plains and the lower Mississippi Valley. Because of the risk of severe thunderstorms, including a few isolated tornadoes, after dark, the eruption could still pose a considerable danger.

Cities at risk for the Sunday severe weather threat include Dallas; Oklahoma City; Shreveport, Louisiana; Little Rock, Arkansas; Memphis, Tennessee; and St. Louis.

CLICK HERE FOR THE FREE ACCUWEATHER APP

AccuWeather StormMax™ thunderstorm wind gusts are predicted to reach 80 mph both days this weekend. Winds of that magnitude could lead to power outages and tree and property damage.

Aside from the risk of storms with damaging wind gusts and isolated tornadoes, a farther-reaching threat will exist from torrential rain and flash flooding, especially from Sunday night to Monday night. The main risk area will stretch from Arkansas to Ohio. Much of this zone has been the target of heavy rainfall over the past couple of weeks, and this event could bring another 1-4 inches of rain with locally higher amounts. An AccuWeather Local StormMax™ of 7 inches is predicted.

Water levels on many streams and rivers in the region are already elevated with ongoing minor to moderate flooding in some cases. A new surge of water or perhaps a second crest can occur on some waterways in the wake of the late weekend and early week rainfall event.

This time of year is no stranger to severe weather events like the ones expected to unfold this weekend. March is notorious for an uptick in severe weather, especially over the South Central states due to surging warmth and moisture in the region as strong storm systems roll through the region.

"There may still be some strong thunderstorms in the Ohio and Tennessee valleys on Monday, but the highest risk by then will be a heavy rain and flooding threat," AccuWeather Meteorologist Ryan Adamson said.

As the second storm system rolls across the Northeastern states later Monday and Monday night, locally heavy and gusty thunderstorms could also develop from the Appalachians to the coastal areas of the mid-Atlantic and New England.

For the latest weather news check back on AccuWeather.com. Watch the AccuWeather Network on DIRECTV, Frontier, Spectrum, fuboTV, Philo, and Verizon Fios. AccuWeather Now is now available on your preferred streaming platform.

Source: Read Full Article