Weather forecasters urge caution for Tuesday after 18 tornadoes across five states on Monday

After 18 tornadoes swept through five states on Monday, forecasters say Tuesday's severe weather threat warrants caution but lacks the same potential.

At least some tornadoes, damaging winds and hail are possible Tuesday in parts of Oklahoma, Texas, Missouri, Arkansas and Illinois, said Jared Guyer, lead forecaster at the Storm Prediction Center.

More than a dozen severe thunderstorm warnings and a few tornado warnings remained active overnight, Guyer added. Flash flash flooding from torrential rains that accompanied the storms also posed a concern.

Flooding threats will also not be as great Tuesday, but eastern parts of Kansas, Oklahoma and Missouri may face heavy rainfall issues, said Brian Hurley, senior meteorologist at the Weather Prediction Center.

Tornadoes in sparsely populated areas damaged homes and barns in Oklahoma on Monday, but no injuries were reported.

Preliminary reports show 18 tornadoes had spawned in Texas, Oklahoma, Kansas, Missouri and Arizona since Monday morning, as of 12:55 p.m. EST Tuesday, according to the Storm Prediction Center.

One afternoon tornado hit parts of the southwestern Oklahoma town of Mangum. Glynadee Edwards, the Greer County emergency management director, said roofs of homes were damaged and the high school’s agriculture barn was destroyed. The livestock survived, however.

“The pigs are walking around wondering what happened to their house,” she said.

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Another tornado severely damaged a house and destroyed a barn in the northern Oklahoma unicorporated community of Lucien.

The prediction center placed parts of the eastern Texas Panhandle and western Oklahoma under a "high risk" area for severe weather, the most serious of SPC’s five risk categories.

The entire Oklahoma City metro area was within the "high risk" area.

"I’d certainly label this the 'nightmare scenario,'" meteorologist Mike Smith tweeted, with a display of the storms that are predicted for later Monday.

The midday forecast from SPC has increased the tornado probabilities from 30% to 45% from northwest Texas into central Oklahoma. This means there's a 45% chance of a tornado forming within 25 miles of any spot in the area.

The last time a 45% tornado outlook was issued was before an outbreak in Oklahoma and Kansas on April 14, 2012, when 122 tornadoes formed, killing 6 people.

Schools closed across Oklahoma ahead of the bad weather. Many of the largest school systems in the center of the state (as well as the University of Oklahoma campus) closed all day Monday, which appears to be the first time such a mass closure has occurred in central Oklahoma on the night before severe weather, according to the Weather Underground.

Tinker Air Force Base near Oklahoma City evacuated several planes to other military installations in anticipation of storm damage.

Atmospheric scientist Roger Edwards tweeted Monday that “this is the rare kind of event that may take many lives. Pray I’m wrong.”

The wild weather Monday will continue a pattern of severe storms that have battered the region: Nearly 40 preliminary tornadoes were reported across Nebraska and Kansas to end this past week, and the severe weather continued on Saturday, AccuWeather said.

Forecasters say four tornadoes struck parts of West Texas in severe weather that damaged some homes and businesses in the San Angelo area on Saturday, the National Weather Service said.

Looking ahead, more bad weather is forecast the rest of the month for the central U.S.: "It looks like there is no end in sight to this very active pattern of severe weather into the end of May," AccuWeather Extreme Meteorologist Reed Timmer said.

High heat will also be another big weather story as May continues: As the Memorial Day weekend rolls in, look for a "death ridge" of heat in the Southeast, forecasters warned.

"Extreme heat and very dry conditions for extended period of time. Days 6-10 averages are 8-10°F above normal in the ensemble mean," meteorologist Ryan Maue tweeted. "Huge signal for record highs – and long duration!"

Contributing: John Bacon, USA TODAY; The Associated Press

This article originally appeared on USA TODAY: Weather forecasters urge caution for Tuesday after 18 tornadoes across five states on Monday