More than 6 million Americans face the highest risk of severe weather Friday as the season’s first major storm outbreak threatens the nation’s heartland, with strong tornadoes, large hail and damaging winds expected across Oklahoma, Kansas and Missouri, the national Storm Prediction Center said Thursday.
Another 22 million people face a slightly lesser risk in a zone that includes Oklahoma City, St. Louis, Omaha and Milwaukee. Emergency managers across the affected states urged residents to identify shelter locations and monitor National Weather Service warnings before storms arrive.
The system marks what forecasters and local emergency managers are calling spring storm season’s first significant outbreak, arriving as warm air streaming north from the Gulf Coast collides with cooler Canadian air behind advancing cold fronts.
First storms expected Thursday night
Some scattered severe thunderstorms were expected to begin late Thursday in the Texas Panhandle and across western Oklahoma and parts of Kansas, the National Weather Service said. Large hail, damaging winds and possibly a few tornadoes were also expected with those initial storms.
The strongest storms are forecast to develop Friday in a zone that includes much of Oklahoma, Kansas and Missouri and areas of some nearby states, forecasters said.
“This is probably our first real event this season where people are really starting to pay attention getting into the spring storm season,” said Melissa Mayes, deputy director of the Washington County Emergency Management Agency in Bartlesville, Oklahoma, north of Tulsa.
Air mass clash drives the outbreak
The general setup for the strong storms is a clash between warm air streaming north from the Gulf Coast and cooler Canadian air behind cold fronts, according to meteorologists with the private forecasting service AccuWeather.
The same weather pattern is expected to push temperatures well above seasonal norms across much of the eastern United States by the weekend. Federal forecasters wrote in their long-range forecast discussion that temperatures would be 20 to 30 degrees above average, “with 80s reaching as far north as parts of the Ohio Valley and Mid-Atlantic” and that “daily records could become widespread.”
The high temperature in Louisville, Kentucky, is expected to reach 81 degrees Fahrenheit by Friday, the weather service said. Atlanta’s high is expected to hit 82 degrees Fahrenheit by Saturday. Washington, D.C., is forecast for a high of 74 degrees Fahrenheit on Saturday.
Emergency managers prepare communities
In Douglas County, Kansas — home to the University of Kansas — deputy emergency management director John Stipetich said he had spent the week working with forecasters to assemble situation reports for schools, government agencies and others in the community.
Stipetich emphasized that residents should not wait for a warning to be confused about what to do. “If you hear the siren, there’s a tornado coming and you need to take cover,” he said.
Mayes said her agency planned to use social media to push safety tips and raise awareness of shelter options, noting that emergency managers rely heavily on those platforms at the start of each storm season.
Where tornado season peaks
The storms are arriving near the start of what is commonly called tornado season, which peaks at different times in different parts of the country. In what has historically been known as Tornado Alley — a designation that typically includes Kansas, Oklahoma and Texas — the peak of tornado season runs from May into early June. In the southern states that make up what is often called Dixie Alley — including Arkansas, Louisiana, Mississippi, Alabama and Georgia — the season typically begins earlier in the year.