Tuesday and Wednesday are shaping up to be very volatile, with more than 100 million people in the path of severe storms, which are expected to produce destructive hail, strong tornadoes and damaging straight-line wind gusts.
Forty-five million people are at risk of severe storms Tuesday along a 1,000-mile stretch from southern Minnesota to the Gulf Coast. Cities at risk Tuesday include Minneapolis; Des Moines, Iowa; Omaha, Nebraska; Kansas City, Missouri; Wichita, Kansas; Oklahoma City; Tulsa, Okla.; Little Rock, Arkansas; Dallas; Austin, Texas; Houston; Shreveport, Louisiana; and Baton Rouge, Louisiana.
Thunderstorms are expected during the afternoon hours and will extend into the evening. Fast moving thunderstorms (sometimes moving over 50 mph) and thunderstorms, which are expected to continue after nightfall, will enhance Tuesday’s dangerous setting.
Nighttime tornadoes are more than twice as likely to be fatal compared to their daytime counterparts.
While tornadoes, high winds, and very large hail are possible throughout the area, there are two specific areas of particular concern.
The first area includes much of Iowa, eastern Nebraska, and eastern Kansas, as well as southern Minnesota. This is where there is the greatest risk of strong long-track tornadoes (EF2 or higher) on Tuesday afternoon and evening.
The second highest severe potential area on Tuesday is in central and north Texas, which has the highest risk of destructive hail, baseball-sized or larger.
Between these two areas there is great uncertainty in storm coverage. A strong boundary in place (a warm layer of air overhead that can inhibit storm formation) can prevent many, if any, storms from firing up late into the night.
On Wednesday, the risk expands north and east to include 60 million people from the Great Lakes to the Gulf Coast. Cities to watch include Chicago; Saint Louis; Nashville, Tennessee; Memphis, Tennessee; Little Rock, Arkansas; Jackson, Mississippi; Birmingham, Ala.; and New Orleans.
Severe thunderstorms will likely continue into the morning hours and persist throughout the day. Damaging winds over 75 mph will be the greatest risk, followed by strong tornadoes and very large hail.
Widespread flooding is not likely, but 1 to 2 inches of rain, if it falls in a short period of time, could cause a few isolated cases of flash flooding, especially in urban areas.
At the same time, a historic April blizzard will hit the northern Rockies and northern Plains Tuesday through Thursday.
Blizzard warnings were increased Tuesday for a combination of heavy snow and wind gusts up to 50 mph, which will make travel impossible and at times life-threatening. Widespread power outages are also possible, and the storm could have damaging impacts on crops and livestock.
A large swath of area will see 6 to 12 inches of snow, but eastern Montana into North Dakota could see up to 2 to 3 feet.
Due to the expected long-lasting nature of this storm, snowfall totals this high could set a record.
Bismarck, North Dakota’s largest April snowstorm on record was 17.8 inches in 2013. The current forecast is likely to top that record, with 12 to 24 inches of snow possible.
Perhaps more impressive, a statewide snowfall record could be in jeopardy. The North Dakota state record for the most snowfall in 24 hours is 27 inches set on April 27, 1984 in Minot. Some localized areas could collect 30 to 40 inches of snow, breaking that record.
On the opposite side of the spectrum, high temperatures in the 90s combined with low humidity and wind gusts of more than 55 mph could lead to an outbreak of wildfires in the western high plains.
Fourteen million people are under red flag warnings and 27 million people are under wind watches Tuesday that span the desert Southwest to the Four Corners and the western high plains.
There is an extremely critical fire risk in the western parts of Kansas, Oklahoma and the Texas Panhandle on Tuesday. Amarillo and Lubbock in Texas are the largest cities in the fire hazard area.
Adding to the wildfire threat, a fast-moving cold front is expected to cross the critical outlook area near sunset. Strong winds along the front combined with a dramatic wind shift to the north and northwest can affect fire direction and rates of spread.