National Break From Tornadoes Ending In A Big Way

A supercell thunderstorm looking north from Sheldon,
Vermont on May 4, 2018. We're safe from any violent
thunderstorms over the next several days. However,
vast areas of the nation's middle are at daily risk of
severe storms each of the next five days at least,
starting Thursday afternoon. 

In an April 19 post,  I mentioned that tornado activity was temporarily stopping in the United States even as we headed into the height of twister season. 

I said that wouldn't last forever, and boy was I right, and so was virtually every forecaster watching the situation. 

We're about to embark on a severe weather outbreak that will last several days.  There's a strong likelihood of at least a few tornadoes daily at least into early next week.

Of course, the U.S. hasn't exactly been immune from severe thunderstorms over the past few days. It's spring, so it's hard to avoid them. 

On Saturday, severe hail and wind storms hit the Carolinas. Rock Hill, South Carolina was hit by baseball sized hail propelled by winds gusting to 90 mph. As you might imagine, damage was pretty extreme in that area.

Video from the Rock Hill storm with the wind and heavy hail is about as chaotic as you can get from a severe thunderstorm. 

Lumberton, North Carolina was hit by hailstones up to 4.5 inches in diameter, which is about the size of a grapefruit.   That size stone would at least tie the record for the largest hailstone ever found in North Carolina.

Tuesday, intense winds from a severe thunderstorm derailed a train near Abilene, Texas.  

However, a weather pattern that is bringing us in Vermont those hard, plant-damaging freezes tonight and tomorrow night also flooded most of the nation east of the Rockies with relatively cool and definitely dry air. 

That combo discourages the types of thunderstorms that can cause big hail, damaging winds and tornadoes,

But that weather pattern is breaking down. Warm, wet air is about to flood into much of the nation east of the Rockies. Dry air will make it into the parts of the southern and central Plains at times.  This pattern will also feature frequent storms forming in the southern Rockies and then moving northeastward toward the Great Lakes.

It's a classic spring tornado pattern and it looks like it will last more or less for a week or more. 

The bottom line: The next few days will be a tornado chaser's dream, but otherwise a threat to tens of millions of people. Unfortunately a tiny percentage of those people are about to lose their houses to tornadoes or other severe weather. 

The best case scenario will be that the strongest tornadoes avoid hitting towns and stick to open rangeland and farms with few or no buildings. 

It's impossible to say how many tornadoes will touch down, but it could be dozens over the next week

DETAILS:

There could be a couple more severe storms and maybe a tornado in west Texas this evening, but the real show starts tomorrow. 

Thursday

Friday afternoon and evening, a broad zone from southern Nebraska to central Texas is under the gun. It looks like western and central Kansas, western Oklahoma and parts of the Texas panhandle have the best chance of seeing tornadoes.

In this part of the nation, population centers are few and far between, so we do have a good chance that even if any tornadoes get particularly strong, they could thread the needle and avoid hitting towns and cities in the risk area. Fingers crossed!

Friday

Saturday's risk areas focus on most of Iowa, Missouri and Arkansas and parts of Oklahoma and Texas.  This area is far more built up than Friday's zone. Big metropolitan areas like Des Moines, Omaha, Kansas City, St. Louis, Oklahoma City and Dallas-Fort Worth are in this zone. 

That doesn't necessarily mean any of those cities or suburbs will take a tornado hit. Chances are they won't. But it'll be a day to keep an eye to the skies in those areas. 

One mitigating factor could be that storms left over from Friday would interfere with the development of new potentially tornado-producing supercell thunderstorms. 

Weekend 

The risk zone appears on Saturday to extend in a band from Texas to Wisconsin, with the biggest risk of trouble in central Kansas and Oklahoma. A second storm system coming out of the Rockies will help to re-invigorate severe storms and potential tornadoes. By Sunday, the risk zone looks like it will back almost where it's expected on Friday  - from Iowa and Illinois to eastern Texas

Other Problems

This new weather pattern also carries other risks. Bone dry, windy conditions in parts of New Mexico Colorado and western Texas could set off new wildfires and rangeland fires. It's already been a busy spring in that next of the woods for fires, so this might just make the whole situation worse.

In the humid air further east in the Midwest, repeated rounds of storms over the next few days could touch off some flash flooding. In some instances it could be locally quite severe.

Vermont Effects

The change in the weather pattern means Vermont's weather will change, too. We'll endure the hard freezes tonight and tomorrow night before the air turns a lot warmer over the weekend and the first half of next week. 

Highs could easily hit the 70s. 

The cold and warm fronts and remnants from those Midwest storm systems will head into Vermont as they weaken. That keeps us at risk for rather frequent showers Saturday night into Wednesday. There could even be a few thunderstorms thrown in next week. At this point, it doesn't look like that activity will be scary or damaging. Just the usual spring shower.s