Severe storms threaten Plains and Upper Midwest states

AccuWeather

A stretch of severe storms will bring flooding rain, hail and even the risk of tornadoes from the Upper Midwest to as far south as Texas on Oct. 30. Wind gusts could reach as high as 70 mph.

Transcript

00:00From our Severe Weather Center in Wichita, Kansas, meteorologist Guy Pearson.

00:05Nobody knows severe weather as well as Mr. Guy.

00:08And Guy, let's begin.

00:09Already behind you, you can see some showers and thunderstorms, nothing that's severe.

00:13But when we talk about severe weather, you know what, we typically are talking

00:18about the same ingredients time and time again.

00:21We begin with a big temperature contrast across the central U.S. today, Guy.

00:28Yep, certainly.

00:30Good morning, everybody.

00:31And temperatures and having a large discrepancy

00:35in temperatures is a big part of that.

00:37You know, so we've been talking about it here all week about how much heat we've had,

00:43records set across parts of Kansas and on to the northeast, the 80 in Chicago today.

00:48All that heat has moved up there.

00:50Well, we finally have a nice, big, strong cold front that's coming in,

00:54and that's going to be the main trigger point that's going

00:56to set off this severe weather later today.

00:58And more importantly, you know, these frontal boundaries over the last couple

01:01of weeks have not had any gulf moisture.

01:04This front is different.

01:05You can see those winds howling now out of the south from Texas and Oklahoma.

01:10These are the sustained winds.

01:12Note the direction coming right in out of the Gulf of Mexico, Guy.

01:15And this front has something others haven't had.

01:18As I mentioned, it does have gulf moisture.

01:20And look at that surge of that higher dew point air of 60 degrees going right

01:25across central Kansas this morning.

01:29Yep. I mean, that's certainly those winds.

01:31We felt it across the Wichita area yesterday.

01:34We had 50 to almost 60 mile an hour winds here yesterday at times.

01:38And just driving in yesterday morning, and then I took a look at the clouds as I was driving

01:43in this morning, and everything streaming in the lower level clouds

01:46that transport that moisture north.

01:49And that's how we're getting, you know, the lower end dew points.

01:52You can see while the dew point's a little bit lower in Omaha, that front and where

01:56that moisture has pooled just southeast of Omaha there, you can see that green line

02:01of higher dew points all the way into the low 60s.

02:04So, yes, we finally have some moisture in place here for, you know, the dynamics

02:10and the cold front itself to be able to work with to generate those storms

02:13that certainly we need much needed rain across the plains here.

02:18Yeah. Now, let's talk about the energy.

02:19There it is, Four Corners area.

02:21You have that little swirl.

02:23That's going to come out in the plain states later today.

02:26So that's going to be the trigger.

02:28And, you know, Guy, one of the ingredients I love looking at, and I know you do as well,

02:34is the low-level jet.

02:36Explain to our viewers why this is such an important, let's say, an important ingredient

02:43or an important tool for severe weather generation.

02:50Yeah, certainly.

02:51The low-level jet typically sets up in your later evening and early overnight hours.

02:56And it's really a low-level, well, just as it is, low-level jet.

03:00It's a huge moisture transport northward.

03:03And so that's why we have those low 60 dew points all the way up southeast of Omaha,

03:09as well as then we go through the next little bit here into the overnight hours tonight

03:15as this graphic works on through.

03:17We actually have the winds increasing later tonight.

03:20You have the surface low that actually starts to develop along the front and dragging that

03:25cold front to the east.

03:26But then also you have that temperature differential from heating during the day.

03:31So you've got all the area across Missouri, southern Illinois, Arkansas, that's been in

03:36sunshine and heat all day, we'll be having clouds back to the west across Kansas.

03:41And then that low-level jet, with that difference between that heating, allows those winds to

03:47really increase and forward that moisture transport farther north and really increasing overnight.

03:54You get that low-level jet into the thunderstorms that are already developed, it continues to

03:59pump more moisture into it, as well as then more wind speed as well.

04:03So to help with some of that directional shear and or just the amount of wind and dynamics

04:08that the system has to work with.

04:10You can see our threat, the some risk all the way from Madison toward Little Rock.

04:14The moderate risk Kansas City and Oklahoma City.

04:16And really quickly, Guy, I want to show you the future radar here because you share the

04:21same concern I do in central Kansas later today.

04:26Yep, certainly.

04:28At the beginning of future radar here through about 5 o'clock, you actually see some of

04:33those individual or discrete cells, as you mentioned earlier today, actually develop.

04:38And those are the types of cells that have the best environment to work with as far as

04:44the directional shear that we look for those turning of the winds in the atmosphere to

04:47help those tornadoes develop.

04:50And so as we start to then work through the 5 to 10 o'clock or 5 to 9 o'clock time frame

04:55here, we see more storms start to develop and then storms, as you talked about earlier,

05:01start to become more linear and line out, meaning then everything is all connected together.

05:07There's not as much opportunity for some of those different directional wind shears to

05:11get in there.

05:13The likelihood of tornadoes will decrease certainly from about 10 o'clock onward to

05:18where it's mainly the line of storms.

05:21There might be one or two very spotty to where there's little notches along the line of storms

05:26itself, but really it'll be winds after 10 o'clock or so.

05:31But certainly that forward at 10 o'clock time frame like we were talking about across Kansas

05:36up towards Kansas City, that's going to be the best time for that tornadic development,

05:40I think.

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