Tornado Alley!  The Great Plains of North America.  Why do so many tornadoes occur here?

Take a look at a topographic map of North America.  The Great Plains, a large area with no significant  mountain ranges that extends eastward from the Rocky Mountains to the Appalachians and northward from the Gulf of Mexico to the Canadian Arctic.

In the warmer months, Spring through Fall, warm, moist air comes north from the gulf and collides with cooler drier air coming down from Canada.  That causes a very unstable condition that spawns severe thunderstorms and some of these thunderstorms spawn tornadoes and squall lines.

Unseasonably warm air in the southern plains colliding with colder air coming down from the north caused the squall lines and tornadoes that devastated Kentucky, Indiana and Tennessee.

I don't think that there is a geographical area anywhere else in the world that has the geography and temperature differences that mark the great plains of North America.

Noel

4 hours ago, birdguy said:

I don't think that there is a geographical area anywhere else in the world that has the geography and temperature differences that mark the great plains of North America.

Noel

I once saw some data on China, which, like the central USA, 1) has a big central-continent landmass off to its north/northwest, 2) cold/dry air can come down if the jetstream is right, and 3) warm moist air can come north from the South China Sea.

BUT...what is different?  China has a lot of mountains which tend to break up these systems somewhat.  At least that's the only reason I can think of as to why China gets fewer CB's than the middle/southcentral USA.

I know China does have tornadoes but to the best of my knowledge they don't have the outbreaks and Tornado Alley like the USA has.

The Himalayas prevent that warm air mass from from the Indian Ocean reaching the Tibetan plateau.  Instead they contribute to India's monsoons.

Noel

Another geographical wrinkle is that I do not live in that boring flat state with Chicago at the top like most people think of Illinois. Southern Illinois is at the confluence of the Mississippi and Ohio rivers, which are pretty big, but best of all, we the Ozark Mountain range (remember Ozark Arilines) trails into this place. It's a very interesting eco-zone or whatever your call it, with a combination of plants and animals you find in both north and south. We have armadillos, (We all them panzerpossusms, since it's only been a few years they've been here, no doubt from Missouri, which sends us all  the tornadoes.) Anyway, we're very hilly down here (think Appalachia, not Kansas). Weather seems to be consistently channeled along certain courses. I've been getting into weather more, obviously like Noel knows his stuff. Interesting, like why we have a jet stream. Ah, Ozark. I remember watching my brothers depart from KMWA in an Ozark DC-3. I later convinced my brother to sit in the back of a Skyhawk for a touch and go. It was my first venture to another airport besides my home one and I was supposed to do a touch and go. (I had my instructor, of course). I learned some things that day. First was I have no sense of direction. I could not make sense of which was which runway and how to get there. KMDH was different,because I knew the patterns and approaches by heart. I also learned that the weight of a grown man in the back seat of a little airplane makes a difference in landing. My older brother got a bit of a thump. Finally, I learned that runways are not always flat. This sucker at KMWA was so humped you expected to see a flag planted at the top.

The last big tornado we had hit Marion, in the next county over from us but it wasn't anything like this. Our own county seat was destroyed in the TriState tornado, along with a lot of other towns because it had a massive footprint and stayed on the ground for a grand tour of southern Missouri, Illinois and Indiana. Of course, we always look at the radar to see what's really happening. I've always wondered why the fronts always go from southwest of here to northwest, and always skirt our property. There must be some feature that channels them in a certain very specific way.

Appears we are in the Bullseye for Tornadoes possibility tomorrow. Very odd for this time of year. 75 degrees, 60 degree dew points and surface wind gust of 65mph+.

https://www.spc.noaa.gov/products/outlook/day2otlk.html

Edited December 14, 20214 yr by Adrian123

Tim, I spent my last 9 years in the service as an Air Force weather forecaster, so I know a little bit about how weather works.

I like to look at WindyT.  It shows Arkansas, Kentucky, and Tennessee under the gun again on Thursday.  That warm gulf moisture coming up from the south colliding with the cold air being brought down by that high over Kansas City.

WindyT has a number of ways to look at the weather.  You can select wind or rain or temperature or any number of things.  And it has a slider at the bottom so you can slide out 10 days into the future.

Noel

 

27 minutes ago, birdguy said:

warm gulf moisture coming up from the south colliding with the cold air

Yup. This is something I've learned, at least.

Thanks for the tip on WindyT. I hadn't heard of it. I generally used Dark Sky, which is just an iPhone app, but does have animated radar, nothing new nowadays. Amazing what we can hold in the palm of our hands. On a downer note, I saw a picture of three kids, an older little girl and two small ones. They went to the "safe place" they had: the bathtub. The older of the little girls took a selfie to show their aunt they were following the rules. Well, you do the best you can if you can't get underground. Life is uncertain. I think the people would rather the newsies just leave them alone, but if it bleeds it leads. Also, the old journalism rule I was taught is people read stories about "heart, health and pocketbook." Some things never change.Pull at the heartstrings, scare people about some health thing, or give them bad news about inflation. Make it personal, in other words. One of the first stories I covered for the first radio station I worked at was a tornado (WHCO in Sparta. IL.)

Storm cellars used to be a very common feature around here. My grandparents had one... sort of a reinforced earthen igloo. Our old two-story farm house was originally built without a basement. (Weirdly. it was added later.} There's still an old storm cellar (also called "root cellars") out front by the road that is now used only by snakes. Which is why we go to the basement on the rare occasion things do seem serious. You can often tell because the sky gets a weird green light... you can almost feel the drop in the barometric pressure... I dunno. It's sort of creepy, even if it doesn't actually produce a tornado on the ground.

2 hours ago, Adrian123 said:

Appears we are in the Bullseye for Tornadoes possibility tomorrow. Very odd for this time of year. 75 degrees,

Yes. Unseasonably warm temperatures are a definite danger sign. When the temperature suddenly drops, it's time to think about taking shelter. (LIke Michael Shannon in the great movie with Jessica Chastain, Take Shelter. Especiallly if you can take shelter with Jessica Chastain.)

 

They're still looking into to it, but one of the tornadoes may have stayed on the ground for over 200 miles:

https://earthsky.org/earth/december-tornadoes-2021-cause-of-outbreak/?utm_source=EarthSky+News&utm_campaign=acdb98f666-EMAIL_CAMPAIGN_2018_02_02_COPY_01&utm_medium=email&utm_term=0_c643945d79-acdb98f666-395549734

 

Hello Tim: Did Crawford County Illinois get hit with  bad weather?

Just managed to dodge getting twisters here in Chattanooga. It was strangely warm for December just before this line hit us.

For sure Jonathan  Very scary stuff!!!!! I got caught in a severe storm near Dayton Ohio back in 1995. My heart was in my throat. The rental truck i was driving rocked back and forth with  hail the size of peas. No place to pull over and let it pass.No damage done to the rental, and the car i was transporting..

Edited December 14, 20214 yr by Paul Deluca

The other area with the most thunderstorms on earth is Uganda in Africa north of Lake Victoria not sure how many tornados come out of that though but the most lightening 

11 hours ago, Matthew Kane said:

The other area with the most thunderstorms on earth is Uganda in Africa north of Lake Victoria not sure how many tornados come out of that though but the most lightening 

When it comes to tornadoes, Canada is a distant second to the US. Although, the UK seems to have more per area.

https://www.theatlantic.com/international/archive/2013/05/where-else-do-tornadoes-strike/276093/

Saw this one this morning, watched it with my 6 year old, boy she had a lot of questions. This is a tremendous bit of footage, great for education and gives an idea on the scale of that storm

 

Currently under a Tornado watch. Looks like their coming.