2024 Tornado Season

[WeatherArc]

Tornado warning issued for Evansville Cell, first of this event.

 

[WeatherArc]

Wall cloud over Evansville a few mins ago

[matty40s]

Cincinnati is directly in the firing line of this, major urban area!!

[WeatherArc]

Storm that passed Evansville moving into a very favourable environment.

 

[Eagle Eye]

This could well be 'the' storm. @WeatherArc good timing ha ha. 

Edited April 2 by Eagle Eye

[matty40s]

8 separate storms now on Tornado watch!!

[Eagle Eye]

 

 

[The Tall Weatherman]

Tornado on the Ground in West Virginia currently ! Storm net predicted this 15 minutes in advance !

[WeatherArc]

I have a feeling those discrete supercells in western kentucky are going to be a problem

 

Edited April 2 by WeatherArc

[The Tall Weatherman]

Hellish signature and Tornado on the ground near Prospect ! Looks violent sadly 

[WeatherArc]

tornado sirens going off in La Grange ahead of that PDS tor

Edited April 2 by WeatherArc

[Eagle Eye]

 WeatherArc

Lots of cars on the street with a high-end potential tornado closing in on them

[WeatherArc]

 Eagle Eye was some people walking around earlier as well 

[matt111]

 

[matty40s]

 

 

[matty40s]

https://x.com/WeatherNation/status/1775268630688883176?s=20

[matty40s]

Too messy, giving up. 

[WeatherArc]

Genuinely wonder what went 'wrong' for those supercells, it looks like the discrete cells in Central Kentucky had abysmal lapse rates stunting development however even the more developed cells, such as the one that went over Evansville and La Grange struggled to produce tors, and did not produce any long tracked tornadoes as predicted by spc. Ive seen a few people say it was to do with the lack of tilting and stretching in the atmosphere, the cells spun but just couldnt undergo tornadogenesis. 

6pm sounding from Nashville here, can defo make out the problem with those lapse rates, additionally cape/3cape isnt the best.

[WeatherArc]

Slow start to the season so far, however May is starting to show up in longer range models as a very active month for severe weather and tornadoes across the plains.

We always thought this would be a back ended year with greater severe weather probs happening in late April, May and June. 

[Robert1981]

 WeatherArc I like your posts I wish I could chase in the US or we had more storms here like us have it would be better. 

[WeatherArc]

 Robert1981 Thank you very much  yeah i do sometimes wish our weather was a little more active, i would kill to see a beefy LP supercell like the ones below in person.

Saying that though im looking forward to storm season, if we have a repeat of last year ill be very happy. Hopefully we get a few big cape days as well. Ill be keeping an eye on sea surface temps, the higher they are the higher the dewpoints. 

I think we'll enter a quieter period for severe weather until late april, GFS seems to of picked up on something. Long way out but something to look out for.  

Even GEFS has some support

 

[Robert1981]

 WeatherArc yeah would love to see a big supercell here does usa get the severe weather because of the rockies gulf of Mexico and land mass.? 

[WeatherArc]

 Robert1981 Essentially, yes. Ill try to explain it.

Bad drawing here but the area in blue is what i would consider the most frequent area in the US for tornadoes, it includes the classic tornado alley (Oklahoma, Kansas, Texas, Colorado and Nebraska) Dixie alley (Alabama, Mississippi, Louisiana, Tennessee, Arkansas, Kentucky and Missouri) as well as the Midwest (Iowa, Illinois and Indiana) and the high plains (North and south Dakota and portions of Saskatchewan and Alberta) during spring large low pressure troughs swing in from the west, as they do they pull up moisture from the warm gulf of mexico. This typically results in dewpoints (the temperature at which water vapor can condense)  of around 15-25 degrees Celsius, we in the Uk often struggle to  get high dewpoints due to the cold waters surrounding us, its only really in August and September that our dewpoints can reach into the low 20s. Higher dewpoints and temps equal more cape/instability.

Typically, cape values 500+ result in strong showers, 1000+ thunderstorms and 2000+ severe thunderstorms. In the summer areas of the US can reach 7-8000 j/kg of cape.

 Now in the UK we typically can reach values of around 2500-3000 in the height of summer, however look at this euro run from last year, 6000 mucape just south of Bristol! We of course never actually got close to that number but just proves that the UK does have the ability to have these explosive values (imo because our sea temps were so warm that year)

Now the area i circled red on that map is what we call the EML (elevated mixed layer) source region, this region comprises of mountains and deserts, meaning dry air. When a trough moves over the plains it will advect this dry air to the north east and push it on top of the moist air being drawn in from the south creating a cap and raising instability further.

A capping inversion acts as a lid on the atmosphere, often in the uk we will get storms firing at around 10/11 in the morning due to the lack of this cap, these storms then use up the little instability available at that time as well as ruin the atmosphere with cloud cover, in classic American tornado outbreaks a strong EML means storms wont fire till around 3-5pm when instability is at its highest. A strong cap also means only the strongest updrafts can develop, meaning storms are more isolated and available to take full advantage of the present conditions. 

Now we in the Uk/Ireland usually struggle to get that cap, however some of our best thunderstorm events the past few years have been when a cap is present. 

Another reason the us is so favourable is due to whats called Lee cyclogenesis, essentially as a trough moves over the Rockies a surface low will develop on the Leeward side of the mountains, this surface low enhances the 850mb winds as well as drawing in even more moisture. The winds at 850mb are known as the low level jet and as the sun goes down at around 5pm they will rapidly strengthen due to higher elevations (Rockies) cooling faster than lower elevations. 

This is why tornadoes are so common in the evening. 

In the uk, we dont have any mountain ranges like this to create Lee cyclogenesis, this means we often lack low level shear to really create much of a tornado threat.

However, when we do get a surface low to either develop or pass over us we can get severe weather, especially in the summer. This is from the Birmingham 2005 EF2 tornado, very well positioned trough bringing us warm, moist air from the Mediterranean while also enhancing upper layer shear for supercells, meanwhile a surface low formed enhancing our low level jet just enough to become supportive of tornadoes, we had outbreaks of supercells across the country this day, mainly producing large hail.

Theres also the 28th june 2012 supercells, while low level shear was much weaker than the Birmingham setup these things did produce large hail and a few weak tornadoes.

Love this vid, shows that the uk can get severe supercells on par with those in the us.

Hopefully ive explained that alright, any questions absolutely feel free to ask.

I would also really recommend giving this channel a watch.

 

[Robert1981]

 WeatherArc thanks very much for the information and explanation

[WeatherArc]

Yes, its one gfs run 210 hours out and will likely not verify but couldn't resist not posting 

Absolute dream of a look for a big plains tornado day