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What's the most unstable sounding you've ever seen?


Hoosier
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Obviously there are different ways to measure instability but I'm focusing on CAPE. I remember one from IA or NE last year or the year before which had MLCAPE well over 5000 (maybe over 6000). 7/13/04 was another crazy unstable day with SBCAPE over 7000 in IL.

Another good one is the Peoria sounding from 8/28/90 with MLCAPE over 5500 (SBCAPE of 7000-8000 IIRC)

post-14-0-83945200-1304746005.gif

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I thought of two days immediately when I saw this with one being the Roanoke day that Hoosier mentioned and the other being 8/4/08 from DVN and ILX roab soundings with the 2nd one from ILX just huge....the most I've ever seen, amazing.

Jesus...I knew 8/4 was really unstable but I didn't realize it was that unstable. :yikes:

I wonder what instability is like in that area of the Middle East that often gets dewpoints well into the 80's.

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Jesus...I knew 8/4 was really unstable but I didn't realize it was that unstable. :yikes:

I wonder what instability is like in that area of the Middle East that often gets dewpoints well into the 80's.

I know we probably won't see an event like last weds again in our lifetime with the mix of high instability (>3000 j/kg) and insane 0-6km shear (60-80kts) and low-level shear (0-1km SRH 600-1000 m2/s2) but I'd be curious what a discrete supercell does in a tornado-like shear environment with 7000 j/kg of CAPE.

Cause 8/4/08 didn't have the siggy tor shear.

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Owe, I just found this one from last year in my collection. WIN.

Haha Chi Storm and I were chasing that day in central IL, never knew it had that much juice...explains why that storm went nuts in a short period of time and one of the most crazy lighthing shows I've ever seen.

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I know we probably won't see an event like last weds again in our lifetime with the mix of high instability (>3000 j/kg) and insane 0-6km shear (60-80kts) and low-level shear (0-1km SRH 600-1000 m2/s2) but I'd be curious what a discrete supercell does in a tornado-like shear environment with 7000 j/kg of CAPE.

Cause 8/4/08 didn't have the siggy tor shear.

Yeah it's harder to get the good shear this far south in summer. Usually you have to rely on some freak meso/microscale interactions to produce strong/violent tornadoes.

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I'd like to see a sounding for northern Illinois the afternoon the F5 tornado hit Plainfield Illinois. There had to be a lot of instability that day, as I recall reports saying how hot and humid it was. The storm moved southeast, so it probably attained some enhanced SRH, so mid and upper winds may not have been too impressive. Still would be an interesting sounding I think.

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I'd like to see a sounding for northern Illinois the afternoon the F5 tornado hit Plainfield Illinois. There had to be a lot of instability that day, as I recall reports saying how hot and humid it was. The storm moved southeast, so it probably attained some enhanced SRH, so mid and upper winds may not have been too impressive. Still would be an interesting sounding I think.

Peoria sounding is the closest thing we have. Given the surface obs at the time of the tornado, I'm guessing the thermodynamic environment in northern IL was very similar.

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The Jarrell, Texas tornado event - for quite some time - was considered one of the more extreme CAPE events.

F5 tornado event - some of you will remember.

post-77-0-03408500-1304820779.gif

post-77-0-71282900-1304820785.png

I read a paper, can't remember where, they ran some modelling of the event at, I think, Texas A&M. Without the windshift aligned near I-35, that storm would have pulse severed and died, That boundary was how the storm could propagate Southwestward down I-35, basically,

Edit to add- many a late Spring sounding from CRP is 3000 J/Kg or better, but it is almost always wasted. FWD 7 am MUCAPE is 4700 J/Kg, and it won't do anything today

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I'd like to see a sounding for northern Illinois the afternoon the F5 tornado hit Plainfield Illinois. There had to be a lot of instability that day, as I recall reports saying how hot and humid it was. The storm moved southeast, so it probably attained some enhanced SRH, so mid and upper winds may not have been too impressive. Still would be an interesting sounding I think.

That first post in the thread is as close to a proximity sounding for Plainfield as you are going to get. The sounding is from the day of the Plainfield tornado...and Peoria is the closest sounding site.

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Probably over 10, maybe even over 15.

We'd need to know the helicity to get a close approximation. Just looking at the CAPE and crudely estimating the helicity, I'd say the EHI would be over 15 and possibly approaching 20.

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