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Severe WX Severe Weather Thread - 6/15/26 - 6/18/26

WeathermanLeprechaun said:
I'm seeing a lot across different platforms calling for LLLRs to be a big issue here, but seems like they've all forgot that with strong forcing for ascent that LLLRs really don't matter when it comes to storm development like @andyhb said.

When you're dealing with the nose of the jet directly overlapping the warm sector, with very adequate instability ignoring the isotropic convection north of the warm front, storms will not falter to form. Remember this when we get closer.
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Both extremely strong forcing and low-level shear out the wazoo. Remember from Enderlin last year that strong low level spin can help maintain updrafts in thermodynamically suboptimal setups.
 
WeathermanLeprechaun said:
I'm seeing a lot across different platforms calling for LLLRs to be a big issue here, but seems like they've all forgot that with strong forcing for ascent that LLLRs really don't matter when it comes to storm development like @andyhb said.

When you're dealing with the nose of the jet directly overlapping the warm sector, with very adequate instability ignoring the isotropic convection north of the warm front, storms will not falter to form. Remember this when we get closer.
Click to expand...
The other thing is that low level lapse rates are highly sensitive to even small variations in heating near the surface.
 
WeathermanLeprechaun said:
I'm seeing a lot across different platforms calling for LLLRs to be a big issue here, but seems like they've all forgot that with strong forcing for ascent that LLLRs really don't matter when it comes to storm development like @andyhb said.

When you're dealing with the nose of the jet directly overlapping the warm sector, with very adequate instability ignoring the isotropic convection north of the warm front, storms will not falter to form. Remember this when we get closer.
Click to expand...
At the end of the day tornadoes care about sheer far more than vertical instability.
The longest track and consistently violent tornadoes occurred in extreme shear environments that force high velocity storm motions (>40knots) with cape values just barely over 1000j/kg to as low as 200j/kg with LLLR just above 6c/km and far lower.
Theres just needs to be some form of vertical instability and that’s really all you need.
It’s just very difficult to achieve that though, but honestly this is one of those setups that unless it downtrends a substantial amount Synoptically, is a slam dunk long track tornado producer.
It’s actually quite difficult NOT to get an sig tornado in environments like this. Again, unless something fundamentally changes synoptically, it’s a matter of how bad will this event be rather than will it b&st.
 
andyhb said:
The other thing is that low level lapse rates are highly sensitive to even small variations in heating near the surface.
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That too. That was another point you touched on in your comment regarding lapse rates, but i couldn't remember it.

jiharris0220 said:
At the end of the day tornadoes care about sheer far more than vertical instability.
The longest track and consistently violent tornadoes occurred in extreme shear environments that force high velocity storm motions (>40knots) with cape values just barely over 1000j/kg to as low as 200j/kg with LLLR just above 6c/km and far lower.
Theres just needs to be some form of vertical instability and that’s really all you need.
It’s just very difficult to achieve that though, but honestly this is one of those setups that unless it downtrends a substantial amount Synoptically, is a slam dunk long track tornado producer.
It’s actually quite difficult NOT to get an sig tornado in environments like this. Again, unless something fundamentally changes synoptically, it’s a matter of how bad will this event be rather than will it b&st.
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I agree. This is why I'm not concerned about LLLRs for a event like this with strong forcing for ascent. With a event like 12/28/24, our support prefrontal confluence bands that day were heavily reliant on LLLRs. They were poor that day and with the lack of strong forcing until later on, it's no matter we struggled to sustain them. The only noteworthy tornado out of that prefrontal band from LA/MS was the Bude EF3, which interacted with a thermal boundary. In such situations, you rely on some sort of mechanism like a boundary but with Wednesday, the jet is overlapping CONSISTENTLY.
Also note that even our band of supercells last week relied on the thermal boundary laid out from the earlier MCS that morning to a extent. The rest was the environment and to some extent, storm-scale interactions doing their stuff. It's undeniable though, in cases of poor LLLRs, nudgers do aid but in a way, nudgers are quite literally mesobeta forcing for ascent to help force a mesocyclone into undergoing tornadogenesis so it's the same thing, just a tad bit different? I don't know. My mind is really on meteorological buzz tonight LOL
 
N0mz said:
Both extremely strong forcing and low-level shear out the wazoo. Remember from Enderlin last year that strong low level spin can help maintain updrafts in thermodynamically suboptimal setups.
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That was down to pressure perturbations and ripping through the surface inversion. Those cells had also developed before the inversion rapidly settled in so they had access to surface based parcels too. Shear overcomes thermodynamics many times.
 
Grand Poo Bah said:
My bold prediction is we'll see a day 2 moderate and a day 1 high risk. If trends the same we'll see our first cig 3 as well.
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CIG3 is reserved for high of the higher end tornado outbreaks. Not events that have the potential to produce a isolated violent tornado. Confidence is rarely ever high enough for that, and if it is, it's usually a event that has a lot going for several supercells capable of EF4+
 
WeathermanLeprechaun said:
CIG3 is reserved for high of the higher end tornado outbreaks. Not events that have the potential to produce a isolated violent tornado. Confidence is rarely ever high enough for that, and if it is, it's usually a event that has a lot going for several supercells capable of EF4+
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Probably things along the line of, say, 04\26\1991 or 05\03\1999 or thereabouts would be my personal guess.
 
N0mz said:
I doubt we see cig 3 tbh. I have a feeling it'll be reserved for once in every 5 years type events with super widespread 10+ stp
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Thats my prediction and I'm sticking to it! Well... Maybe I'll actually wait to see if that tropical storm develops in the gulf, because if it does that could really cut off our moisture return.
 
Grand Poo Bah said:
Thats my prediction and I'm sticking to it! Well... Maybe I'll actually wait to see if that tropical storm develops in the gulf, because if it does that could really cut off our moisture return.
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Doubt it'd be much of note. Moisture return will not be easily cut off by what appears to be a potentially weak tropical system that still has uncertainties to develop. It may not even develop at all.
Kds86z said:
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Want to ask if this type of synoptic look with two lows has produced similar tornado outbreaks in June in the past? Any fellow analog guys?
 
jiharris0220 said:
The remnants of Cristina could develop into a full blown hurricane and it still would have zero effect on this setup.
A complete non-factor.

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It's not disrupting the moisture return severely at all with this setup and by the time it would have a chance to, it's Thursday. We wouldn't be sitting here looking at a high end ceiling if this was the case of it disrupting the event which would've been evident days out
 
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