July 9-10 Severe Potential

[Hoosier]

This is kind of far out for a severe weather thread, but there isn't much going on and it looks like a synoptically evident severe setup on paper.  We look to have a respectable surface low (by July standards) that will move through the region, accompanied by sufficient moisture and a plume of at least modestly steep mid level lapse rates.  Should have some nice flow aloft/shear to work with as well.  Putting it all together, I think the potential is there for a significant severe wx event, but obviously we'll have a better idea as the time approaches. 

[StormfanaticInd]

7 minutes ago, Hoosier said:

This is kind of far out for a severe weather thread, but there isn't much going on and it looks like a synoptically evident severe setup on paper.  We look to have a respectable surface low (by July standards) that will move through the region, accompanied by sufficient moisture and a plume of at least modestly steep mid level lapse rates.  Should have some nice flow aloft/shear to work with as well.  Putting it all together, I think the potential is there for a significant severe wx event, but obviously we'll have a better idea as the time approaches. 

Been eyeing this since yesterday. Looks interesting 

[RCNYILWX]

This is kind of far out for a severe weather thread, but there isn't much going on and it looks like a synoptically evident severe setup on paper.  We look to have a respectable surface low (by July standards) that will move through the region, accompanied by sufficient moisture and a plume of at least modestly steep mid level lapse rates.  Should have some nice flow aloft/shear to work with as well.  Putting it all together, I think the potential is there for a significant severe wx event, but obviously we'll have a better idea as the time approaches. 

agree, and for the LOT CWA, the slower timing similar to the 12z Euro would up the ante.

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[Malacka11]

This is the snowstorm equivalent of a severe outbreak in that there's actually medium-range model watching and hype involved. I'm very glad that something like this has finally happened. 

[CheeselandSkies]

2 hours ago, Malacka11 said:

This is the snowstorm equivalent of a severe outbreak in that there's actually medium-range model watching and hype involved. I'm very glad that something like this has finally happened.

Guess I'll have to actually look at some modeling for this, haven't done anything other than read SPC's Day 4-8 discussions the last couple days. Been spending too much time on another forum reading posts arguing back and forth whether T.S. Elsa is strengthening or not.

*Edit* On latest GFS at least, looks like another I-74/I-70 corridor event for Friday.

[CheeselandSkies]

Last few GFS runs have slowed things down quite a bit, now has a western Iowa/eastern NE threat on Friday; perhaps E IL/IN on Saturday.

[CheeselandSkies]

SPC has now added a Day 5 risk area for Friday encompassing western IA/eastern NE, but they mention that they expect primarily a linear storm mode with a wind threat.

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[Jim Martin]

From the NWS in Cleveland Area Forecast Discussion this evening.

[StormfanaticInd]

Indy hinting at severe potential this weekend 
The weekend system
looks to have better rainfall coverage and perhaps better shear for
severe potential, but still a lot of variability in the solutions
and thus low confidence in the specifics (beyond higher PoPs

[A-L-E-K]

miss south stank

[Chicago Storm]

miss south stank

more like miss well west.


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[Hoosier]

Been some changes in the setup since I made the thread.

[hawkeye_wx]

The GFS is well south with the heavy stuff.  The other globals track it across Iowa.  That is how it was before the big event two weeks ago as well.

[Hoosier]

ENH risk in the west/southwest sub.

[CheeselandSkies]

Miss well southwest. See @cyclone77's avatar.

[Malacka11]

I'm thinking about going down again, but I feel like the real supercell thread is too far west and I'm not driving 150 miles away for a heavy rain cluster.

[WeatherMonger]

ILX with a rare descriptive mid-morning update.

 

 

.UPDATE...
Issued at 1041 AM CDT Fri Jul 9 2021

A pair of observations from the 12z HREF: (1) impactful
convection is trending later into the evening, and (2) picking
a favorite hi-res model is not going to help nail down the
forecast; there is simply too much spread and uncertainty among
them.

To gain a better understanding of the convective potential, it is
best to take a step back into the synoptic space. Current GOES WV
imagery depicts a shortwave trough digging southeastward across
central Iowa, coinciding with a 50+ kt speed max at 500-mb. At the
surface, a warm front is draped from roughly Sioux City to
Nashville. This front and upper-level forcing will provide the
focus for convective initiation this afternoon across portions of
southern Iowa and northern Missouri as the capping inversion
erodes.

Storm relative hodographs suggest any discrete convection that
develops late this afternoon and early evening west of the
Mississippi River Valley will become linear as it approaches
central Illinois and interacts with the LLJ. The current
expectation is for an MCS to initially propagate along the warm
front/MUCAPE gradient, which runs roughly parallel to a Galesburg
to Effingham line. But, as the cold pool becomes more mature late
this evening, the MCS should show a tendency to follow the 0-3 km
shear vectors into portions of central and southern Illinois.
Depending on the strength of the cold pool (will need to assess
theta-e differentials from 00z ILX sounding), there could be some
bowing segments along the leading edge of the MCS. This will lead
to a damaging straight-line wind threat late this evening with
pockets of 70+ MPH gusts possible. A few brief tornadoes will also
be possible within these bowing segments wherever the
3-ingredients method (QLCS mesovortex system) comes into
alignment.

As mentioned previously, timing all of this out is perhaps our
biggest challenge. But for now, we`ll peg the peak severe weather
threat between 9pm - 3am.

Perhaps the bigger and understated threat this evening is hydro.
While the HREF doesn`t offer much continuity with convective mode
and timing, we do believe it offers a helpful solution on QPF;
namely the LPMM, which suggests a widespread 0.5"-1.0" with
localized streaks of 3.0"-5.0" wherever the heaviest convection
occurs.

[Chicago Storm]

I'm thinking about going down again, but I feel like the real supercell thread is too far west and I'm not driving 150 miles away for a heavy rain cluster.

Don’t waste your time today.


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[snowlover2]

Currently a couple of tornado warnings in west central IL.

[Chicago Storm]

Currently a couple of tornado warnings in west central IL.

Environment overall is terrible, but enhanced LL SRH associated with the MCV is enough to do it.


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