May 7th-9th Severe Weather Episodes

[weatherextreme]

This is some of the more intense motion I've seen in a CO tornado. Certainly was no landspout.

 

https://twitter.com/tornadotrackers/status/729114954247249920

 

 

They posted another video from the same tornado 

 

 

 

[andyhb]

So the 00z BRO and CRP soundings have 65˚ and 64˚ Tds respectively. Going to need some serious help for tomorrow.

[andyhb]

Less impressive wind profiles at 00z on the 00z NAM. So now we have downtrending shear and overdone moisture.

[jojo762]

00z RAP already shows widespread 65 DPs in OK at 18Z lol... Evapotranspiration may be playing a role given all the recent heavy rains... Anyways why would a, lets say, 63 degree DP be such a limiting factor to the potential sig tor threat? 

[Jim Martin]

Setup was not that great today either. Seems like some in here want a perfect setup all the time. Does not always happen that way.

[jojo762]

Less impressive wind profiles at 00z on the 00z NAM. So now we have downtrending shear and overdone moisture.

On the wind profile... only by a bit. Just gonna have to disregard the moisture on all the models I guess as being wrong by a bit.

[brettjrob]

So the 00z BRO and CRP soundings have 65˚ and 64˚ Tds respectively. Going to need some serious help for tomorrow.

 

Comparing the 6 h forecast from the 18z GFS and NAM to sfc obs over TX at 7pm CDT made me cringe. Watching the 00z NAM roll in, it initialized much closer to reality than the previous 6 h forecast. The new 24 h moisture forecast for OK/KS is of course less bullish, but not devastatingly so. There was always going to be an adjustment from the 67-69 F forecasts as we approached verification time; now we just have to hope it's not too steep a fall.

 

SBLCLs at 00z Mon along the dryline are still very manageable on the NAM, with even a bit more headroom for increase on subsequent runs before we have real problems. On the other hand, it now shows no convection whatsoever along the dryline, even in S KS. The lack of QPF on the NAM isn't a huge deal in itself, given the poor performance of its convective scheme along sharp drylines. But point soundings show a really ominous capping inversion around H85, which I'm increasingly worried about.

 

If nothing else, I think the more northward placement of the MDT risk issued today may prove to have been prescient. I'm increasingly skeptical of multiple storms down the dryline in OK, though it's certainly not out of the question. The HRRRx is honing in on KS the past several runs, as well. We aren't really getting a break from the very challenging forecasts of last week's events, because the moisture return tomorrow has major implications on both the tornado threat and storm coverage.

[jojo762]

4K NAM environment in KS at 00Z is pure weather porn. A 66 dewpoint is not very likely in this area, but the wind profile is just something else, probably wrong to an extent on the strength though.

[Chinook]

Less impressive wind profiles at 00z on the 00z NAM. So now we have downtrending shear and overdone moisture.

To contrast that statement, the NAM/GFS (in general) have strong wind fields on Monday. The 00z NAM has an area of over 500 m2/s2 of 3km SRH in Arkansas. Even though this isn't normal chaser-territory, this could be a signal for some more severe reports (of all types) Monday.

[jojo762]

00z RAOB at AMA shows some pretty insane lapse rates. 10.0C/KM 0-3KM Lapse Rate, whereas the SPC mesoanalysis page currently shows AMA at ~7.0C/KM... Same goes for 700-500mb layer being off by a bit... These lapse rates will be completely untouched-- due to the absence of overnight/morning convection and be allowed to advect into the warm sector tomorrow, should help instability quite a bit, among other things...  Should also make for some prolific hail producers. 

[JasonOH]

Looking at the lapse rate source regions, we may do better than the nam is showing lapse rate wise, which would be a huge help.

[bjc3395]

At the same time the temperatures at the base of that EML are going to be pretty warm.

[andyhb]

At the same time the temperatures at the base of that EML are going to be pretty warm.

 

Yeah, which with moisture likely underperforming certainly increases the chances of a blue sky bust. Might help in KS though.

[weatherextreme]

Here's a longer version of the previous video I posted  (From Reed Timmer)

 

 

 

 

[Chicago Storm]

00z RAOB at AMA shows some pretty insane lapse rates. 10.0C/KM 0-3KM Lapse Rate, whereas the SPC mesoanalysis page currently shows AMA at ~7.0C/KM... Same goes for 700-500mb layer being off by a bit... These lapse rates will be completely untouched-- due to the absence of overnight/morning convection and be allowed to advect into the warm sector tomorrow, should help instability quite a bit, among other things... Should also make for some prolific hail producers.

Not that it will affect the flow of lapse rates into the area, but there likely will likely be some sort of morning/day convection across portions of TX/OK/KS. Most of that should be along/east of I-35 by 18z though.

[OUGrad05]

Here's a longer version of the previous video I posted  (From Reed Timmer)

 

 

 

 

Awesome video...

I'm still thinking Monday is going to be the better day for the southern plains.  While tomorrow holds potential I'm simply not sold on the moisture return.  

[Quixotic1]

Here's a longer version of the previous video I posted (From Reed Timmer)

https://www.youtube.com/watch?v=bjb7QtMEBUg&feature=youtu.be

Phenomenal.

[andyhb]

At the same time the temperatures at the base of that EML are going to be pretty warm.

 

I should also mention that if tomorrow dies out further south, that might play right into the hands of Monday's setup since tomorrow's convection is one of the lead caveats for that.

[OUGrad05]

00Z NAM runs hold the cap strong in OKC...

[bjc3395]

00Z NAM runs hold the cap strong in OKC...

Not too surprising given observed AMA obs and expected dews

[andyhb]

21z SREF is hitting Monday harder than tomorrow. Three straight frames of 60 on the STI plots from 21z to 03z (still 51-57 hrs out).

 

Makes sense given an extra day of moisture return and more likelihood of convective initiation assuming tomorrow's stuff that fires further SW doesn't foul things up.

[Ian]

You have to live there, spend all spring trying each of the 15-25 days that look similarly mediocre/flawed, or hit the lottery. Head out there the next day that looks qualitatively similar to today, perhaps with a few ingredients stacking up a bit better, and you'll be treated to the most outflow-dominant garbage this side of the Mississippi. It's the most frustrating thing.

Colorado is the worst.

[Chinook]

I just watched the local news. They said that a RV campground was hit by a tornado in Morgan or Weld County (Empire Reservoir, next to Wiggins/ US-34). Several RVs/motorhomes were flipped or tossed into the lake by a tornado. They said no one was injured there, (minor injuries?) because people weren't in their RVs. They mentioned injuries in the Wray area from the tornado(es).

 

local news stories

 

http://www.9news.com/weather/tornado-topples-trailers-in-wiggins/179318240

 

http://www.9news.com/weather/structures-damaged-by-wray-tornado/179505518

[Msalgado]

I'm far more skeptical of tomorrow now than I was earlier today.  Just took a couple of random soundings at 21z from near Lawton, and it looks like CI will be a lot tougher than was forecast even earlier today.  Convective temps at the 12z run where 80F, while at 0z it was up to 87F.  

 

The cap does look to break down further north, but that's probably not within a range I can realistically make it to.  I'm gonna look things over in the morning, but right now that cap is looking rather stout.

[KSWx]

In light of all of the issues we were concerned with earlier likely coming to fruition, I'm wondering if they may change the Mod to Enhanced with the 06z outlook.

[KSWx]

I just watched the local news. They said that a RV campground was hit by a tornado in Morgan or Weld County (Empire Reservoir, next to Wiggins/ US-34). Several RVs/motorhomes were flipped or tossed into the lake by a tornado. They said no one was injured there, (minor injuries?) because people weren't in their RVs. They mentioned injuries in the Wray area from the tornado(es).

 

local news stories

 

http://www.9news.com/weather/tornado-topples-trailers-in-wiggins/179318240

 

http://www.9news.com/weather/structures-damaged-by-wray-tornado/179505518

 

Good news when you consider how that could have ended. Wonder if they weren't in their RVs because they were following tornado precautions or if they weren't there by happenstance.

[jojo762]

00Z WRF-NSSL, WRF-NMMB, and WRF-ARW still all point to at least one to a few discrete tornadic supercells tomorrow afternoon/evening. Models seem to like NW OK/ SC KS more than areas south... Looks like the current MDT risk is probably about right for now.

[andyhb]

In light of all of the issues we were concerned with earlier likely coming to fruition, I'm wondering if they may change the Mod to Enhanced with the 06z outlook.

 

I'm thinking they might shift it north into KS further.

[brettjrob]

A cursory glance at 00z CAM guidance really highlights the capping concerns with southward extent. There is a strong UH signal among runs near and N of the OK-KS border, but far less of a signal as you approach and get south of I-40. Forecast soundings in OK confirm a substantial capping inversion that will require impressive heating and/or moistening to overcome, if it verifies.

At the same time, a very impressive jet streak is set to transect the dryline in W OK, and the large-scale forcing is no slouch. What a forecasting challenge. I recall seeing a lot of these scenarios back in 2007-08, but not as many in recent years. Dates that come to mind include: 4 May 2007, 5 May 2007, 1 May 2008, 23 May 2008. All of those except 1 May were generally more impressive (read: major outbreak) scenarios with more established moisture, but there were serious questions about capping along the OK portion of the dryline. The CAM guidance at the time, obviously more primitive than what we have now, largely failed to highlight the OK threat that actually materialized. Even 19 May 2013 might be another example where storm coverage, at least, was underestimated down the dryline by CAMs the night prior. Perhaps someone else can recall in more detail.

Speaking strictly for myself, then, I'm not very well calibrated on how much to trust CI failure down the dryline in a relatively dynamic situation like this from present-day CAMs. Back in the late 2000s, I would've been extremely skeptical, based on the examples I listed. So often, that one last storm to punch through a moderate cap slightly south of the expected cutoff ends up being otherworldly (Arnett 5/4/07, Sweetwater 5/5/07, Osage Co. and Norman-Del City 5/1/08, and then debatably Cherokee 4/14/12 and Shawnee 5/19/13 which had mixed model support).

So SW KS is likely going to be the surer bet, but it's a scenario where any chaser or forecaster would be foolish not to recognize the conditional high-end potential in W OK. With moisture return being such a question, the OK scenario holds even more appeal than it otherwise might. Lots of chaser stomachs in knots tomorrow morning, especially those of us trying to avenge CO today.

 

And right on cue, the HRRRx stopped running after 23z today.

[jojo762]

I'm thinking they might shift it north into KS further.

yeah me too. Generally the most recent model trends have been to... 1. Maintain the conditionally significant environment across W/C OK, 2. make the environmental conditions in SW/SC KS more favorable for severe storms including tornadoes, and 3. show CI occurring mainly in KS, and possibly south into OK... If any CI were to occur in OK, and maintain itself, I'd really hate to be in front of that storm. Really a boom or bust in OK. If the S/W can eject at a "good" time, might get some nasty sups in OK.

Edit: On a random side note, I really wish someone would fix the equipment at KRCE showing the erroneous Dewpoint values. It's been doing it for years... Also moisture is progressing about as expected thus far across TX.