2024-05-25 EVENT: OK/KS/TX/MO/AR

[Jeff Duda]

Whoa...quite the rejection of hopes by the 00Z CAMs that go out 60 hours...







3 km NAM shows a pretty decent capping inversion at 00Z in SW OK, so that's probably the cause. The HREF-FV3 member also has that.

 

[Jason N]

Well , the SPC seems to like the area I was thinking about staging in with the 10% area , but are they buying into the CAM hype now ? .. this still could be a zeppelin event (oh the humanity!).. post sunset nocturnal fears CI rising ,lol.

 

[Matthew Crowther]

I don't think CAMs are very reliable that far out. Global models like the EC and GFS have some action around of just before 0Z, and the 06Z NAM nest has storms before dark. I am not giving up hope quite yet. I doubt there will be no storms at all before dark, even if we are only looking at the area up north of the surface low in NE. We will decide whether to stay out by this afternoon.

 

[Jason N]

While there is still plenty of time to resolve the microscale, still a lot of divergence in timing and bang/bust scenarios. So I think, keep the course. I plan to stay firm in my location, maybe adjust just slightly north, and west... Kiowa/Perryton/Medicine Lodge. I Still want a north shot, but it's going to come down to crunch decision @ 22/23Z. Are there juveniles trying to break through? or is it hard capped at Congestus. If I call an audible and move towards N-CNTRL KS to get in touch with the SFC low ejection, the moisture environment drops and it could be some mothership, maybe an isolated spin up, with DP's touching 60 and higher LCL's up there, but the hodo shapes IVO and above I-70 don't seem as favorable at 1-3, but are above 4-6 until after 01Z currently. SO!!!.... based on my proposed location, if I call it and roll north after 23Z +2hrs to get to 70 its dark and the day is a bust. - - should be interesting either way!

Think I am going to sit tight for now. got a whole bunch of time to see more stuff.

 

[Matthew Crowther]

More models are now getting with the program, if storms do form the hodographs at about 00Z are pretty insane. Remember there is light until almost 02Z. So we are staying out.

 

[Dan Robinson]

CAMs favor the southern target for the best overall tornado environment: a scary juxtaposition of parameters with extreme instability, 0-1km SRH in excess of 400 and the HRRR now has a storm exploding right before sunset. The downside is it's right over or in the OKC metro. The storms in Kansas have a linear look to them on the latest HRRR, with the better tornado parameters materializing after sunset. Oklahoma looks like the best play right now, but the non-storm factors (metro area on a Saturday) are a big concern.

 

[Brian McKibben]

More models are now getting with the program, if storms do form the hodographs at about 00Z are pretty insane. Remember there is light until almost 02Z. So we are staying out.

Yup... Civil twilight in OKC is 904pm tomorrow.

 

[Patrick K]

I still think the SPC’s 5/6 forecast discussion was wrong in a number of ways (not that it was categorically wrong), notably with the cloud cover, instability and stubbornness of the cap in OK. Storms struggled to get going within a forecasted very favorable environment. Part of this is the nature of translating a probabilistic forecast into a more deterministic discussion. It’s not like anything super obvious was missed, although I seem to recall Jeff being one of the few concerned early about lack of tornado potential.

Back to this setup - the 48-60hour CAMs are still consistent in sparse DL initiation. But behold, 12z HRRR, 06Z NAM3km, 12Z FV3 all show development somewhere from central OK to the Red River around 00Z Sunday. Still waiting on the 12Z WRFs. Almost comically, a few of these models are simultaneously showing very little action in KS near the surface low. Looks like a combo of cloud cover and moisture not quite in time may be responsible.

Several of the CAMs incidentally were capturing the rogue Altus supercell from last night on the far edge of SPC SLGT risk, just without capturing the locally favorable environment.

Also, the recent runs of GFS and Euro global models show similar in OK for 00Z Sunday, although the run-to-run consistency is not great (past two 06Z GFS like this scenario but not the other initializations).

 

[Brian McKibben]

CAMs favor the southern target for the best overall tornado environment: a scary juxtaposition of parameters with extreme instability, 0-1km SRH in excess of 400 and the HRRR now has a storm exploding right before sunset. The downside is it's right over or in the OKC metro. The storms in Kansas have a linear look to them on the latest HRRR, with the better tornado parameters materializing after sunset. Oklahoma looks like the best play right now, but the non-storm factors (metro area on a Saturday) are a big concern.

I am glad i haven't seen anyone on social media post that clickbait/fear fest run of the 06z HRRR. It has plenty of intense storms along the I-35 corridor. Looks to be forming on a higher theta-e axis near HWY 81 where the Tds are in the mid-70s vs the rather diffuse dryline of low 60s

Interestingly the MPAS 00z runs also started hinting at convection too. It has a sharper dryline and pops a storm along the DL bulge near hwy 81 corridor.

Further CAM models will be interesting to evaluate as we get closer to the event.

 

[Mike Smith]

Here is the latest Nadocast hot off the press.

Kansas is looking like tornado territory tomorrow late afternoon and night.

The 3km NAM has rapid pressure falls over KS. A 988 low is very deep for late May, if the model is correct (7p Saturday). Two hours later, the low (990) is over Greensburg. Any storms that develop in this region would be candidates to produce strong tornadoes. Td at Greensburg at 9p is 72°.

 

[Jason N]

Here is the latest Nadocast hot off the press.

Kansas is looking like tornado territory tomorrow late afternoon and night.

The 3km NAM has rapid pressure falls over KS. A 988 low is very deep for late May, if the model is correct (7p Saturday). Two hours later, the low (990) is over Greensburg. Any storms that develop in this region would be candidates to produce strong tornadoes. Td at Greensburg at 9p is 72°.

that's exactly what I have been focused on lol

 

[Patrick K]

I am glad i haven't seen anyone on social media post that clickbait/fear fest run of the 06z HRRR. It has plenty of intense storms along the I-35 corridor. Looks to be forming on a higher theta-e axis near HWY 81 where the Tds are in the mid-70s vs the rather diffuse dryline of low 60s

Interestingly the MPAS 00z runs also started hinting at convection too. It has a sharper dryline and pops a storm along the DL bulge near hwy 81 corridor.

Further CAM models will be interesting to evaluate as we get closer to the event.

Let’s not pretend like an OKC metro supercell amidst textbook hodos isn’t going to make it to Twitter.

By the way, 12Z WRF is not enthusiastic about the southern target area.

https://twitter.com/x/status/1793913510247924184

 

[Jeff Duda]

Interesting disagreement between the HRRR and the rest of the HREF models so far today. The HRRR is the only HREF member that convects in OK before 00Z (aside from a left split in the HRW-FV3 member that rockets over the Red River). It is also the only model that has little or no capping inversion. I would have thought capping inversions would be easier to forecast accurately at this range. Then again, the HRRR's tendency to overmix may be at work here, mixing out that cap.

It's also interesting to note that the the two 60-h MPAS runs that NSSL does that use the HRRR's initial conditions do have storms in OK by 00Z. But the same one that uses the RRFS initial conditions doesn't. Looks like we are right on the edge of a predictability bifurcation with this event -- one little bit on either side of this bifurcation is the difference between little/no storm coverage in OK and a fair bit of storm coverage.

 

[Brett Nickeson]

It is also the only model that has little or no capping inversion. I would have thought capping inversions would be easier to forecast accurately at this range. Then again, the HRRR's tendency to overmix may be at work here, mixing out that cap.

That's likely what it is. HRRR almost always overmixes and runs hot and dry at the surface, eliminating most CINH. Once you start getting into June-type environments (warmer, high CAPE, more prevalent EML) the HRRR doesn't quite perform as well and generally over-convects in those situations. That certainly doesn't mean it's necessarily wrong here (it's my favorite model for a reason), but it's a bias that needs to be taken into account as you get later in the year.

 

[Brian McKibben]

It appears the 700 mb shortwave is a little slower in the later runs of the ECMWF. This could be one of the reasons why we aren't seeing as much convection in the CAMs. The system slowed down.

Comparison of 12z (5/22) run vs the 12z (5/24) run. Check the 309 dam difference.