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

[Mikayla Norris]

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.

Not just the metro area on a Saturday, but the metro area on a Saturday on a holiday weekend! I'm planning to chase, but I'm pretty nervous about the chaser convergence. Especially after all the convergence I saw yesterday afternoon around Eldorado, and we were hours from the metro.

 

[Andy Wehrle]

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.

Great insight from the most knowledgeable poster on here about how CAMs actually work. Thanks, Jeff!

 

[Jason N]

Not just the metro area on a Saturday, but the metro area on a Saturday on a holiday weekend! I'm planning to chase, but I'm pretty nervous about the chaser convergence. Especially after all the convergence I saw yesterday afternoon around Eldorado, and we were hours from the metro.

It could be substantial, if coverage is limited ..and if the okc thing happens .. I'm not even getting close to it no matter what. I'm sticking to my previous post locations

 

[Brian McKibben]

My target for tomorrow is Choctaw OK. Not by choice. Coaching kids baseball in the afternoon. Gonna spend my evening plotting potential escape routes in case things get dicey, but should be out of there well before something closes in.

For any new or inexperienced chasers... a bit of advice.

If possible you want a 4 person chase crew.
1. Driver
Only does driving (unless pulled off road to watch storm). Focus on the road and anticipate bad drivers.
2. Navigator
Plans routes and escapes so driver can focus
3. Guy that watches the storm and gives updates on rotation/funnels/wall clouds/tornadoes.
4. Person that is checking radar and providing updates via social media to NWS if possible.

Stay safe guys. There will 100% be a hoard of chasers tomorrow. Don't get caught in the notch with no escape. Plan for chaos.

 

[Brett Nickeson]

Still clear as mud. Entirely depends on the actual moisture return, especially for southern KS. Some impressive CINH numbers on a few of the models, even the ones that are convecting. I guess just drive somewhere within a 200 miles radius of El Reno and hope for the best.

 

[Mikayla Norris]

Still clear as mud. Entirely depends on the actual moisture return, especially for southern KS. Some impressive CINH numbers on a few of the models, even the ones that are convecting. I guess just drive somewhere within a 200 miles radius of El Reno and hope for the best.

Yeah that's about all I'm coming up with as far as a target too. I like to have some idea before going to bed ahead of high potential days, otherwise my brain won't shut off. Hopefully in the morning there will be some more clarity.

 

[Matthew Crowther]

Well, the models giveth and the models taketh away, Back to a very late show mainly in OK and TX. The northern half of SPC's high tornado risk is in trouble, with moisture return being the biggest issue. Since we are winding down this part of the chase season and will be heading back to Atlanta, I am currently leaning towards TX, I want to avoid OK on Memorial Day weekend if possible. 12Z runs will help me make the final call.

 

[Brett Nickeson]

Moisture returns are literally three to four hours late of optimal in southern Kansas. Didn't think we'd be having these problems in late May but here we are. Southern OK might steal the show.

 

[Andy Wehrle]

Was just typing when Brett posted that it does seem surprising to have JIT moisture be an issue this late in May given the lack of Gulf-scouring cold intrusions. We've had a number of cool springs recently where a cutoff parks over the Ohio Valley and just drives Canadian air into the central US for two weeks on end. This May has been pleasant to warm. What is happening to restrict the moisture with this setup?

 

[Patrick K]

Moisture return to KS sucks (technical term) with 60s dewpoints barely reaching the OK/KS border by 22z. That's a shame, especially with nearly 80F dewpoints near DFW by the same time, bolstering some insane CAPE numbers there. SPC has been aggressively revising their MDT and ENH southward with ENH now as far south as KDYX. Presumably this is reflecting both the recent CAM and global guidance which has now been consistent in blowing up storms near the Red River.

 

[Brett Nickeson]

Can someone smarter than me describe why there's that pocket of dry air in NW OK that lags so far behind the moisture advection just to the east? Can't find a reason for it.

 

[Matthew Crowther]

12Z HRR shows messy evolution in OK and TX, but a nice evening supercell in far southern KS. but moisture up there is just OK. Decisions, decisions.

 

[Dave C]

Moisture return to KS sucks (technical term) with 60s dewpoints barely reaching the OK/KS border by 22z. That's a shame, especially with nearly 80F dewpoints near DFW by the same time, bolstering some insane CAPE numbers there. SPC has been aggressively revising their MDT and ENH southward with ENH now as far south as KDYX. Presumably this is reflecting both the recent CAM and global guidance which has now been consistent in blowing up storms near the Red River.

Agree. No southerlies to pull moisture rapidly are evident now, and 3 hour DP change is nil. I'd say KS gains maybe +5-10 max by 7PM based on what I see right now. I'd love to chase around Protection KS area vs. OK if latest to HRRR runs are any good, but not any further south as the border area roads suck. OK is too far for me today but for anyone out I would seriously be considering TX and SW OK and then leave room to come back north later.

I am getting frustrated seeing a lot of people posting run max helicity tracks of CAMs a day before, or making decisions on one run of CAMs. Seems like a lot of people are CAM crazy and ignores surface observations or satellite, or don't even bother to check multiple CAMs.

EDIT: There are now agreements with NAM 3k and HRRR on a far southern KS/OK border possibility at sunset or dusk.

I'll continue watching to see if RAP hourly mesoanalysis will uptick DP change, or any stations report a wind shift. The moisture just doesn't look like it will make it north until too late. Everything I am seeing still showing a risk for a dusk and after event in the northern part of the risk area. Of course, this year many days have performed better than expected and I cannot logically justify that against any models.

 

[Dave C]

12Z HRR shows messy evolution in OK and TX, but a nice evening supercell in far southern KS. but moisture up there is just OK. Decisions, decisions.

I don't think I am any smarter but the advection on models shows mixing out in that area to my eyes, or just lack of current moisture and nothing to move it into the area. Some models show strong southerlies later in the day which have yet to begin to materialize in surface observation. Right now models say we should have 15 knots easterly or NNE, and observations show many staions at 5 knots or zero. I'd like it better if a couple models match surface obs. at their closest valid hour.

If you animate models, you can see where moisture is currently positioned and which wind fields are going to move it by what vectors throughout the day. That wind field just produces a shape where the moisture doesn't make it up to NW OK or SW KS.

 

[Dan Robinson]

The first thing I did upon waking up was look at the surface chart - I said holy cow, the moisture's way down there aT 9am - how is this day going to happen? In addition to the moisture issues in Kansas, the main upper support looks to stay south. I'm concerned about more HP tendencies in the northern area even if we can break 65F Td's up there. I like the south of the Red River area for the best storm, but I really don't like chasing down in that area.