Quincy

Enhanced Risk issued for a small area in and around Oklahoma City. The more impactful storms (in terms of population impacted) may be - cluster of evening/overnight storms with large hail and damaging winds.

Models have also been trending toward less moisture return. HRRR had lower 60s dews reaching to I-40, while now it has CDS struggling to hold around 60F through CI time. Cloud-cover is finally moving out of the eastern panhandle/western Oklahoma region, at least. It looks like there might just be enough moisture in place by peak heating. Wind profiles stronger favor supercells, so as long as a robust updraft can form, it should go spinning into the night... or aleast for a few hours near/along the Red River.

It’s 1977 all over again

Was it really the cap, or more of a function of less boundary layer heating and poor low-level lapse rates? I know a cap is influenced by boundary layer heating, but the models were way off. 1-2C difference in lapse rates is huge. It’s not like they progged 13C at 800mb and it was 17C. When I think of too much cap, I think of orphan anvils and failed CI. We had plenty of CI today, but I’m guessing bad lapse rates and meager low-level cape led to less intense parcel acceleration. Updrafts weren’t necessarily as intense as many expected. Ever since that busted tornado outbreak “swarm” in Oklahoma, I’ve started taking LLLRs a lot more seriously. There is a strong correlation between higher end tornado episodes and LLLRs. Likewise, a lot of busts have junky low-level thermodynamics.

Storms in NE Oklahoma look weak so far. Lapse rates are still pretty awful.

I haven’t been too impressed by the HRRRv4 this season. Mixed results, but also some bad stuff, like today: It shows substantial 0-3km CAPE where mesoanalysis shows little to none.

Pretty ugly and satellite shows thick cloud deck, particularly across the Missouri side of the 10% hatched.

Just ran back three runs to 15z and HRRR was progging 6.5-7 C/km LLLRs where the 18z run at hour 1 has 5.5 C/km... Definitely trending down, but there still is some time.

As of 18z low-level lapse rates were anemic from far northeastern OK into southwestern MO. There still is some time to heat, so we’ll see...

This. Watch temperature trends closely. HRRR is not far off as of 15z, just 1-2F too cool in parts of central OK. However, it may only take an extra degree or two of heating to break the cap. That’s what we saw happen on 4/28.

Morning storms exiting NE Oklahoma are near an effective warm front. Elevated instability exists to the NE, while most surface-based instability is SW. Note that the 700mb thermal ridge is over western OK at the moment. As it shifts east, storms lift into/through Missouri and capping takes over. Morning storms have little to no impact on mid/late afternoon activity. Unless there’s some outflow boundary... Let’s say that scenario doesn’t reduce the severe threat.

Ran into some large hail producing elevated storms in north-central Kansas this morning.

I don’t really have too much to add. Looks like a one-two punch. Morning/early afternoon hailers from northeastern KS into MO, then watch the front/trough unzip by 21-23z from SW MO into OK. HRRR showed some steep low-level lapse rates, but 0-3km CAPEs may be limited with southwest extent. Biggest question in my mind is storm mode in Oklahoma. CAPE/shear will be there. Deep shear vectors probably favor mixed modes and a few supercells, but how long can storms stay discrete? We’ll see.

A quick and dirty comparison shows some similarities to 4/28 and almost in the same area. There might be slightly longer residence time for discrete storms this go around. Could have another SE to S moving tail end Charlie in the central Oklahoma vicinity. There’s also a signal for morning convective activity, a storm cluster or even an MCS dropping from northern Kansas toward the Ozarks. Wonder if that may shunt the front farther south and/or reintensify across Missouri. Currently wrapping up a chase in Nebraska. I’ll take a closer look in a couple of hours.

After tomorrow, the following seven days look very quiet and generally unfavorable for severe weather across the central states. NW flow can’t get it done this early in the season, as moisture return is usually anemic north of I-40. With that said, it is common for a lull in activity that in early May. We just had the most active April since 2011, so it was bound to quiet down eventually. It’s rare to have an extended period of consistently active severe weather during the first half of spring. Interestingly enough, 2011 has followed a similar tornado curve to this year. Recall that in 2011, after late April, the pattern basically shut down for two weeks. It wasn’t until mid to late May (roughly four relatively quiet weeks) that the pattern became active again.

About to fall asleep... but I’ll leave this here

More than ample instability and virtually no surface based convective inhibition across the western half of GA. It’s going to be a rough night. The warm front is roughly bisecting South Carolina east to west, FWIW.

Scooba got hit by a long track sig tor on 2/2/16...

Damage width SW of Soso is probably about one mile...

Unfortunately based on radar imagery and the amount of emergency responders, I’m sure there is. Once I saw damage and road blocks I got out of the way.

Tornado warned.

I’m guessing for a combination of continuity and the background environment... I am NOT saying this will be a total bust, but even when the Oklahoma high risk busted last May, they kept high even during the 01z update, which made almost no sense.

By the way, it’s been mentioned, but the convective line that produced QLCS tornadoes has been accelerating somewhat ahead of schedule. The HRRR depiction hasn’t been far off, but it’s been enough to lead to a messy evolution north of I-20. Aside from the southern target this afternoon, maybe this is mostly a late afternoon/evening event. Once the LLJ really cranks tonight, I think bad news is spelt for AL.

Today is a good example of why STP is not always helpful. Sure, it’s maxed out near the warm front, but lapse rates are sub-marginal. We had a high risk bust in Oklahoma last year that was largely due to junky lapse rates. 6 C/km is a good benchmark. 6.5 C/km is the mean for most tornado environments. I’m curious to see what happens down in LA/southern MS. Can the convection remain sustained? If so, does it evolve into a broken line? There’s good 0-3km CAPE, steeper lapse rates and strong low-level flow there.

If you want supercell tornadoes, steeper low-level lapse rates are preferred. If you have a QLCS moving into an area with marginal lapse rates, like we’ve had today (around 5-5.5 C/km), but substantial low-level shear, that’s different. If you dig back, I cited that 6-6.5 C/km lapse rates will get it done. If you look at mesoanalysis right now, that’s confined to southern MS/LA. They’re barely around 5 C/km along the warm front, which is where SPC has been highlighting an “enhanced” sig tor potential. As the warm front lifts, you should see lapse rates improve a bit, mainly down near I-20, not up near the TN border.