WhiteoutWX

Definitely looks like multiple days of potential middle to end of next week. Mid to upper flow is relatively weak but adequate for some slow moving supercell potential. GFS lights up the dry line each day. It’s been a slow start in the plains but that looks to be changing quickly.

I guess technically there was severe weather in portions of the previous outlined area. I just question the utility of the CPC putting out such a graphic when the area is huge and the time period is a week long. I mean yeah there’s likely gonna be some severe weather somewhere in the plains any given week in May. That’s just climo. A more useful forecast would be above or below normal chances for it IMO.

Ensembles definitely showing a relaxation of eastern US troughing towards and beyond day 10. Light at the end of the tunnel perhaps.

Yes I think that was the failure today. Great low-level lapse rate really seem to make up for a lot of other deficiencies, and conversely seem to break a lot of setups that should produce. It doesn't take a lot of spin down low when you've got intense stretching ability.

Storms firing northeast of Norman.

12z CAMs seem to be extremely consistent with their respective 00z runs, CI/placement wise. Maybe a very slight nudge eastward with the westward edge of the CI. Going to be close for OKC metro but consensus suggests the front will be fast enough to push through before significant CI. Although the two events aren't the exact same, may be worth noting that CI occurred a little further west and was more widespread than CAMs suggested on 04/28. With stronger capping today though, I'd be more inclined to agree with the CAMs and say this should be mostly confined to east of I-35, south of I-44.

Main differences between today and the 04/28 event last week appear to be slightly better low-level shear today with winds staying a bit more backed ahead of the dryline/cold front, but also a stronger cap and less synoptic scale lift as the upper wave is further removed to the north. Also, the boundary-relative cloud layer flow is a bit more parallel to the boundary today so storms *may* try to go upscale a bit more than last week, although the stronger cap could work to counter that. Overall I'd say tornado potential is slightly higher today owing to the better shear, but very conditional given capping, weaker low-level CAPE, questions on storm mode.

Two sentences before the bolded it clearly says medium to long range which is what I was referring to. Regardless, I hardly think that one localized event which was focused east of I-35 and outside of decent chase terrain disqualified the broader point I was making that the overall pattern has been and looks to remain for the foreseeable future extremely poor for the plains states as far as a tornado/chase standpoint. So I’m not really sure what your point is here but I stand by what I said. When and if the pattern changes and starts to look better I’ll be right there with everyone else getting excited but until that happens I’m just telling it like it is, the fact being it’s been a very slow season for anywhere outside the gulf coast states.

I don’t want to keep posting the same thing over and over and be super pessimistic but I’m really struggling to find anything encouraging in the long range that suggests a pattern change. The western ridge/eastern trough just keeps reloading again and again. As we go deeper into May you don’t need perfect setups to achieve severe events but still, the long wave pattern is leaving little room for even smaller events.

I’m taking the under on that forecast

Big TOR near Dougherty

Looking at the mesonet these storms appear to be initiating west of the wind shift, as Medicine Park has light westerly winds currently. The wind shift is going to need to slow or the winds will need to somehow back ahead of these storms otherwise the low level wind fields are a problem.

Lawton to Paul's Valley is the zone to watch ahead of that storm near the boundary. Boundary appears to still be edging southward, and does not appear to be much potential for modification on the north side of the boundary with clouds socked in. If storms cross the boundary the tornado threat is probably very low.

Some pretty potent soundings on the 18z HRRR along the I-35 corridor tomorrow, all the way up to the triple point which comes pretty close to OKC metro. Great low level lapse rates, low LCLs, plenty of shear, critical angles near 90 degrees. Not much more you could look for on a sounding really.

SPC going with a Day 2 ENH now for SE OK and E TX into AR and LA. Even a small 10% Hatched Tornado risk ahead of the dryline. As mentioned in their discussion, a lot of uncertainty remains regarding capping and potential early day convection, but wind fields look impressive enough if we can get some discrete cells along the dryline in the afternoon.

Put this in the wrong thread earlier: Deterministic and ensemble guidance are all in relative agreement in this pattern persisting in the mid to extended range, with a trough over the east and ridge over the west. Even occasional hints of transient high-latitude ridging over the NAO domain which suggests this pattern may be slow to budge. I think it's pretty safe to say April is probably toast at this point for anyone outside the Gulf Coast states as far as tornadoes are concerned. May is still 10+ days away so we'll see how things evolve, but no real sign of a change to a more favorable plains tornado pattern for the foreseeable future. That being said... looking in closer range. Tomorrow evening offers some localized tornado risk for portions of the TX Panhandle into western and southern Oklahoma as the warm front lifts northward. If sufficient moisture can return for surface based convection, deep and low level shear is favorable along this corridor for at least a tornado or two.

Eventually climo will win out as we get into May. But for now it seems any sign of a pattern change is far enough in the extended I’m just in wait and see mode.

The GFS is a dirty liar.

Looks like another incredibly slow start to the season here in Oklahoma, after very slow starts in 2018 and 2019 as well. We've had 5 tornadoes so far this year, with 3 back in January and 2 in March. Extended range guidance suggests it not at all out of the realm of possibility we get to May without any additional tornadoes. For comparison, 2019 had 2 tornadoes in April until a big day on 04/30/2019, while 2018 made it all the way to May without a single tornado on the year. 2019 ended up being a record year for number of tornadoes while 2018 was fairly slow, so there's not much you can say at this point on whether the pattern will flip to a more active than normal May. While the severe enthusiast in me is disappointed at another slow start, it's good mother nature could cooperate at least for our EM's across the state who are already overloaded with COVID-19 related tasks.

Well looking back I'd say it's hard for me to claim a "correct" forecast out of this, but some of the event did play out as I expected. My biggest mistake was underestimating the strength of some of the QLCS tornadoes, as it appears we had multiple EF3 spinups from the event. However, it did appear that the strong forcing and shear profiles likely both contributed to very messy storm modes for the vast majority of storms, which may have prevented an even more widespread/higher end event. Another potential limiting factor may have been weak low-level lapse rates, especially across northern half to 2/3rds of the risk area. Still, the intense low-level shear was enough in this case to produce dozens of tornado reports. The two supercells that were able to stay discrete and attain some deviant easterly motion produced the most intense tornadic signatures, with the Bassfield, MS prelim rating coming in at EF4 and the trailing storm EF3. I thought it was also interesting to note that if you look at the SPC reports you can see three clear "swaths" of tornado reports, one with the supercells in southern MS and another tracking through northern LA/MS/AL/GA and into SC associated with a mixed mode QLCS. A third cluster appears along the SC/NC coasts from yesterday morning, also mostly from QLCS. The vast majority of reports for the event came from these three main swaths. Fascinating event for sure and a learning experience for myself. My heart goes out to all the communities impacted.

I was just trying to point out some potential fail modes that I hadn’t seen mentioned and giving my opinion on what might play out. May 20 of last year was higher end on both shear and instability and barely any strong tornadoes occurred. I’m not saying a high end event is impossible here, just that there are definitely factors in play that could derail the event. I don’t pretend to know all the answers though. No one does.

Im not assuming anything just my interpretation of the data I’m seeing and my own personal forecast. We’ve seen events with much better parameters produce much less than what you are describing. Plenty of events that are hyped days out end up being messy and lacking many strong tornadoes. I could be wrong that’s just my interpretation though.

I think this setup has some potential, but the strong forcing will likely mean a lot of storms. Hodographs are decent in spots but the VBV signature is there in many of them and critical angles are not very ideal. I think you will see a lot of storms struggling to maintain discrete modes. I would bet on a ton of wind and hail reports with mostly weak/brief tornadoes. If we can get some discrete supercells with some deviant easterly motion there could be a strong tornado or two but I am just not seeing large widespread tornado outbreak out of this setup.

I'm still not entirely sure how much weight to give the CFS dashboard...but I know last year we went the whole season without it looking anywhere close to as active as some of the recent runs have for later in the month, so I guess that's encouraging.

Yeah seems pretty clear the pattern will be unsupportive of much severe in the plains for at least the next 10 days. After that, like you said, models begin to diverge on whether we can get some western US troughing or continue with more of the same.