andyhb

It's convectively contaminated.

GFS (0z) a step in the right direction.

Euro is where it's at. GFS *potentially* trending that direction.

Eh, this run of the Euro wasn't so favorable. Trough gets more blocked in the west and the waves tend to shear out as they eject eastward. Need the larger scale trough to make it further east on its initial amplification.

Last four runs of the Euro (and three runs of the EPS) suggest a more progressive pattern in the mid range than the GFS/GEFS with that large upper trough amplifying in the W later this upcoming week then ejecting eastward (or at least pieces of it) by 5/22-5/24 and really amplifying the flow fields across the Plains. Might be quite the start to many chasecations (including possibly mine) if it turns out to be more on the right track. Would like to see more multi-model consensus on this less blocked idea though.

Seems like most of the models aside from the GFS want to eject a lead southern stream wave that basically screws the setup by stealing away the LLJ from the second trough (i.e. Monday's system) and shunts moisture southward.

Departing Friday morning and probably chasing northeast/eastern NM on Saturday then some better days to follow across the plains. We'll see how the models shake out 

12z GFS is basically suggesting a potential outbreak over a large area of the central/S Plains on Monday. Thing that really gets my attention is how broad the LLJ axis is, with 40-50 kt H85 flow covering much of OK, KS and N TX ahead of the dryline. The low amplitude nature of the shortwave trough was another red flag. Looked at some soundings basically from I-20 north to I-70 and my eyes just about popped out of my head.

Euro isn't as enthused, showing a more disjointed trough ejection with weaker wind fields overall, but still plenty of CAPE. Finding it interesting that 5/9 produces majorly (anniversary of last year's CO, KS and Cisco tornadoes) and now 5/16 may try to do it as well (Elmer).

An ugly pattern coming up for the next week. Even next week's trough ejection may be muddled by continued troughing in the eastern U.S. It's not all that common for a lull in severe weather to start May, but still...

While it could obviously screw things up like the wind fields, I'm less inclined to believe it portends a lack of moisture return, especially into the High Plains. We've reached the time of year now where any sliver of the Gulf open to poleward advection for at least a day means there likely will be sufficient BL moisture. If this was March, obviously it would be an exercise in futility.

50 kt LLJ over ICT on the 00z Euro at 00z Wed, shear seems to be ramping up here in the last runs.

Not to mention there's already 2000-3000 J/kg SBCAPE at 12z Tuesday across a significant portion of OK and KS.

There's really nowhere to go but down from this GFS run for next week. The four-day stretch from Tue-Fri would probably rival a lot of great historical stretches in May/June, and be virtually unprecedented in April for the Plains in modern history.

 

Emphasis on "nowhere to go but down." It's not a matter of whether we fall, but how far.

I'd argue that the 12z Euro was more impressive than this GFS run (stronger LLJ, stronger flow overlapping the dryline, etc.)

Maybe not quite as strong in terms of buoyancy, but still easily >3000 J/kg pooled up against the boundary. The upper jet orientation with this is classic as it looks right now, there's really no meridional concerns with the low amplitude nature of the low latitude ridging out ahead.

ah okay, didn't know. Not really well versed in model-tendencies. So that ridiculous cap doesn't really exist. Thanks!

There's probably a moderate cap in place until initiation, which is exactly what you need to get supercells vs. a big linear mess.

Yeah. This 00Z run of the GFS is the best one yet as far as the parameterized environment goes--pretty insane across the board with everything, nuts to see widespread 6+ 0-1KM EHI's, and widespread 500+ 0-3K SRH. Still feel the trough is a bit too slow tho, and there is a pretty substantial amount of CIN. It's funny because last year, we could hardly get any events with an EML to hold things off, then this year on the first possible big event, we get a big time cap. But feel free to correct me if I'm wrong on those.

That low level inversion is not realistic (happens time and time again with the GFS), and it's likely cooling the boundary layer too fast.

So if you get rid of that unrealistic decoupling of the boundary layer like the GFS always does at 00z, not much else to say but holy smokes. Depth of the BL moisture could be a bit better on the OK sounding, but man those wind profiles are basically textbook.

How's the euro look compared to the GFS?

Looks pretty favorable as well, although it was further south for Tuesday last night (closer to the Red River Valley).

Take this with a grain of salt, but...

Popping 6/24/03, 5/3/99 and 4/26/91 in SARS on the same sounding? Not bad.

Tuesday next week is looking like a pretty legit threat at this point for somewhere in the Plains. Seeing some pretty top-tier instability/moisture values for late April, which makes sense with that lead shortwave this weekend assisting with poleward moisture transport.

Oddly, it's falling directly on the 25th anniversary of 4/26/91.

The 12z EPS looked pretty substantial to me, especially in the 7-10 day period, as did the 12z Euro op. The trough at 192-216 hrs would likely have a more significant potential since that lead wave helps advect mid 60s dews into the Plains (sacrificial lamb more or less). Then there's also that fact that it looks to reload right behind that.

Well that's an interesting #1 analog (some other big periods there too especially in the Plains)...

Things seem to be shaping up for a more favorable look later next week into the following one with multi-model/ensemble consensus of a western trough (and currently a rather progressive regime) setting up shop. Would have to think there would be one or more setups in the Plains if that ends up coming to pass, perhaps even on the more robust end assuming seasonable moisture return (which doesn't look to be out of the question). Not a huge fan of the Hudson Bay troughing that persists, but otherwise things are certainly looking more active for the tail-end of April.

*sigh*

Not sure I've ever seen a signal this strong from the CFSv2 SCP chart for 3 days in a row...especially this early in the season.

Pulled a sounding off the 12z Euro at SGF at 180s and it was pretty incredible. Very steep mid level lapse rates (SBCAPE near 2000 J/kg) with SRH in excess of 650 m²/s² and just a huge sickle shaped hodograph. Hopefully we get some more agreement among guidance for this period in the coming days, because it looks like it could shape up to be a more significant event assuming even rather marginal moisture return (given the impressive thermodynamics aloft).

Figured I'd bump this to let everyone know that the gaps in the ABC 33/40 coverage (on John Brown's Youtube page) of this event are going be filled in over the coming days since Bill Castle found it. The morning coverage (of the intense QLCS that swept through the state) between 3:30 and 6:00 AM is already uploaded.

https://www.youtube.com/watch?v=SGqjHgLzibY

https://www.youtube.com/watch?v=aZ9S0rFhRHw

Euro + EPS + Euro parallel (and the UK now that it has gotten in range) have been consistently hitting this potential for several days now. A lead shortwave trough ejection and strong lee cyclogenesis looks to occur March 7th (Monday) leading to a strong southerly LLJ of 40-50+ kts encouraging BL dewpoints to rise into the lower 60s across OK and KS ahead of a very sharp dryline. While this moisture may seem rather meager, keep in mind we're also looking at EML-assisted mid level lapse rates of 7.5-8+ C/km with this event, so that should be enough for moderate destabilization assuming some decent insolation (may need to watch for moisture mixing if it turns out to not be overly deep). This will also lead to a rapidly moistening BL further south for the next day.

On day 2, the primary upper impulse looks to eject towards the Rio Grande Valley as the low level jet strengthens in excess of 55 kts across E TX, the Arklatex and LA. While the flow does appear to be a bit meridional, there is certainly enough of an upper level jet component ejecting ahead of the trough to encourage storm development out ahead within a potentially very unstable warm sector (strong low level shear as well with backed SSE/SE surface winds underneath the aforementioned LLJ). If this setup turned out to be just a bit less amplified and/or meridional, we'd be talking some serious potential given the amount of instability that looks like it could be present (still think there is quite a bit of potential how it sits now). We'll see what happens as it is still a week out.

Definitely looks like the first more significant threat may be on the way with more possible afterwards given GWO progression through at least phases 8-1 and a shift towards a +EPO (Gulf of Alaska trough) through the first two weeks of March. CFSv2 chiclet chart has been lighting up March for the better part of a month now, so this definitely seems to have some legs. Quite a contrast to the past 3 Marches.

If I were a chaser/living in OK/KS/N TX, I'd be keeping an eye on next Monday with the Euro's idea of a strong lee cyclone developing in response to that negatively tilted shortwave trough ejection. Healthy EML overspreads the dryline leading to a pretty wide axis of moderate destabilization along with great directional shear in the lowest 3 km (12z run via 180 hrs).

https://twitter.com/antmasiello/status/698172872704028672

Brilliant,   

Bug report: I think the SCP algorithm on the site needs a tweak.

Then it comes down to what character the trough ejection assumes, and whether it will be sheared out if the ridge amplifies too much ahead of it, or whether it amplifies too much and becomes too meridional.

This looks to be what most recent guidance has suggested.