brettjrob

It's hard not to feel sick, watching a trough reminiscent of 28 March 2007 amble into the Four Corners and probably lack in high-end severe potential. This blocky pattern is beyond maddening. On the other hand, the blockiness could ultimately be worth it if 2-4" of rain fall over much of the southern Plains over a 3-day period, which looks quite possible. Assuming a real pattern shift in our favor is somewhere up the pipeline, that could have a significant impact on future setups. I will say that I'm not too concerned about current progs beyond D+10 that look unpleasant. With meandering cutoff lows the rule over the next 7-10 days, predictability is simply piss poor. There's no denying that we've been kicked in the you-know-what yet again with an exceptionally awful start to the Plains season. Yet another year of hearing murmurs from veteran chasers about their latest first chase to-date -- the new normal, it seems. There's no upside to that at all, in my view. But at the same time, it's still early enough that if things turn around in the next 2-3 weeks and May/June are rockin', it won't matter very much. If we're still having this kind of discussion on April 30 with abysmal medium range progs, that will be a far different story.

That's for damn sure. Was just commenting on this earlier. After 2013-2015, anything besides full-fledged winter east of the Rockies feels like a godsend. I'm not even worried about whether this upcoming system is a big severe weather producer - just moisture, rain, warmth, and a continued favorable pattern will suffice. Sunday or Monday may at least offer the customary first surface-based supercells on the Plains to kick the season off, as things stand.

Between the analogs and medium-long range guidance, it looks like potentially another season with southern stream disturbances undercutting broad ridging at higher latitudes (not exactly newsworthy coming out of a strong Nino). That happened a lot last year, too. 1987 and 2007 don't look all that different from each other in terms of mean springtime height anomalies, illustrating how relatively unpredictable details can make such a difference in the severe weather season.

Medium range guidance is optimistic about shifting to a mean western trough around next weekend into the following week. That should at the very least mean rain chances on the Plains and a lack of Gulf-wiping fronts, if not some severe weather opportunities.

Trend over the past 24 h since your post has been toward focusing the most interesting period on Monday over OK/TX, before the system becomes more barotropic thereafter. Right now it looks a bit too positive-tilt to get me excited about the hodo shape (particularly given that instability is likely to be seasonably modest), but it's nice to see the above-average November severe activity continue. http://www.pivotalweather.com/model.php?m=GFS&p=03ehi&rh=2015111212&fh=108&r=sc&lat=33.5000&lon=-98.3780&metar= ECMWF looks relatively similar this afternoon, with 1000 J/kg SBCAPE nosing into SW OK by Monday afternoon.

The next 7-10 days aren't looking too promising, at least anywhere in the Plains. The fat lady may have been warming up as the June 4-6 sequence concluded and we didn't even know it at the time. After an exceptionally active April-May pattern wise, it's not too surprising. That said, it is still June, and there will still be tornadoes on various days. And "real" setups can't be ruled out north of I-80 even heading into late June and July.

If only that upper low progged to sit over CA late next week into the weekend were shifted 300-400 mi. E, we'd complete our 1995 analog with style.

Been watching the period next week on the Euro for several runs, and I'm concerned that it's consistently depicted most of the upper flow north of the front. There should be at least a half-state area of 25+ kt H5 flow over the warm sector for several days, hopefully.

Agreed -- we'll just have to see whether we can manage 35-40 kt of bulk shear over good instability to determine whether those nickel-and-dime events are fruitful. Really, almost every Plains event this entire spring so far has been nickel-and-dime in terms of results, though, despite so many promising longwave troughs. So results-wise, this may not be that much of a dropoff.

Recent operational runs are a bit concerning heading into early-mid next week, but it's a period of low predictability per ensembles. I'd be fine with some downtime next week for a pattern "reset," hopefully featuring a period of drying for the Chihuahuan and Sonoran deserts and reduced STJ influence. Plus, so far this season since late March, a broadly favorable pattern has found a way to reassert itself quickly during every period of doubt. With the amazing ET this year, all we need is one or two decent (even subtle) troughs the rest of the spring without the overwhelming STJ influence, and periods comparable to late-season 2004 or 2010 should be easily within reach. It will be a crying shame if the grungefest setups continue unabated through May and June, but still better than some recent years.

Looking at the ECMWF and its ensembles, and considering what's already in the books and about to occur this week, this will easily rank up there with 2008 and 2010 as among the most active May months on the Plains over the past decade. It could easily surpass those, too, since neither had much of anything during the first 10 days. (Speaking of which, since around April 10, there's been no extended downtime lasting more than 5-7 days really... it's been a long while since that's happened, too). Unfortunately, I'm speaking in terms of the broad continental pattern, rather than the results. Last week was something akin to having a 980 mb low pass just SE of Cape Cod in January and Boston only picking up 3-4". "Oh well, there'll be more" -- except we'd been waiting years to see a trough like that in May or June, especially without extreme PBL mixing over the High Plains. We'll see about this Fri-Sat. Even as it stands, and assuming this week falls short of its potential, the "results" for May should be better than all but 2013 out of the past four years. Still, you can go quite a few years without an optimally-timed pattern like this, and it would be nice to cash in finally...

Major morning convection on the 00z GFS for both Fri and Sat, and the STJ is still carving across N Mexico into TX. I'm certainly taking model QPF at face value this time and assuming an outcome substantially less than the ceiling suggested by H5, rather than falling for the "holy crap, that trough in mid-May without drought concerns can do no wrong" voodoo I did last week. This is the second trough in a row that looks like a borderline-inevitable outbreak at this time of year, and better than most anything we've seen late season since 2010-2011... but this is no ordinary season. Now, obviously, there will still be some tornadoes (at least Saturday), just as there were every day last week.

If you take the H5 evolution from the 00z GFS literally, there's no way that doesn't get the job done kicking out over mid-upper 60s dews in mid-May, no matter the timing or prior convective evolution. "Bad" timing could hurt chaseability and/or prevent it from being an outbreak, but there'd still be at least a few tubes in the area centered on SW KS, methinks. At this point, the only thing that would make me think Saturday won't be noteworthy is a wholesale change in the trough evolution.

The Euro wants to make this an issue virtually every day this week, with at least one convective QPF bomb somewhere along the dryline by 18z. Aside from that, I'm becoming very optimistic about this four-day stretch from Wed-Sat. There isn't a day in there that doesn't feature realistic potential for classic tornadic sups across the Panhandles, W OK, and SW KS. Wednesday could be big, and Saturday almost certainly would find a way to be big even if it fires early, unless the synoptics change substantially from the current Euro depiction. The fact that several setups in April were wrecked by morning convection makes me nervous, but we'll see. It's May, and I doubt that can be a dealbreaker four days in a row.

Yeah, May 1991 easily blows anything we've seen since May 2010 out of the water, at least for my tastes (I know 2013 has an argument, if you ignore the I-35/OKC magnet aspect). Between 5/10, 5/16, and 5/26, it would be hard to ask for a lot more -- and there were a lot of other localized tornado days across the Panhandles and W KS.

Agreed with all of this. Next week reminds me some of the first week in June last year. We finally had decent moisture and instability after an abysmal mid-late May, but upper flow was lacking. Still, it was the kind of pattern that can sometimes lead to a string of localized but impressive tornado events (ala late May 2010 or late May 2013)... or sometimes lead to virtually nothing except lots of wasteful chasing (ala early June 2014). Now, because ET (evapotranspiration) should be at least somewhat better than we saw at any point last spring south of I-70, I think the odds of at least one day coming through are decent. But for chasers, it will require a lot of miles, skill, and luck to be there if something in the vein of Bennington 5/28/13 or Texline 5/23/10 pops up at the last minute. These are obviously speculative and preliminary thoughts, though. After all, the ECMWF went from showing a crashing cold front late next week on last night's run to a decent Four Corners closed low around the same time this afternoon. Oh, and that tropical low sitting off the Carolina coast next week dragging crappy air into the eastern Gulf can GTFO.

I can't be the only one getting concerned about the "jet disappearing into Canada act" (ala May 2009/2012) that seems to be a theme on MR guidance. There may be several days of semi-interesting high CAPE/low shear potential next week, and there's always a chance one of those days could emerge as more significant. But if we're talking amplified western CONUS troughing and large-scale organized threats, it seems we might be waiting until closer to mid-month, at least.

By 48 hours from now, the drought across most of OK and N TX will have been beaten into submission to the point that minor to moderate long-term hydrological impacts are all that remains. Even farther W into the Panhandles, this drenching should probably ensure average-or-better evapotranspiration for awhile. Bring on May, and good riddance to this active but underwhelming April.

Yeah, there's certainly some potential on multiple days; didn't mean to dismiss it entirely. And if the downstream troughing trends weaker on subsequent runs, there could end up being a higher-end day after all.

The past 10 days have been among the best we've seen in years for drought relief in the most dire areas, as long as you're not in the western Panhandles or SW KS. The active STJ looks to continue unabated into next week. If not for the substantial Great Lakes/Northeast troughing, there'd probably be one or more major severe weather days on the southern Plains next week. It's been way too long since the southern branch has been remotely active like this, with energetic waves translating across N Mexico and the Desert SW. If this can continue into early-mid May (big "if"), this would most likely be the best southern Plains season in several years, particularly out west.

Yeah, I don't know if I could've jinxed it better if I tried. Moisture return will in fact be a problem tomorrow, and then the STJ closed low starts filling to the point where shear over the warm sector is unremarkable by Sun-Mon. The much-advertised big trough next week is now but a whimper, and another positive-tilt one at that, most likely. With shortening wavelengths and multiple attempts at cutoffs, who knows what the medium range will bring... but with the raging +PDO showing no signs of abating, it's hard not to panic when you see that Pac ridge even try to start settling in. But if recent GFS QPF over TX/OK between now and Tuesday verifies, I guess I can wait a bit. #payitforward

The 8-9 April event notwithstanding, the medium range (D6-15) currently looks remarkably active on the guidance. Pretty much a parade of significant disturbances crashing onto the west coast and translating across the CONUS without any crazy amplification east of the Plains to scour moisture out of the Gulf. The interval between systems and associated moisture return to areas well north of the Gulf could potentially be an issue, but otherwise, this is shaping up to be the most active April for this subregion since 2012 -- as of now, anyway. If this pattern materializes despite the continued record +PDO, I'll be mighty impressed.

https://discoveringdifferent.files.wordpress.com/2014/04/and-its-gone.jpg At least there's something to watch early-mid next week. If that turns into 3-4 days of a sloshing dryline as the trough junks out too far west, though, full ragemode may commence.

Cautiously optimistic that at least some changes are afoot for the medium range. It seems unlikely that the months-old Hudson Bay vortex will break down anytime soon, and most (maybe all?) of the guidance agrees on that point. That might put somewhat of a cap on just how favorable the pattern can become, particularly being that it's still early in the season, when higher-amplitude troughs tend to be preferred for substantial Plains events. Any progress is welcome, though.

The H5 pattern somewhat resembles each of those. The important thing to keep in mind is that moisture was unseasonably rich for both events, particularly 1998. Unless we can manage widespread 65-70 F Tds along the dryline and avoid mixing issues, the usual mid-level thermal issues of autumn will likely be a limiting factor.