brettjrob

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.

This is the biggest reason why I hate the second season. So many wasted setups over the past decade I can recall due to this problem.

Environment for Wednesday 8/20 in the mid-Missouri Valley should be very impressive for August. I haven't delved into the guidance enough to assess the likelihood and possible timing of CI, but the parameters certainly grabbed my attention.

Interesting -- I'll check that out, and be on the lookout for any publications from his work. I've driven through the Hackleburg-Harvest damage path where it crossed US-72A near Trinity a few times already. Impressive. (Actually, when I visit my parents in HSV next, my trip will be bookended by that and the Moore/Shawnee paths on I-35/40 -- three incredibly impressive swaths across major highways).

That doesn't make much sense to me, from a practical standpoint. A vet's "sacrifice," in general, does not correlate with forecasting aptitude or even the potential for development of such aptitude. (Granted, if the veteran was a forecaster in the military, that is valuable experience and should be treated as such). A graduate student or private forecaster, while arguably not "sacrificing" as much, has gained additional experience and knowledge relevant to the job. I'm not trying to minimize yours and other vets' sacrifice (any more than you were trying to minimize those of us in academia), but I do think that with such a surplus of applicants to most NWS positions, MIC's should be selecting from among the most-qualified. That will include some vets and some non-vets, of course.

It is somewhere in the neighborhood of 75%.

Limestone/Madison Co. tornado (W HSV area) rated EF-4 with upgrade to EF-5 possible: http://forecast.weather.gov/product.php?site=HUN&issuedby=HUN&product=PNS&format=CI&version=2&glossary=0 Video of the wedge approaching I-65 near Athens/Tanner:

I was focused heavily on the HSV-area storms yesterday, since I have family there, and I agree to an extent. It appeared to me that the outflow boundary from the MCS may have been draped across the northern row of counties in AL for several hours during the height of the outbreak. One storm in particular, which initially produced the catastrophic Hackleburg/Phil Campbell tornado, seemed to weaken a bit as it moved northeast from that area. Then, it suddenly went crazy upon reaching the Tennessee River, producing the Limestone Co. wedge near Tanner/Athens with visibly much-lower LCL's than the southern storms. For the rest of the afternoon, supercells trained over this general corridor and would each develop strong low-level rotation as they entered the Dectaur/Huntsville metro area. On the other hand, it still seems that the most prolific, violent tornado-producers were over the open warm sector, south of any clearly-defined boundaries from early convection. So, while I don't believe the MCS is what "made" this outbreak by any means, it may have at minimum not reduced its overall severity.

RIDICULOUS debris ball over Hackleburg

Cullman tower cam video will go down as one of the top tornado clips of all time, IMO.