State of the Chase Season 2021

[Warren Faidley]

Finally have a "tentative" departure date set of May 15-16. Target will be the Texas Panhandle vicinity on the 17th - with a classic four-corners low forecast. Could be 1-2 premium days of chasing -- although the usual 200+ hour model error disclaimer applies. The Hudson Bay, anti-gravitational vortex (yes, the region actually has lower than usual gravity), is forecast to magically appear following this event, so that's a monkey wrench to watch for.

 

[Jason Boggs]

@Warren Faidley I'll be ready to join you when you get here!

 

[Brett Roberts]

At this point, I suspect we may be looking at a worse peak season than 2020. The psychology and sociology of the chase community during dire times is nothing if not fascinating, and surely worthy of an NSF funded study! (And by the way, I'm hardly exempting myself or my screed below from that proposition.)

Over the past week, there have been only occasional NWP cycles with a plurality of solutions offering hope for more than a seasonably modest tornado setup in the 7-10 day range. The tenor of some discussion on social media seems markedly more optimistic than that, though. We have been in a Groundhog's Day loop with vague, tenuous hope of a pattern shift in the D10-15 range since at least mid-April, and I don't see anything more convincing now. The opportunity for this coming weekend into early next week (5/16-5/18) is already devolving into full on split flow with broad western ridging and a weakening, detached upper low spilling out onto the Plains amidst bulk shear characteristic of July. Beyond that, it's the usual high-spread potpourri of solutions that perennially lean, on the whole, toward Rockies ridging and eastern Canada troughing: like midsummer, but colder.

The 00z GEFS now integrates out to 840 hours (35 days, for those keeping count at home), and essentially every run asymptotes toward an upper high over Chihuahua and trough over Quebec as the primary NA features at 500 mb throughout weeks 3-5. Time-lagged CFS output is qualitatively similar. I suppose (OK, OK, I know) I'm going out on an ill advised limb saying this on May 10, but my synthesis of the available dynamical guidance combined with the MJO already in phase 2 leads me to think the ceiling on peak season 2021 is a smattering of fortuitous mesoscale accidents and 5% type days... maybe a more coherent decent period somewhere between the last week of May and mid June ala 2005/2009, if things break our way. The floor may be worse than the same period in 2020. That may sound absurd, but late May into June 2020 was more active than historical examples like 2006; the setups were just fatally flawed, one after another. Sometimes, there aren't even setups, exempting upslope cells you hope can make their own shear and channel enhanced streamwise vorticity through topographic features.

 

[Warren Faidley]

I think if people are seeking "outbreaks" with big HP wedges, then it looks very bleak. If you are seeking isolated, long-shot tornadoes, lightning, storm structure and maybe a landspout or two, then it's not looking too bad. The GFS has acceptable RH in the Southern / SW Plains from Sunday through the remaining hours. If the RH is there in mid-to-late May, you chase. The slim-appearing pickings will also keep the crowds down -- especially those who don't like long shots. The same global models that were hinting of a busy May have flip-flopped several times and I simply don't trust them this close to peak season. Then again, if shear completely vanishes, it's going to a boring season as noted.

 

[Spencer Dant]

My goodness. One would think based on these conversations that Oklahoma on fire again.

Brett, you are an incredible photographer and chaser and I have followed your work for a long time, and you're a damn good forecaster too. But look at your profile photo on here and tell me that "a smattering of fortuitous mesoscale accidents and 5% type days" - or, perhaps, a synoptically boring, poorly forced, highly capped setup with little aloft to speak of can't produce something amazing. Tell me that you haven't seen monsters under a big EML with a split flow regime, characterized by slow moving, sculpted mesocyclones that cycle in and out with little competition until the low level jet hits and everything goes nuts. You've seen it all in both the good and bad years, and given that I'm surprised to see you so down about a year that, despite your insistence otherwise, shares very little in common with bad - or good! - years of the recent past.

Here are the things that we don't have that have marred most of my chase seasons to this point in one way or another:

• Plains drought. ENSO may or may not be overrated (we can have that conversation another day), but it's not really arguable that this winter and spring hasn't behaved like the typical weak-to-moderate first Niña years of the past, which generally saturate the southeast and leave the plains begging for a drink. Take 2011, the one everyone was talking about this past winter, for example. Nobody wants the dryline mixed into Tulsa County, and so far we haven't had that! That's a huge plus, and that's why we have seen (and will continue to see) western Texas, western Oklahoma, and western Kansas drylines for the foreseeable future. This, for what it's worth, takes 2018's biggest problem off the table too.



• Lack of flow aloft. Do you like jet extensions? I like jet extensions! We've had a couple (we're wasting a pretty nice one right now) and we're likely to have a couple more. This is where your 2020 comparison falls flat. While cutoffs and western ridging and all that nonsense can and probably will at some point take over, we've got some juice to kick the crappy patterns out of town. Does that guarantee greatness? Of course not. Does it assure you that these troughs will all amplify correctly, moisture will be there, and storms will form? Nope. Does it promise that the western ridge won't play like a Hall of Fame offensive lineman that doesn't let even the nastiest wave through? Sadly, no. But unlike last year, we're not waiting around playing the "if we can get some flow aloft" scenario. This year we've had it and we'll have it again.




Here are a couple of things that we do have that, in my limited experience, can help us out:

• Big EML in the source regions. How much is too much? I don't know the answer to that, but if it stays in the desert, I'm okay with a little heat on my dinner plate. Sure, we might get a sunburn. I'm the palest white person on this planet, so I'll get a sunburn anyway. We might cap bust. We might watch our 18z 81/71 loaded gun soundings turn into 88/62 inverted V hailers by the time the dryline circulation pops off. But we might get dry air infused into our late evening storm, lighting up the land with bolts and stacking pancakes on pancakes. We might find our classic supercell a little less rainy and a little more hail-y, opening up the views from all kinds of angles even if we don't all have the stones to take baseballs (I don't!). We might find initiation waiting until 6 PM, storm maturing by 7 PM, backlit cone by 7:30 PM, and beers and crappy steaks at Applebee's in Salina by 9. Sorry for my obsession with drought, but another first Niña that got some attention was 2017, which was a great season if you liked being to your hotel before the sun went down. I don't. Initiation before noon is no bueno.



• Clueless models. Is this good? It's good if you only look at the operational GFS, which seems to be at least one of the prevailing methodologies among storm chasers as of late, for your daily dose of emotional distress. These things are performing awfully! (I don't think I could do a better job, but I'm also not a supercomputer funded by the US government.) Here are just a couple of examples that I stole from a few friends of mine today of the operational GFS in particular being incredibly bad:



Is it odd that the control runs a higher PNA than its entire ensemble and falls well on the opposite side of zero as its ensemble mean? It should be.



Is it odd that the jet is supposedly heading into Canada and a western ridge is supposedly roasting Billings when the ensemble spaghetti plot could provide us more information if a three year old drew it with crayons and stuck it on the refrigerator? It should be.

I am hopeful that this post provides no new information to anyone because it shouldn't. Likewise, I don't intend to portray myself as some hyped up, wildly optimistic nutmeg who only looks at what he wants to see and blindly follows it, ignoring all signs to the contrary. I simply see signs of hope - and plenty of things that could yet trip us up, just as these Great Lakes troughs and scouring fronts already have. To me, that makes the doom and gloom hard to fathom. Why write off a season when we have seen so many seasons that appeared bad in numerous ways but had glimmers of light at the end of the tunnel turn out great? There's time left, and it is clearly possible that we use it in a favorable way going into the height of peak season in late May and into June. Maybe it works or maybe it doesn't, but there's no writing on the wall either way, and that alone is reason to keep your head up and eyes open in the coming weeks.

 

[Jeff Duda]

At the risk of speaking for Brett...
I got the impression he was talking more about the predictable synoptic scale type events that are pretty clear 3-5 days out (or more) so that everyone has a solid shake at comfortably setting up the day before (rather than having to make a 300-mile drive in 3 hours...do the math). That is, he was speaking as much on the medium range trends as he was speculating using the 35-day GFS forecasts. On the other hand, Spencer, your outlook focused almost entirely on the S2S scale and using analogies. That is by no means invalid, but it is not the same scale to which Brett was referring. And the signals we are seeing on the medium range/synoptic and S2S scales don't seem to be lining up.

Case in point...we just had a MASSIVE 8-1-2 MJO progression that resulted in pretty meager Plains severe activity:

I mean...this map should have had all of us salivating grotesquely!

And even though there was a spike in tornado reports during this period, (1) a huge fraction occurred on one random day in MS (with nearly no other reports), and (2) the majority of tornado reports occurred in areas either far removed from typical synoptic forcing or just flat-out east of the Mississippi River, where most of the terrain is less favorable for chasing. The Plains have once again been very quiet so far, whereas in the 2000s you could almost set your watch to solid dryline setups every 3-7 days somewhere between I-80 in NE and I-20 in TX. Those days seem to be almost extinct at this point.

Also, landspouts.

Spring severe weather activity in the Plains the has become so abjectly pathetic the past few years that I've stopped memorizing specific event days. I used to have a pretty impeccable recall of specific big Plains days (e.g., 23 May 2008). But I have almost none from 2018-2020, and 2021 only has the TX PH double-wedge day that I recall as memorable so far.

 

[Brett Nickeson]

The Plains have once again been very quiet so far, whereas in the 2000s you could almost set your watch to solid dryline setups every 3-7 days somewhere between I-80 in NE and I-20 in TX. Those days seem to be almost extinct at this point.

Also, landspouts.

Spring severe weather activity in the Plains the has become so abjectly pathetic the past few years...

This. I'm not sure when Spencer started chasing, but each of the last five years in the Plains would just about qualify as the worst year from any stretch from about 2000 to 2016, and there were some horrendously slow years in there. Almost every year has those diamond-in-the-rough setups that overperform, but what the last five years have missed are the prototypical longwave or even multi-shortwave troughs that bring southwest flow over good moisture several days in a row. Those just don't occur anymore in typical chase areas. Severe weather has been relegated to south of the Red River and Dixie Alley. If you don't chase those areas, you've been sitting on your hands and complaining - like I have - since 2016.

All of this is not to say that there won't be a rogue career day in June for some of us, but we're looking at the overall pattern. And the overall pattern is enough to make you choose a different hobby.

 

[Spencer Dant]

Prototypical longwaves, eh? May 1, 2018 (and the day following if the ejection hadn't been screwed up) may have been a bona fide synoptic outbreak across the southern plains if not for dramatic plains drought that contributed to excessively mixing out the atmosphere in the early hours of the afternoon and the daytime capping further south down the dryline from advecting masses of dry air since there was nowhere without dry air to advect from at that point in the year. That was a background state problem, not a setup problem.



I don't know much about the mid-May sequence of 2017 - I was working until the end of the month that year and couldn't travel to the plains that spring - but this looks great to me. It's no wonder a high risk was issued here even if it did not turn out to be warranted.



2019 was, of course, a record breaking sequence that did not meet its ceiling in the way chasers would like because there was no EML to speak of after an incredibly wet spring in the desert but it was an impressive sequential wave train that would make chasers of the good ol days drool too.



2002, 2006, 2009, 2012, 2014, and plenty more years have suffered from poor this, bad that, or just downright dreadful everything even in the past. Is climate change affecting chasing? Absolutely. Is it eliminating chasing? I don't know, and I'm far enough removed from my studies to call myself an expert anymore. Regardless, in no world have we ever been able to without fail "set your watch to solid dryline setups every 3-7 days somewhere between I-80 in NE and I-20 in TX" and I don't know where this nostalgic lore comes from. The fact is that if you chase the plains, you are going to experience a below average season fairly frequently. My arbitrary numbers for your generic overall chase spectrum are 20% good, 30% terrible, 40% average or below average, and 10% exceptional. I don't have any data to back that up, but I bet Brett Roberts does. Either way, you can pull incredible stuff out of the average years, and I would argue that 2016, everyone's favorite year ever, barely sneaks in as average looking at the number of landfalling troughs alone.

No matter, I will enjoy having 283 to myself since you guys are sitting this one out. Surely you are, right?

 

[Mike Smith]

Clearly, with warmer global temperatures, violent tornadoes are less frequent. See nearby graph.

The increasing number in the South and Southeast are likely temporary and part of the somewhat cyclical pattern first documented by Ted Fujita. There Is Nothing New About the Hypothesis Tornado Alley Has Moved East



"Is climate change affecting chasing? Absolutely. Is it eliminating chasing? I don't know, and I'm far enough removed from my studies to call myself an expert anymore."

 

[Mike Smith]

Using Kansas as a proxy for the central Great Plains, here is a graph of tornadoes ≥F/EF-3. It is the most recent I can find. The 1980's was an exceptionally low period for strong tornadoes in the region.


We all know that the number of "all" tornadoes has been highly influenced by both Twister and the installation of the WSR-88D network. If we use numbers before 1992 (the first year of NEXRAD installation) we see lulls.



After the extremely active period from 1971-74, the bottom fell out until '80. Then, there was another exceptionally low period in the late 1980's. So, given what seems to be the cyclical nature of "all" tornadoes in the central Plains, it seems premature to be attributing the recent paucity of tornadoes to global warming. As I posted above, however, there is a very clear trend toward fewer violent tornadoes.

If one considers the classic global warming hypothesis, it is not surprising that violent tornadoes are fewer in number. It was hypothesized that the polar regions would warm more quickly than the tropics. If so, that would mean a weakening of the jet stream which would imply fewer violent storms.

 

[Kem Poyner]

It seems that this "State of chase season 2021" thread has turned into a thread about historical evidence of global warming. That would be a good topic for a new thread.

 

[Brett Roberts]

@Spencer Dant , I don't want to short change your response, but am genuinely swamped this week and will have to be brief. I agree with plenty of what you say, but don't think it directly contradicts my last post. Jeff and Brett N. summed it up well: we're talking about the state of the season, and with nothing of interest in the short range, the discussion naturally flows toward broadly favorable patterns or obvious synoptic opportunities in the medium to long range. As of now, the preponderance of numerical guidance looks less promising in that regard (to me) than it did in this same timeframe in most other years I've chased. (Admittedly, I also commented that I feel some in the community are viewing our prospects through rose-tinted glasses just because the baseline we're starting from in early May and the last few years overall is so dismal, which was more contentious.)

I completely acknowledge we may have a Chapman day this year. We could even have three or four if we're lucky (although Plains soil moisture and transpiration is still not on par with 2016, which is probably relevant). I just don't see anything compelling in the ensembles suggesting a better-than-climo pattern is on its way. That doesn't mean one couldn't materialize as early as 10 days from now if we are in an especially low predictability regime -- which, given run to run shifts, I can buy. But I want to be clear: I'm not just looking at random 18z deterministic runs and melting down. I've been watching the ensembles consistently for weeks, and any impressive* signal across modeling centers has been confined to 10-12+ day lead times, then circles the drain by 5-8 day lead times. This has been happening for almost a month. For whatever it's worth, CFSv2 monthly output depicted a western ridging regime for May and June as early as last fall; although I certainly didn't watch it continuously through the winter, that scenario stayed relatively consistent. One can probably find reasonable statistical arguments or teleconnections to support an active period sometime over the next month, but in the domain of time-lagged, ensembled NWP, I'm just not seeing it right now.

*By impressive, I mean a pattern suggestive of sustained opportunity for more than "hope and pray" setups, regardless of whether there's a deep trough or outbreak scenario in play. A 4-day period of 35-kt SW flow in the ensemble mean, far removed in time from any Gulf scouring, would qualify.

 

[JamesCaruso]

It seems that this "State of chase season 2021" thread has turned into a thread about historical evidence of global warming. That would be a good topic for a new thread.

I think it’s a logical extension of the topic. If we are to evaluate what we perceive to be a meaningful decrease in the number of good chase years in the past decade, it is reasonable to ask whether that correlates with climate change, or just reflects normal distribution across the years, i.e. a trough in activity that we have also seen in past decades like the 1980s.

 

[JamesCaruso]

All of this is not to say that there won't be a rogue career day in June for some of us, but we're looking at the overall pattern. And the overall pattern is enough to make you choose a different hobby.

Well said, and reminds me of a quote I saved from @Brett Roberts from last year: “Plains storm chasing may now be a less sensible obsession than its short history of wide participation (i.e., the 1980s-2010) had perhaps led us to believe.”

It has always been tough to be so invested in something I can only do two weeks per year, and is so subject to disappointment at the whims of nature. At least when you live on the Plains, you always have the hope that something good will come up any day, but when you pin your hopes on a one or two week chase vacation it can get pretty depressing. I’m not going to stop chasing, but it does tend to reduce my motivation to spend a ton of time improving my skills in analysis, forecasting, etc. during the year. I just don’t want to build myself up for disappointment. The return on investment of time and energy, not to mention money, just doesn't seem to be there anymore. Although, I continue to question how much of our perception is statistically valid, versus subjective. Are we too nostalgic about “the good old days,” and failing to realize just how few and far between the best days have always been?

In any event, looks like there could be a couple days of good chasing in TX on Monday and Tuesday next week, but it’s far from a classic pattern, with a closed low that appears to weaken as it ejects. Maybe enough residual flow to squeak out an opportunity on Wednesday, but it looks pretty bad after that. My own trip doesn’t start until the weekend of the 22nd. In past years I’ve had flexibility to change the timing of my trip, although still limited to two weeks. I don’t have that flexibility this year, but if I did it would be a tough call as to whether to head out for this next setup. It doesn’t look great by any means, but there’s always a risk in letting it go in exchange for a future period that might be better but could more easily be worse. It’s somewhat liberating to have my times set and not have to make such a decision this year, although it would definitely be agonizing if next week did in fact look more classic.

 

[Jeff House]

Up until this morning I was about to settle for next week (May 17). Upon looking at the 00Z guidance, ECMWF and GFS meeting in the middle, I just can't justify a trip next week. @JamesCaruso I think starting May 22 is as good as any time.

End of May both CFS and ECWMF weekly shows hope. EC is more May 24 week. CFS is more May 31 week. Both have been awful; however, those are excellent weeks by climo.

Back to next week. So I'm debating whether to go ahead, but I'm flexible. Wait for May 24 week? Ensemble spaghettis show a mix of West trough, closed low, and ridge. Typical spread tbh. OK, so go with the known - closed low week of May 17. Looking at today's guidance I just can't justify the trip. Postponed again!

Personal calendar is a hot mess the end of May and beginning of June. I don't open up again until the middle of June. That's a longer trip from Tenn. Perhaps this is the year to stop jawboning about it, and actually chase the High / Northern Plains.