2018 severe wx/chase season discussion

[Jeff House]

1. I think 3-5 chase days will happen the next 7-10 days. Might be 5% mesoscale stuff, but doable with some forecasting work. Thu-Sat this week has moisture issues, but so did that elephant trunk on Sunday. Middle of next week another wave is forecast by all NWP. I know Day 10, but agreement is there. Plus, you know, climo.

2a. Let us not bite each other's ankles in a frustrating wx pattern. Plains chasers have the luxury of deciding the morning of an event. Travel chasers need at least 36 hours to decide. However once out there, travel chasers are free to just go for it!

2b. It is like the commitment vs dispatch question for a power plant. Travelers have a huge commitment question, but generally dispatch every day, kind of like baseload. Plains locals are more flexible like a peaker plant, but picking days has its own stress.

3. SPC and ERTAF discussions are depressing; but, I infer SPC thinks something will go later this week. Sever wx potential appears relatively low for mid-late May - SPC. They do not say zero. In fact less than 15% is right 4-6 days out this pattern. Probably be 2-5% TOR day1s. 2-5% is quite chasable. Just need a good forecast and some luck!

 

[JamesCaruso]

If most recent (14/00z) CFS is to be believed, at least modest potential for something in KS next Saturday, and then in SD/NE the following Wednesday.

*Of course, it also shows an area of SCP AOA 7 over KS for hour 24, 00z/15 (this evening) and based on today's outlook that doesn't actually translate to much.

I haven’t looked at data today, but based on Warren’s post of the DDC area forecast discussion there could be something to it.


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[JamesCaruso]

I have no intention of canceling my trip, I am willing to go out there and take my chances. I may not stay the entire two weeks though. Once I’m out there, I wouldn’t bail on an unfavorable-looking “week two” right away because models can change, but if I’m at the start of week two and that week still looks bleak, then I would go home. To clarify, I’m always happy to look for the “diamond in the rough”, but there’s a difference between a marginal pattern that can hold some surprises, versus a completely dire pattern i.e. death ridge.

For me it’s not a question of affordability, I’ve got the trip budgeted and that’s that. It’s more a question of having personal and professional responsibilities, and missing things like my daughters’ play. I don’t mind any of that, and my family is supportive, but there’s always some guilt on my part, and I just don’t want to be jerking around out there for no good reason.

On a related note, I would never cancel the trip totally, it’s more a matter of trying to time it better, but to shift around plans at this late date is challenging and stressful. So at this point I’m pretty much resigned to avoiding such machinations and just heading out, taking my chances for better or for worse, with the possible exception of staying home for family stuff this weekend if it looks pretty obvious nothing is going to happen. Not saying it looks like that right now, just saying “if”...

 

[Andy Wehrle]

GFS still has been pretty consistent with Friday and/or Saturday looking like chase days of at least modest quality. Some VBV in the forecast soundings over KS, but what else is new? There's AOA 40kt SW flow overtopping some instability, with 3KM EHI values from 5 to 8. I'm honestly surprised that didn't at least warrant a "predictability too low" (instead of "potential too low") in the outlook for SPC.

 

[Brett Nickeson]

Sorry, but repeating that mantra every spring this decade is getting old.

Ain't that the truth. I started chasing late in 2011, so I can't even imagine what it was like in 2008, 2010, or April and May in 2011 with all the opportunities. These days, it seems you're lucky if you get more than two chaseable setups a month - and I'm not talking diamond in the rough setups. Most of us don't have the ability to drop everything and drive 4-8 hours the morning of after reading an AFD or seeing a minuscule short-wave.

Anyway, the only day I see with even remote potential is Saturday. On Friday the pinched off trough is dying and winds are decreasing, which would lead to an even weaker version of what we saw last night. Saturday is at least showing 35+ knots at 500 over some moisture in eastern KS, but with no upper level support at all. Probably unorganized HP blobs but hey, by all appearances it's the best we've got over the next two weeks.

 

[John Farley]

In today's 1630Z outlook, SPC mentions possible upgrades in the next outlook for three different regions. Not sure I have ever seen that before, but I think that is a good example of what people have been talking about in this thread, i.e. days where you don't know much until the day of or very close. This can work out great if you live near the threat area and have a flexible schedule or are on chasecation already in the area. Of course, as others have said, not so much if you have to travel or have inflexible schedules. But for those whose situations are right, opportunities will arise, though they may not be evident too far ahead. I will say this, though - some of my best chase days have been when something has arisen on short notice near where I already was. So if you have some flexibility, pay attention to the short term.

 

[Brandon Centeno]

Just because SPC is upgrading for wind or hail doesn’t make it a good chase day.

 

[John Farley]

It might be a good chase day in the Colorado potential upgrade area, though. If I lived in DEN, I would be out there today. A little too far from Pagosa Springs, though, given the marginal nature of the setup. That is what I meant by if you live in the area. One other thing - perhaps unlike some others, I don't have to have a tornado to have a good chase day, though that is always nice. A spectacular supercell or even a really impressive shelf cloud counts as a good chase day for me.

 

[Alex Elmore]

Just because SPC is upgrading for wind or hail doesn’t make it a good chase day.

I'd say that depends on what your goals are when chasing. As @John Farley expressed above, if you just want to see or experience a good, strong storm, I see no issue with this logic. Seeing an increase in confidence of any severe hazard for an area, whether you are targeting that area, live in that area, or were on the fence about driving to that area, I would argue, is seldom a bad thing from a chasing perspective.

 

[Dan Robinson]

My first storm on the Plains was the May 27, 2001 derecho. Looking back, that was a really junky NW flow setup tornado-wise (by my standards now at least), but it was pretty memorable and I'm glad I was there. I would probably bite on a similar setup today.

 

[Quincy Vagell]

I almost went to Colorado today, but I couldn't justify a 9-hour drive, gas and a hotel stay, plus missing work, for a one off. It definitely looks like a worthwhile local chase and I've certainly had a bunch of memorable chases on <2% tor days as well. I've even had solid chases on days that were sub-MRGL at 1300z.

Not everyone has the flexibility, but I'm saving for later in the season, or at least until we get a better moisture/instability/shear combination. For those on chasecations, at least we're getting thunderstorms. If you're willing to stray a bit from "typical" chase territory and ride some conditional plays, I'm sure you'll have at least a few memorable chase days over the next two weeks. Be adaptive and expect the unexpected.

One of my favorite unexpected chases was 6/13/16. I started the day, if I recall correctly, in South Dakota. My target was eastern Colorado. By early afternoon I bailed south because storm modes were turning into garbage. I ended up catching a tornado at sunset near Amarillo, an area that didn't even get a 2% tor delineation until 1630z. You never know.

 

[Dan Robinson]

As bad as it is, we're not at rock bottom (yet). At least we are seeing daily storms -supercells even - on the dryline and on the Front Range. There will be short puffs of flow here and there over 60s dews in the southern/central Plains for the foreseeable future. It's not great, I know - bad, in fact - but not as bad as it *could* be. In late May 2006, you practically had to go to the Dakotas or the Midwest to see a thunderstorm with more than 15kts of flow.

That being said, this year could certainly be a contender for the worst ever if June does not perform. 2006 had several good early-season events before it went to junk. This year's late winter coupled with a 2006-like peak season would be one for the record books.

 

[Devin Pitts]

I'm pretty much committed to my chasecation that starts Friday and runs through Memorial Day(cant shift it unfortunately) so this pattern is definitely disappointing, but I see a few opportunities at some shortwave action this weekend and mid next week possibly. Gotta take what I can get, and a 5% tor day is more than chaseable. Some of my best tornado days were on 5% days with meh flow aloft so I'm still a little optimistic at least.

 

[Quincy Vagell]

Even with pronounced ridging being progged for late May in the vast majority of the ensembles, there is another way to look at it. Verbatim, I would think the High Plains would see a fair amount of activity. I could even see a scenario where Montana and the western Dakotas come into play, earlier than climatology suggests. The beauty about that happening is that as you become farther displaced from the southern Plains, one would expect less chaser convergence. Sure, it's probably not worth a drive from Oklahoma City to Montana, unless it's a Moderate Risk event, but anyone who is chasecationing should be open to chasing up north, assuming adequate boundary layer moisture return. If there's a setup with 20kt flow at 500mb in West Texas vs. 40kt in eastern CO/WY, even if buoyancy is much lower, I'd favor the northern area.

Who knows. I rarely look at the ensemble control runs, but just to get an idea of one possible scenario, I glanced at the latest European ensemble control run. It does show substantial ridging into southern Canada in late May, but there are multiple (albeit subtle) shortwaves that impinge on the High Plains. It would be silly to take that one run seriously, but it supports the idea that just because an ensemble shows mean ridging, does not mean that every single member shows a stout ridge that doesn't budge for two weeks. Yes, the signal overwhelmingly favors positive height anomalies across the Plains, but even that idea suggests that the pattern gets shifted north (and probably west a bit). I'd much rather chase in Colorado in late May than Missouri.

I almost forgot that the Euro weeklies come out this evening. I've learned to not take them too seriously more than 2-3 weeks out, but it will be interesting to see what the model shows happening from late May into early June. We'll follow up after that data is released.

 

[Warren Faidley]

Even with pronounced ridging being progged for late May in the vast majority of the ensembles, there is another way to look at it. Verbatim, I would think the High Plains would see a fair amount of activity. I could even see a scenario where Montana and the western Dakotas come into play, earlier than climatology suggests. The beauty about that happening is that as you become farther displaced from the southern Plains, one would expect less chaser convergence. Sure, it's probably not worth a drive from Oklahoma City to Montana, unless it's a Moderate Risk event, but anyone who is chasecationing should be open to chasing up north, assuming adequate boundary layer moisture return. If there's a setup with 20kt flow at 500mb in West Texas vs. 40kt in eastern CO/WY, even if buoyancy is much lower, I'd favor the northern area.

Very well stated. I've been eyeing eastern Colorado, SW NE and the Goodland areas as a base point for the team this season starting this weekend. With limited forcing / shear forecast in most traditional areas this might be play considering RH is still forecast to be good. Eventually, the cap will be factor, especially further south. Pueblo's latest discussion noted next Monday as an "interesting day" and I agree.