State of the Chase Season: 2019

[Quincy Vagell]

One thing to keep in mind regarding the SPC Day 4-8 Outlook and its historical significance in that it's the first of its kind: SPC outlooks are not a steady, objective measure when looking back at events/patterns over the last decade. Human bias that is different in each forecaster will cause differences in outlook issuance and magnitude to some degree. Additionally, the guidance available has changed over the years, as well as SPC's minimum probability in the day 4-8 period (used to be 30%). Given the right forecaster, the guidance we have at our disposal today, and SPC's current methods of Day 4-8 outlook issuance, there very well could have been outlooks that looked like this in the past. The outlooks also have to verify, but that's a whole other conversation.

While it is definitely promising and great to finally see a pattern like this, the hype I've seen on social media of it being the severe pattern to end all severe patterns is a bit too much. For those not able to chase during this stretch: there will be other chances. Just because a pattern screams severe does not mean it will necessarily yield photogenic storms or tornadoes either. I've had to sit out a lot of events for various reasons, and I know the anxiety caused by not being able to chase them. However, there's always been great storms after that still.

This is a good point about 30% vs. 15% outlooks. The latter of which is a relatively recent addition with the day 4-8 outlooks.

I do agree that the hype on social media is out of control. I'm all about highlighting the synoptic pattern, but the posting of soundings that are for 144 hours out, for example, is silly. It's one thing if one or two people do it, but I can't tell you how many people in my feed are going on about details to Monday, when we don't even have the details clearly sorted out for Friday yet!

 

[Dan Robinson]

Agreed - we don't know if and how each day is going to play out. Outbreaks are possible, Dodge Citys are possible, epic junkfests and busts are also possible. That being said, we do have the main ingredients for an active pattern in place, daily, for an extended period. For at least one or two of those to not produce something higher-end in terms of chase quality would be very unusual.

 

[Ethan Schisler]

I'm not a chronic #wxtwitter follower up until the past couple years, but the amount of hype I've seen on my feed is akin to that of a major hurricane coming. Maybe even worse. Like Quincy said, its not even Friday yet, we don't know the details on each day. Each day is probably going to have boundaries to work with from previous day convection, stuff you can't pick up on a synoptic scale. Also agreed that with such a favorable pattern it would be highly unusual to not see something significant out of it, but stranger things have happened! Hoping we can ride the pattern into June and the Midwest, we are overdue for a good season here. That being said, I plan on making a run at things at least Friday and then most of next week. Very excited to get out there after missing the first part of May in Texas.

 

[Brandon Centeno]

As noted earlier the op euro was on the extreme end of its ensemble solution. A lot of spread with how that second wave will behave/amplify. FV-3 and GFS illustrate point nicely. GFS is not as amplified leading to a weaker mass response, although still favorable wind fields for a confined tornado event. FV-3 has more latitudinal expanse thanks to a more amplified (but not too amplified) trough.. Which would favor a more robust tornado event.

Lots to sort out. This is quite a favorable synoptic pattern for multiple tornado events, one or more of which could be high profile. But we won't really know for a while.

 

[Kem Poyner]

I am leaving Arizona tomorrow to be in place for Friday. If the current forecast for storm locations for each day on SPC holds true I will shift East for Saturday but probably let Sunday go without me. I hate chasing in the Jungle and that will make Monday much easier to reach.
So you know that means Sunday will be an historic event!

 

[JamesCaruso]

I won't spoil all of the results, but I will share this image that shows the mean pattern in the five most active periods, which included, not in this order, May 21-30, 2016, May 23-28, 2015, May 18-25, 2010, May 22-29, 2008 and May 16-30, 2004. These years averaged 166 tornadoes from May 16-31, which is roughly twice the climatological average...

Quincy thanks for doing that research and posting it for us. Since I cannot chase until the last week of May this year, I find it encouraging that four of the five most active periods you listed include the last week of May. On the other hand, four of the five periods were also only one week long. So knowing what the 7 days starting this Friday look like, it doesn’t seem as likely that the last week of May continues to be quite as active. Of course, it did happen in 2004 per your list, and also in 2013 which I am surprised is not on your list. More importantly, as we all know, a statistically “most active” period is not necessarily a prerequisite for a good and reasonably productive chase vacation.

 

[Paul Knightley]

Mods - I hope this is OK here, as I'm not focussing on any one day (which, I know, would require a post/posts in Target Area)

As is being discussed, a multi-day severe weather event is likely to unfold over the central USA - but will it be a multi-day chaseable severe event? Let me define 'chaseable' as a mixture of decent supercells, and also fairly decent chase country.

Friday looks interesting - stout dryline, strong SW flow, front on the northern end of the moisture return...a broad chase region should unfold from NE into SW TX...tornadoes possible close to the front around NE, and down the dryline - the question for the latter is how much capping there is.

This is clearly a chaseable set-up! With strong moisture advection on a very stout LLJ evening/overnight, it may be that some nasty after-dark tornadic supercells are roaming the Plains too.

Saturday, for my money, looks rather tougher to call - plentiful lift/moisture through TX and OK, and up into E KS, etc - but the strong dynamics may initiate lots of convection, perhaps leftover from one or more MCSs from the previous night. I'm sure there will be a few nasty supercells lurking around, but it may not be so chaseable...perhaps eastern NE and IA for the warm front could be best? It hinges on the previous day/night, and also the evolution of the upper flow - it could still be very prolific!

Sunday looks like shifting the risk well to the east and south...southern TX might be OK.

Monday looks like a potentially decent chase day - from around NW TX into SW KS.

Thus, there will be some great chase action in the coming 5 days or so - but perhaps also some tough calls and frustrations!

Good luck to all those out there - and stay safe!

 

[Quincy Vagell]

Quincy thanks for doing that research and posting it for us. Since I cannot chase until the last week of May this year, I find it encouraging that four of the five most active periods you listed include the last week of May. On the other hand, four of the five periods were also only one week long. So knowing what the 7 days starting this Friday look like, it doesn’t seem as likely that the last week of May continues to be quite as active. Of course, it did happen in 2004 per your list, and also in 2013 which I am surprised is not on your list. More importantly, as we all know, a statistically “most active” period is not necessarily a prerequisite for a good and reasonably productive chase vacation.

2013 was #6 on the just, just behind 2016.

In 2013, there were 153 Plains states tornadoes from May 16-31 with 139 occurring between May 18-31, for an average of 10 tornadoes/day for the last 14 days of the month. The 1993-2017 average is roughly 5 tornadoes/day for the second half of May.

I'm not sure there is a slam dunk correlation, but you mentioned May week 3 vs. week 4. I almost wonder if this current setup, May 17-21, is about a week "too" early. Meaning that if this setup took place a week later in the year, would that be just enough to help overcome some of the issues? Climatology goes north with time and it does seem like a lot of the most memorable chase events/periods took place between the final 7-10 days of May.

Either way, maybe expectations coming up were just too high. As many have said, even if the next 1-2 weeks don't verify as a historic period, there will undoubtedly be many chase days. At least we're not looking at a shutout like recent years of 2014, 2012, 2009, 2006, 2005 and 2003. Each of those years saw dreadful chase periods in mid to late May.

Anyway, there are some flaws in the next few events (May 17-21), but both climo and model data suggest that setups improve during the latter part of next week and into the final week of May.

 

[JamesCaruso]

Thanks @Dan Robinson @ScottCurry @Jeff Duda @Mark Blue @Jeff House @Alex Elmore and any others I forgot for responding to my lamentations yesterday about not being able to chase this upcoming setup. Dan I agree with what you said about conflicts with family events (“FE”), I have the same view that I do this a lousy 2 weeks a year (4% of the year) so nothing should be allowed to interfere with that. But it’s all about how important the FE is, and this one involves my young girls performing in a play; so it’s not like family scheduled something disregarding my needs, and kids can’t reason like we do as adults about why dad wasn’t there...Mark thanks for sharing your own constraints, I empathize with your situation, sounds like it affects you much more than this one particular week of chasing I am whining about. I hope it all works out.

I have decided not to try to do an out and back type of thing; the combination of personal and business commitments would make it impossible to catch both Fri and Mon, and to do just one is simply not worth the time, expense and aggravation. In my mind there is almost always more downside (i.e., stuff that can go wrong) than upside in these types of events.

I have not looked at any models myself yet. I don’t want to drive myself crazy, and I don’t have time anyway. But based on what others are saying, my impression of next week is coming back down to earth. Even SPC seems to have slightly walked back the strong language in its Day 4-8 compared to yesterday - no more talk of 100 knot 500mb jet streaks or “impressive” shear. Not saying it won’t be an active period, and if I could head out now I certainly would, but I figure I will at most miss two good days in prime chase territory; I don’t care about stuff in the hills and trees east of I-35. I can live with that. As @Paul Knightley said, a good chase day is chaseable weather in chaseable territory. As long as it doesn’t shut down with a death ridge immediately after I get there.

Like a married man temporarily distracted by a hot woman, I was ready to cast all my plans aside just to get out there, but I now have a more balanced view, thanks largely to all of you that either directly responded to my post or just by providing insights about the coming pattern. My only decision at this point is whether to head out at my earliest opportunity (the evening of 5/22) or if that’s going to put me under a ridge for days in which case I would rather spend Memorial Day Weekend at home with my family and save the days to tack onto the end of my trip instead.

 

[Mark Blue]

June my friend usually produces some great events. Hopefully that isn't chock full of FEs for you.

 

[Matthew Crowther]

New Euro is pretty crappy, but based on the fact it is been very inconsistent with its previous run AND does not jibe at all with all of the other guidance I will assume that this run is an outlier until I see what the EPS does.

 

[Jeff House]

My take is Monday improved to a chasable day on the ECMWF. Initiates slightly later AND farther west. Yeah that's all good. Still starts around 15Z which is too early. However, additional development can be chased. Figure Monday will produce, but I have no idea where or if it will be visible.

I'm questionable Monday. Already postponed to skip Fri/Sat. Either one could be chasable days, but I also had some FEs pop up. They are not yuge, but enough to require a better set-up. Again Monday is still on the table for me.

Now @JamesCaruso I think later next week looks good when you get out there; but, it might be north and west. While parts northwest Nebraska (not PH) and southwest SD have road holes, the rest is great. Good roads grace the eastern Dakotas into SW Minn. However eastern Nebraska has some flooding issues.

All, the following is hypothetical and in no way targeting a week out. Geography provides some help in CO/WY with the Palmer Divide and Cheyenne Ridge. Winds can be a little more backed north side of such ridges all else equal. If outflow lines up with physical geography, it's even better. Roads are a little sparse but visibility is excellent.

Speaking of possible changes in the forecast a week out, several GEFS members had lee troughs in more traditional ares farther south some of those days next week. Too early to really narrow down.

Finally looking way out, the week of/past Memorial Day could remain active anywhere in the Plains. Majority of ensemble members favor more southwest flow. However the spread is the usual that far out.

 

[JamesCaruso]

June my friend usually produces some great events. Hopefully that isn't chock full of FEs for you.

Thanks Mark. Nope right now I'm all good on the FE side from 5/23 through 6/8. It's more the work side of things. I only have two weeks, so if I'm out starting next Thursday, I may need to be back at work by Thursday 6/6 instead of staying until the weekend. Still, a bird in hand is worth two in the bush as they say, if there are any opportunities at all next Thursday/Friday I intend to take them and worry about June later.

 

[Quincy Vagell]

The overall synoptic pattern still looks favorable through at least next weekend (25/26). The 00z Euro ensembles show mean troughing in the West/ridging over the Southeast through about the 27th, before spread increases and there’s a signal for more Midwest/Great Lakes troughing.

I think back to late May 2015 when I had a couple of underperforming chases in the High Plains before I gave up*. I thought the pattern for the upcoming week looked junky, but I ended up missing a string of decent tornado chase days, including Canadian, TX.

As long as there is troughing over the Rockies vicinity, there will be storms to chase in the Plains. There may not be a string of outbreaks and some days might feature a more ambiguous or challenging chase target, but don’t bail out.

*In 2015 I had a week of travel time with an old friend and after an abysmal trip in late May 2014, I didn’t want a repeat. It turns out 2015 actually had a relatively busy back end of May.

The advice: Don’t lose hope!

Remember that climo says the Plains averages only about five tornadoes per day in late May. That’s really not a lot if you think about it, but most days starting tomorrow and through next week should feature at least some tornado potential, especially with a favorable upper level pattern.

 

[Jeff House]

I feel like next week (May 20-24) will be bigger than currently shown. Euro and GFS have a lot of North stuff. I can remember past years that look day 7-10 became Kansas by game time. Some of it is outflow. Some is models discerning subtle features.

Thank you @Quincy Vagell my 2015 was so similar. I busted Mother's Day weekend (2nd time in a row also 2014) hence my no Mother's Day rule now. FF to 2019. This Saturday reminds me so much of that OKC 2015 MCS washout, and the desperate attempt from Bucklin, KS. My best buddy in Wichita joked, I'll see you next weekend. I did not attempt. Missed beautiful tornadoes.

So I can see this Saturday doing the same thing, heck maybe even same placement. So I'm still chillin' in Chattanooga. Might miss a tube Friday, but doubt anything long-track siggy.

Now instead of sitting out the next one, I think one should be out in the Plains next week May 20-24. Euro and GFS show ugly rising heights after Monday. However the GFS Para and some EPS members keep heights neutral. Southwest flow upstairs, LLJ most days and 68 dews, neutral will definitely get the job done!

While I've talked trash, esp on Discord, about waiting until week 3 it really is trash talk. Quincy gives me/all an important reminder. That's the great thing about Storm Track to share ideas. The Plains is calling next week, yes indeed!