2018 severe wx/chase season discussion

[Jeff House]

I held my breath the last 24 hours after calling off a couple chasers. @JamesCaruso I'm glad the message found you well. Another person I know punted too. That said, we of course wish the best for those chasing this trough.

Next week looks surprisingly good for mesoscale accidents, despite building 500 mb heights. Even SPC notes, I guess kind of surprised like me, 700 mb is not on fire. Perhaps modest flow (vs even moderate) is a blessing in disguise to check the inferno aloft.

Yes mid-upper flow improved slightly overnight. ECMWF and its parallel both agree with the GFS, nice if it all holds. Part of me is surprised, and cannot believe the slight improvement after such an emotional roller coaster. Yes Mental Capital is a thing! However it is the last week of May. One could argue it is thee peak of climo. Why not go?

Action could reload back in the Plains Mon/Tue. I have a Major FE on Wednesday morning. I'll fly right after if needed; otherwise, start driving west. Thursday through Saturday might be my last chance, except for June, but I really prefer May. Modest flow over seasonably high dews with outflow cooking each day can work in late May.

 

[Andrea Griffa]

Hi all,
It's a long time I don't write on STMTRCK and I am happy to come back and say hello to old a new chasers.

Now as I am leaving on May 25th to chase in the Plains, I am not happy at all about the medium and long range. As many of us, I am having a look at many models, ensemble, ECMWF, GFS, climate prediction center projections and so on. The story is always that: damn ridge and May chase season finished.
But when I came across this, a little hope came in my mind.

Look at May 20th 2012 GFS Reanalysis and May 20th 2018 analysis. They look almost equal.
Now, many of you guys know how May 2012 ended, and the word "La Crosse" is vivid in our mind. I am not saying that the evolution will be the same, but something similar could be possible. One thing I am pretty sure about, is that the evolution predicted by models doesn't not convince me at all.

What do you think about? Feel free to post models, maps, images and what do you believe useful.

 

[Jeff House]

Flexible chase vacations, especially for those with Passports, are still doable. Forecasts will become increasingly more challenging away from the heart of the Alley, but opportunities may pop up. Ideas below are highly conditional in the extended forecast.

This coming week could be some northern Plains action, from Nebraska and all the way to the Dakotas and perhaps Colorado a day or two. Modest flow is forecast over quality Plains dewpoints; but, keep an eye out for more pesky Southeast troughs disturbing moisture return.

Memorial Day weekend (and lead-up) could go closer to Montana and Wyoming if moisture can get up there. Like Colorado, dewpoint requirements are less stringent, but a quality LLJ is still needed. Models have a trough, but stay skeptical a week out.

Week of Memorial Day action and Canada is possible if Pac NW trough verifies and spreads past the northern Rockies. Another option (speaking of La Crosse) is a more zonal solution for the Upper Midwest.

Some of those times and targets overlap due to uncertainty. This time of year extended forecasts are fickle without big troughs, esp this year.

 

[JamesCaruso]

I continue to delay my trip, although I am now at the point where a delayed start ends up shortening it, not shifting it. I agree there could be some opportunities in the Dakotas Tue-Thu this week, but after that the Plains are scoured of moisture with a frontal passage, with weak NW flow and even northerly surface winds in its wake. The week after Memorial Day doesn’t look great either but at least the NW flow is stronger; won’t spend too much time worrying about “Week 2” just yet.

As much as I love chasing, I just can’t get motivated for a couple of sub par days in the Dakotas, followed by nothing at all for a few days, leaving my family home alone on Memorial Day weekend while I’m jerking around out on the Plains for no good reason. So for now I am just hanging tight, I would rather go out there for just a week in these conditions and not miss the holiday weekend at home. I can always change plans during this week if something changes, and I am pretty sure I’ll go out regardless for one week after Memorial Day unless it’s a total death ridge, but for now I’m staying put.

If anyone thinks this is a mistake then let me know!

 

[Clarence Bennett]

I continue to delay my trip, although I am now at the point where a delayed start ends up shortening it, not shifting it. I agree there could be some opportunities in the Dakotas Tue-Thu this week, but after that the Plains are scoured of moisture with a frontal passage, with weak NW flow and even northerly surface winds in its wake. The week after Memorial Day doesn’t look great either but at least the NW flow is stronger; won’t spend too much time worrying about “Week 2” just yet.

As much as I love chasing, I just can’t get motivated for a couple of sub par days in the Dakotas, followed by nothing at all for a few days, leaving my family home alone on Memorial Day weekend while I’m jerking around out on the Plains for no good reason. So for now I am just hanging tight, I would rather go out there for just a week in these conditions and not miss the holiday weekend at home. I can always change plans during this week if something changes, and I am pretty sure I’ll go out regardless for one week after Memorial Day unless it’s a total death ridge, but for now I’m staying put.

If anyone thinks this is a mistake then let me know!

James, my feelings are the same. In my head, I've pretty much closed the book on the season and moved on. I am actually planning a non-weather related trip to Tx after Memorial Day to do some cycling (avid cyclist here) and relaxing. You are doing the right thing by putting your family first. This pattern isn't magically changing. It's over as far as I am concerned...moved on.

Sent from my SM-N950U using Tapatalk

 

[Brett Roberts]

It's becoming fairly clear that the rest of May is a lost cause, at least for anything more than extreme fluke overperformers (think Campo or Jarrell) and marginal upslope opportunities. The only thing I'd caution against is declaring the entire season dead. I'm as disgusted with 2018 YTD as anyone, but long-term climo says June 1-20 is also part of the prime Plains chase season. And as dreadful as everything looks now, NWP is not skillful beyond D14, and most of June lies in that range. Years like 2005, 2009, and 2014 have shown that the pattern can turn around very late, even after a miserable May (sometimes extending into early June).

It's somewhat unlikely that we'll see any more high-end setups in the southern Plains this season (especially OK/TX), but if you're able to chase N of I-70, there's no particular reason as of today to think that June will be completely dead. Unfortunately, there are some haunting examples of terrible May patterns that simply persisted or got worse in June (1988, 2006, 2012), but there seem to be an equal or greater number of cases where things at least returned to climo for the final few weeks of the season.

I'm no optimist, and I think it's already safe to say 2018 will go down as a bad season, with the likelihood of "unspeakably bad/2006 bad" rising by the day. But if you totally take frustration and emotion out of the equation, it's still too early to close the coffin on the season just yet.

 

[Brandon Centeno]

It's becoming fairly clear that the rest of May is a lost cause, at least for anything more than extreme fluke overperformers (think Campo or Jarrell) and marginal upslope opportunities. The only thing I'd caution against is declaring the entire season dead. I'm as disgusted with 2018 YTD as anyone, but long-term climo says June 1-20 is also part of the prime Plains chase season. And as dreadful as everything looks now, NWP is not skillful beyond D14, and most of June lies in that range. Years like 2005, 2009, and 2014 have shown that the pattern can turn around very late, even after a miserable May (sometimes extending into early June).

It's somewhat unlikely that we'll see any more high-end setups in the southern Plains this season (especially OK/TX), but if you're able to chase N of I-70, there's no particular reason as of today to think that June will be completely dead. Unfortunately, there are some haunting examples of terrible May patterns that simply persisted or got worse in June (1988, 2006, 2012), but there seem to be an equal or greater number of cases where things at least returned to climo for the final few weeks of the season.

I'm no optimist, and I think it's already safe to say 2018 will go down as a bad season, with the likelihood of "unspeakably bad/2006 bad" rising by the day. But if you totally take frustration and emotion out of the equation, it's still too early to close the coffin on the season just yet.

Right.. even the unspeakable '88 had an active July and.. a 100+ tornado November (lol). The main message is that we're more likely to be "very bad" than to be "historically bad," meaning at some point this year something of an active day or two is probable. Or.. we could drop to that bottom tier and set new lows. If I could chase June I'd be substantially less frustrated/worried, but with June 3-17 totally off the table.. I'm convinced I'm going tornadoless, and that aside from a comical May 1st shattered windshield.. This season will be completely without a good memory.

 

[Jeff House]

This week I believe will offer a surprise or two up North. However I'm out of the field with my daughter's Kindergarten performance Wednesday. I believe Wed/Thu will be the best days (SPC thinks Thu/Fri).

If one considers Tue-Fri the sequence, Tue/Wed could be day(s) before the day the main trough ejects through the Dakotas. Tue moisture could be JIT. Wed moisture should be there. Both days feature and adequate somewhat backed LLJ. Upper winds are meager but nonzero. Tue/Wed appears northern High Plains (Denver/Cheyenne north) attm.

Later this week Thu/Fri the trough starts to eject and upper winds get to modest perhaps moderate. LLJ looks aligned well Thursday. LLJ veers off a bit Friday, even considering veering upper levels, and it gets more into forest areas. Thu/Fri appears Dakotas to Minn and Wisc. Nebraska or Iowa could get involved southern flank. NWP verbatim best flow north, but outflow could sink south still under modest flow.

I may have more to say tomorrow about after Memorial Day pending ECMWF weeklies tonight. Extended forecasts have less value later in the season as the meso-scale takes over, but more evidence of a northern Rockies trough starting around Memorial Day would be nice.

James I think you have a good plan attm. Mine is similar. If my personal thinking shifts toward SPC (slower) maybe I try this week. Option to keep waiting also remains. Punted last year, but that was easier while looking fwd to an eclipse.

 

[Royce Sheibal]

Tuesday-Friday, 4 Straight days of strong SE winds and temps near 90, with Td's flirting with 70 (and a lot of recent rains to ETP might not be being factored in well yet). Looks like June has arrived early. I would not sleep on these days, but they will be heavily meso-dependent and will rest on the strength of the shortwaves that eject. If any of you are still desperate to chase, I would park myself out in Central Neb / SD /KS. Maybe around Valentine as the north bsae, Kearney as the south, and use that as your home for the next week or four. Might move back south to OK near the end of the week.

 

[Andy Wehrle]

Not super impressed by Thursday on the GFS ATTM. You have to go to either far western NE or almost to the Canadian border in ND to find 500s above 35kt, and winds are totally unidirectional on forecast soundings in those areas. Same is true on NAM, and winds are even weaker.

 

[Brett Nickeson]

Not super impressed by Thursday on the GFS ATTM. You have to go to either far western NE or almost to the Canadian border in ND to find 500s above 35kt, and winds are totally unidirectional on forecast soundings in those areas. Same is true on NAM, and winds are even weaker.

The 12Z runs took a nosedive on Thursday's setup, which I figured they would. What was originally looking like a SD target with a well-timed shortwave now appears to be a near-Canadian target with the shortwave moving much quicker, and also mostly unidirectional winds as you mentioned. I suppose it can always move back the other direction, but the trend is not looking good at this point.

I suppose the best news we can gather so far is that the cold front prog'd for this weekend is trending much weaker and isn't a gulf sweeper. If only we could get more than 20 knots at 500mb in freaking May...

 

[JamesCaruso]

I remain uninterested in this week’s potential. I don’t see much of interest on Tuesday. Wednesday may have marginal 500MB flow in WY , possibly northeastern CO, but moisture is barely adequate in WY and hardly any in CO. (Thank goodness I’m not out chasing and in southeastern NM today and having to drive all the way up north for such marginal opportunities). Thursday could be interesting in the Dakotas or eastern Nebraska but the best flow (“best” being a relative term in this case) appears to be west of the best moisture, and relying on a cold front as the surface boundary - and an ill-defined one at that - isn’t a good situation. Even if I was out there I generally wouldn’t venture east into the terrain of WI or MN for Friday. The traditional Plains chasing regions should be under weak NW flow and even northerly surface winds (except in TX), with no moisture west of I-35, on Friday/Saturday. On Sunday the ridge axis shifts east into the central plains, with some southwesterly mid level flow edging into parts of CO/WY but these regions remain moisture-starved at that time. On Monday, too soon to worry about but it looks like the next trough follows the same pattern of lifting out and weakening, with some flow into CO/NEB, but no moisture to work with in CO and the better flow lags west of the moisture in NEB.

Next week still doesn’t look great but I ignore the models that far out and the good news is that there seems to be some changes from prior runs which could mean a pattern change as things settle out. Doesn’t necessarily mean it will be a favorable change but I’d rather see fluctuations than the same exact bad pattern every run.

Not denying there could be some chasing this week but my main reason for staying home is to not be away from my family for the holiday weekend if there isn’t going to be any chasing during that particular period. If it was really good this week, I would be out there and just deal with the down time on the weekend, I’ve done it before (including last year). But this week’s prospects just didn’t seem worth it.

 

[Eric Bucsela]

A glance at today's ensembles and 12Z deterministic GFS and ECMWF, and the word abysmal comes to mind - more or less consistent with previous runs. Perhaps some years are just intended for conserving resources. A recurring question I have: How often is high season completely hosed? It's easy to recall dead years like 1988, 2006, 2012, but these are anecdotes. Can anyone here say whether such years are becoming more or less common? Maybe this is a question for another thread. I do plan to sift through SPC's tornado database for an answer in my copious free time (lol).

 

[Greg McLaughlin]

Nothing scientific to back this up, but to me it appears as if the dominant pattern for the last several years has been for the Hudson Bay low and subsequent dreaded east coast troughing to hold tight with only brief breakdowns which lead to west coast troughing/east coast ridging.

 

[Eric Bucsela]

Nothing scientific to back this up, but to me it appears as if the dominant pattern for the last several years has been for the Hudson Bay low and subsequent dreaded east coast troughing to hold tight with only brief breakdowns which lead to west coast troughing/east coast ridging.

Yes, Greg, I've noticed this too. Another thing to look at is whether such patterns are balanced by exceptionally good years over a "medium" or "long" block of time and whether the standard deviation of "good" days is changing. Dan Robinson has some great thoughts on a metric to track quality of chase days in his thread a couple months ago "Coming up with an objective way to rank chase days/seasons". Maybe this would be a place to start for a more quantitative investigation. I took a look at this myself a few years ago with a simple count of days that had tornadoes meeting some size/diameter and/or tornado-count threshold and found it tracked pretty well with chasers' subjective impressions of whether a season was good or bad. I dunno, just idle thoughts in a season when there's time to sit home and ponder. How abnormal is 2018? (also worth a look: Brooks et al, 2014 in Science)