2018 severe wx/chase season discussion

Discussion in 'Advanced weather & chasing' started by Warren Faidley, Feb 6, 2018.

  1. Jeff Duda

    Jeff Duda Resident meteorological expert
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    Staff note
    There have been a number of digressive tangents that have spurred off of this conversation lately. Please put discussion of individual past events in their appropriate EVENTS threads and send other unrelated discussion to their appropriate threads so this thread can remain on the topic of discussing future chaseable/severe weather events in 2018.
     
  2. Stan Rose

    Stan Rose EF4

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    Guess I should be happy since between marriage and moving I had no time to chase anyways, but yeah this has not been a good season. Fortunately some of the better days have been close so Tescott and Cope were decent days. But anytime we get a string of 99-100 degree days in eastern Colorado in early June, usually not a good sign of things to come. May see some regional events coming up next week as pointed out, but CAPE looks limited. Hopefully the monsoon season will be a good one since that is where I am headed next...will have to seek photo inspiration from Warren's lighting collection... Hope the last couple years are not the start of a long term trend, cause 2018 did not have much to offer from a 'classic' Plains trough standpoint.
     
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  3. Brett Roberts

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    This didn't age well. The large scale pattern only got worse heading into June, and aside from a couple flukey mesoscale accidents and landspouts, so did the chase season.

    Now that work commitments are at a minimum for me, I'm willing to head north for virtually any string of marginally interesting days -- but I'm just not seeing it on the guidance over the next 10 days. Thursday in ND is intriguing but flawed, and none of the days around it look remotely chase worthy, even by the lowest standards. Every time decent flow impinges into the Plains this month, it seems to be associated with an anafrontal regime where the surface front is collocated with the leading edge of >25 kt flow aloft. This is forecast to be true most days this week into this weekend, for example.

    As the late June climatological falloff comes into focus in the medium-range guidance with no encouragement in sight, it's becoming quite likely that 2018 will find company with 2006 and 1987/1988 as one of the very worst Plains seasons on record. It's true that some stunning imagery and a few quality tornadoes came out of the season (primarily the "73/45 miracle at Laramie" and Tescott), but this is the climatological tornado hotspot for the planet, and even the worst season ever will have a few big storms. I'm convinced that underreporting, no smartphones, and a general lack of "never stop chasing" folks even 12-15 years ago makes it difficult to assume something truly flukey like the Laramie storm would even get noticed back then (at least, if it didn't happen to be near a large town). With that in mind, it certainly seems within the range of possibilities that 2018 has been even worse than 2006 and other bottom dwellers of the historical record.

    For those of you heading to ND/MB/SK this week, you can either thank me now or after the fact for this anti-jinx!
     
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  4. Quincy Vagell

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    Reoccurring themes from the past 5-7 weeks, some of which are evident over the next three days, in addition to the ever highlighted weak deep layer flow:
    • Inverted V profiles from hot surface temps, and/or poor boundary layer moisture
    • High LCLs
    • Weak low-level shear
    • Storms lining out/growing upscale quickly
    Today features dew-points up near 60F as far west as the CO/KS border and mid to upper 60s in southwestern Kansas. Despite vertically veering winds with height and "good" moisture, 0-1km and 0-3km shear are both very weak and even with the moisture, surface temperatures in the 90s produce glaring inverted V profiles in most areas.

    Tomorrow is another nuisanced day with a similar pattern, but you can't rule out a flukey tornado somewhere in the High Plains as shear improves to some degree.

    I haven't gotten into a heavy analysis of Thursday yet and at quick glance, the combination of shear and quality moisture looks appealing, but one has to wonder how quickly storms may line out.

    Even though there may be some western U.S. troughing next week, the Euro shows more weak upper level winds. The CFS, for a third day in a row, has a glaring signal for a very unfavorable pattern around June 17-21.
     
  5. Devin Pitts

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    Seeing some signals for some increased flow over the midwest towards the end of this week/beginning of next week. Expectations are low, but at least its something.
     
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  6. chrisbray

    chrisbray EF4

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    Given its likely the last weekend of the season, I am eyeing Sat/Sun for a possible trip. A decent signal for something to occur on saturday, although who know exactly what at this point. Sunday has a lot more uncertainty.

    [​IMG]
     
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  7. Billy Ahlers

    Billy Ahlers Lurker

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    Hello all!! New here. Figured I throw in my two cents worth... For me its been a rather successful chase season. Catching both the Landspout tornadoes 5/28 near Anton Co and the tornado on 6/19 in prospect park Co. There have been numerous out and out busts too. This was a bad snow year in our mountains due to the jet stream being too far north. My experience on years like this, is that severe weather isn't as frequent in NE Colorado. I have been amazed at how little lightning has been associated with any of my chases all year. Even the two tornado days had little to no lightning. I assume we are not getting the instability we usually have. I am guessing and its really just that...most of our storm systems have been hugely outflow dominant so the missing ingredient has been that strong updraft. Capping and low level cloud cover has hurt too. Am I even close ? As to why so little lightning? Not getting the friction due to lack of height?
     
  8. Mark Blue

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    I’ll probably be proven wrong by those who do deeper analysis of severe setups, but my anecdotal thoughts follow. There have been a handful of nice tornadoes and landspouts in CO and WY this year, so I’m not complaining by any stretch

    However, if you look at the four primary ingredients required for a severe thunderstorm: instability, moisture, lift, and wind shear; and speaking mainly for the Palmer Divide, I’ve noticed a lack of well-defined boundaries this season. During years past I recall east west boundaries, such as stationary fronts lining up along the Palmer Divide, which would allow for differential heating along the boundary and/or low level convergence to provide additional lift. It seems this year the boundaries (cold fronts tied to upper level short waves) have been located to the north in WY and the dryline to the east along the CO/KS border a majority of the time. There have been a few setups with a lee side trough as well, but some of the aforementioned setups have been wrecked by persistent stratus decks that inhibit surface heating. It seems fewer outflow boundaries from previous evening’s (MCS activity) have also been lacking, such as the one that produced Simla.

    In any event I was able to witness the landspout-fest out by Flagler on 5/28, so I’m satisfied with the season. I also took a few baseballs for my trouble on the southern cell on 6/19, so that was a rather new experience for me. In 13 seasons I have tried my best to avoid gorilla hail and have been able to do so, but not that day. I was caught out by a 15 minute old radar scan that slipped my attention. Having a partner really helps in those scenarios, but I have to go solo if my wife isn’t on vacation. We’ll hopefully have a couple of July setups left with the DCVZ, so I’m hoping to bag one more landspout for the books.
     
  9. Dave C

    Dave C EF1

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    I agree with that assessment. In general, winds are what has been wrong this year. The placement of jet stream and resultant lack of upper level support or organized turning with height has been the missing ingredient in almost every setup, plains or otherwise. Lack of that upper level movement is also the reason for stagnant patterns that produce harmful outflow regions or stratus decks, etc. that normally would have cleared out or setup to enhance storm activity, but have ruined a lot of #2018 borderline setups during shortwave events. I've seen plenty of moisture and instability and initial weak forcing for initiation but rare that it has been timed with sufficient strong forcing or bulk shear for anything but a rainy mess time and time again this year. Bad hodographs almost every event, and the ones that produced were all reliant on localized increase in SRH, orographic forcing, perfectly placed OFB, or the rare well timed LLJ. The atmosphere has been becalmed and stagnant on more days than I can remember and I see this not just with storms season but with sunsets / sunrises frequency greatly reduced to grey mush. I never felt like I saw a storm this year explode out in clear air with good shear. I've become very selective on what I chase now and add a #2018 pessimism factor to most setups.


    Still, if some thinking is correct, we may have an active monsoon which will bring increased pulse storm activity for those of us inclined to chase summer lightning. That is where I'm turning my attention.
     
  10. Jeff House

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    All of the above problems would be solved by a true synoptic system, which were few and far between. Rather than closed lows, one looks for shortwaves within a broad trough. Earlier in the season a phased system brings the outbreak. Just did not happen this spring. Good for the people, but it frustrates chasers.

    Perhaps the PDO is the problem. It was positive. Good years in the past had a -PDO background. Like anything it's never a perfect correlation. I have eyeballed* the data and believe the PDO is more important than ENSO or even TNI. PDO has been awful the last few years. Some of the good chasing a decade ago was during the more favorable PDO phase. Ditto for the early 90s and the late 50s through 70s. The slow years in the 80s and later 90s were unfavorable PDO.\

    * not a rigorous study but looks reasonable
     
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  11. Andy Wehrle

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    Agree PDO seems to have the strongest correlation to Plains/Midwest chase opportunities of any of the teleconnections. However, according to this:

    https://www.ncdc.noaa.gov/teleconnections/pdo/

    the PDO was slightly negative for all of spring 2018. The atmosphere had/still has bigger problems producing severe weather in the central CONUS on a significant/synoptically predictable scale.
     
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  12. Jeff House

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    That NCDC site is a great resource.

    Yes the PDO was slightly negative, but got to that reading in a strange way. Central Pac is clearly warmer than the area near the North American West Coast. However the latter still has AN SSTs. So while the PDO was negative the ATMO really did not respond in kind.

    Yes this year the ATMO did have other big problems. SSW going into spring was awful. Then upper level lows from the Gulf came early and often.

    We need some good BN SSTs off our West Coast.

    All of this 2018 debacle would be so much easier to take if we had another total solar eclipse coming, lol.
     
  13. Jeff Duda

    Jeff Duda Resident meteorological expert
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    No individual low-frequency climate oscillation singlehandedly explains any given event. You need to look at the sum of all the oscillations. While there may be a correlation between -PDO and quality spring chasing, there are many other factors such as ENSO, NAO, NPO etc. that will also exert a substantial influence on the ingredients needed for a good chase season.

    I agree with Jeff that the problem this season was just a general lack of synoptic scale waves that came through the central US. For whatever reason they just were not being generated over the E PAC and W CONUS like they usually are. I don't know the cause of it.
     
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