State of the Chase Season: 2017 Edition

[James Gustina]

There might be a slight sliver of hope with some more low-key setups towards the end of next week but the details are still extremely muddled. GFS has been hinting at the possibility for a NW flow dryline day tossed in with a somewhat more pronounced westerly component to the jet by the next Monday. Obviously this doesn't really help out the chasecation crowd but:

 

[James Gustina]

Just building off my previous post, GFS and Euro are coming more in line with a possible event next Friday/Saturday with a late May massive instability/modest shear day along a pretty sharp dryline. In the more immediate future, Monday also has the possibility to maybe put out some weak upper level flow supercells along the edge of the Edwards Plateau/Llano Estacado should things not all congeal at once (a big if when your shear is <30 knots).

 

[JamesCaruso]

^ Yeah, my trip is supposed to start next weekend, I was thinking about delaying a couple days, didn't want to miss Memorial Day Weekend with family if nothing was going to happen out there anyway, but Friday looks like it has potential. One problem is that GFS paints the highest instability in the trees of OK east of I-35. But maybe a triple point play in southwest KS, the instability and 500mb flow are both weaker there but probably better forcing, backed surface winds, and far better chase terrain, some of my favorite actually. Need to figure out today where I am going to fly into.


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[Ethan Schisler]

My original trip was supposed to start May 26th, but we pushed it back to June 5-12th at the last minute. I'm seeing the GFS showing some interesting stuff this weekend, so it might be enough to bait me out. Considering I've been out chasing for the past several days, I gladly welcome some down-time, especially when you're a solo driver lol. I have my best tornado luck in June anyway, so bring it on!

 

[Jeff House]

Agree Thu-Sat this week has potential for chasers, though no big outbreaks. Modest WSW flow over DL, instability and perhaps other boundaries. Though national wx chart is a mess, in late May only the regional Plains chart matters. Then centered around weekend of June 3 could be another chance. Heights are up on ensemble averages, but some ensemble members hint of another West trough. MJO is friendly to first week of June as well. While synoptic days may be winding down, chase season still looks good for a few weeks.

 

[Ethan Schisler]

I don't really like what I see the next week over the plains. Each day certainly has some potential with high instability values, but I question whether or not the moisture will return by Thursday/Friday to get the full potential out of this. Saturday looks like things may shift eastward now toward the Mississippi River valley and Sunday is gone. I know its late May and anything can happen, but the overall synoptic pattern coupled with the fact that on each of these days the low level jet appears incredibly veered, doesn't leave me too exited. And then for the fact that it looks to take a break for a few days at least next week. All I know is I'm glad I pushed my chase-vacation back. I may be sitting close to home as that is an historically active period for IL/IA for tornadoes (June 5-12). We will see I suppose.

 

[Jeff House]

Early June looks good, esp if one considers the northern Plains. MJO assisted forcing should be friendly to the model forecasts of jet extension(s) into the Plains. Yeah this week is on the down trend. Might be some warm front action in Illinois. Plains is hampered by cap and LLJ issues; but, the latter might solve the former. Still a high CAPE environment with boundaries. Really both periods are doable for trips.

 

[JamesCaruso]

I am hopeful there may be some CO upslope on Friday. There is sufficient moisture, and the LLJ is southeasterly in that area. Negative is the 500mb flow is not as strong as in TX/OK. Also as Jeff H. noted, magic can happen in high CAPE environments.

For me personally, it is very tempting to delay my trip so I can spend Memorial Day Weekend at home with my family and then next week take care of some recent work emergencies. But I feel like the longer I delay getting out there, the more additional things can go wrong to keep me from leaving the following weekend. I have a hard stop on June 10 so might as well optimize the time available to me.


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[Jeff House]

I agree with some Palmer Divide magic in Colorado Thursday and maybe Friday. If the boundary sinks south one could work the Raton Mesa magic Friday. Both days storms may move into Kansas in the easterly flow, but esp Thursday may get messy in KS. Colorado would be the target.

Tough call going out for the event. Friday and Saturday will have high CAPE under enough WSW flow in the central/southern Plains. Cap near DL could be breached with enough convergence. My main concern is squirrelly LLJ progs. Trying to remember some good days where the LLJ did not resolve until morning. Day before and day after DDC last year, including Chapman? Maybe even Bennington a few years back? Anybody remember? It is a big question if facing an 8-12 hour drive, lol.

Pattern recognition still says, heck yeah. However this year seems to be real fickle, perfect set-up or goes to slop. Perhaps late May magic will take over. Otherwise hope beginning of June works out.

 

[JamesCaruso]

While I am still optimistic about Friday in Colorado, the GFS looks absolutely pitiful for most of my chase vacation after that (I come home the weekend of June 10). Northwest flow in CO and the northern Plains, weakening as time goes on. No sign of the trough that was supposedly going to be centered around the weekend of June 3, at least not on the GFS although the Euro still seems to hint at that, with a weak trough over AZ under the main flow up north at 240 hours. Meanwhile the ERTAF forecasted average tornado activity next week and above average the week after that. The CFS dashboard had been looking good for the period as well. Obviously we are far enough out that the GFS can flip back, and admittedly it's just one model, with the Euro looking a little better. So there is still hope. But next week does not look too exciting, we just have to hope for smaller perturbations not yet resolved and/or northwest flow events. I almost feel guilty going out there, leaving work responsibilities and family for pretty much no reason (although I can at least handle some of the work stuff from the road).


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[Jeff House]

I would fly to Denver. Palmer Divide Thursday. Raton Mesa Friday. Rocky Mountain hiking over the weekend. Blow off the southern Plains. Central Oklahoma Saturday of Memorial Day weekend? Nah. Honestly if one had to stay out all next week, no going home, I'd just delay the start of the trip instead.

Better trough is still forecast on ensembles and weeklies after June 1. Waiting is not such a gamble. Per ERTAF climo, the first week of June is as good as the peak weeks of May.

 

[chrisbray]

Things aren't looking so good this next week+. Feels like a broken record

 

[James Wilson]

There looks like a lot of marginal days coming up but then again those are the days that seem to pan out. Looking forward to a few 2% days this next week.

 

[Jeff House]

Next week (of June 4) the Euro is starting to introduce modest westerly flow over the central Plains. GFS has been bullish for a while. Both models have the LLJ responding some days, but it will depend on impulse timing.

Following week (of June 11) ensembles favor moderate flow over the Plains. Lots of spread on position and strength of flow. Also weekly charts hint at a bullish pattern change mid-June. Now this is a week later than first forecast, but delays do not always mean cancellations.

One thing is constant. North Pacific jet is screaming and forecast to continue to do so. Despite the North American debacle, this Pacific forecast is persistence which adds some confidence. If just a piece comes over the Rockies by mid-June it is game on!

 

[JamesCaruso]

Nothing after next week is of much help to me as I am only out until the 10th. After arriving Friday morning and chasing Friday/Saturday, today is our third down day and I don't see much of interest on the horizon until Sunday or maybe Monday. I wouldn't say GFS has been "bullish," unless I am missing something I saw at best marginally adequate (30 kt) westerly flow mainly Tue/Wed next week (did not look at 12Z runs yet so maybe that's what is being referred to?) My chase partner is actually heading home for a few days rather than sit out here for nothing.


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