Well our little active stretch that is in full hype mode within the chaser community still looks to kick off on Friday. The setup looks fairly straight forward with a surface low in NE Colorado and a dryline running north south through western Kansas and down into the far eastern Texas panhandle (near OK border). A mid level jet will nose into western Kansas during the afternoon, which should give us around 40kts of deep layer shear. Dewpoints are forecast to be in the mid 60’s and with good surface heating over the warm sector we should have moderate instability. Shear/CAPE combos are definitely supportive of supercells and with shear vectors nearly perpendicular to the boundary discrete supercells should be the favored mode of convection along the dryline. There’s a bit of a question mark with storm coverage. The models haven’t shown much in the way of precip before 00Z, but you can’t trust them at all on precipitation. I think there will be scattered storms along the dryline if we realize dew points in the mid 60’s, so moisture return will be something to watch later this week as we get closer since it could be important. My thoughts on the tornado potential are about the same as before. I think slightly high LCL heights and only moderate shear will be mitigating factors for tornado potential to some degree, but we’re still looking at a 10% or so tornado probability type threat if you want to go by SPC standards. My plan as of now is to take off at noon on Friday and head out towards the Dodge City area (target obviously subject to change). I still like the SW Kansas area where I think you have the best compromise of overlap with the mid/lower jets and better quality moisture coming up from the south. That’s where I’d put the best tornado potential as things stand now.
As far as Saturday goes, I’m really not impressed. I’m a tornado chaser mind you. I’ll get out occasionally for structure, but I’m after tornadoes 99% of the time and it just doesn’t look like a good setup. There’s the potential for storms over the warm sector early in the day and I think low level winds will be veering which will put a major dent in the 850-500mb crossover relative to Friday’s setup (the GFS also shows backing in the mid to upper levels). For that reason I didn’t even include a tornado threat area on my map despite SPC including it in their latest 4-8 day outlook. You may eek out a weak tornado or two with a setup like that, but I doubt I chase as things stand now. Long ways out though so things could change.
Sunday appears to be a down day. Any severe potential will be lower end. It’s also the final episode of Game of Thrones so ole Mikey will probably be staying home and prepping for the next round of chasing which looks to be Monday. The models have been jumping around a lot with Monday’s setup, so take this with a huge grain of salt. Even though they’ve been jumping around a lot, there’s also been consistent indicators that this could be a high end tornado setup. Dewpoints are forecast to be in the low 70’s with surface heating over the warm sector leading to very strong CAPE values across the warm sector in south central Kansas and Oklahoma. There isn’t a distinct shortwave with any sort of amplitude, it’s just strong SW flow aloft so there isn’t going to be much upper level support to help kick storms off. That may not be a bad thing considering that extensive storm coverage probably screws up more tornado setups than anything. It is way too far out to be getting that cute with forecast details, but I’ve been watching it so close it’s hard not to talk about tendencies your seeing with finer scale details even though you’re 7 days out. Despite the lack of upper level support, the GFS has consistently broken out storms near the triple point and along northern portions of the dryline. Assuming we get storms, the GFS has been showing a very potent combination of CAPE and shear across the warm sector. Hodographs have been quite impressive with strong low level curvature and good length. What the GFS is selling is a high end tornado setup. Long ways to go, but it looks the best day to me for strong tornadoes.
Beyond Monday there is still way too much uncertainty with the evolution of the upper air pattern to take a guess at what may happen. Earlier runs of the GFS had another shortwave ejecting into the plains Wednesday/Thursday, but later runs have shown a ridge building in over the plains. The GFSV3 is a little less aggressive and centers the ridge farther SE allowing shortwaves to still move out into the plains. Given the uncertainty I’ll hold off for now on getting into it. I imagine we’ll stay in an active pattern and the ridge building in is exaggerated in the most recent runs of the GFS, but we’ll have to wait and see.
That’s all I got for tonight. Don’t take any of this too seriously. We are a long ways out and it could easily change. I’ll be watching it as always and update again tomorrow some time so check back then if you’re interested.