Wednesday is looking a little bit better with the 00Z NAM. I haven’t had time to check other models yet, but the NAM is usually my model of choice in the 12-72 hour window anyway.
Decent quality moisture is starting to work its way back on shore in south Texas tonight. Corpus Christi and Brownsville soundings had dewpoints at 62 and 66 with okay depth at 00Z. Low level winds are currently moving better quality moisture into south Texas tonight and should continue to do so through Tuesday. The LLJ should really start to ramp up by Wednesday and we start to get a good fetch of moisture from south Texas/the gulf back into the plains. Dewpoints are forecast to get into the low 60’s over eastern Kansas by Wednesday afternoon and for the first time this season I think I might actually be buying what the NAM is selling on moisture return. I don’t think it seems unreasonable given the moisture available in south Texas and the NW gulf and the decent window for advection. My one big concern on that topic is morning convection/crapvection over the warm sector in southern Oklahoma/northern Texas inhibiting moisture return. We got burned on that so many times last year. A southern stream jet streak nosing into the area early in the day seems to be the trigger. If convection isn’t more extensive than is currently being forecast, I think we’re okay in the central plains. The NAM currently shows precip being pretty sparse until it moves into Arkansas and northeast Texas early in the afternoon. We can work with that as it shouldn’t have any major impact on moisture return into Kansas. However, if morning storms get well established closer to the dryline in Oklahoma and it persists over that area it could be an issue. Below is a grab of the NAM reflectivity graphic for 18Z on Wednesday showing the morning crapvection getting going over southeast Oklahoma and northeast Texas.
I’m kind of getting ahead of myself though so I need to jump back to the basic surface pattern for Wednesday.
A surface low should deepen through the day on Wednesday and migrate east along the Nebraska/Kansas border. The dryline should be located just west of the 135 corridor across Kansas by early afternoon (see map at beginning of post). Storms should develop along the dryline from central Nebraska down into at least northern Oklahoma during the afternoon. Deep layer shear approaching 60kts and moderate instability ahead of the dryline will be favorable for supercells. Despite this being a positive tilt trough and the LLJ veering a bit and shifting east, the NAM still shows a pretty much straight N-S dryline orientation. The GFS is a little quicker with the shortwave and drags the dryline out into more of a NE to SW orientation. Storm motions should be northeast, keeping them normal enough to the boundary (assuming it’s N-S oriented) and they should also get off the boundary pretty quickly, so I’d expect at least semi-discrete storms across Kansas and northern Oklahoma.
The biggest change that I saw with the 00Z NAM from earlier runs is it is showing fairly solid 850-500 crossover later in the day ahead of the dryline. With positive tilt troughs you tend to get veering low level winds and poor directional shear. The NAM has 850’s backing later in the day. The surface low is deepening, but the NAM may be a little too aggressive with backing low level winds. The 12Z GFS wasn’t nearly as aggressive with backing low level winds, but it seems like the GFS is usually on the opposite end of the spectrum from the NAM when it comes to juicing setups. I’d guess the truth is some place in the middle. I’d also guess how much low level winds back is a big driver in the tornado potential on Wednesday. If something closer to the NAM verifies then I do think we’ll see some tornadoes (assuming moisture return is half way decent and not interrupted by morning storms). Below is the forecast hodograph for east central Kansas from the NAM
I think I’m chasing regardless since this is close to home, but if low level winds can back like that and we get dewpoints in the low 60’s with moderate instability, then I think it’s game on Wednesday evening. It looks like the best tornado potential could be right across the flint hills area, which is god’s country if you’ve never chased there before. I’m not a huge fan of chasing the flint hills, especially with fast storm motions, but I’ll go wherever I think the best tornado potential is on Wednesday. Plenty of time still to sort out those details.
That’s enough rambling for tonight. I’ll try to get my post a little better organized for tomorrow lol. Usually I try to follow an organized sequence with my forecast posts, but I was tight on time so you got the quickly typed shoot from the hip version tonight. Long story short, there is definitely some potential for tornadoes on Wednesday, but there are still some uncertainty in details that will play a big role on whether or not that potential is realized. I’ll try to get a quick post up after I see morning runs. I’ll also get a more thorough forecast post up later tomorrow night. I’m pretty busy at work still and I’ve been scrambling trying to get some of my equipment ready. I’ve been blowing that off like it’s my job. I have the basic stuff I need setup in my car so I’m good, but I’m still trying to get my roof mount camera setup. That and I’m trying to figure out the layout for my interior cameras and I changed video editing software so I need to get up to speed on that real quick. Lots to do and not much time to do it. Anyway, check back tomorrow for updates if you’re interested.