Jeff Snyder
EF5
Well, at first glance, model forecasts show a pretty robust setup tomorrow across parts of western and central OK and adjacent areas of KS and TX. Hodographs, particularly below 700 mb, generally look quite favorable for even a significant tornado threat. I won't spend time on the "pros" for the event since they are apparent (high CAPE, strong low-level shear, adequate deep-layer shear, relatively low LCLs, etc.). So, I'll spend some time on a potential negative...
As we all know, the devil is in the details, and minor things can have major effects on a forecast. It's worth noting that the ongoing MCS in western TX northeastward into southwestern OK is putting down a lot of low theta-e outflow across far western OK and the TX panhandle right now. Temps have dropped into the mid 50s and dewpoints have fallen into the low-to-mid 50s. This may be relevant for tomorrow because, with such an expansive cold pool, it can take non-trivial amount of time to advect or vertically mix that slug of cold/dry outflow air away. I'm stating the obvious a bit here since we've had a couple of cases this year in which prior storms detrimentally modulated the severe risk anticipated for later. This may indeed happen for tomorrow's setup depending upon how long this MCS lasts. For example, 19 z temps are a good 15-20 F colder in these areas compared to the 18z forecast from this morning's NAM run. I'd have to think that this mess will continue to drift southeastward given recent radar obs, which may mean that the outflow pushes closer to central Texas. In turn, this means that the good juice will have quite a way to advect to get up into KS for the northern part of the target area. There is no synoptic push for this outflow at least (the "background" low-level flow is southerly or southeasterly), but it's entirely unknown how far south this outflow will get today.
I don't think this will have a major impact since we're 24+ hours before the event and the LLJ should be pretty strong tonight. You never know, though. The 12z 4 km NAM is too far north with this ongoing activity as it is. *If* outflow from today's activity doesn't affect the low-level thermo tomorrow, then we could see a potential severe weather outbreak across the area.
As we all know, the devil is in the details, and minor things can have major effects on a forecast. It's worth noting that the ongoing MCS in western TX northeastward into southwestern OK is putting down a lot of low theta-e outflow across far western OK and the TX panhandle right now. Temps have dropped into the mid 50s and dewpoints have fallen into the low-to-mid 50s. This may be relevant for tomorrow because, with such an expansive cold pool, it can take non-trivial amount of time to advect or vertically mix that slug of cold/dry outflow air away. I'm stating the obvious a bit here since we've had a couple of cases this year in which prior storms detrimentally modulated the severe risk anticipated for later. This may indeed happen for tomorrow's setup depending upon how long this MCS lasts. For example, 19 z temps are a good 15-20 F colder in these areas compared to the 18z forecast from this morning's NAM run. I'd have to think that this mess will continue to drift southeastward given recent radar obs, which may mean that the outflow pushes closer to central Texas. In turn, this means that the good juice will have quite a way to advect to get up into KS for the northern part of the target area. There is no synoptic push for this outflow at least (the "background" low-level flow is southerly or southeasterly), but it's entirely unknown how far south this outflow will get today.
I don't think this will have a major impact since we're 24+ hours before the event and the LLJ should be pretty strong tonight. You never know, though. The 12z 4 km NAM is too far north with this ongoing activity as it is. *If* outflow from today's activity doesn't affect the low-level thermo tomorrow, then we could see a potential severe weather outbreak across the area.