Complex Texas Setup 4/26
Model forecast for 1 p.m. showing three areas of focus.
After a brief break in the action, the severe weather threat is ramping up again in the Plains today. The focus is on the southern Plains, particularly in central to north Texas.
What complicates this chase day is how complex the setup is. Ripples of energy will swing through Texas today, ahead of a potent shortwave. That shortwave will not bring strong forcing into central Texas until tonight, so it’s what happens before that will be closely monitored. A small perturbation in the vorticity field is progged around midday, which will most likely fire some showers or weak thunderstorms in north-central Texas. Assuming that convective activity does not completely overturn the atmosphere, some stronger thunderstorms, with a few embedded supercells, should then fire by mid to late afternoon. This is along and just ahead of the dryline and as better dynamics move in aloft. Into the evening, as the shortwave approaches, convection should continue into the night, although the significant severe risk should tend to ramp down after 10 p.m.
The greatest risk today appears to be large to very large, destructive hail. Although some storms may have hail early in the afternoon, watch for that threat to increase through the day. Damaging winds are also possible with the strongest storms and more widespread damaging winds can develop into the evening as thunderstorms merge into complexes. As for the tornado threat, it’s there, but it will take just the right chain of events for it to be significant. If midday/early afternoon convection does not disrupt the environment much, that will enhance the tornado threat. Additionally, if discrete storms can fire in or mature into the late afternoon and early evening hours, look for a greater tornado threat. This is when the low level jet cranks and models insist on stronger backing of near-surface wind fields. The high resolution, short-term model guidance shows mixed signals on the tornado threat, as the storm mode could get messy, limiting any isolated, discrete supercells.
In terms of chasing, tornadoes or not, I think today holds some good potential. At the very least, we get a couple of rounds of storms firing and the aerial extent is larger than the 4/24 chase in Kansas. Also, we’re looking at at least moderate instability, as a worst case, and quite possibly strong instability in pockets, especially if enough of the area can maximize daytime heating. For tornado prospects, I think at least one or two tornadoes appear likely, but can they be long-lived and/or strong? While the potential is greater for that than we saw on 4/24 in Kansas, it’s highly dependent on how the setup evolves late this morning into the afternoon.
