Expect supercells to form this afternoon across NE Texas and SE Oklahoma with an attendant risk of very large hail and tornadoes. The threat should last until after dark with the risk slowly waning after 9 p.m. or so.
The Setup
Broad southwesterly flow aloft atop very rich moisture will result in low to moderate instability across the risk area today. This is a classic early season setup for this part of the country.
- In a lot of ways, this feels like a warmer setup than we’ve had. This is because it isn’t necessary immediately ahead of a major system, which actually ejects tomorrow.
- A lot of times, setups in these broad SW flow regimes ahead of major systems result in much more robust supercell development because the forcing/capping balance is more favorable for more isolated storms.
The Environment
- Wind shear todeay is on the very solid end of the spectrum, but it isn’t like what we saw earlier this week to be sure. More than adequate shear for supercells is in place with 0-6km bulk shear over 55 knots and with 0-3km storm-relative helicity at or above 250 m2/s2.
- Instability is low to moderate, with MLCAPE on some forecast soundings topping 2000. Generally, instability is running above 1500 which is, again, pretty solid this time of year.
Storm Mode and Timing
Storm modes should be complex and mixed — but some supercells are likely to evolve this afternoon across NE TX/SE OK and into the Southern 1/2 of Arkansas. Most models maintain a reasonable environment until at least 9 p.m. tonight, with the threat slowly waning after that.
The Bottom Line
This is another storm setup that I’m not a fan of for storm chasing. Complex and mixed modes with the early season fast storm motions aren’t usually that great for imagery, especially in the terrain these storms are going to be running through. Still, if you live in these areas, have a source of weather information handy throughout the day!
