There will be a locally enhanced threat of thunderstorms for portions of the Plains up into the Midwest/Ohio Valley. Strong to severe storms are likely tomorrow, with big hail and damaging winds as the primary threats. However, a couple of tornadoes will also be possible.

Locations:

  • Eastern Missouri
  • Southern Illinois
  • Extreme southwest Indiana
  • Northern Texas
  • Central Texas

Threats:

  • Powerful wind gusts (main threat in the Ohio Valley)
  • Large hail (including the potential for hail 2+ inches, especially in central Texas)
  • Potential for a few tornadoes (mainly Ohio Valley)

Timing

  • Thursday afternoon into the evening

Discussion

Atmospheric Setup: A weakening surface low and trailing cold front will push through the region, triggering storm development.

Favorable Conditions:

  • Ample low-level moisture and cooling temperatures aloft will create instability.
  • Sufficient wind shear will support storm organization.

Storm Evolution:

  • Storms will develop along the cold front during the afternoon over both areas.
  • In the Ohio Valley, multicell storms will quickly grow into an MCS (Mesoscale Convective System), posing the most significant threat of widespread damaging winds.
  • In Texas, multicell thunderstorms with a couple of supercells are likely, with a severe hail and wind risk expected. Due to steeper lapse rates and stronger mid-level winds, Central Texas could see a few instances of very large hail. 

Tornado Potential: The Ohio Valley has some potential for embedded mesovortices and a few tornadoes within bowing segments of the storm line.

  • The risk is not zero further south and west from Arkansas to Texas, but it is very, very low due to weak low-level wind shear.

Technical Storm Chase Discussion

Refcmp uh001h.us sc-26.

Storms will form into a line to the north and will be more cellular to the south and west. In either location, expect storms to fire in strong instability by mid-afternoon. With the weak 0-1km hodographs and slightly elongated shear profiles aloft, very big hail is possible — especially in Texas.

Rrfs a 2024041712 033 area 35.4-36.02.-94.47--93.61.

A sounding analysis of the northern target area shows unidirectional winds with over 40 knots of 0-6km shear. Vectors are actually more perpendicular to the cold front than not with the WNW flow aloft, but the linear forcing and lack of strong capping will still result in a more linear mode rather quickly. Still, given 0-3km SRH of 180+, along with 3CAPE values of 50 j/kg and higher, a tornado or two could occur early on. As storms line out, quick spin-up tornadoes on the front edge of the line will be possible, especially as low-level winds increase in the evening.

Rrfs a 2024041712 033 area 32.42-32.87.-97.58--96.73.

Further south, the setup looks like something out of June. Strong to extreme instability will be present but with 0-6km shear values generally below 30 knots. Still, this setup can yield a highly deviant, right-turning supercell, given the curvature in the wind profile. Deviant movers should be nearly due south at a very slow pace. I honestly have a concern for one of these supercells to form over the DFW metroplex as they’d drop giant hail for extended periods in any given place. This is something to watch for and could be a locally very high-impact severe weather event. Tornado risk-wise, despite extreme instability, the wind shear is very meager overall. I’ve seen a tornado happen in an environment like this before, but they’re more rare.