Strong to severe thunderstorms are expected today from the Upper Midwest to the Southern Plains. The greatest potential for severe weather, including large to very large hail, severe gusts, and a couple of tornadoes, is over parts of northwest, north-central, and central Texas.

Locations:

  • Primary Focus: Northwest, north-central, and central Texas.

Threats:

  • Large to Very Large Hail: Hail sizes may exceed 2 inches in diameter.
  • Severe Wind Gusts: Potentially damaging wind gusts.
  • Tornadoes: A tornado or two are possible, despite very weak low-level wind shear.

Timing:

  • This afternoon into the overnight.

Discussion:

Weather Patterns: A mid/upper-level complex cyclone over southern Saskatchewan and eastern Montana will slowly move eastward along the international border. Shortwave troughs orbiting this cyclone will influence the weather across the central and eastern Dakotas into the evening.

Atmospheric Dynamics:

  • Surface Features: A surface low near St. Joseph, Missouri, with a cold front extending from northeastern Kansas through the northern/western Texas Panhandle and into north-central New Mexico. A dryline is positioned over the Llano Estacado near the Texas/New Mexico line.
  • Storm Development: Isolated to scattered thunderstorms are expected to develop this afternoon along the dryline and cold front from southwestern/central Kansas to southwest Texas. The greatest concentration of severe potential will be in northwest, west-central, and south-central Texas.
  • Severe Potential: The environment will support large to very large hail as the primary threat due to strong lapse rates and substantial CAPE (3000-4500 J/kg). Tornado potential may increase due to interactions with the residual outflow boundary, providing low-level vorticity that could enhance supercell organization despite some weaknesses in flow aloft.

Impact: Today’s weather setup suggests severe thunderstorms capable of producing very large hail, damaging winds, and maybe a couple of tornadoes, particularly in the designated areas of Texas. This region will be key for monitoring as thunderstorm activity intensifies in the afternoon and persists into the evening.

Technical Discussion

500mb mean.sp.f01100.

Overall flow today will be weaker than in days prior, with only a small pocket of enhanced 500mb winds in the region. With no discernible powerful system, cyclogenesis and low-level wind fields likely won’t respond as readily as in days past into the late-afternoon and evening.

850mb mean.sp.f01100.

Indeed that is apparent with 850mb winds generally at or below 10kts across the entire region. You have to get east of the mid-level flow into an area we aren’t expecting much activity to see the low-level jet really cranking up into the evening.

Srh01 mean.sp.f01100.

Unsurprisingly, this is leading to 0-1km SRH values at or below 100 for the entire chase target, with many areas at or below 50. These are unfavorable numbers for tornadoes. To get a tornado today, I think you’ll need a combination of storm and boundary interactions (very fine mesoscale processes) that probably will only be in place for one or two storms for a brief period of time. I don’t want to rule out a tornado given the presence of a boundary and the degree of instability, but today’s risk is further south and lower than in prior days.

Uh25 004htotal nh075.sp.f01200.

The highest chance of a supercell and perhaps a tornado will be over NW Texas today, where the HREF is pointing to a pretty clear target for ‘spinny storms’ this afternoon.