An Enhanced Risk of severe thunderstorms exists across portions of Nebraska, Kansas, western Oklahoma, and western North Texas. Scattered severe thunderstorms are likely.

Locations:

  • Nebraska
  • Kansas
  • Western Oklahoma
  • Western North Texas

Threats:

  • Large to very large hail
  • Damaging wind gusts
  • A few tornadoes

Timing:

  • Monday from the afternoon well into the overnight hours.

Discussion

Weather Development: A deepening upper-level low in the Great Basin will drive storm development across the Plains states. While moisture across the region will be limited with northward extent, it will be offset by strong wind shear and rising motion within the atmosphere.

Storm Evolution:

  • Initial storms are expected to develop late afternoon/early evening across the Central High Plains, moving eastward along the warm front into the Mid-Missouri Valley.
  • Storms farther to the south, in Northern/Western Texas, may form along the dryline within a very unstable airmass. While initial coverage may be sparse, storms that form will quickly become supercellular.

Main Threats

  • Very large hail is the primary threat, especially across central/eastern Nebraska and parts of northeastern Kansas.
  • Isolated severe wind gusts are possible with any developed clusters.
  • A few tornadoes are possible, mainly with any supercells that can take root and maintain themselves in the late afternoon and early evening.

Overnight Concerns: Thunderstorm activity is likely to increase and spread overnight, continuing the severe threats.

Uncertainties:

  • The exact location of greatest storm coverage remains uncertain and the pinpointed areas may require adjustments in later forecasts.

Technical Discussion

Sfctd mean.cp.f03500.

A dryline will set up tomorrow with dewpoints into the 60s possible as far north as Nebraska according to the HREF. Most models are showing a more diffuse boundary to the north and a slightly sharper one to the south. Given the location of the surface low and warm front, I’d expect storms to first form to the north tomorrow.

Ref1km 004hmax pb40.cp.f03600-3.

As of this writing, the HREF is showing where the highest-resolution weather models are pointing towards for storm development tomorrow before sunset. One area from southern Oklahoma into Northern Texas will need to be watched for giant hail potential. The other area across Nebraska also will have severe weather threats associated with it.

Uh25 004htotal nh075.cp.f03600.

The ‘spinny storms index’ shows the highest chance of supercells running both from SW Oklahoma into North Texas and also across portions of Nebraska and nearer the surface low to the NW. 

850mb mean.cp.f03500.

The ‘unfortunate’ thing for storm chasers is that the two targets guaranteed to have storms tomorrow have different problems when it comes to tornado potential. To the north, more limited moisture will be in place, so despite much more favorable wind shear — storms may struggle to produce tornadoes despite the proximity to the surface low and with more favorable upper dynamics. Further south, the low-level jet diminishes in strength rapidly once you get to SW Oklahoma. Additionally, models show capping is much stronger to the south. Surface heating and some upper lift will help storms get going, but it is likely they will struggle to organize in the low-levels thanks to capping and weak low-level shear. 

Hrrr_2024041418_028_area_37.51 38.15. 99.37  98.17.

There is a perhaps idealized middle ground tomorrow from Northern Oklahoma into Kansas, where models are producing uncapped soundings with much better jet dynamics. However, my chief concern with this target according to soundings (one pictured above) is that to get the cap eroded, the atmosphere must mix moisture down and heat the air up — which creates very high cloud bases. This is a target that could pay off if a storm can form right before sunset when better moisture is surging north — but the cap also increases in strength rapidly after sunset so the window is narrow.