An Enhanced Risk of severe thunderstorms exists on Monday and Monday night across portions of the Southern and Central Plains northeastward into the Mid-Mississippi Valley. All severe hazards are possible, including large hail, damaging winds, and tornadoes. The severe threat may extend into parts of the Ohio Valley Monday night.

Locations

  • Southern Plains (Texas, Oklahoma, portions of Kansas)
  • Central Plains (portions of Kansas, Nebraska, and Missouri)
  • Mid-Mississippi Valley (portions of Missouri, Arkansas, Illinois)
  • Potential for limited impacts in the Ohio Valley

Threats

  • Large hail (including the potential for widespread hailstones larger than 2 inches)
  • Damaging wind gusts
  • Tornadoes

Timing

  • Monday afternoon through Monday night

Discussion

Weather Systems: A strong upper-level trough moving across the West will push a cold front through the Plains states, creating a very favorable environment for severe storm development.

Storm Evolution:

  • Initial storms will likely form along the cold front and dryline during the afternoon.
  • Some of these storms are expected to rapidly grow into an MCS (Mesoscale Convective System) by evening.
  • More isolated storms are possible further south on the dryline. Still, the overall degree of forcing mixed with shear vectors is more parallel to the initiating boundary, which means storms will tend to crowd up fast.
  • The storm system will produce a widespread severe threat across the outlined area, continuing into the overnight hours.
  • Ohio Valley Impacts may be more limited as the system arrives overnight. However, damaging winds and isolated tornadoes remain possible.

Technical Breakdown

Storms will form as forcing for ascent arrives to weaken the cap, perhaps as early as 1-2 p.m. on Monday afternoon. Initially, wind shear is unfavorable for robust storm organization, but transient supercells should be the primary threat.

As we move through the afternoon, storms will likely organize a bit better in an environment with ample low-level instability and lower cloud bases. The effective SRH values of 200+ m2/s2 will likely lead to an increasing tornado threat with time as storms move east into the low-level jet. The low-level winds to the west are quite slow, which may prevent a more robust tornado threat from this event, as storms will tend to be more linear with time.

What I am noticing is initial storms will have small 0-1km hodographs with very elongated cloud-layer shear in the hodographs. This, combined with a lot of instability above 0°C, will likely lead to giant hail with initial storms.