We’re officially at that point in the year where the atmosphere seemingly can reload for another go of it just a couple of days after a major event like yesterday’s.

This time around, we’re expecting a very low chance of severe weather for any one location, but we’re likely to see a supercell or two develop off of the dryline tomorrow.

A compact shortwave embedded in the flow tomorrow will overspread the dryline in the mid-afternoon hours.

Compact Shortwave Ejecting Out

We’ve talked about this in a few other forecast blogs (and I’ll hit this through much of the season) but for a dryline to convect you need 1)surface convergence (and lift) and typically 2)upper lift from a wave of some sort.

This is because there is typically an EML (cap) over the dryline source region, which requires lift from both ends to overcome. In this case, you’ll have both strong surface convergence on a moist boundary layer and a shortwave moving overhead at the opportune time.

Strong surface convergence is apparent on the dryline in North/Central Texas with WSW winds and a strong dry air push behind the dryline.

Environment Evolution Tomorrow

Tomorrow is a pretty standard low-end dryline severe weather day. I don’t want to oversell the threat too much, but any mature supercells will be capable of big hail and perhaps a brief tornado.

The environment is, at best, only marginally supportive of supercells with poor storm-relative helicity (SRH) but strong 0-6km bulk shear by mid-afternoon. The hodograph shape also leaves much to be desired overall.
The environment does begin improving fast into the late-afternoon and early-evening. SRH improves and 0-6km shear vectors are really solid (perpendicular off of the dryline). This is an environment supportive of large hail and a brief tornado threat.

What I Expect

There will be an initial wave of storms with limited severe weather potential forming in the early afternoon just east of the dryline.

Initial wave of storms forming at noon or just slightly after.
Initial storms forming off of the dryline by 3-4 p.m.
The dryline storms move east towards the stabilized air from earlier storms by 7 p.m. or so.
  • Storms that pose the greatest severe threat will form off of the dryline, likely from 3-5 p.m.
  • The dryline storms will move east for a couple of hours and one or two will likely become obvious supercells after an hour or so of being up.
  • These storms will pose a big hail threat and may briefly reach tornado warning criteria before weakening in the cooler/more stable air that’ll be present just east of the dryline.
  • If the first wave of storms forms further west, much closer to the dryline, these initial storms may not survive long enough to become mature supercells.

Schedule of Severe Weather Potential This Week:

  • Sunday: Very low risk along a dryline in North Texas.
  • Monday: Very low risk to low risk along a dryline from Missouri to Texas.
  • Tuesday: Enhanced threat of severe weather in the Mid-Mississippi Valley including Missouri, Iowa, Illinois.
  • Wednesday-Saturday: A front will sweep through from Tuesday’s system, ending the severe weather threat in the middle of the country most likely through the end of the week (and likely for 7-10 days beyond).