Tomorrow (Monday, March 20th) is the first day of spring and it won’t take too long for spring-time thunderstorms to occur. A strong storm system will approach the Southern Plains late in the day on Thursday into Friday, which should aid in severe thunderstorms by Friday–and potentially overnight on Thursday.
As the upper-level trough moves into the Southern Plains late Thursday into Friday, a dryline should sharpen across western Texas/Oklaoma and move towards the I-35 corridor overnight on Thursday into Friday. Thunderstorms could develop along this dryline overnight on Thursday despite the unfavorable timing. If storms manage to develop late Thursday night or Friday morning, they would likely face meager instability. Despite the meager instability, due to the other parameters, it’s possible a couple storms could produce hail.
By Friday afternoon, the latest numerical guidance shows the upper-level trough moving overhead and the dryline moving to–or east–of I-35.
GFS 2-m Dewpoint Map (Friday Afternoon)
GFS 500 mb Vorticity Map (Friday Afternoon)
At this point, a second round of thunderstorms (with a greater chance of reaching severe levels) could develop across eastern Oklahoma, northeastern Texas, western Arkansas, and northwestern Louisiana. It’s still too early to determine the storm modes and evolution, but looking at shear values, it appears isolated thunderstorms along the dryline in eastern Oklahoma/northeastern Texas would evolve into an eastward moving complex of storms that would eventually impact parts of Arkansas and Louisiana. Initial storms potentially could produce all modes of severe weather with the threat of damaging winds increasing as the storm move east and evolve into a complex. The consistent support of the numerical guidance has allowed the Storm Prediction Center to allow for a 15% severe thunderstorm area in this region.
SPC’s 15% Contour Area (Friday Afternoon)
It should be noted, if the system slows down or speeds up, there may be an increased chance of severe thunderstorms and the SPC’s 15% area may at that point be adjusted to encompass different areas. Please keep checking back for updates.