5:45 PM CDT | March 11, 2019
A strong weather system will impact the state beginning late Tuesday afternoon. This system will spark thunderstorms across Eastern New Mexico and the higher terrain of West Texas late in the day. This activity has the potential to become severe with large hail, damaging winds, and even a tornado or two. As we progress into Tuesday evening, a squall line will gradually take shape in the western part of the state. The Storm Prediction Center has a Slight Risk issued for a good portion of Western Texas and western parts of North/Central Texas for Tuesday. This will be primarily from late afternoon through the overnight hours. The risk progresses eastward on Wednesday with a Marginal Risk across the eastern portion of the state. More details can be found below.
This system is slated to be the strongest one we have seen this year. Strong upper-level lift and wind fields, favorable wind shear, a surface boundary, gulf moisture - all things that point toward severe weather will be present EXCEPT... greater instability. As discussed yesterday, this is the one limiting factor that argues against widespread severe weather. The weather models show only marginal instability Tuesday night into Wednesday morning. Regardless, we should see a strongly forced line of storms take shape and roll across the state.
As it stands right now, the main risk will this squall line Tuesday night and into early Wednesday appears to be strong to damaging winds. The large hail risk appears low given the lack of instability, but hail up to the size of quarters will be possible. There will be an isolated tornado risk, even with just marginal instability. Cloud bases will be low, and given the moisture and wind fields, we could see a couple brief spin-ups. This would be most likely to occur along the leading of the line. If you watch the radar closely, you may see little circulations called "mesovortices". I could not find a graphic to illustrate what I wanted to show, so... I drew one myself. It shows the basic evolution of a squall line. The circulations form on squall lines that have begun bowing out. Farther down, I also attached a real example of a tornado-warned mesovortex on radar from March 8, 2016.
Not all mesovortices spawn tornadoes, but they all indicate a locally enhanced risk for wind damage. To sum up today's discussion, some severe storms are expected late Tuesday and into Wednesday. The potential for widespread severe weather appears low or at least uncertain, given the lack of instability being forecast by the models. I will continue to keep an eye on the trends and update as necessary both here and on Facebook. For the latest local weather information for your area, please visit the National Weather Service website. To help make sure you do not miss any updates, LIKE the Facebook page and join the Facebook group.