4:15 PM CDT | June 8, 2019
Over the last couple of days, I have mentioned that there will be a possibility for severe weather on Sunday. This is still the case. Most outlets seem to be downplaying (underestimating?) the setup as it is not a classic, "textbook" one. Nonetheless, the environment will be supportive of supercells capable of quarter to golf ball-size hail and damaging winds. The greatest storm chances will be along and west of the I-35 corridor. I want to step you through what I am monitoring. First, we have the 4:00 PM CDT surface temperatures and winds as depicted by one of this afternoon's weather models. I have drawn the surface features on the graphic to illustrate the following...
We will have a triple point develop in Northwest Texas Sunday afternoon. This feature will drop toward the south-southeast through the evening hours. Near and to the south of the surface low, a very unstable environment will exist. Storm motion will be toward the south and southeast. While low-level wind fields would not appear real supportive of rotating storms, the storm direction will actually serve to enhance storm-relative helicity values. What are storm-relative helicity values? The Storm Prediction Center defines SRH (storm-relative helicity) as "...a measure of the potential for cyclonic updraft rotation in right-moving supercells, and is calculated for the lowest 1-km and 3-km layers above ground level." Wind fields that turn clockwise with height favor storm/updraft rotation. When storms move more toward the right, this rotation is increased. An example of a right-mover would be if the mean storm motion were east, and a storm began to turn more toward the southeast.
In short, I believe that golf ball-size hail is a real possibility along with damaging winds. The tornado risk appears generally low; however, any storm that can track parallel along the frontal boundary or any outflow boundaries would have the potential for a tornado. These cells would also produce the larger hail sizes. The Storm Prediction Center finally upgraded portions of North Central Texas to a slight risk earlier this afternoon.
The main time-frame for severe weather will be from 4:00 to 10:00 PM. It could not begin earlier, BUT this is the primary window I am seeing based on the data. Not everyone who is at risk will see severe weather. Keep an eye on the forecast as adjustments can be expected as this unfolds. Where exactly the triple point sets up will determine who is at greatest risk for storms and severe weather. I will be posting periodic updates on the Facebook page. Do not solely rely on your newsfeeds to see these weather updates. Check the Facebook page personally throughout the day to make sure you do not miss anything.
For the latest local weather information for your area, please visit the National Weather Service website. You can find Texas Storm Watch on Facebook. To help make sure you do not miss any updates, LIKE the Facebook page and join the Facebook group.