This morning is quiet across the state with areas of fog and clouds. Enjoy the quiet weather because by this time tomorrow I expect we’ll be dealing with severe thunderstorms in the Big Country, Northwest Texas, making their way toward western North Texas. A significant threat of severe weather, including the potential of tornadoes, will exist from late tomorrow morning through the afternoon hours across eastern North Texas (just east of D/FW), East Texas, the Brazos Valley, into East Texas. We still have a few questions that once answered will dictate where the relative highest threat for tornadoes will exist. Stick with me and we’ll talk it out.
Round one could begin as soon as the late afternoon across the eastern Permian Basin into West-Central Texas. Temperatures may be able to warm enough to overcome a capping inversion. Should that occur we’d see isolated strong to severe storms fire up with a threat of hail. For the most part, we’re expecting most of the stronger activity to hold off until around midnight. By that time stronger upper-level lift will be arriving and scattered thunderstorms should erupt. Those storms, in the western sections of the risk zone shown above, would move east/northeast as semi-discrete cells or one or more clusters. Large hail up to the size of golfballs would be the primary threat with stronger storms. A stable layer of air near the surface should keep the threat of damaging winds low, and the tornado threat very low tonight.
Those storms will likely approach Interstate 35 between 9 AM and 12 PM tomorrow (Saturday). They could still pack a wallop with a threat of hail and damaging winds. I want to see more data throughout the day to determine the exact timeline and scope of the severe weather threats. If a surface warm front is able to lift farther north more quickly or if the system overall is slower than shown we could see a higher threat of severe weather materialize farther west. Speaking of which…
Do not focus on the exact line placements. Thunderstorms don’t read maps and certainly don’t care about fancy computer generated graphics. These outlooks are based on the probability of experiencing severe weather within 25 miles of any given point. The higher the risk the higher the chance of severe weather. Threats aren’t that different between risk zones. For Saturday’s case, the Storm Prediction Center has introduced a level 4 risk of severe weather across far East Texas into Lousiana. It runs east of a Marshall to Carthage to Center line.
A level 3 risk includes much of East Texas. This enhanced risk runs east of a Texarkana to Pittsburg to Lindale to Palestine to Livingston to Kirbyville line. Both the level 3 and level 4 risk zones have the highest risk of experiencing all modes of severe weather, including a tornado threat. The standard level 2 risk includes the eastern half of North Texas, the Brazos Valley, and Southeast Texas.
For the most part, the western delineation of the risk zones is just because these outlooks take effect at 7 AM Saturday. The overnight outlook tonight covers the period up until that time. I want to be particularly clear in this case that we’re still uncertain about the number of discrete/semi-discrete storms that may fire up in eastern North Texas, East Texas, the Brazos Valley, and Southeast Texas tomorrow. I
If it becomes clear that we have a higher chance of those storms firing up in the aforementioned regions versus beginning in Lousiana I have no doubt we’ll see those higher risk zones expanded west into more of Texas. Likewise, it’s also possible the highest risks shift a bit more east. The next outlook for tomorrow from the Storm Prediction Center will be issued around 12:30 PM.
Wind shear values are going to be very strong in all levels of the atmosphere across East Texas from the mid-morning all the way into the late afternoon. As storms move into the region from the west and/or storms fire up ahead of the ‘line’ coming in from the west they’ll have the potential to rotate.
Damaging straight-line winds, large hail, and tornadoes are all possible. Any sustained supercell in East Texas tomorrow that becomes tornadic does have the potential of producing a strong, long-track tornado.
At this time the highest threat for significant tornadoes seems to be highest in far East Texas as storms move into Lousiana. However, if this system slows down at all, that threat will end up being more of a Texas problem too. I hope this ends up being like April 2, 2017, where storms didn’t get rowdy until they exited Texas to the east, but we need to be prepared.
Long-time followers know I am extremely picky in my choice of wording when describing severe weather threats. Most events I’ll say ‘very low tornado threat’ or ‘an isolated tornado is possible’. Tomorrow is not that kind of day in East Texas.
Storms should be exiting Texas to the east by the late afternoon, perhaps around dinner-time. They’ll continue producing significant severe weather well into the night across Lousiana, Arkansas, Mississippi, and eventually making their way to the eastern seaboard of the United States. We’re going to be the starting gate for what’ll be a multi-day severe weather event for the southeastern United States.
Take the time now while the weather is nice to review your severe weather safety plan. Are you new to Texas? No worries! Make a plan or just spend some time reviewing your plan with your family. We’ve got a page of tips and advice set up here.
My next detailed blog update will likely be before dinner this evening with an interim update by the mid-afternoon hours.