7:00 PM CST | November 29, 2018
A strong storm system is moving into the Desert Southwest right now. This system will progress eastward reaching Southeast Colorado by sunset on Friday. The base of the trough will extend through West Texas. As it moves into the Plains late Friday, it will take on a negative tilt. What does this mean? It means that the trough axis will become oriented from northwest to southeast. As the system becomes negatively tilted, greater lift and stronger winds aloft will overspread the warm sector (the moist, unstable environment ahead of a dryline or cold front). This is very favorable for organized storms, and in the spring, it often leads to robust severe storms in the Plains.
In the cool season, the forecast is a bit more complicated than similar setups in April or May. Fewer daylight hours and weaker daytime heating often results in more limited instability. When the gulf moisture returns, we see more widespread cloud cover. The National Weather Service in Fort Worth wrote an EXCELLENT discussion today, which touched on this. As the stronger lift and forcing overspreads western North Texas by mid-afternoon, we should see modification of this increasingly moist airmass. As they later stated, however, "This of course is all what the models tell us, and we know they`re not perfect, especially when rapid airmass modification is taking place, which is why the uncertainty is higher than normal with this forecast." This is not to diminish the risk, but to emphasize that a few adjustments are likely.
Right now, there is about a 2:1 split among the weather models. The majority show isolated storms developing along the dryline/Pacific cold front in western North Texas during the mid to late afternoon hours. They show this activity increasing in coverage and strength as it tracks through the I-35 corridor of North Texas toward and after sunset. A smaller number of weather models show storms igniting near or possibly just east of Dallas Friday evening. The latter would dry slot the western half of North Texas. While the western extent of the more severe storms is still uncertain, severe storms, including supercells, are expected tomorrow. Quarter to Golf Ball-size Hail, Damaging Winds of 60-70 MPH, and a couple Tornadoes will be possible across parts of Texas, Oklahoma, Arkansas, and Louisiana. The evening model guidance is just now starting to arrive. This model run will have a more complete set of data available since the system has moved onshore. If there are any changes worth discussing, I will post an update on Facebook.
For the latest local weather information for your area, please visit the National Weather Service website. You can also find us on Facebook. Most of tomorrow's weather updates will be posted in the Facebook group, where the posts reach a greater percentage of people. Weather pictures are always encouraged. Please share the location and approximate time. Remember, only take pictures when it is safe to do so. :)