3:00 PM CST | February 23, 2018
The Southern Plains and Mississippi Valley may see its first Severe Weather Outbreak of the season on Saturday. For this discussion, let me explain what is going to happen over the next 24 hours or so. Right now, a shallow, cold airmass is still in place across Northern Texas, A warm front is slowly lifting northward into Northeast/Central Texas. On satellite, you can see partly sunny skies behind the warm front, and dense low-level clouds ahead of it. How quickly this remaining cold air erodes will have an impact on the Severe Threat for North Texas tomorrow morning.
First, let me show you the forecast dew points by 1500z or 9:00 AM CST from one of our more reliable models. It has the warm front located near DFW Airport, dividing the metro from southwest to northeast. North of the front, Fort Worth has a dew point of 51*F with a temperature of 54*F. South of the warm front, Dallas has a dew point of 62*F with a temperature of 69*F. Quite a difference!
Let's look at the skew-t soundings for each location at 9:00 AM. It is a vertical look at the atmosphere. For this, all you need to know is that the green line is the dew point, and the red line is the temperature. Each value decreases to the left and increases to the right. The base is the ground level, and the top is the upper atmosphere. For Fort Worth, you can see that both lines make a drastic cut toward the left near the bottom. This is the shallow, cold air. Above the surface, temperatures are warm and the atmosphere unstable. This sounding would suggest elevated Supercells with Large Hail and Strong to Damaging Winds. The Tornado Risk would be very low due to the cool air at the surface. Now, take a look at Dallas.
You will notice that the dew point and temperature lines do not make that drastic shift. The temperature is warmest at the surface and gradually cools with height. Storms would have the potential to be surface-based in this environment. Given the strong shear and winds turning with height (right side of graphic), there would be the potential for Tornadoes. This is why it is important to see how far north the warm front lifts into North Texas Saturday morning. It will have an impact on where the greatest threat will reside.
This is the latest outlook from the Storm Prediction Center. Right now, it looks like scattered showers and storms will develop in western North/Central Texas late tonight. This activity will lift northeast into Saturday morning. A few Hailers will be possible late tonight. Storms will gradually become more organized after daybreak. As they encounter better moisture and instability near and east of DFW, the potential for surface-based storms will increase. All types of Severe Weather will be possible. Activity will progress into Northeast/East Texas Saturday afternoon. A couple Strong Tornadoes are a possibility, mainly in the Enhanced Risk area. It is going to be one of those days, so you need to keep an eye on the weather. Make sure you have a way to receive the latest watch and warning information from the National Weather Service beginning late tonight/tomorrow morning. Some adjustments to the risk areas can be expected as we refine the location of the warm front. You can get the latest from Texas Storm Watch here and on the Facebook page.