First severe weather risk of 2014 for Texoma?

The month of March comes to an end Monday quietly but that may not last long as April kicks off Tuesday. 

A few key ingredients may come together Tuesday into Wednesday to give us our first chance of strong to severe thunderstorms. We've discussed the players before on tv but here is a very quick refresher on those ingredients. The Storm Prediction Center in Norman has already highlighted an area along and east of I-44 that is under the risk (Image 1).

Image 1

The 4 main ingredients to produce severe weather here in Texoma are moisture, instability, lift, and wind shear. 

We get our moisture from the Gulf of Mexico most of the time and by mid next week, forecast models are showing dewpoints in the 60s to 70s, (image 2) indicating plenty of moisture. Now, we will have to contend with the dry line which separates the moisture from very dry air and it will be close-by, so locations to the west of the dry line will not be in a favorable environment for storms. Right now, the best call would be for that dry line to setup between Altus & Lawton but things may change. Another ingredient is lift which usually comes from developing areas of low pressure, fronts, or disturbances in the jet stream. A serious of what we call shortwave troughs will approach the Southern Plains starting on Monday. The first wave is weaker and stays to our north mostly. A second, stronger wave approaches by Wednesday into Thursday and this may be the trigger needed to produce thunderstorms. (Image 3). We can measure how much lift we have by looking at the lifted index. (image 2).

Image 2 (lifted index & dewpoints)

Image 3

What about instability? We can measure instability in a few ways and one of them is by looking at what is called convective available potential energy (CAPE). I won't get into how exactly we calculate CAPE but just know that we can look at forecast CAPE values on various forecast models. CAPE values increase quite a bit, especially by Wednesday, with values exceeding 2,000 J/kg in the black boxed in area (image 4). This is more than sufficient to support the development of thunderstorms.

Image 4 (CAPE forecast)

Lastly, we need wind shear. What is wind shear? We are most interested in vertical wind shear which is how speed and/or direction of the wind change with height. In the case of mid next week, we do have wind directions changing with height and we have speeds increasing with height. Both of these factors can promote a strong updraft in thunderstorms. (image 4).

Image 4, Wednesday evening GFS forecast sounding

So after going over all of these ingredients you must be saying "wow, we are going to get bad storms!". Well, hold on just a second. It is hard to get all these ingredients to come together in the right mixture at the right time to produce severe weather. Is there a possibility of severe storms in Texoma by mid next week? Sure, but we have several days to watch trends and changes in our forecast models to better fine tune the forecast. This is just an early heads up and a nice refresher to get yourself acquainted with terms we may use throughout this Spring storm season. Be sure to stay with SkyWARN 7 weather over the next few days, we will keep you updated!