You will often hear us mention on television the formation of a low level jet that feeds into thunderstorms; moreover, LLJ's serve as a great initiator for overnight thunderstorm complex development, and locating them can be a key to pinpoint thunderstorm formation. Last night we saw a complex of storms called a Mesoscale Convective Complex (MCC) initiate across western Oklahoma and move southeast all the way into Louisiana. This organized complex of storms was responsible for 20 severe wind reports. Could we see these types of storms in our area?

Our current weather pattern has a broad upper level low spinning around the upper Midwest. Low level moist air is surging into this low from the south, creating a favorable environment for these complexes to develop. Let's take a look at some of the latest model data that suggests a possible scenario for nocturnal storms by Friday morning.

This 850 mb forecast chart above let's us know where to start looking. Notice the winds are moving north toward our low pressure area across the upper Midwest. This ribbon of strong air around 5,000 ft is responsible for transporting rich moist air from the Gulf of Mexico. We call this ribbon of air the "low level jet (LLJ). It's typically a wind at 850 mb that's stronger than 35 knts that can provide moisture and lift for storms to form.

The maximum wind speed appears to be close to 50 knts across west Texas into western Oklahoma around midnight. The LLJ becomes stronger at night due to less friction in the lower part of the atmosphere we call the boundary layer. Radiation from the sun stops, so the ground begins to cool rapidly. Air aloft remains warmer, so the boundary layer becomes stable. Since friction drops off on top of the boundary layer, the winds become faster, and transport more moisture north. LLJ's are almost always apart of MCC development, so this is our first clue, but now we need to find a disturbance aloft to kick all of this off.

This is a 500 mb chart. We look for atmospheric waves aloft to indicate areas of rising air. We want to find a point where the 500 mb wave intersects the 850 mb LLJ. If we can find a correlation, then we'll have an idea on where convective initiation will occur. Look at the wave over west Texas and Oklahoma that's created by our main storm to the North. This is where the LLJ pools in from the south. This disturbance aloft is depicted by the WRF model at Midnight on Friday morning.

Most likely convective initiation will occur across western Oklahoma/Texas, and eventually move southeast. The stronger the cold pool, the faster the MCC movement. We'll have to watch our eastern Oklahoma counties closely as we head into the early morning hours on Friday.