Good morning bloggers,
There is a slight risk of severe thunderstorms later today, but right now there are some limiting factors that must be overcome for us to have a thunderstorm. A capping layer, 8,000 to 10,000 feet above us will prevent thunderstorms from forming most of the day. By the end of the day this capping layer will erode, but there are other questions.
- #1: A low cloud deck will form and become quite extensive, will this prevent heating?
- #2: How high will the dewpoints get later this afternoon?
- #3: Where will the front line up around 7 PM this evening?
- #4: When will the cap erode away?
- #5: There is no strong wave to organize any convective activity, so what will trigger the thunderstorms?
Let's address the cap first. Thunderstorms rapidly developed along the leading edge of the cap around 7 AM this morning and are tracking east of I-35, northwest of Chillicothe and northeast of Cameron, moving away early this morning. Below you can see the 700 mb forecast map for 10 AM this morning. A capping layer (around 10,000 feet above us) is moving across Kansas, Oklahoma, and Texas this morning. A cap is a warm layer of air, that is warmer than the air below it, which prevents thunderstorm development, until it breaks. How does it break? There are two main ways. One way is when that layer is forced to cool, which is likely going to happen later this afternoon as temperatures aloft drop a few degrees. And, another way is when it heats up enough to allow the warmer air below to rise and break through the cap, this is how you can go from nothing to intense thunderstorms in a very short period of time. Through most of the day, heating will be limited by a thick low cloud deck which is developing right now. So, we will have to rely on the cooler air aloft to move in, which is still questionable. The cap can be seen below by looking at the 700 mb level and finding the 10 degree isotherm:
The surface map, below, shows 66 degree dewpoints crossing the Red River on the Oklahoma/Texas border. This Gulf of Mexico air is surging our way. So, moisture will likely be available for thunderstorms later this afternoon, but what will trigger them? The cold front is heading our way. This wind shift line will be the main trigger today, and should be near Kansas City by 7 PM. There is really not a big upper level storm, only weak disturbances moving up in southwest flow. The main upper low is developing well back over the southwestern United States. So, this cold front will be the main triggering mechanism.
The Storm Prediction Center still has us in a slight risk, with a moderate risk from where the tornadoes hit over the weekend and extending to the southwest across Oklahoma into northern Texas. We will continue monitoring our risk as we move through the day, but at this moment it appears the best chance of any signficant thunderstorm activity will be south of our local region, and to the northeast of Kansas City this morning as the cap hasn't built into that area yet.
Have a great day. We will update the blog later. Brett Anthony will keep you updated on NBC Action News through the morning, and with the new data on our Mid-Day newscast at 11 AM.
Gary