Morning balloon data (soundings) from Birmingham and Jackson show strong cap in place. Basically, when a parcel of air tries to rise from the surface, it cools, and keeps going as long as it is warmer than its environment. But, the warm temperatures above 800 mb this morning will cause any parcels that rise to that level to suddenly be cooler than their environment, and sink back toward the ground. This will keep any significant storms from developing, at least for a while. As long as this cap is in place, temps would have to rise to near 90 (which they won’t), or dewpoints would have to rise to 65-70 (possible in a few areas later), for storms to form. So, it should stay quiet over Alabama for the next few hours.
The cap is much weaker to our NW, so storms should develop over Arkansas and northern Mississippi over the next few hours. Later, the cap will start to cool off as the atmosphere gets lifted, allowing storms to develop in Alabama. The question right now is…does this happen late this afternoon/early this evening, or does it not happen until the squall line comes in late tonight. The other question that remains is how much sun we get today. With a few hours of sun, temperatures will reach the mid to upper 70s, making the storms later more intense. With no sun, we may hold near 70.
We’ll keep watching it…
