Right now we have a bit of a protective shield that has moved in to the area. The shield has moved in from down in Tennessee and Arkansas. The shield I am talking about is the "cap".
The cap is indicated in the blue shaded area in the above map. Basically, it is warm air aloft that is in place a few thousand feet in the air. The warm air limits vertical development of the storms/clouds.
In order to break the cap we need something to come along and upset the warm air aloft. That should happen a little later as the nose of a strong jet stream moves in from the southwest. Computer models have been suggesting that could happen between 12pm and 2pm. Once that happens we will start to see thunderstorms go up quickly.
The reason storms will go up quickly is due to the amount of instability we will have in place. We already have instability overhead. Look at the map above. The solid red lines indicates the CAPE (Convective Available Potential Energy) in place. The higher the number, the higher the instability. Give it a few hours to "percolate" and those should go up to the 3,000 range.
- Posted from my iPhone