Stormy Morning - Wednesday August 22nd

There was no Tucson sounding yesterday evening. This morning's sounding (above from SPC) isn't going to tell us much, since something went seriously bonkers.

There is heavy cloud cover this morning, and the IR satellite image at 8:30 am MST (above) indicates a large, active MCS in northern Mexico and parts of southeast Arizona. The Tucson composite radar image (below at 8:25 am) indicates thunderstorms both to the southeast and west of Tucson.

The latest NAM forecast for 500 mb (above valid at 5 pm this evening) indicates a short-wave in the westerlies moving across the Southwest. This is the first intrusion from the Pacific in along while. None of the models seem to have a good early forecast (relative to actual precipitation occurring) this morning, and we'll just have to watch as things evolve today.