High Summer

It's interesting that we've stumbled very much into a late August, high summer air flow pattern in the American Southwest, after having been stuck in spring for so long: it took one month to make the transition, whereas it usually takes three. The big, westward-drifting mesoscale convective complexes just south of the border, like we see today (in part because of Emily) are something we usually see in late August. The zone where eastward air flow meets westward air flow, and which today lies in southern Arizona, is the effective boundary of the tropics: not the standard geographic definition, but the effective climatic definition. Welcome to the tropics!

Also interesting - lots of clouds in the lower deserts, but no clouds up on the Colorado Plateau. The Flagstaff temperature sounding shows a strong inversion, suppressing cloud formation there, but Tucson doesn't have the same inversion, so - clouds away!

Today's weather should be similar to yesterday's. Big flux of moisture from the south, with the potential of the same split between north and south, with Phoenix left into the lurch until late.

The remnant of Emily will slowly drift west, halt, then slowly drift NE, and eventually make landfall, as a weak disturbance crossing the California coast around Santa Barbara next Friday. Eventually, what once was a hurricane will cloud up Sacramento!