Bit More On This Event

Photo from backyard at 6 am MST looking toward the northeast. Light, anvil rain was falling at the time.

Time series from Atmo of T and Td indicating the passage of the two outflows. Atmo had a bit over a tenth of an inch of rain with each event. Winds gusted to 50 mph with each outflow - anemometer is on roof of their six storey building.

Atmo time series of RH. Note that during both events RH peaked at only about 80% - a typical characteristic of anvil rain that wasn't preceded by heavy convective cores.

The TUS sounding from last evening (I have to admit that I didn't even look at the weather obs last evening) doesn't appear to be very favorable for what occurred durng the night. There is some CAPE present, with only a small amount of CIN. Cloud base would be at about 650 mb. Note the L/V winds below 400 mb. The 0000 UTC RRS sounding was of course too dry in the boundary layer, which was probably well mixed from about 900 mb. PW had fallen to about 1.4 to 1.5 inches (as per GPS data), after a number of days with higher PW, so the outflows forced the most out of an apparent marginal situation. Several nights ago (Sunday) conditions appeared to me much better primed for a nocturnal MCS. Although there was a nice outflow from south nothing developed, so these are very difficult events, and it seems that one or two of these per summer is par for the course. This morning's sounding, a classic MCS onion sounding, was terminated at about 350 mb. But of course, it is completely unrepresentative of the larger scale environment for rest of day. The Phoenix morning sounding appears much like last night's at Tucson. It appears that two outflows went by up there also, but not with enough umph to trigeer storms.