An early morning MCS was located between Tucson and the border with Mexico this morning at sunrise. Above is 6:30 am MST composite radar from TUS. When I walked along the Rillito I could see flashes to the south. I went out to get the paper at 5 am there were frequent flashes visible to the distant south; howeve, the airport obs did not report lightning until 6 am and DM noticed lightning at 7 am - both sites several hours behind the power curve. Below is the IR image from 6 am. The model runs at 06 UTC (WRF both versions and NAM) totally missed forecasting this event, so I haven't looked at those forecasts in detail.
Graphic above shows CG lightning lightning strikes detected through 6:30 am this morning. The MCS appears to have had its origins in nocturnal, Mexican storms from along the Continental Divide. Current (7:45 am MST) TUS radar loops seem to indicate an MCV spinning near Nogales - that will move toward central Pima County this morning, adding further complications to the forecasts for today.
The 12 UTC TUS sounding (below) is very unstable for the layer below 800 mb, but this air requires substantial lift to feed storm updrafts. Perhaps the combination of higher terrain and stronger outflow kept storms going south of here during the early morning hours, but storms did not move into the lower elevations of metro Tucson. The ALERT data at 7 am indicated only 7 sites with rainfall during past 24-hours (east end of Catalinas and far south - Tubac reported 0.63" from the sunrise storms).
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