East winds with gusts of 15 to 20 mph continued through the night, and it was another very warm morning here in Tucson (yesterday had a low of 80 F and high of 101 F at the airport). A couple of thunderstorms managed to get going near mountains yesterday. Above is TUS composite radar at about 1:30 pm MST and below shows lightning strikes detected during the 24-hours ending at 5 am this morning (I've zoomed in to focus on Pima County). Two stations in the ALERT network reported rainfall yesterday afternoon - White Tail in the Catalinas had 0.04" and Picture Rocks at the north end of the Tucson Mountains reported 0.14" - nothing here at house for over a week now.
Low-level moisture continues to hold across much of southern Arizona, but the upper portion (above 600 mb) of the troposphere remains very dry and even warmer this morning. There is a very ugly inversion in this morning's sounding just below 500 mb. Both early forecasts of the WRF model at Atmo forecast only some moderate cumulus over eastern Pima County this afternoon. Below is the forecast TUS sounding from the WRF-NAM valid at 4 pm MST this afternoon. It is an interesting sounding with CAPE present - but only above the warm middle-level layer. Release of this CAPE would require boundary layer parcels to be lifted from 600 mb up to around 400 mb - certainly a very long-shot given the hostile shear and dry air in this layer.
Both models do indicate a chance for increased activity by Thursday, as a 500 mb trough moves from the west coast across the Great Basin, affecting Arizona. Perhaps the trough will bring some middle-level cooling with it?
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