During past 24-hours 27 sites within the Pima County ALERT network recorded rainfall. Above plot shows amounts over the metro west part of the network and plot below shows amounts over the southwest portion of the network. Most of the recorded rain was in these parts of the network, and as indicated amounts were very light. The maximum amount was only 0.28". So, even though we had storms over the metro area, they did not produce much rain. The rains in the central metro area were not from the storm I photographed (see below), but from a new cell that developed to the southeast of that storm.
As for the early morning storms - looks like they did occur (above is regional radar from NCAR RAL at midnight) out in central and western Pima County. The WRF-GFS run at 12 UTC forecast the Pima County storms well (see posts from yesterday). All the WRF variants yesterday had their good, bad, and ugly aspects. This was nice example of how difficult it is to forecast the local details when convection is involved - it's a tough game, even with very high resolution model guidance.
Finally, I want to consider the TUS sounding from 00 UTC (5 pm MST) yesterday (sounding is shown above from SPC). The common problem of the NWS RRS sondes indicating too dry conditions for a hot, deep boundary layer occurred yesterday. The sounding indicated only a possible sliver of CAPE, even as thunderstorms cells were developing in the area. The comparison (below) of GPS and TUS sounding values of PW shows that the evening sounding data were too dry by about 4/10s of an inch. That's serious trouble, meaning that the sounding data did not capture the true potential for storms that was present. Also of interest is that the local recycling of water vapor has pushed values up to around 1.6" this morning - a quite nice value compared recent days.
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