View north yesterday at 4:00 pm MST showing the clear skies that prevailed over metro area yesterday, after the early morning rains. ALERT rainfall for 24-hours ending at 7:00 am this morning shows that only the far south parts of the network had storms and rain yesterday - much as the 15 UTC WRF-RRX forecast. There was little mixed layer CAPE over the region where the heavy rains occurred, and storms that tried to move toward the metro area from the west rapidly dissipated.
This morning (as per TWC sounding plot above) moisture remains high below 600 mb, while very dry air has moved over the state above 500 mb. Strong westerly winds in upper-half of troposphere are present, above very light westerlies below. Some CAPE remains and models forecast storms late in afternoon over eastern Pima County.
Above graphic is the composite radar forecast from the 00 UTC WRF-GFS run valid at 6:00 pm this evening (the WRF forecasts from 00 and 06 UTC are all consistent, forecasting the eastern Pima County storms). However, a slight shift toward the east would leave the metro high and dry again.
Forecast below is from same run and shows PW valid 6:00 pm. Dry air is intruding strongly at that time with a gradient of about an inch from Tucson to Yuma. The next few days will bring a dry-out as low PW air from the west prevails.
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