Very Big Storm Day - August 11th

Perhaps the most active thunderstorm day for most of Arizona this summer occurred yesterday, with storms widespread as per the plot of detected CG flashes above (from Vaisala and Atmo for 24-hours ending at midnight last night). Many areas had two rounds of storms with the early morning event followed by heavier storms during the evening.

Many reports of severe winds in Arizona as per SPC plot above for August 11th - significant activity up in Idaho also. Here at the house we had gusts around 45 to 50 mph from the east with the morning storms. The evening storms were severe with several gusts from the south, between 7:00 and 7:15 pm, estimated at 60+ mph. Photo below is of small mesquite tree broken apart over in the Natural Resources Park.

Across the ALERT network it was another very high POPs day with ~90% of the sites measuring rainfall for 24-hours ending at 5:00 am MST this morning. Only the far southern portion of the network stayed dry. There were 34 sites with over half an inch; 14 sites with over an inch; and 2 sites with over two inches. Shown above is metro-east sector plot where the heaviest rains maximized. Not surprisingly, the Rillito was flowing this morning - photo below was taken looking west from Christmas Wash. Graphic (second below) from the USGS gauge at Rillito and Dodge indicates that flow reached 3000 CFS around midnight. Here we had only 0.02" in the morning, followed by 0.31" in the evening - sad state of most of year is indicated by fact that the 0.33" yesterday was the largest rain event here at house since January 31st.

This morning drying has occurred in lower levels, but there is some CAPE remaining at mid-levels and there are some light showers around.  Very dry and stable air is to our east, and the 06 UTC runs of the WRF model at Atmo forecast decreasing PW through the afternoon and night. Both the NAM and GFS versions forecast PW to drop below an inch by morning tomorrow - that may be a bit too dry. But, this afternoon the clash between air masses will likely take place just out to the west of here.