Rains Across Much Of Tucson Area Since Noon Yesterday

"I woke last night to the sound of thunder 

How far off I sat and wondered...."

Bob Seger - Night Moves

Actually, given my deafness, this isn't quite true, but when I got up at 4:30 am MST the wind was blowing around 25 to 30 mph, light rain was falling, and there was some nearby lightning. A pleasant surprise and mild winds were blowing during my morning walk. Mike Leuthold had mentioned in his discussion yesterday that some of the model forecasts had early morning storms in southeastern Arizona.

At 6 am the ALERT network data indicate that 77 of 92 (84%) of the stations measured rainfall during the past 24-hours. This has been the first event of the summer with more than 35% of the network reporting rainfall. Here at the house two thundershowers during the afternoon left 0.15" in the gauge and the early rain this morning added only another 0.04" (so 0.19"). Across the ALERT network 14 stations had 0.25" or more and 9 stations (almost all in the Catalina Mountains) had 0.50" or more. One station in the Catalinas reported 1.18".

The composite radar chart from the NWS radar is shown above for 4:30 am this morning. The IR satellite image below is from 4 am MST.

This event illustrates a problem with having so many different, high-resolution forecast models. Yesterday's early WRF-GFS forecast much stronger storms across the Tucson metro area yesterday afternoon than actually occurred, and had nothing forecast in southeast Arizona after about midnight. However, the 12 UTC run of the WRF-NAM had a better afternoon forecast that was followed by a forecast of new, early morning storms across southeast Arizona. Above is the WRF-NAM forecast of composite radar echoes valid at 2 am MST. Timing is a bit off and areal extent to the east is too great. The most recent midnight run of the  WRF-GFS this morning forecast the early morning storms, but kept them to the east of Tucson over Cochise County. Which model forecast was best? - probably depends upon the perspective, and location, of an observer.

Finally, TS Dalila is still near Cabo Corrientes this morning (1130 UTC IR image below) and may have some impacts upon continuing a flow of mT air northward up the Gulf of California.