Big Storms In Metro Tucson

Today has developed into a big storm day for metro Tucson. At 3 pm MST (TUS radar above) there were large storms on the northern Santa Rita Mountains, but there was also a large area of storms that had been active for several hours out in central Pima County. Both areas of storms were producing outflows that would converge here in metro Tucson. Note that a new line of building storms is visible to the east of the central Pima County storms. These storms built above westerly outflow and moved from the west into eastern Pima County. The storms over the Santa Ritas produced a very strong outflow from the south. The two outflows converged over metro Tucson and all hell broke loose.

The TUS composite radar for 4:45 pm MST is shown above - it was thundering with light rain here at house after an outflow from the west with winds of 30 to 40 mph at about 4:30 pm.The Santa Rita storms had propagated north into southern parts of Tucson, riding above severe outflow winds from the south. The airport reported gusts from the south of 60 mph at 4:33 pm - thus the two gust fronts were converging right over the Tucson central and north metro area. The gusts from the south blew by the house around 5 pm MST with gusts I estimate at about 50 mph. The storms were producing heavy rain and lots of lightning - I shut the PCs down here for about an hour.

The sounding at 5 pm MST (above), had recovered nicely and didn't have as much CIN as I'd expected this morning. There were moderate amounts of CAPE with a mostly light and variable wind profile below 400 mb, which let the storms propagate toward wherever the most unstable air was. Note the very high K-Index of 43. Here at the house we had well over an inch of rain in about 90 minutes - it's still raining lightly outside and I can't measure the precise amount until things come to an end. (Edited to add: at 7 pm have just measured and amount here was 1.55 ".) Finally, the IR image for 5:30 pm MST (below) shows the very cold storm tops over Tucson, as a clear extension of the intense Sierra Madre convection typical of the Mexican Monsoon. What a day - things came together better than I could have ever have guessed this morning.