July 10th - Another Day With Mostly Light Showers At Lower Elevations

Tucson's string of 100+ F days ended at 39 when the official temperature only reached 98 F at the airport yesterday. Some areas of the metro, mostly north and northwest, reached over 100 F, since the gust front that came in from the south arrived later.

Yet another example of how everything must come together just right to have widespread, heavy storms in the low elevation areas. I think that the poor, unidirectional shear, along with too little CIN, resulted in widespread, relatively early storms and heavy anvil cloud over much of Tucson yesterday. Here at the house we had rumbling thunder from storms on the Catlinas (above image is from 4:21 pm MST), and then light showers during the night. There was 0.09" in the gauge this morning (giving us 0.30" since June 15th - in contrast Art Douglas reports over 5.50" for the same period at about 5,000 ft MSL in ash Canyon). the water vapor image below, from 11 pm last night, shows that storm activity in the Southwest was focused over Arizona.

Rainfall was widespread across the ALERT network the past 24-hours with 50 of 52 (~100%) stations reporting rain. Amounts were mostly quite light, with only 12 stations reporting more than half an inch and two stations with over an inch - the heavier amounts occurred at higher elevations, mostly in the mountains.

This morning the high mountains are in the clouds (above is from 6:24 am, 11 July) - somewhat rare for summer. When I walked I saw that the Tucson Mountains had low stratus along their eastern flanks - rare any time of the year. The plot of CGs below for 24-hours ending at 5 am shows increased activity in the low deserts, but well west of the low-elevation corridor from Tucson to Phoenix. So it goes in the tough world of weather forecasting.