There was an upturn in storm activity yesterday, particularly to the west to northwest of our area. Plot of CG flashes for 24-h through midnight last night is shown above (from Vaisala and Atmo). Biggest changes were out in western Pima County and across all of Maricopa County, where severe winds were common from Luke AFB area east to Roosevelt Dam. Here in the Tucson metro area storms developed late and focused on the east side of town, the Rincons, and Redington Pass area. There was thunder here at house and gusty outflows, but again, no rain. The composite radar chart below shows the situation a bit after 7:00 pm MST.
Two sectors of the ALERT network data for the 24-hours ending at 5:00 am this morning illustrate the geographical coverage of the storms well. The metro W sector above was almost free of rain amounts of 0.04", while the metro E sector (below) had nearly 100 percent coverage with several sites having over half an inch of rain. Across the entire network 36 sites measured rainfall, but only 7 stations had half an inch or more, and no site measured three quarters of an inch.
Photo below apparently shows a small, landspout type tornado in the Phoenix area yesterday afternoon - photo by L.W. Wilbrand taken in the Goodyear/Buckeye area. Luke AFB base measured gusts to 61 mph, while Sky Harbor airport had winds to 53 mph.
Today seems to be yet another with only small changes happening in the large-scale setting. The 500 mb anticyclone is centered over southern California this morning and will shift back eastward during today and tomorrow. Winds in much of the troposphere are light and variable, and CAPE is down slightly here in the Tucson area. I looked at both the WRF-NAM and the WRF-GFS model runs from 00 UTC and also 06 UTC - all of those forecast runs indicate isolated mountain storms this afternoon for southeast Arizona. One of those runs forecasts a thunder storm over the east metro area during the late afternoon. I do think that the models may be a little conservative for this afternoon, since there are indications that mid-level winds will become light northerly and that there may be some slight bit of cool advection to increase CAPE relative to this morning. Would be a nice change if a storm drifted south from the Catalinas into this part of the city!
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