Friday, July 04, 2014

July 3rd - Significant Storms For Much Of Southern Arizona

The above graphic shows detected CG flashes though 2 am MST this morning and indicates the widespread character of the thunderstorms yesterday afternoon and evening. Some of these storms produced significant downbursts and outflow,s with south-central Arizona (Pinal and Maricopa Counties) having dust storms and haboobs. Phoenix Sky Harbor reported dust and winds to 56 mph, but little rain, while Luke AFB had gusts to 52 mph along with 0.64" of rain. Severe thunderstorms reported included: wind damage central Phoenix; gusts to 61 mph in Safford; and a convective gust to 63 mph at the Guthrie RAWS station at 5:03 pm.

Here in the Tucson metro area there were several outflows during the afternoon and evening. The first outflow came in from the southwest with winds of around 30 mph. Later in the evening a strong outflow came across parts of town from the north to northwest - winds were strongest here at the house between 6:30 to 7:00 pm MST when I estimated gusts to at least 40 mph. I also see reports of gusts to 46 mph at the Mt. Hopkins RAWS and gusts to 44 mph at the Sasabe RAWS site.

Rainfall across low elevations of the Tucson metro area was spotty and light. Here at the house we had a total of 0.19" for the entire day (including the 0.06" around 3 am); the airport reported 0.16"; Atmo reported 0.09"; and DM had only a Trace. Still hard to tell that it had rained much in this part of town, since the ground heat quickly evaporated what little rain had fallen - best evidence is puddles on paved areas.

Rains were heaviest over the north and western Catalinas, including spots off to the immediate west of the mountains. Across the entire ALERT network 63 of 92 sites measured rainfall (70% coverage) with few reports across the south and southeastern parts of the network. In the Catalinas area there were 13 sites with more than a half inch of rain and 6 of these had over an inch. Heaviest amount occurred at the Mt. Lemmon station. Above plot shows rainfall over the Catalinas, while plot below covers the northwest Catalinas and west metro area. The plot at the bottom (from MesoWest, University of Utah) indicates how widespread the rainfall was across all of south-central and southeastern Arizona.

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