Interesting Weather Continues in the Southwest

Weather Update - 8:00 am Friday July 4, 2008

Yesterday was a very active day with most reporting stations in southeast and south central reporting thunderstorms and wind gusts of 30 mph or greater. Douglas reported a gust to 75 mph, and others of note were: 53 at Mt. Hopkins RAWS, 45 at Scottsdale airport, and 44 at TUS. The Pima Flood Control District monitors rainfall at 91 sites in eastern Pima County and 56 of these sites reported measurable rain for the 24 hours ending at 6 am this morning. Notable amounts: 4.61" at Manning Camp in the Rincons (this is from a RAWS site and may be suspect) and 1.77" at Oracle Ranger Station. The most rain reported in the main part of the City was 0.47" at Pantano and Houghton. Of the 18 City gauges only 6 reported measurable rain, showing that the higher elevations did much better. Here at the house we had lots of lightning and thunder, several outflows and a couple of brief spits of rain, amounting to a trace. But the cool outflows and strong smell of rain made for a great evening.

This morning the moisture contents over southern Arizona have continued to increase. The TWC sounding is very moist and indicates the most CAPE present for the season so far. The IPW products and surface observations show that the surge of GoC moisture which began midday on Wednesday has pushed north almost to Las Vegas. IPW at Tucson is 38 mm this morning and Phoenix has 41 mm.

Winds in the upper and lower troposphere are light and variable, but steering level winds from 400 to 600 mb are from the east-northeast at 15 to 30 kts. There are no synoptic features of note today, except for the moderate wind flow around the midlevel anticyclone and perhaps a bit of midlevel cool advection. Expect that it will be another active day across much of southern Arizona. With higher moisture and lower cloud bases, the threat of heavy rain is greater today and the possibility of severe downbursts remains significant. The increased CAPE will allow better propagation of mountain storms into the deserts during the afternoon and evening.

So, another active day likely with lightning fireworks for the Fourth.