Tuesday, June 09, 2015

Widespread Early Morning Rain Event

Showers and some thunderstorms began moving into the Borderlands last evening - radar composite above is from 5:30 pm MST yesterday afternoon. Early this morning a shower band with some embedded moderate to heavy rains moved across the general Tucson area - radar below is from 4:50 am. This band produced a brief period of moderate rain here at the house and left 0.14" in the gauge. The band produced an event with essentially 100 percent areal coverage (second below is ALERT 24-h rain for the metro-west sector) with highest amounts approaching an inch over the mountains. The site with no rain indicated just west of the NWS ASOS station at the airport (0.21") may not be reliable, since it is only site in entire ALERT network with no rain (or perhaps an amount just under 0.04" might have occurred there).

The thunderstorm activity stayed mostly to the southeast of Tucson, although there were a couple of CG flashes over the Rincons with the recent shower band. Graphic above (from Weather.Graphics with data from Vaisala) shows CG flash density for the past six hours. This fits with the generally low echo tops with this shower band - below shows echo tops from the TUS radar at about 5:00 am MST - from CoD weather page.

The thunderstorms and lightning activity over the Pacific west of southern California has been related to the northward push of moisture from Blanca interacting with the relatively cold 500 mb cyclone that is spinning out there.

Finally, the morning sounding data are plotted below for TWC's 12 UTC sounding. The most amazing aspect is the record-setting PW amount of 1.73 inches. There is also some degree of CAPE present, even though the recent band produced mostly warm rain.

Obviously, the GFS model forecasts were better wrt the moisture influx and precipitation from decaying TS Blanca than were the drier forecasts from the NAM

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