Tuesday, July 21, 2015

Quick Look Yesterday/Today

View of Baboquivari Peak (above) this morning at 7:09 am MST, looking south from Kitt Peak. There was a bit more thunderstorm activity yesterday afternoon - as shown in the plot of detected CG flashes (from Vaisala and Atmo, below through 1:00 am this morning). Storms were mostly over southwest Cochise County and northeastern Sonora - some nice views to east and southeast from Tucson during late afternoon. Across the ALERT network it was the first day with zero reports of rainfall in quite a while.

The dry-out that is underway has not managed to scour its way down to surface and PW remains over an inch. While there were two subsidence inversions aloft in TWC's sounding yesterday afternoon, only one remains this morning (TWC skewT above from SPC for 12 UTC), up at around 400 mb. Some CAPE remains and the very dry air remains in upper-troposphere above 500 mb. Below is a forecast (from the 06 UTC run of the WRF-GFS) of the TWC sounding for 3:00 pm MST this afternoon (21 July). The model forecast minimizes the elevated warm layer and indicates a surprising amount of CAPE (over a 1000 m2/s*2). The CAPE is probably over-done, but is one of various model indicators that yesterday was probably the worst of the dry-out for southeast Arizona. The wind profiles in both observed and forecast soundings remain absolutely pathetic, with light westerly winds through the troposphere. This seems to be something that I've been moaning about for three or four summers now.

The WRF-GFS (from 06 UTC, above) does forecast thunderstorms at 4:00 pm this afternoon over eastern Pima County - the NAM version is similar but with less coverage. Perhaps a bit of a chance for a storm or two back within the ALERT network today.

Finally, from the Sleeping Frog Farms newsletter last week - nice photo of storm and rainbow over the San Pedro Basin north of Benson, Arizona - day that photo was taken was not stated.

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