Light showers did move across parts of the metro area last evening - here at house we have 0.07" in gauge this morning (better than the "event" of Sunday night). Cool air moving in with and behind the showers has led to an unusual desert morning with thick fog across much of eastern Pima County. Photo above is looking north from Kitt Peak at the fog across the lower elevations. Photo below is from the house looking toward the Catalinas with the visibility about a 1/4 of a mile. Both photos were from a bit before 8 am MST.
The 500 mb analysis at 12 UTC this morning, Wednesday, January 14th (above from NCAR RAL), shows that the short wave has dug south-southwestward and is now centered over Arizona. Temperatures with this feature are -20 C or colder and the cold pool will move eastward today, just to our north. The morning sounding from TWC on campus (below, from the SPC) has a surprising bit of CAPE below 500 mb. There is an indication of drier air moving in aloft on the westerly winds. So the forecast issue for today is whether or not convective showers will develop before the dry air invades eastern Pima County. Some sunshine would also be needed. So this is a difficult forecast question for late morning to early afternoon. My assessment, based on a very quick look, is that showers that develop will probably be just off to the east.
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