This morning's Tucson sounding indicates that moisture has increased slightly and that the 500 mb T is -7C, which are both good indications for incresed storm activity. The vertical wind profile indicates steering flow from southeast of 10 to 20 kts and also that anvils would stream out to the east. Skies are clear across southeast Arizona - so several pros for slightly better storms this afternoon. The 1300 UTC IR image above indicates disturbed weather and storms, or storm debris, stretching north from Cabo Corrientes all the way into central Arizona.
The Sonoran MCS has left behind a fairly large MCV that is over the north end of GoC this morning. The Atmo early run of the WRF-GFS has captured this feature in it's forecast - the above image shows WRF-GFS forecast of Outgoing Longwave Radiation (OLR) valid at 7 am MST, and shows the MCV circulation pattern over western Pima County. In contrast, this feature was not picked up in the 1200 UTC NAM analysis. Thus, a fair amount of difference in the forecasts from the two models by midafternoon.
The WRF-GFS forecasts a nearly total down-day across all of southern Arizona today - the NAM forecasts only a band of isolated, high-elevation showers strecthing north across eastern Pima County. So, the models forecast a considerable down turn in thunderstorm activity today. The WRF-GFS forecasts drying from the northwest today, with falling PW and the 850 mb Td also dropping. The forecast sounding at Tucson for 4 pm MST is shown above - basically a dry sounding with no CAPE.
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So, what to forecast? I guess that I would go with the WRF, given its track record, and say that things are not going to pan out as I initially thought when I looked at the early morning observations. Time will tell.
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