First, a different view of the thunderstorm doughnut hole over Tucson metro - above from Vaisala and Weather.Graphics shows 24-hour CG flash density ending at 7:00 am MST this morning. Compare with different version shown in earlier post this morning - below, and also compare relative to day before. I think the 12 UTC WRF forecasts yesterday got this northward shift of the storm activity, as well as its early nature, quite well.
This morning's upper-air sounding from TWC (above skewT plot for 12 UTC from SPC) seems to indicate that we should batten-down the hatches, as CAPE is very large. However, as has so often been the case this summer, the wind profile aloft is truly pathetic, and there are other problems as well. The blended PW analysis from CIRA (below for 12 UTC) shows that the sounding was taken within a relatively small area of high PW over southern Arizona. This pool of high PW seems to be the result of numerous moist outflows from yesterday afternoon's storms.
Both versions of the WRF model run at Atmo at 06 UTC forecast the thunderstorm activity to shift eastward today, as the PW over eastern Pima County falls during the day. While the models forecast early storm development over the nearby mountains, the activity shifts eastward mostly into Cochise County. The 06 UTC WRF-NAM forecast of composite radar echoes (below, valid at 6:00 pm MST this evening) is as active as it gets in Pima County. I suspect that the forecasts may be a bit under-played and, again, the new 12 UTC WRF forecasts should be the ones of interest.
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