Sunday, August 20, 2006

Severe storms in southeast Arizona this afternoon?

Has been a busy week and I have not had a chance to do much here in blogland.

The morning observations today - Sunday August 20 - are very interesting and indicate some potential for a tropical-like squall and significant storms this afternoon.

The morning Tucson sounding, view at:

http://www.rap.ucar.edu/weather/upper/tus.gif

went bonkers above 350 mb, so we have to decide whether to accept the data below 350 mb as being good. If I accept the observations below 400 mb, it appears that CAPE is substantial for out here, that there are some easterly steering winds above well-mixed BL cloud base (~700 mb), and that anvil level flow is from the southwest (favorable).

The 500 mb anticyclone has a split off a lobe right over Phoenix this morning - not a favorable position. But, there is not a deep, barotropic anticyclone aloft over Arizona.There is a deep trof/shear zone from 700 to 200 mb over New Mexico between the large anticyclone to the east and features to the west. The flow above 300 mb appears highly difluent this morning (favorable). The weak flow in middle levels continues - the storms of August 8th got organized with similar weak flow, so we'll have to see what happens today.

The models at 0600 UTC provide little help - NAM continues with the near TS it has somehow genertaed off to the SSW. Thus, one has little feel for how much credance to give the predicted wind profiles. In general, the wind patterns predicted by GFS for this evening are less favorable than what's observed this morning.

Certainly should be a much more interesting day than have been the last couple of days, since the early morning deluge of Wednesday the 16th.

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