A quick comment on the thunderstorms in southeast Arizona this afternoon so far. The storms have appeared, visually, much less vigorous than were the storms yesterday at this time. The towers that I've observed locally have appeared fuzzy, or soft, and not strongly boiling and bubbling. This kind of appearance can indicate that entrainment is weakening the updrafts. The two top graphics are the visible satellite image and the corresponding TUS radar composite at about 00Z on the 30th. There are some strong radar reflectivities but a check of VILS and storm tops indicates most tops only 30 to 35 thousand feet, with quite low values of VIL. Lightning loops indicate CG activity has been much reduced also this afternoon. The bottom graphic is a special sounding taken at 18Z today at Tucson. The SPC parcel analysis seems to indicate moderate values for CAPE. However, GPS data indicate that the PW indicated is 4 to 5 mm too great - obviously having some kind of impact on sounding diagnostics. Further, the parcel analysis shown is for virtual temperature. It has been my experience that sometimes the Tv diagnostics seem quite optimistic (i.e., high values of CAPE). The classical lifted parcel analysis, even for the too wet data, indicates considerably less CAPE. So, it appears to me that the atmosphere has been acting more like classical diagnostics would indicate and that Tv CAPE was optimistic today. Tough forecasting situation, especially with the bad RRS sounding data.
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