Monday, June 25, 2012

Thunder But No Rain

Storms evolved basically similar to the WRF-GFS forecast yesterday afternoon. Above is a shot of the anvil from a storm near Picture Rocks at about 4 pm MST and below is 3 PM NWS radar composite. The storm to the west produced a couple of rumbles of thunder here a, the anvil thickened some overhead. Radar shows that an area of storms formed to the west and these produced an outflow (passed here at 3:50 pm MST) from the west that was gusty and dusty, but not nearly as strong as the model had forecast. Generally the storms were weaker than forecast by the model, and there was more activity to the east of Tucson.

Only 8 of the 93 Pima County ALERT gauges had rainfall, with the only significant amount falling at Picture Rocks - from the storm whose anvil is shown above - 0.59 inches.

This morning's TWC sounding is similar to yesterday's with the SPC analysis indicating a sliver of CAPE. However, comparison with the GPS data indicates that the sounding was 2/10" too dry, so there may be better CAPE around this afternoon. The wind profile remains a bit chopped up, with no good steering flow. So, another afternoon of mountain-initiated storms drifting toward wherever the CAPE is best. The axis of high precipitable water remains out to the west of Tucson - so activity may be heaviest from south to west, as per yesterday. No WRF-GFS output available this morning.

Final note - the NHC forecasts switched to the eastern path yesterday. However, global models still break off an inverted trough from the large circulation over the GoM that they forecast to move westward.

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