Saturday, September 22, 2012

A Lightning Strike?

Edited to add: The Tucson sounding from 00 UTC (above), released a bit over an hour after the detected lightning strike. What can I say?

During the heat of the afternoon today (Saturday, 22 September) the shallow convection at the top of the deep boundary layer produced weak radar echoes (above is 1.5 degree tilt at 3:10 pm MST). One tiny cell southwest of Tucson indicates reflectivity of 35 to 40 dBZ. This shallow cell apparently produced a CG lightning strike (below is IR satellite data with CG superposed at 2:40 pm MST) - note the red dot (indicating a detected CG) associated with the echo above. The radar reflectivity is large enough to indicate that graupel was present in the the convection, so the detection is probably valid.

The image above is VIL at 3:10 pm - values are very small, although the slowly varying color scale prevents me from making an estimate. The image below is radar detected echo tops at 3:10 pm. Note that the echo tops are only in the 18 to 22 thousand ft range - which certainly fits the morning sounding (see previous post). It appears that we had a thunderstorm produced by a remarkably shallow cumulus buildup - quite amazing actually.

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