Monday, January 04, 2016

Nice Rain Event So far

Rain started here at house around noon and has accumulated to 0.31" at 2:30 pm MST. Areal coverage of 0.04" or more across the Pima County ALERT network reached 100% by around 2:00 pm. Image above is from the General Store in Summerhaven and shows an inch or two of snow up there.

Image below (all below from CoD weather page) shows base-scan reflectivity from the NWS Tucson radar, located in the Empire mountains southeast of the City. The terrain blockage is very substantial. The narrow spike to the west of the radar results from the radar having been sited so that Mt. Fagan would block the lowest two beams over Kitt Peak. 

The bottom two graphics show echo tops above the radar elevation (second below) and current radar estimated rainfall totals (bottom) - times are indicated in lower right of the graphics. With the low echo tops, the radar rain estimates are being severely compromised by the terrain blockage. The radar estimates appear too high also - likely due to the low freezing level and high reflectivities due to wet ice and possibly some graupel.

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