Air Quality Violations Last Tuesday

First - temperatures this morning (Friday 19 April) and yesterday morning were quite chilly here at the house. The low yesterday was 36F and this morning it was 35F. So, I expect that the farms along the San Pedro probably had two more mornings at or below freezing (the low yesterday was 28F at the Empire RAWS station) - see earlier post about winds and below freezing temperatures over at Sleeping Frog.

The photo above shows the ugly dust cloud that moved into the area early on Tuesday morning, the 9th of April. Mike Leuthold reported that satellite images seemed to indicate that the dust had come in all the way from the southern California deserts. Trajectories from Air Resources Lab HYSPLIT model also indicate that the low-level air over the greater Tucson area on Tuesday morning had indeed been over the California deserts 24-hours earlier, with the dust particles carried along by the strong winds and/or also picked up anywhere along the way. The particulate counts at some local monitoring stations far exceeded EPA guidelines during the morning hours. The data and information below are from the morning article about the poor air quality that was in the Tucson Star.