Friday, July 31, 2015 - Yesterday's satellite observations and model outlook through Saturday

Observations and modeled smoke for yesterday (7/30) agreed fairly well, showing the Central Valley filled with haze and smoke.

Monitors at surface also agreed, showing afternoon concentrations in the moderate AQI range up and down the Valley, with a hotspot of impacts around the Willow fire.

Statewide view of monitors at 7:30 pm yesterday (7/30), both mobile (triangles) and permanent (circles), showing moderate AQI in many sites throughout the Central Valley, and hotspots around the Willow Fire.

Going forward, the model shows that localized impacts around the fires, especially the Willow and Cabin fires, are likely to continue, but with decreasing influence on Central Valley today as SW winds begin to take over.  Clouds and rain associated with the monsoonal moisture that moved into the Sierra yesterday will also help scour the air and improve air quality where they continue to manifest.

The exception to this pattern may occur in the Fresno/Visalia area and the Sierra foothills from Mariposa/Tuolumne County south, where smoke from night-time containment operations on the Willow fire last night (7/30) and tonight (7/31) may cause increased or at least similar impacts to the last few days through Saturday morning.  By Saturday evening, whatever smoke isn't scoured out of the air by clouds and rain may be able to make it over the Sierra Crest, into Mammoth, Tahoe, and other east side communities. Again the model assumes today's level of smoke emissions persist, which may not necessarily be the case.  Illustrations below: