October 13, 2009
Very Unhealthy PM10 Forecasted for Today in San Joaquin Valley, California; Volcanic Activity Continues in Montserrat
Much of the nation was covered in clouds today, as shown by the Aqua MODIS true color image (below on left, overlaid with the synoptic surface analysis in Google Earth). Of particular interest is a very strong extratropical cyclone (low pressure system) that is approaching the West Coast; the center of low pressure is currently located over the Pacific, west of Washington state (indicated by "970" in the lower left image, which stands for 970 millibars of pressure). Much of California and parts of Nevada and Utah are experiencing strong southerly winds associated with the system. Forecasters for the San Joaquin Valley of California expect PM10 to reach the Code Purple (Very Unhealthy) range today due to blowing dust generated by these winds. I couldn't find air quality measurements for today from the San Joaquin Valley Air Pollution Control District, so I'm not sure what today's PM10 conditions are, but AIRNow reports that PM2.5 is in the Code Orange (Unhealthy for Sensitive Groups) range in Bakersfield. Across the rest of the nation, air quality is almost uniformly Code Green (Good), as shown in the preliminary PM2.5 loop of AQI values (below on right). NOAA's Hazard Mapping System reports essentially no fire activity today, and the National Interagency Fire Center indicates that there are only three current major wildfires, one each in California, Oregon, and Washington.
 |  |
Volcanic activity in the Caribbean continued today. Patricia has been following the volcanic eruptions in Montserrat, Leeward Islands, for the past few days on the Blog. Today's Aqua MODIS true color image of the region (below on left in Google Earth) is not as impressive as yesterday's, but some ash and possibly vog (volcanic smog) are visible streaming to the west of the city of Plymouth. The OMI SO2 image from 17:34 UTC (below on right) shows that high concentrations of SO2 were emitted from the Soufriere Hills volcano this afternoon.
 |  |