GOES-West GOES-R IFR Probabilities from 0500 UTC through 1400 UTC 11 Sept 2012

Low clouds and fog are a climatologically normal feature of the Pacific Ocean off the coast of California, abetted by the upwelling of cold water there.  It’s also common for those low clouds and fog to spread inland over the course of the night, and the animation above shows how the IFR product handled the evolution of the low clouds during early September.  There are several sites where IFR conditions develop as the IFR probability field values increase:  Hollister, CA (KCVH), South Santa Clara County Airport (KE16), Hanford (KHAF) and San Francisco International (KSFO).  Monterey, Salinas and Watsonville (KMRY, KSNS, KWVI) spend the night in IFR conditions, and a tongue of higher probabilities extends down that Salinas Valley as well.  At 1500 UTC, the sun has risen, and cloud detection allows the elimination of many IFR Probabilities in regions where — at 1500 UTC — any fog/low clouds that developed over night have dissipated.