Friday, January 30, 2009
There is dense fog around the Sound right now....that is generally a very good sign for day ahead. To get dense fog at low levels, one generally needs intense surface cooling...which generally requires clear or nearly clear skies aloft. You also need little mixing (otherwise you would have a thicker fog layer, which tends to be less thick at any one level). So in many areas, particularly away from the Sound, this fog should burn out during the next few hours.
There is a well-defined surface-based inversion over us right now (see graphic), with the cool, moist air only about 500-700 ft thick. Pilot reports at Sea Tac indicate the low clouds and fog top out at around 700ft.
Posted by Cliff Mass at 10:18 AM