Fog!                                                            10/31

     1.  Why is an occluded front, which is moving, neither designated as a cold nor warm front?

              There are two reasons why a different term is used.  (1) There are three air masses rather than the usual two
                  involved and (2) the temperature change is usually smaller than that associated with either a cold or warm front.
                  Simply stated, it has a different kind of structure than either a cold or warm front and therefore is distinguished
                  by a different name.

    2.  When a cold front passes, is the subsequent cold weather considered to be part of the cold front.

              Technically speaking, only the boundary between air masses constitutes the cold front.  That boundary may be
                  somewhat ill-defined and the transition to a colder, drier (in the sense of a lower dew point) air mass typically
                  requires several minutes of time at a particular location.  That transitional period is considered to be the frontal
                  passage.  The often protracted period of cold weather which then occurs is not consider to be part of the cold front,
                  but rather a consequence of the frontal passage.

    3.  How can you distinguish a cold front from a warm front by just looking up into the sky? 

              A cursory observation of the sky, current precipitation and wind direction is sometimes sufficient to distinguish a cold
                  front from a warm front.  Sometimes it is not and observations over a period of time are need to resolve the issue.
                  Please click on the graphic, Differences in Warm and Cold Fronts, for a list of criteria which can be used to answer
                  the question.  A quick call can be made if any of the following are present:  lightning, hail, very heavy precipitation,
                  strong gusty winds, low-based cumulonimbus clouds (cold front) or freezing rain, sleet or frontal fog (warm front).
                  Locally, in the winter months, the appearance of the sky is a help.  If the sky is uniformly gray, with light precipitation
                  occurring over and obscuring the mountains and sometimes very light precipitation in the valley, an associated
                  front is probably a warm one.

    4.  Why are summertime surface ocean temperatures colder near Point Arena, California, than anywhere else
         along the west coast (excluding Alaska) including near the Canadian border?

              This is entirely a consequence of upwelling.  This is stronger adjacent to northern California than anywhere else
                 on the West Coast, because there the prevailing summertime winds are almost perfectly parallel to the coastline.