Donald Gansauer wrote from Canton last week: "When I got up it was clear. Shortly afterward a dense fog occurred. A few minutes later the fog was gone. All before sunrise. Can you explain this?" The simplest explanation is that there was plenty of surface moisture over the harbor. Clear skies overnight and radiational cooling sank air temperatures to the dew point, condensing the moisture and creating fog. Light, pre-dawn winds then moved it over Canton, then pushed it away. Or, it was the Crawling Eye.