Western Washington will experience the coldest temperatures of the fall early Thursday morning as clear skies and calm winds will allow the mercury to fall quickly overnight. Morning lows will be in the upper 20s to lower 30s in parts of the South Sound, where fog and freezing fog are potential issues for the morning commute.
A Freezing Fog Advisory has been issued for areas from Thurston County south and west.
Parts of Lewis, Mason, Thurston and Grays Harbor counties will be most at risk for freezing fog, which is fog that occurs when temperatures are at or below freezing. The small water droplets in the fog can create a thin layer of ice on surfaces, especially elevated surfaces such as bridges and overpasses.
Elsewhere, fog is not as likely but some frost can be expected with widespread temperatures in the low to mid-30s to start the day Thursday.
We'll have another chilly morning Friday before a bit of a warmup of the chilly overnight and early morning temperatures by the weekend.
More news from KIRO 7