* WHAT...Visibility one quarter mile or less in dense fog.
* WHERE...Lowlands of Western Skagit and Northwestern Snohomish Counties and Downtown Everett / Marysville Area.
* WHEN...Until 1 PM PDT this afternoon.
* IMPACTS...Low visibility could make driving conditions hazardous.
* ADDITIONAL DETAILS...The densest fog is mainly focused along the coastal areas and in the Snohomish river valley.