Travelers in Southwest Washington the last few mornings may have needed to tack on extra time to get through fog what Maddie Kristell, a meteorologist with the National Weather Service in Seattle, described as “dense.”
Fortunately for the greater Lewis County area, Friday morning is the last day where heavy fog is in the forecast.
Kristell said a high pressure system is to blame for the dense, dewy air.
“The flow is light at the surface (of the ground),” she said. “And moisture off the ground radiates out and creates fog.”
Residents may have also noticed air quality warnings reaching between “moderate” and “unhealthy” air due to the fog, which Kristell said can trap emissions commonly used during cold spells, such as wood burning stoves.
With high pressure systems, she added, there is little airflow to move bad air out and fresh air into the region. However, she said this kind of system is not unusual for this time of year.
“(The fog is) again possible along I-5 in the southwest interior the next few mornings,” she said. Definitely we encourage the use of fog lights on your car. … Give yourself extra time. Take it slow.”
She added high beams should be avoided in fog as the brightness can be reflected back at drivers, making other headlights harder to see. To learn more, visit https://www.weather.gov/.