The National Weather Service has issued a dense fog advisory in effect until 9 a.m. Friday.

Visibility in Carbon and Monroe counties is one quarter mile or less in dense fog, causing hazardous driving conditions due to low visibility.

If driving, slow down, use your headlights, and leave plenty of distance ahead of you.

Here’s the complete forecast:

Tonight: A chance of rain, mainly before 1 a.m. Widespread dense fog. Otherwise, cloudy, with a low around 42. Calm wind. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Friday: A slight chance of rain before 8 a.m. Widespread dense fog before 9 a.m. Otherwise, cloudy, with a high near 51. Calm wind becoming southwest around 5 mph in the afternoon. Chance of precipitation is 20%.

Friday Night: A chance of rain, mainly after 10 p.m. Patchy fog after 1 a.m. Otherwise, cloudy, with a low around 45. Southwest wind around 5 mph becoming calm. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

New Year’s Day: Rain. Patchy fog before 10 a.m. High near 54. Calm wind becoming south around 5 mph. Chance of precipitation is 90%. New precipitation amounts between a quarter and half of an inch possible.

Saturday Night: Rain, mainly before 1 a.m. Patchy fog after 1 a.m. Low around 46. Calm wind becoming south around 5 mph. Chance of precipitation is 90%. New precipitation amounts between a quarter and half of an inch possible.

Sunday: A chance of rain. Mostly cloudy, with a high near 56. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Sunday Night: Mostly cloudy, with a low around 21.

Monday: Sunny, with a high near 30.