The National Weather Service has issued a winter storm watch in effect from 10 a.m. Saturday through 6 p.m. Sunday.

Heavy snow is in the forecast, with 5 to 8 inches possible in Carbon and Monroe counties.

Weekend travel could be very difficult, especially at night. Snowfall rates may reach one inch per hour at times.

Check back for updates.

Here is the latest forecast:

Tonight: Mostly clear, with a low around 20. Blustery, with a northwest wind 10 to 20 mph.

Friday: Sunny, with a high near 36. West wind 5 to 10 mph.

Friday Night: Mostly cloudy, with a low around 23. West wind around 5 mph.

Saturday: Snow likely, mainly after 5 p.m. Cloudy, with a high near 36. Light and variable wind becoming southeast 5 to 10 mph in the afternoon. Chance of precipitation is 60%. New snow accumulation of less than one inch possible.

Saturday Night: Snow. The snow could be heavy at times. Low around 29. Northeast wind around 15 mph, with gusts as high as 25 mph. Chance of precipitation is 90%. New snow accumulation of 3 to 7 inches possible.

Sunday: Snow likely before 2 p.m., then a chance of rain and snow. Mostly cloudy, with a high near 37. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Sunday Night: A chance of snow before 8 p.m. Mostly cloudy, with a low around 26. Chance of precipitation is 30%.

Monday: Mostly sunny, with a high near 40.

Monday Night: Partly cloudy, with a low around 20.

Tuesday: A chance of rain and snow between 8 a.m. and 2 p.m., then rain. High near 46. Chance of precipitation is 80%.

Tuesday Night: Rain. Low around 38. Breezy. Chance of precipitation is 100%.

Wednesday: Rain. High near 45. Breezy. Chance of precipitation is 80%.

Wednesday Night: Partly cloudy, with a low around 28. Breezy.

Thursday: Mostly sunny, with a high near 41.