Two storm systems are taking aim at eastern Utah and western Colorado this week, according to the National Weather Service.

The first is expected to arrive Monday evening and continue through early Wednesday, bringing moderate snowfall to the mountains and rain showers to the valleys.

A winter weather advisory was issued for the mountains extending from 6 p.m. Monday to noon Wednesday. Travel may be especially difficult at Lizard Head on Colorado Highway 145 and at Molas and Red Mountain passes on U.S. Highway 550.

Snow levels will drop from 8,000 feet Tuesday morning to about 7,000 feet by the time precipitation ends on Wednesday morning. Six to 12 inches of snow may fall across the San Juan, Flat Top and central Colorado mountains, with locally higher amounts in the highest elevations.

In Montezuma County on Monday, there’s a slight chance of showers before 3 p.m., and a 70 percent chance of showers and thunderstorms after 4 p.m. There’s also a chance of rain and snow between 2 a.m. and 5 a.m. early Tuesday. A high of 53 degrees was forecast for Monday, with an overnight low of 32.

On Tuesday morning, there’s a 50 percent chance of snow showers about 9 a.m., with rain and scattered thundershowers after 10 a.m. The high Tuesday was expected to be about 47 degrees; the low, 31.

A second storm system is expected to arrive on Thursday evening and last through Saturday. This storm is expected to bring snow to all mountain zones in western Colorado, but the National Weather Service said it was too early to predict snowfall amounts.