DENVER (AP) — The University of Northern Colorado is closing down early as a winter storm taking aim at the northeast part of the state threatens to hamper travel during Thanksgiving week.

The National Weather Service has issued winter storm warnings for northeastern Colorado, southern Wyoming and a large part of Nebraska. Up to 20 inches (50.8 centimeters) of snow is possible in parts of Colorado.

Ahead of the storm, the University of Northern Colorado at Greeley announced that classes would be canceled Monday afternoon and Tuesday.

The storm isn’t expected to hit northeast Colorado, including the Denver metro area, until later Monday, but the university says it wants to encourage students traveling for the holiday to leave before the storm.

No classes were scheduled the rest of the week because of Thanksgiving.