The National Weather Service has declared a winter storm watch for southern and western Maine, New Hampshire and eastern Vermont on Saturday as a brief but intense snowstorm is followed by sleet and freezing rain, making driving hazardous and promising a sloppy end to the holiday weekend.

A storm system forecast to move up from Texas, then pick up moisture and energy over the Great Lakes, is due to hit Maine early Saturday night. It should start with snow, possibly an inch an hour, before turning over to icy conditions before dawn Sunday, said Andy Pohl, a meteorologist with the National Weather Service in Gray.

“That’s when things get interesting and when we lose a little confidence in the forecast,” said Pohl, noting that a front could set up over Cumberland County with some communities getting rain, and nearby towns getting freezing rain. “It’s a fairly dynamic system. Eventually warm air will win out and everything turns to rain. When that happens is the magic question.”

The Portland area should get 4 to 6 inches of snow, with higher accumulations inland before the changeover, he said.

While motorists may resent the precipitation, the storm is welcome news to snowmobilers, many of whom have been idle since a warm spell dissolved the snow cover on many of the state’s trails.

“The trails are not fit to drive on,” said Steve Fox, trailmaster for the Stoneham Knight Riders in Oxford County. “Our trails around here are very rough and they need a good foot of snow before we can start grooming them and maintaining them.”

“We have somewhat of a frozen base now. As long as we don’t get a lot of rain after it, there’s a good chance some of the trails will open up by the first of the week,” Fox said.

Maine ski mountains won’t see the snow until late Saturday, and by Sunday morning skiers may well be contending with a icy glaze on the trails, Pohl said.

In eastern Vermont, the National Weather Service forecast calls for up to 5 inches of snow and some ice in Caledonia, Orange, Washington, Windsor and in eastern Addison and Rutland counties this weekend, The Associated Press reported.

Freezing rain after snow is easier for road crews to deal with than ice on black pavement, said Vermont state highway dispatcher Larry Dodge.

“We’re not looking forward to it, but I’m sure they’ll be able to handle it,” he told the AP.

Some areas that didn’t see a white Christmas welcomed the snow, but not the rain.

The Rikert Nordic Center, which makes snow on the Bread Loaf campus of Middlebury College in Vermont, expected to have nearly 2 miles of cross-country trails open Saturday. The storm could drop 5 to 8 inches of snow on the 35 miles of trails, followed by rain, director Mike Hussey said.