Weather forecasters say the state probably won’t see a crippling ice storm this weekend, but if conditions break just right, things could get pretty messy late Saturday and into Sunday for much of the state.

“You need warm air aloft, which is coming from the south, combined with cold air on the ground, which is blowing down from Canada,” said Tom Hawley, a meteorologist with the National Weather Service office in Gray. “So when that precipitation falls as rain, it freezes instantly on the ground.”

Freezing rain is not uncommon this time of year, Hawley said, but it usually doesn’t last long enough to create havoc. This weekend’s storm, however, has the potential to bring as much as an inch of precipitation. If that is all rain, it would not be a big deal. Similarly, if it is all snow, it would mean up to a foot, but would still be manageable.

If it’s all ice, though, it’s the nightmare scenario.

“Fluffy snow, like we had last weekend, that’s probably the easiest to deal with,” said Dale Doughty, director of maintenance and operations for the Maine Department of Transportation. “But anytime you get a mix, that’s when things get tricky.”

The words “ice storm,” to anyone who was living in the state 16 years ago, often bring an immediate response. That’s when a prolonged storm in January 1998 left more than half of all Maine households without power for as long as three weeks. The Maine National Guard was mobilized. Six people died. Cleanup took several months. Damage was in the hundreds of millions of dollars.

“I think any time you say ‘ice storm,’ people’s brains go back to 1998,” said Lynette Miller, spokeswoman for the Maine Emergency Management Agency. “That was not a happy time for a lot of people.”

More recently, powerful and memorable ice storms hit Maine in December 2008 and March 2010, although neither matched 1998.

Although forecasters don’t expect this weekend’s storm to come close to being as destructive as either of those recent ones, emergency crews are planning for the worst just in case because the weather models are still unsettled.

Gail Rice, spokeswoman for Central Maine Power Co., said all of the utility’s employees have been told to be prepared. Trucks have been fueled and equipped to go out at a moment’s notice. Final numbers are still being worked out, but Rice estimated that at least 200 line workers will be available to work Sunday.

If the storm necessitates additional crews, CMP is part of a regional cooperative where workers could be brought into the state to assist, but as of Thursday, no arrangement for additional crews had been made.

“We’re not panicking, but we have been watching the forecast closely and will continue to do so because as we know it can change,” Rice said.

In Portland, city public works director Mike Bobinsky said crews are still cleaning up from Tuesday’s storm, but will be ready for the weekend. He said salt and sand application will be the biggest priority for this storm.

State DOT crews also use a combination of salt and sand on the roads. Salt helps delay ice from forming over the road, and sand helps increase traction.

Ice is also among the biggest concerns for power companies because it can build up on trees and power lines much more easily than snow, leading to widespread outages.

In the past five years, CMP has been much more aggressive about trimming tree branches that grow close to power lines.

“We’ve never going to be able to prevent all outages, but we’ve done things to reduce the impact,” Rice said.

Doughty said DOT crews have removed a lot of limbs as well, but Maine is still a heavily wooded state. “You can’t trim everything,” he said.

Miller said Maine Emergency Management is always updating its emergency response plan and has learned a great deal since 1998. The biggest improvement has been in communication and coordination across agencies.

Already this week, weather professionals, utility companies and state emergency officials have participated in conference calls about the upcoming storm. There will be another conference call Friday when it is hoped the weather pattern will be more set.

“The best thing people can do is to keep checking the weather,” said Miller. “Don’t assume that what you saw on Wednesday is going to be the same.”

Weather forecasters are certain that there will be some precipitation. Whether it freezes and how much falls could determine the storm’s severity. Either way, Hawley said, Maine and New Hampshire will be hit hardest because temperatures in those states will straddle the freezing point. Metro areas such as Boston and New York are expected to see only rain.

Because the storm will hit on the weekend before Christmas and it’s likely to be a busy travel weekend, officials are urging people to leave early, if at all possible, and stay put once they get to their destination.

“People will probably try to travel if they think they can, but that does make our job a little harder,” said Doughty with the DOT.

Eric Russell can be contacted at 791-6344 or at:

erussell@pressherald.com

Twitter: @PPHEricRussell