Dozens of flights have already been canceled at the Portland International Jetport, schools have made plans to close early and public works crews are strategizing where to put all the new snow, even before the latest snowstorm hits New England.

The storm forecast for Thursday is threatening to dump up to a foot of snow on Maine, possibly mixed with sleet and freezing rain at the coast. The same storm has already hammered the Eastern Seaboard, paralyzing Southern states including Georgia and the Carolinas.

Tom Hawley, a meteorologist with the National Weather Service in Gray, said the snow will make its presence known quickly.

“By early afternoon, 1  or 2 (p.m.) or so, it should be snowing pretty hard,” Hawley said, and that will continue until early evening. He said some sleet and possibly rain will mix with the snow along the coast by about 8 p.m., and it could even switch over to all sleet or rain for several hours. He said the Maine Turnpike will be a rough snow/rain dividing line, although parts of the state as far inland as Lewiston and Sebago Lake could see some mixed precipitation.

Hawley said it should change back to all snow before sunrise Friday and that will add another two or three inches before 10 a.m.

All told, Hawley said, he expects about 7 to 9 inches of fresh snow on the ground by late Friday morning, although totals are hard to forecast because it’s difficult to say how much mixing will take place.

Inland, where the precipitation remains all snow,  about 10 to 14 inches is forecast, with totals tapering off slightly in far northern Maine to about 8 to 10 inches.

And, he said, more snow is on its way Saturday, although only about an inch is expected.

Hawley said another storm on Tuesday could bring a mix of snow and rain. Temperatures are expected to moderate for the end of next week, with highs of above freezing.

Road crews in Maine started preparing Wednesday for the latest storm in a season that has already brought 18.7 inches above normal snowfall.

“We’re lining up equipment right now,” said Mike Bobinsky, director of public services for Portland. “We likely will be using outside resources to assist our crews.”

“We’re making sure our salt and storage locations are ready to go, doing repairs on equipment, getting personnel lined up to supplement existing shifts,” Bobinsky said. The city anticipated bringing in additional people to supplement the morning crews working to clear the main arterials, not just plowing but loading snow into trucks and hauling it out of the downtown area.

The city is also keeping an eye on the height of its ever-mounting snow pile near the jetport, where it stores the bulk of the snow hauled from downtown.

The huge mound is located on outer Congress Street near the Maine Turnpike Authority offices. It is also in the glide path of approaching aircraft.

“There are restrictions on how high I can go,” Bobinsky said. “We’ve not really ever pushed the envelope.”

The maximum height for the snow pile is 30 feet.

The round trip to unload trucks at the snow dump takes about 40 minutes, so crews will also use areas like the snow dump on Somerset Street and possibly areas off Cleaves Street and Franklin Arterial, he said. Bobinsky said that during breaks between storms, the city will sometimes haul snow from Somerset Street to the pile near the jetport to make room at the in-town location.

Flights through Portland that pass through Southern hubs along the track of the storm, such as Atlanta, Philadelphia, New York and Washington, D.C., were delayed or canceled as early as Wednesday, with some Thursday flights canceled in anticipation of bad weather.

Some flights that don’t rely on East Coast hubs will still arrive and take off. Crews were preparing to lay down a pretreatment of chemicals if conditions turn icy, said jetport Director Paul Bradbury. The jetport uses front-end loaders with 30-foot blades, giant sweepers, and snowblowers powered by twin turbo-diesel engines.

“The snowbank like we have on the roads, we’re not allowed to have those on the edge of the runway because they can be an obstruction for the aircraft,” he said. The giant snowblowers are used to spray the snow into safety zones where it won’t pose a hazard, he said.

The arrival of the storm around midday could contribute to a slow and sloppy evening commute, and depending on how long the storm stays, could also affect the Friday morning commute.

Parking bans have already been declared for several communities, including Sanford, Scarborough – beginning at 10 a.m. Thursday – Freeport, Falmouth, Yarmouth and Gorham. Bobinsky said Portland typically waits until closer to the storm to declare a ban.

Portland schools have announced they will dismiss early Thursday, with afternoon and evening classes and activities canceled. Gorham and Falmouth are among other districts announcing that early dismissals are planned for Thursday.

Snowfall totals for the winter so far in Portland stand at 58 inches before Thursday’s storm – 18.7 inches above normal for this time of year. Last year’s total at this time, however, was 68.9 inches, according to the National Weather Service in Gray.

The record snowfall for a year is 141.5 inches.

“To come anywhere near a record, we have a long ways to go,” said Steve Capriola of the National Weather Service in Gray.

Central Maine Power Co. announced that it is preparing for possible outages due to the storm.

“We’ve put our storm response plan into motion, and we’re watching the forecast closely,” Gail Rice, spokesperson for CMP, said in a statement. “The heavy snow, sleet, and rain forecast for Thursday could cause considerable snow and ice buildup on roadways, tree limbs, and power lines. Combined with gusty winds, this could result in power interruptions and difficult travel, so we’re getting crews, equipment, and materials in place to respond.”

David Hench can be contacted at 791-6327 or at: dhench@pressherald.com