The unprecedented warm weather that gave southern Maine a green Christmas will end Tuesday when the Portland area will likely see its first measurable snow of the season.

Most of Maine will get snow, with about 6 inches in the forecast for Portland and surrounding areas. Central and northern parts of the state could get 7 to 12 inches by the time the storm ends Tuesday night.

The National Weather Service in Gray issued a winter storm warning late Monday afternoon, advising travelers that the storm will bring freezing rain as well as snow. The warning takes effect at 4 a.m. Tuesday. A winter storm warning means significant amounts of snow, sleet and/or ice are expected.

The storm was forecast to drop 4 to 8 inches of snow along with about a tenth of an inch of ice in southern Maine, and was expected to affect the Tuesday morning commute, said meteorologist James Brown. Snow was expected to start between 5 and 7 a.m. and to be heavy at times before mixing with sleet or freezing rain by early afternoon, Brown warned. The storm should end Tuesday evening.

“The big thing about this storm is it’s our first snowstorm of the year. People need to be careful,” Brown said.

Dec. 29 is the second-latest date recorded for Portland to get its first measurable snowfall. The latest on record was Jan. 16, 2000, and the second-latest had been Dec. 24, 1912.

On average, Portland has received 13.4 inches of snow by Dec. 29, Brown said.

“We will cut into that tomorrow,” he said.

Several municipalities in southern Maine banned on-street parking for Monday night or Tuesday morning, including Windham, Old Orchard Beach, Scarborough, Sanford, Kennebunk, Lewiston, Rumford and Auburn.

As of midnight, Portland had not instituted a parking ban. The city did announce a new location for its residential sand and salt pile, now located on Kennebec Street between Paris and Brattle streets, directly across from the Post Office Garage.

Several superior and district courts will be closed Tuesday. Among them are: Androscoggin, Franklin and Oxford County superior courts, and Farmington, Lewiston, Rumford and South Paris district courts.

December temperatures had been mostly mild in Portland through Sunday. But the city recorded a high of 34 degrees Monday, and highs Tuesday were expected to hover around the freezing mark, Brown said.

In Portland, the high on Friday, Christmas Day, reached 62 degrees, smashing the previous Christmas Day record of 54, recorded last year and in 1994. Bangor also reached a record high of 54 Friday, tying the previous record set on Christmas Day last year. Millinocket reached a record high of 53, surpassing its previous high of 51 set in 2003.

Through Christmas week, December high temperatures in Portland averaged 47.1 degrees, roughly 10 degrees above normal.

With the realization that snow is finally coming, shoppers started buying the tools of winter.

Maine Hardware on St. John Street in Portland was busy Monday as shoppers bought shovels, ice melt and rock salt, said manager James Joyce.

“I think people have been waiting but are finally buying now that the storm is coming,” he said. “Before today they haven’t really been thinking about it, but we are loaded up and ready to go.”

At Aubuchon Hardware in Buxton, assistant manager Don Pelkey said things have been “a little odd” this year because customers hadn’t been in to buy salt and shovels. But on Monday, business was steady as people stopped in for last-minute supplies. Wood pellets seemed more popular than shovels, though plenty of those were purchased as well, Pelkey said.

“It hadn’t been what we’ve seen in past years,” Pelkey said. “I think everyone was procrastinating and trying to save money for Christmas.”

Patrick Moody, a spokesman for AAA Northern New England, warned drivers to plan for extra travel time, leave plenty of space between cars and make sure they’re prepared for the weather as they head out of the house Tuesday. He said drivers should make sure their tires have adequate tread and that car batteries are in good condition.

“We know we need to flip the switch every winter and make adjustments for the driving conditions,” Moody said. “Usually it takes a few storms to remind people they need to adjust their driving to make smooth changes in direction and speed.”

Tuesday’s storm comes during an especially busy time on the roads. From Dec. 23 to Jan. 3, the number of travelers nationally is expected to top 100 million for the first time on record, according to AAA. Moody said many Mainers may already be planning to stay off the road because they’re home with their children during school break.

“When things are forecast out like this storm has been, some people can alter their travel plans,” Moody said. “That should help out with the number of folks who find themselves stuck in the ditch.”

Tuesday’s snowstorm comes in the wake of deadly weather in the South last week and over the weekend that included tornadoes that killed 11 people in the Dallas area as well as flooding and other bad weather. The country’s midsection was seeing a range of precipitation, including heavy snow, ice and blustery winds in parts of several states, and heavy rain in already waterlogged parts of Missouri and Arkansas, much of it associated with the storm heading into New England on Tuesday.

The Texas Panhandle was expected to get a blizzard that could bring as much as 15 inches of snow to Amarillo and Lubbock, with high winds that could drive the wind chill factor as low as 10 below zero.

Dozens were injured by the tornadoes that swept through the Dallas area Saturday, causing substantial damage. That, plus flooding in Missouri and Illinois, resulted in at least 43 weather-related deaths nationally in the past week.