PORTLAND – A storm that’s expected to wallop the East Coast will stretch far enough to the north to pose problems in Maine.

The National Weather Service grappled with conflicting computer models for hours before determining Sunday afternoon that the storm will come close enough to cause major problems in southern and central Maine.

A winter storm watch was issued for the storm to reach southern regions on Monday, with 3 to 6 inches of snow by evening.

“It’s going to be a classic nor’easter. That’s what it is,” said Bob Marine, a meteorologist from the weather service in Gray.

The storm was expected to be centered south of Massachusetts’ Cape Cod before stalling out for about 24 hours. Then it was expected to shuffle to the southwest and ultimately shift eastward before moving out to sea.

That means plenty of snow, but the snowfall could be even heavier if the storm moves farther to the north, Marine said.

“The brunt of it appears to still be to the south. They will get the full brunt of the storm. We’ll be a little north, away from it. We’re going to be watching it very closely,” he said.

The National Weather Service was not willing to make predictions for snowfall during what has been a snowy season.

As of Sunday, there had been 59 inches of snow recorded at Gray. That’s less than an inch higher than the average for the date. But cold temperature has kept the snow on the ground since Dec. 31.

The snow wasn’t the only problem associated with the storm.

Strong winds, combined with an astronomical high tide, were expected to create the potential for coastal flooding during high tides on Tuesday and possibly on Wednesday, Marine said.