Winter arrived quickly, with above normal snowfall and below normal cold to start the month, and despite the recent warmth, there's plenty of cold and snow to come."More colder outbreaks, more opportunities for snow storms here along the East Coast. This could be a very active winter," winter forecasting expert Dr. Judah Cohen said.Cohen is predicting this year to be a classic New England winter.The key is found in the polar vortex, a large swirling storm located over the arctic region. When it is strong, Maine sees mild conditions. When it becomes disturbed, winter can hit hard, making for a cold January and February."It takes about four to six weeks to disrupt the polar vortex. Leading up the the disruption of the polar vortex, you tend to be very mild, and then after the polar vortex is disrupted, you tend to be cold for another four to six weeks," Cohen said.The initial disruption of the polar vortex appears to be underway, so any mild temperatures recently will likely be short lived.Snowfall amounts are predicted to be above normal; nearly 80 inches in Portland.That would be more than last year, but less than two years ago."I'd say between Martin Luther King and President's Day weekend, that would be my odds on favorite for the heart of winter," Cohen said.