Overnight on the 8th a warm front lifted into the Northeast and stalled along the coast. A strong upper level vorticity maximum crossed the the stalled boundary on the morning of the 9th and led to rapid cyclogenesis along the New England coastline. Low pressure moved northeast along the Maine coast before moving into New Brunswick. While it was cold enough to snow in the mountains, warmer temperatures in the low to mid levels allowed for precipitation to begin as a mix of sleet, freezing rain, and rain to the south. As low pressure strengthened, heights aloft lowered and precipitation transitioned to heavy snow as it exited the area. Low level moisture and northwest flow behind the departing system kept upslope snow showers going into the morning of the 10th.

Heavy Snow in SOUTHERN OXFORD, MAINE
From 09-JAN-19 07:00:00 to 09-JAN-19 18:00:00 (EST-5)
Reported by: Trained Spotter

Light mixed precipitation changed over to moderate to heavy snow during the morning of the 9th. Snow was especially heavy in the higher terrain of the Mahoosucs, with lighter snow farther south through the foothills.

Heavy Snow in SOUTHERN FRANKLIN, MAINE
From 09-JAN-19 07:30:00 to 09-JAN-19 19:00:00 (EST-5)
Reported by: Trained Spotter

Light mixed precipitation changed over to moderate to heavy snow during the morning of the 9th. Snow was especially heavy in the higher terrain, with lighter snow farther south through the foothills.

Heavy Snow in SOUTHERN SOMERSET, MAINE
From 09-JAN-19 08:00:00 to 09-JAN-19 23:00:00 (EST-5)
Reported by: Trained Spotter

Light mixed precipitation changed over to moderate snow during the morning of the 9th. A persistent north-south band of snowfall into the evening allowed accumulating snow to continue much later in the day than areas farther west.

Heavy Snow in NORTHERN OXFORD, MAINE
From 09-JAN-19 07:30:00 to 09-JAN-19 18:00:00 (EST-5)
Reported by: Trained Spotter

A band of heavy snowfall developed on the morning of the 9th and pivoted over the mountains of western Maine. Snow accumulations reached 6 inches or more by midday. Low pressure moving into New Brunswick kept winds northwest over the area into the overnight, and low level moisture forced over the mountains resulted in additional upslope snow accumulation.

Heavy Snow in NORTHERN FRANKLIN, MAINE
From 09-JAN-19 08:00:00 to 09-JAN-19 19:00:00 (EST-5)
Reported by: Trained Spotter

A band of heavy snowfall developed on the morning of the 9th and pivoted over the mountains of western Maine. Snow accumulations reached 6 inches or more by midday. Low pressure moving into New Brunswick kept winds northwest over the area into the overnight, and low level moisture forced over the mountains resulted in additional upslope snow accumulation.

Heavy Snow in CENTRAL SOMERSET, MAINE
From 09-JAN-19 09:00:00 to 09-JAN-19 23:00:00 (EST-5)
Reported by: Trained Spotter

A band of heavy snowfall developed on the morning of the 9th and pivoted over the mountains of western Maine. Snow accumulations reached 6 inches or more by midday. Low pressure moving into New Brunswick kept winds northwest over the area into the overnight, and low level moisture forced over the mountains resulted in additional upslope snow accumulation.