A frontal wave developed in the lower Ohio River Valley on the 18th and lifted northeastward towards Lake Erie. Cold air damming remained entrenched and secondary low pressure began developing farther east along the warm front, south of New England. This low slowly strengthened as it moved east northeastward just over the tip of Cape Cod. While snow overspread the entire area, the mid level warm front was able to advance into extreme southwestern Maine and changed precipitation over to sleet and freezing rain. As the storm continued east northeastward the snowfall struggled to Midcoast and west central Maine. The heaviest snowfall ran roughly west to east from the Lakes Region of New Hampshire to Portland.

Winter Storm in INTERIOR YORK, MAINE
From 18-DEC-21 14:00:00 to 19-DEC-21 09:00:00 (EST-5)
Reported by: Trained Spotter

Snow overspread southwestern Maine in the afternoon on the 18th. Snow became moderate in the evening but otherwise remained light for the duration of the storm. After midnight on the 19th snow began to mix with sleet and freezing rain, mainly south of Route 109. Precipitation tapered off on the morning of the 19th. Storm total snowfall ranged from 7 inches near Lake Arrowhead to 4 inches near Berwick.

Winter Storm in SOUTHERN OXFORD, MAINE
From 18-DEC-21 14:00:00 to 19-DEC-21 08:00:00 (EST-5)
Reported by: Trained Spotter

Snow overspread the western Maine foothills by mid afternoon on the 18th. Snow became moderate in the evening but otherwise remained light for the duration of the storm. Snow tapered off in the morning on the 19th, finally ending as a couple of waves of light snow enhanced by upsloping winds over the mountains. Storm total snowfall ranged from 5 to 7 inches.

Winter Storm in INTERIOR CUMBERLAND HIGHLANDS, MAINE
From 18-DEC-21 14:00:00 to 19-DEC-21 09:00:00 (EST-5)
Reported by: Trained Spotter

Snow overspread southwestern Maine by mid afternoon on the 18th. Snow became moderate in the evening but otherwise remained light for the duration of the storm. Snow tapered off in the morning on the 19th. Storm total snowfall ranged from 5 to 7 inches.

Winter Storm in CENTRAL INTERIOR CUMBERLAND, MAINE
From 18-DEC-21 15:00:00 to 19-DEC-21 09:00:00 (EST-5)
Reported by: Trained Spotter

Snow overspread southwestern Maine by mid afternoon on the 18th. Snow became moderate in the evening but otherwise remained light for the duration of the storm. Snow tapered off in the morning on the 19th. Storm total snowfall ranged from 5 to 7 inches.

Winter Storm in COASTAL CUMBERLAND, MAINE
From 18-DEC-21 14:00:00 to 19-DEC-21 09:00:00 (EST-5)
Reported by: Trained Spotter

Snow overspread southwestern Maine by mid afternoon on the 18th. Snow became moderate in the evening but otherwise remained light for the duration of the storm. Snow tapered off in the morning on the 19th. Storm total snowfall ranged from 4 to 7 inches.

Winter Storm in COASTAL YORK, MAINE
From 18-DEC-21 14:00:00 to 19-DEC-21 09:00:00 (EST-5)
Reported by: Trained Spotter

Snow overspread southwestern Maine in the afternoon on the 18th. Snow became moderate in the evening but otherwise remained light for the duration of the storm. After midnight on the 19th snow began to mix with sleet and freezing rain, mainly south of Wells. Precipitation tapered off on the morning of the 19th. Storm total snowfall ranged from 7 inches near Biddeford to 2 inches at Ogunquit where sleet and freezing rain mixed in.