Winter Storm in Northern Grafton, New Hampshire

Early in the day on the 12th precipitation was mainly rain, especially in the valleys. By late morning precipitation rapidly changed over to snow as low pressure developed off the coast of southern New England and colder air filtered in from the north. Snow became heavy at times through mid-afternoon. Light snow continued through most of the overnight in the White Mountains. Snowfall totals ranged from 3 inches in the valleys to locally higher than 12 inches in the higher terrain.

On the 12th a frontal boundary was stalled over the higher terrain of northern New England. A wave of low pressure developed over the interior of the Mid Atlantic and warm air advection brought light precipitation to the region. With temperatures above freezing most of the precipitation fell in the from of rain, except for the highest elevations where it was below freezing. Low pressure began to deepen as it approached southern New England and that increased the drain of colder air from the north. Eventually precipitation flipped from rain to snow from north to south through the morning. While the bulk of the heavy precipitation was over by the afternoon on the 12th, light snow continued for much of the night with minor additional accumulation.