Heavy Snow — Northern Grafton, New Hampshire

2018-11-26 to 2018-11-27 · Northern Grafton, New Hampshire

Event narrative

Steady snow began late on the evening of the 26th. Orographic lift of southeast flow into the White Mountains allowed snow to be heavy at times early on the 27th. Significant accumulations occurred in the higher terrain and south facing slopes, while much lighter accumulations occurred near the Connecticut River. Once flow became westerly and upslope enhanced snowfall began accumulations near the river began to catch up to those in the mountains. Surface temperatures near freezing made for a heavy, wet snow and scattered power outages due to downed tree limbs. Total snowfall ranged from 6 inches to a foot or more in the higher elevations, though additional accumulation continued in upslope snow showers into the 28th.

Wider weather episode

This winter storm began as a blizzard over the Midwest. The storm moved into the eastern Great Lakes early on the 26th and snow broke out over northern New England that afternoon and evening. Secondary low pressure developed in the vicinity of Cape Cod on the evening of the 26th helping to ensure cooler air remained trapped across much of New Hampshire. Surface temperatures hovered within a couple degrees of freezing, but aloft temperatures were much colder. As a result snowfall was heavy and wet, and very dependent on elevation. While lower elevations mixed at times with sleet, freezing rain, and rain, the higher terrain remained predominantly snow and significant accumulations occurred. Low pressure slowed to a crawl on the 27th and snow continued into the 28th, although the bulk of the accumulation was from the evening of the 26th to the afternoon of the 27th.

Source: NOAA Storm Events Database, event_id 788138. Narrative written by the NWS forecast office that issued the report.