Winter Storm — Southern Coos, New Hampshire

2020-12-05 to 2020-12-06 · Southern Coos, New Hampshire

Event narrative

Snow moved into the North Country early afternoon on the 5th. Snow became moderate to occasionally heavy on northern edge of the precipitation shield through the late evening. Some downsloping winds and warmer temperatures resulted in significantly less snow in the Connecticut River Valley than the higher elevations. Snow totals ranged from around 2 inches in the valley to as much as 18 inches in the Presidentials.

Wider weather episode

An upper low ejecting out of the Rockies ultimately phased with a northern stream shortwave trough leading to cyclogenesis off the East Coast on the 5th. Low pressure formed over the southern Appalachians and moved northeast towards Nantucket by the evening of the 5th. The storm tracked into the Gulf of Maine and eventually began weakening in the Bay of Fundy early on the 6th. While the radar presentation looked like a classic northern New England snow storm, the antecedent air mass was marginal for snow and precipitation type became elevation and/or precipitation rate dependent. Most notably the snow that did fall was wet and sticky. The wet snow bonded to trees which led to downed tree limbs and widespread power outages.

Source: NOAA Storm Events Database, event_id 926506. Narrative written by the NWS forecast office that issued the report.