Winter Storm — Southern Coos, New Hampshire

2022-01-17 · Southern Coos, New Hampshire

Event narrative

Strong warm air advection forced a laterally translating band of snow into the White Mountains during the morning of the 17th. Within a couple hours snow was moderate to heavy. Snowfall rates were near 1 inch per hour for two or three hours leading up to midday. The dry slot and warmer mid level temperatures were only about 6 to 8 hours behind the onset of snow. Snow briefly mixed with some sleet and freezing rain before ending in the afternoon. Snowfall totals generally ranged from 6 to 8 inches, but lesser amounts occurred near the Connecticut River where downsloping winds warmed and dried out the atmosphere, and as much as 11 inches fell on top of Mount Washington.

Wider weather episode

On the 16th low pressure formed over the Gulf Coast and began to lift northeast. The low continued to track along the East Coast and strengthen until eventually occluding near Chesapeake Bay late in the evening on the 16th. The low continued deepening into central New York where it ultimately got picked up by the next trough and moved northeast. Ahead of the warm front a strong low level jet developed and brought a round of moderate to heavy precipitation to New Hampshire on the 17th. The strongest forcing moved so quickly that mixed precipitation across the interior did not last for a significant amount of time before coming to an end.

Source: NOAA Storm Events Database, event_id 998113. Narrative written by the NWS forecast office that issued the report.