Winter Storm — Northern Coos, New Hampshire

2020-04-09 to 2020-04-10 · Northern Coos, New Hampshire

Event narrative

Precipitation overspread northern Coos County during the morning of the 9th as mostly rain at the lower elevations, and some snow in the mountains. Temperatures gradually cooled into the upper 30s, but by late afternoon heavier precipitation moved in, temperatures fell to the lower 30s, and rain changed to snow. Snow continued moderate to heavy at times into the very early morning hours of the 10th. As low pressure pulled away significant upslope snow showers continued into the morning of the 10th. Snow totals ranged from around an inch along the Connecticut River bordering Vermont to 10 inches near First Connecticut Lake.

Wider weather episode

An upper low pressure ejected out of the Southwest and reached the East Coast by the 9th. A strong jet streak exiting the Mid Atlantic coast with a coupled jet to the north helped initiate intense secondary cyclogenesis along the New England coast. Pressures in the center of the storm fell over 30 mb in 24 hours by the time it reached peak intensity near Penobscot Bay on the 10th. This storm spread snow over interior areas with rain at the coast. By the afternoon of the 9th rain flipped to heavy, wet snow generally along a north of a line from the White Mountains to Portland, Maine. Rainfall amounts were around 1 inch south of there.

Source: NOAA Storm Events Database, event_id 878417. Narrative written by the NWS forecast office that issued the report.