Winter Storm — Southern Coos, New Hampshire

2024-01-09 to 2024-01-10 · Southern Coos, New Hampshire

Event narrative

Precipitation began during the evening of the 9th with a band of heavy snow lifting northeastward through the White Mountains. Snowfall rates were briefly 1 inch per hour, before settling to a steady light to moderate snow through midnight. Snowfall rates increased again after midnight and snow continued into the morning hours on the 10th until an warm front advancing up the Connecticut River Valley changed precipitation over to rain. Snowfall totals ranged from 12 to 18 inches in the White Mountains to around 2 inches along the Connecticut River before rain began.

Wider weather episode

A powerful storm tracked northeast through the Mid Mississippi River Valley on the 9th, rapidly deepening as it approached the southern Great Lakes. Precipitation formed along and ahead of the advancing warm front, which arrived in part of northern New England during the evening of the 9th. High pressure anchored to the north of Maine dammed low level cold air up against the mountains and allowed precipitation to start as snow for most locations in New Hampshire, except for those east of the coastal front along the Seacoast. The coastal front was able to quickly mix westward as heavier precipitation moved into the area, and snow changed to rain into the foothills through midnight and the early morning hours. Rain closer to the coast and snow across the higher terrain was heavy at times through the overnight hours. Snowfall of 6 to 12 inches occurred in the higher terrain, with locally higher amounts in the high peaks. Rainfall was a widespread 2 to 4 inches where precipitation remained mostly rain. A strong low level jet accompanying the deep low pressure over the eastern Great Lakes arrived during the early morning hours on the 10th, with strong to damaging wind gusts along the Seacoast as well as on the northwest side of the White Mountains. These warm winds along with rainfall helped to melt much of the fresh snow pack that had fallen on the 7th. The strongest east southeast winds also arrived just ahead of high tide, as they were approaching their monthly spring tides. Moderate to major coastal flooding and large, battering waves occurred all along the Seacoast leading to major damage. By the morning of the 10th, snow, rain, and wind had all moved east of the area.

Source: NOAA Storm Events Database, event_id 1147170. Narrative written by the NWS forecast office that issued the report.