Winter Storm — Southern Grafton, New Hampshire

2019-12-29 to 2019-12-31 · Southern Grafton, New Hampshire

Event narrative

Precipitation moved in late on December 29th as a mix at onset. Freezing rain, sleet, and snow were all observed with marginal temperatures across the area through the overnight. In the late afternoon the approach of the upper trough increased forcing for ascent and precipitation changed over to snow. Light snow continued into the morning of the 31st. Snow and sleet totals ranged from 6 to 10 inches, with the lowest totals near the Connecticut River.

Wider weather episode

On December 29th a primary low pressure moved into the Upper Midwest with a warm front draped off to the east. Air rising over the warm front brought precipitation into New England late on the 29th as a mix of freezing rain, sleet, and snow with a relatively mild air mass in place. The feed of colder air strengthened through the 30th with significant amounts of mixed precipitation occurring over the southwestern part of New Hampshire. A nearly stationary band of moderate to heavy snow set up over the eastern part of the state. As the upper trough approached in the afternoon thunderstorms developed south of the warm front and moved across it into the cold air. Thunder was reported with freezing rain and sleet across southern New Hampshire before the convection weakened. It was around this time that precipitation began to change over to all snow. Light snow continued into the 31st as secondary low pressure developed south of New England.

Source: NOAA Storm Events Database, event_id 864021. Narrative written by the NWS forecast office that issued the report.