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.

Winter Storm in SOUTHERN COOS, NEW HAMPSHIRE
From 29-DEC-19 23:00:00 to 31-DEC-19 08:00:00 (EST-5)
Reported by: Trained Spotter

Snow moved in late on December 29th. Drier air from the northeast pushed snow back to the southwest for a time early on the 30th, before a band of moderate to heavy to snow developed and then stalled overhead. Snow lightened up around midday but light snow continued into the morning of the 31st. Snow and sleet totals ranged from 6 inches in southeast downslope areas near the Connecticut River to 15 inches in the White Mountains.

Winter Storm in NORTHERN COOS, NEW HAMPSHIRE
From 30-DEC-19 00:00:00 to 31-DEC-19 07:00:00 (EST-5)
Reported by: Trained Spotter

Snow moved in late on December 29th. Drier air from the northeast pushed snow back to the southwest for a time early on the 30th and snow came to an end briefly. A band of moderate to heavy to snow then developed and then stalled overhead. Snow lightened up around midday but light snow continued into the morning of the 31st. Snow and sleet totals ranged from 6 inches in southeast downslope areas near the Connecticut River to 12 inches in the higher terrain.

Winter Storm in NORTHERN GRAFTON, NEW HAMPSHIRE
From 29-DEC-19 21:00:00 to 31-DEC-19 07:00:00 (EST-5)
Reported by: Trained Spotter

Precipitation moved in late on December 29th as a mix at onset. Freezing rain, sleet, and snow were all observed with marginal temperatures especially near the Connecticut River with snow in the higher elevations to the east 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.

Winter Storm in MERRIMACK, NEW HAMPSHIRE
From 29-DEC-19 20:00:00 to 31-DEC-19 08:00:00 (EST-5)
Reported by: Trained Spotter

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. Very cold temperatures in the lowest 2500 feet of the atmosphere supported snow showers below the inversion for much of the day on the 30th, despite mixed precipitation originating above it. In the late afternoon the approach of the upper trough increased forcing for ascent and thunderstorms developed over southern New England and moved into New Hampshire, producing snow, sleet, and freezing rain. It was around this time that precipitation changed over to snow. Light snow continued into the morning of the 31st. Snow and sleet totals ranged from 4 to 8 inches.

Winter Storm in STRAFFORD, NEW HAMPSHIRE
From 29-DEC-19 21:00:00 to 31-DEC-19 09:00:00 (EST-5)
Reported by: Trained Spotter

Precipitation moved in late on December 29th as snow at onset. Early on the morning of the 30th continued warm air advection aloft allowed precipitation to change to a mix of freezing rain and sleet. Very cold temperatures in the lowest 2500 feet of the atmosphere supported snow showers below the inversion also, despite mixed precipitation originating above it. In the late afternoon the approach of the upper trough increased forcing for ascent and precipitation changed back to snow. Light snow continued into the morning of the 31st. Snow and sleet totals ranged from 4 inches in the southwestern part of the county to nearly 12 inches around the Moose Mountains.

Winter Storm in BELKNAP, NEW HAMPSHIRE
From 29-DEC-19 21:00:00 to 31-DEC-19 09:00:00 (EST-5)
Reported by: Trained Spotter

Precipitation moved in late on December 29th as snow at onset. On the morning of the 30th continued warm air advection aloft allowed precipitation to mix with sleet at times. In the late afternoon the approach of the upper trough increased forcing for ascent and precipitation changed back to snow. Light snow continued into the morning of the 31st. Snow and sleet totals ranged from 6 to 10 inches.

Winter Storm in SOUTHERN GRAFTON, NEW HAMPSHIRE
From 29-DEC-19 21:00:00 to 31-DEC-19 08:00:00 (EST-5)
Reported by: Trained Spotter

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.

Winter Storm in SOUTHERN CARROLL, NEW HAMPSHIRE
From 29-DEC-19 21:00:00 to 31-DEC-19 09:00:00 (EST-5)
Reported by: Trained Spotter

Precipitation moved in late on December 29th as snow at onset. A band of moderate to heavy to snow stalled overhead on the morning of the 30th. In the afternoon warm air advection allowed snow to briefly mix with sleet at times. Precipitation changed back over to snow in the early evening and light snow continued into the morning of the 31st. Snow and sleet totals ranged from 12 to 15 inches.

Winter Storm in NORTHERN CARROLL, NEW HAMPSHIRE
From 29-DEC-19 22:00:00 to 31-DEC-19 10:00:00 (EST-5)
Reported by: Trained Spotter

Precipitation moved in late on December 29th as snow at onset. A band of moderate to heavy to snow stalled overhead on the morning of the 30th. In the afternoon warm air advection allowed snow to briefly mix with sleet at times. Precipitation changed back over to snow in the early evening and light snow continued into the morning of the 31st. Snow and sleet totals ranged from 12 to 15 inches.