Heavy Snow in Interior Rockingham, New Hampshire

Snow broke out across southeast New Hampshire just after midnight on the 20th, with heavy snow moving into area in the early morning hours. Snow changed to significant amounts of sleet during the morning and continued for much of the day, keeping snow amounts lower than areas farther north and west. Snowfall totals generally ranged from 5 to 7 inches. The highest totals were observed just inland from the coast, where ocean effect enhancement and coastal front convergence likely contributed to greater low level lift.

Frigid, Canadian high pressure nosed into the Northeast on the 19th and settled there into the first part of the 20th. Low pressure developed in the southern Plains and lifted through the lower Mississippi and then Ohio Valley. Strong warm air advection along the warm front, pinned offshore by the strong high pressure, allowed secondary cyclogensis to occur farther up the Northeast coast as the open wave aloft approached. Heavy snow overspread New Hampshire early in the morning on the 20th. As warm air advection continued ahead of the upper level wave precipitation changed over predominantly sleet, as far north as the White Mountains, before ending as snow showers.