High Wind — Northern Grafton, New Hampshire

2022-12-23 · Northern Grafton, New Hampshire

Event narrative

A significant downslope windstorm occurred in the White Mountains on the 23rd. With a temperature inversion sitting right around ridgeline, strong to damaging wind gusts were able to mix down the lee side of the higher terrain. For most of the day winds gusted between 40 and 60 mph. Numerous trees and wires were reported down in the area, and power outages approached 30 percent of customers across the county.

Wider weather episode

Beginning on December 22nd a powerful storm was developing over the Ohio River Valley. On December 23rd the center of the storm was deepening rapidly (974mb) as it lifted through the eastern Great Lakes. While the center tracked into southern Ontario, high pressure retreated into the Canadian Maritimes creating a strong pressure gradient across the region. Strong southerly winds developed as a result, with speeds in excess of 80 knots at around 2,000 feet. Several rounds of strong to damaging wind gusts occurred, which brought widespread power outages with over 120,000 customers without power.

Precipitation moved into western New Hampshire during the late evening hours of December 22, and moved across the remainder of the state by the early morning of December 23. Snow quickly changed over to rain on the night of December 22nd, with a changeover later in the mountains towards daybreak on December 23rd. The precipitation continued through the evening hours of December 23, then gradually ended from south to north that night. Overland flooding was prevalent for areas where rainfall exceeded 2 inches. The impacts varied from standing water in fields to complete road washouts. The runoff exceeded capacity for most feeder creeks and rivers.

The rapidly deepening area of low pressure over the Great Lakes region combined with very high astronomical tides to produce the fourth highest storm tide ever in Portland. In addition, storm to hurricane force east to southeasterly winds occurred along the coast with nearshore waves of 15 to 20 feet coinciding during peak storm surge. Significant to major coastal damage occurred during the morning high tide cycle across the Seacoast of New Hampshire.

Source: NOAA Storm Events Database, event_id 1065113. Narrative written by the NWS forecast office that issued the report.