Heavy Snow — Southern Centre, Pennsylvania

2011-10-29 · Southern Centre, Pennsylvania

Event narrative

Snow accumulations ranged from 3 to 6 inches.

Wider weather episode

An early season, high-impact, winter storm delivered heavy, wet snow to southern and eastern sections of the CWA on Saturday, October 29, 2011. The snow began just after midnight and ended during the evening, leaving a widespread 3 to 8 inches of accumulation with as much as 10 to 12 inches reported over many higher elevations and ridge tops. Despite snowfall rates between 1-2 per hour with convective enhancement in heavier bands, marginally-cold air temperatures in the low to mid 30s combined with warm road/ground temperatures and wetness of the snow reduced accumulations in some areas particularly in the central and southern valleys. Like most early-season snow events, elevation played a significant role in storm total accumulations.

A 1010mb low pressure system centered near the Carolina coast during the predawn hours rapidly intensified to as it moved northward just offshore the Mid-Atlantic coast. The storm became a classic Nor'easter and deepened to 984mb as it passed east of Nantucket, Massachusetts. The strengthening low produced wind gusts between 20-30 mph over eastern Pennsylvania and gusts near hurricane force over the open ocean waters near the southern New England coast and Gulf of Maine.

In most locations in central Pennsylvania, observed snowfall accumulations set all-time daily and monthly snowfall records for October. The heavy, wet snow produced widespread damage to trees and utility wires. This resulted in more than a half-million (520,000) power outages state-wide at the height of the storm. Warming shelters were opened to accommodate the power outages. Several secondary roads were closed due to the downed trees and wires. The weight of the snow (snow to liquid ratios generally less than 10:1) along with remaining leaf foliage contributed to the significant tree damage. There was one indirect storm-related death in Conewago Township, York County.

Source: NOAA Storm Events Database, event_id 345900. Narrative written by the NWS forecast office that issued the report.