Lake-Effect Snow — Southern Erie, Pennsylvania

2021-02-15 to 2021-02-17 · Southern Erie, Pennsylvania

Event narrative

Three rounds of snow moved through Northwest Pennsylvania on February 15 and 16. The first round on the morning of the 15th brought a quick inch of snow to the region. A second round of snow entered during the afternoon and evening hours, bringing an additional 2 to 6 inches of snow to the region. For a brief period during the evening of the 15th, snow transitioned to sleet and freezing rain, as some warmer air aloft melted the snow but near surface temperatures below freezing allowed for wintry precipitation to continue. Sleet amounts of a few tenths and ice amounts up to one tenth were observed across the area. A third round of snow came in the form of lake effect snow and an additional 3 to 8 inches of snow fell, which ended up being the most impactful round for portions of the Northwest Pennsylvania snow belt. Total snowfall for the event in the southern portions of Erie County ranged from roughly 6 to 11 inches of snow. The maximum snowfall for this event was northwest of Edinboro, where a trained snow spotter measured 11 inches of snow for the event. Other selected snowfall totals for the event include: 9.5 inches in Greene Township, 9 inches in Greenfield Township, 8.1 inches in North East Township, 8 inches in Summit Township and Colt Station, 6.1 inches in Union City, and 6 inches in Corry.

Wider weather episode

Low pressure developed over the northern Gulf of Mexico on the morning of February 15 and moved northeast into the Tennessee and Ohio River Valleys through the afternoon and evening hours. Well ahead of this low pressure system, a band of snow overspread the region with a weak front during the morning hours of the 15th, allowing for a quick inch or two of snow across the area. As the low crept closer to the region, deepening over the Ohio/Pennsylvania border and bringing ample Gulf moisture into the region, a broader area of precipitation moved through the area during the afternoon and evening hours. For Northwest Pennsylvania, this precipitation started in the form of sno, but by evening, a nose of warmer air just above the surface allowed for snow to melt and for the end precipitation type to become a mix of sleet and freezing rain significantly lessening snowfall amounts in several locations. Behind the low pressure system, colder air surged into the region and lake effect snow developed over Lake Erie and entered Northeast Ohio on the 16th. By the late evening of the 16th, an additional 4 to 8 inches of snow fell in portions of the snow belt, adding to the wintry mix from the night before. Impacts were mixed in Northwest Pennsylvania as the first half of the event underperformed but the lake effect on the 16th overperformed, leading to mixed preparedness for the region. For the entire event, the highest total snowfall measurement in Pennsylvania was 11 inches by a trained snow spotter northwest of Edinboro in south central Erie County. Erie International Airport only recorded 2.8 inches of snow for this event. There were no known injuries or fatalities in Northwest Pennsylvania on account of this winter storm.

Source: NOAA Storm Events Database, event_id 949712. Narrative written by the NWS forecast office that issued the report.