Examining a Synoptic Climatology of Northeast U.S. Snow Events

The Northeast United States is known for frequent high impact winter storms, with wide-ranging hazards including heavy snow, damaging wind, heavy rain and coastal flooding that are capable of causing significant socioeconomic impacts. Located in a climatologically favorable baroclinic zone, the region experiences frequent snow events during the wintertime, often associated with deepening offshore cyclones. There have been numerous studies on these snow events and their associated cyclones, including a snowfall impact scale developed by Paul Kocin and Louis Uccellini that weights both snowfall accumulation and population impacted by snowfall (Northeast Snowfall Impact Scale; NESIS).

Most studies on Northeast U.S. snow events have focused on cases with large snowfall amounts, often in excess of 15.2 cm (6 in). A snow event does not need to have such high snow amounts to be impactful; for instance, frequency of snow events generally increases with latitude, thus snow events in lower latitudes are often more impactful than similar accumulations at higher latitudes, and even minor snow events can cause socioeconomic disruption.

This study utilizes an individually created and quality controlled climatology of the majority of Northeast U.S. snow events during 2000–2019 for any synoptically forced event, including mesoscale bands or upslope enhanced precipitation but removing lake effect snow, that produced over 7.6 cm (3 in) of snowfall in multiple observation sites within the region. This presentation will show how this gridded climatology can be used for various applications, such as constructing a modified NESIS scale utilizing normalized anomalies of snow events relative to a local climatological distribution, spatial frequency of snow events and associated cyclone tracks by accumulation threshold, and comparison of synoptic regimes and teleconnections associated with periods of frequent minor snow events, frequent major snow events, or infrequent major snow events.