Development of a New Jersey snowfall climatology (1895-present)

A unique dataset of divisional and statewide average monthly snowfall for New Jersey has been generated by utilizing Cooperative Weather Observer station observations back to 1895. To the best of our knowledge, this is one of the few statewide and divisional assessments of historical snowfall, joining states such as Iowa, Minnesota and Wisconsin. NJ statewide and division values were calculated using 13 primary stations. These stations have lengthy and relatively complete snowfall records. Secondary stations were used as surrogates to fill gaps at the lead sites, with tertiary station data used sparingly to fill out the record. Monthly observations were compared amongst stations in each of the three divisions (north, central, south; not the common National Climatic Data Center divisions) to ensure that there were no obvious data quality issues. Notable interannual and decadal variations in seasonal snowfall were observed.

As expected, the most snowfall usually occurs in the northern division, with seasonal totals decreasing to the south. The snowiest decade during the 1895-2011 period of record was the 1960's, followed by the 1900's and 1910's. The snowiest season on record was 1995-96, in which the statewide average totaled 62.8” (159.5cm). This was 36.9” (93.7 cm) above the 25.9” (65.8 cm) period of record average. Other snowy seasons included 1898-99 and 1966-67. The least snowy season was 1972-73, with a statewide average of only 3.9” (9.9cm). The seasons of 1918-19 and 2001-02 also saw very little snow. The past two winters have included the snowiest statewide February (2010: 33.2" (84.3cm)) and January (2011: 23.1" (58.7cm)) on record.

Relationships of seasonal snowfall with climate indicators suggest an inverse relationship between NJ snowfall and the North Atlantic Oscillation (NAO). Snowfall is most often below average during La Niña events. A notable exception to this rule occurred this past winter (2010-2011) when a negative NAO in December and January trumped eastern North America circulation patterns most often associated with La Niña conditions.