Monthly Summaries

Season transitional months are often known for the wide swings in daily and weekly weather conditions. October 2016 did not disappoint when it came to exhibiting such variability. Moisture associated with a weakening hurricane to the south contributed to south Jersey’s heaviest rain event. A modest late-month storm brought the first frozen precipitation of the season to northern counties. Record warmth for so late in the season was part of a dry mid-month week. Halloween eve seeing the temperature touch 80° in some locations before a thunder-strewn frontal passage dropped temperatures to more seasonal temperatures for trick or treating.

The second half of the 2016 NJ weather and climate year began with plenty to talk about. Maximum temperatures were 90° or higher somewhere in the state on 20 afternoons. This, along with many warm nights, helped boost the mean monthly temperature into the top 10, based on statewide records back to 1895. Yet, remarkably, this was only NJ’s 5th warmest July in the past 11 years. The 77.2° mean was 2.2° above the 1981–2010 average.

On 15 July days an inch or more of rain fell somewhere in NJ. This included eight days with greater than 2” in spots and four days where a few locations exceeded 4”. Statewide, the average rainfall was 6.85”. This was 2.33” above average and ranks as the 14th wettest July since 1895. It was the wettest July since 2004, and the 4th wettest in the past 41 years. The northern half of the state (Mercer/Somerset/Union northward) averaged 7.27” (+2.49”, 14th wettest), while the southern region averaged 6.77” (+2.38”, 12th wettest). This all came in a month where the northern half of the state remained classified as being in moderate drought (D1) on the US Drought Monitor, with about half of south Jersey considered abnormally dry (D0). Also, on July 26th the NJ Department of Environmental Protection placed the northern half of the state in a drought watch. These actions were the result of notable rainfall deficits dating back to the early spring, with the warmth of the month exasperating low soil moisture, stream flow, ground water, and reservoir conditions. Clearly, the late-month heavy rainfall in a good portion of the state warrants a re-evaluation of drought status as NJ heads into August.

Mild and dry conditions prevailed throughout the Garden State during most of March. This included record-breaking early-season warmth, only one event that dropped more than an inch of rain over multiple locations, and a few minor forest fires. There were also two episodes of measurable snow that focused on coastal counties and 11 days where winds gusted to 40 mph or higher somewhere in the state. The statewide average temperature of 46.7° was 5.6° above the 1981–2010 average. This ranks as the 6th mildest March since 1895. Precipitation averaged 2.09”. This is 2.14” below normal and ranks as the 13th driest March.

March snowfall average 2.4” across the state, which is 1.9” below average. Northern counties saw only 0.8”, which is 5.3” below normal, while the central portion of the state received 1.6” (3.3” below normal). The southern counties were the winners, averaging 0.7” above normal at 3.7”. While snow may fall in April (the morning of April 3rd saw 2.7” at Highland Lakes [Sussex County]), a look at what are likely close to the final seasonal totals includes a statewide average of 27.9”, which is 1.8” above normal. North Jersey took it on the chin, with an average of 26.3”, some 8.4” below average. Central NJ was the winner at 31.0”, 4.0” above normal. Meanwhile the south Jersey total of 27.1” exceeded that of the north, even in an absolute sense, and was 7.1” above normal.

The climatological fall season ended on a mild note, with the statewide November average temperature of 49.3° coming in at 3.7° above normal. This ranks as the 5th mildest November on record, tied with 1948. Observations go back 121 years to 1895, yet five of the nine warmest Novembers have occurred since 2001. The month had an abundance of sunny days, during what is commonly a rather cloudy time of the year. Precipitation averaged 2.33” across NJ, which is 1.31” below normal and ranks as the 41st driest November. Only two significant rain events occurred during the mid-month interval.

This month had quite a variety of weather conditions around the state. This resulted in some areas experiencing flash flooding and others encroaching drought conditions. Damage resulted from the flooding and one storm even produced a nocturnal “heat burst.” Some minor brush fires and declining river, ground water, and reservoir levels accompanied subnormal rain totals. The dry conditions helped produce some wide daily swings from cool nighttime temperatures to consistently warm daytime maximums. Preliminary values show August 2015 to have a statewide average rainfall of 2.18”. This is 2.03” below normal and ranks as the 13th driest since statewide records commenced in 1895 (Table 1). The 74.5° average temperature was 1.1° above the 1981–2010 mean and ranks 21st warmest.