Monthly Summaries

If you think it has been a long time since New Jersey experienced as chilly an April as this past one, you are correct. With snow accumulating in a storm on the 2nd to snow showers on the 30th, one was hard pressed to find many days when pleasant spring conditions could be found. Toss in two mid-month days when temperatures soared into the middle 80°s and another with strong thunderstorms delivering flash flood-producing rains, and weather-oriented heads kept spinning. However, overall, it was the persistent chill that captured the most attention, with the green up of lawns and foliage, accompanied by the blossoming of spring flowers, delayed from normal by upwards of two weeks.

Statewide, the April average temperature of 47.7° was 3.2° below the 1981–2010 mean (2.0° below the 1895–2017 mean). This ranks as the 28th coolest April since 1895 and the chilliest since 1982 (also 47.7°). The highest temperature observed in NJ was 87° at Stewartsville (Warren County) on the 14th and the coldest 16° at Walpack (Sussex) on the 11th.

April precipitation across NJ averaged 4.20”. This was 0.21” above the 1981–2010 mean (0.48” above the period-of-record mean). This was the 38th wettest April on record. Plentiful precipitation since February has eliminated drought concerns as we enter the summer water consumption season. Reservoirs and ground water levels are in good shape. However, this never means we should let our guard down and not use water in a responsible manner.

While remarkable deadly and destructive hurricanes pummeled portions of the Caribbean and southern states, September weather conditions in the Garden State were generally quiet. The most notable exceptions were the dangerous rip currents at the Jersey shore associated with the latter stages of Hurricanes Irma and Jose, which resulted in several drowning deaths and numerous water rescues. Minor to some moderate back-bay flooding and beach erosion accompanied the tumultuous surf, particularly between the 18th–21st. Otherwise, little more than some clouds and light rain reached NJ from these storms, while earlier some remnant energy and moisture from Hurricane Harvey brought one of the month’s few notable rain episodes. Dry conditions prevailed through much of the September, especially the second half. As a result, statewide precipitation averaged just 2.23”. This is 1.82” below the 1981–2010 average and was the 28th driest September since 1895.

While the first half of the month had an average temperature of about a degree below normal, September finished on a warm note. Some locations experienced three consecutive days with maximums of 90° or higher from the 23rd–25th. This backwards turn to warmth while the calendar suggested there should be a decline in temperature resulted in the month averaging 2.6° above the long-term mark. The 68.4° average made this the 10th warmest September on record. The last three Septembers and six since 2005 all fall into the top 10.

The atmosphere was in a progressive mode throughout December, which explains why no particular weather feature lingered in NJ or elsewhere across North America for too long. The seemingly day-to-day changes resulted in the statewide mean temperature of 36.4° being just 1.2° above the 1981–2010 normal. This ranks as the 28th mildest December since statewide records commenced in 1895, a far cry from last year’s record mild conditions. Despite there being seven precipitation events, one of which was mainly a carry over from November 30th, the rapid movement of these systems meant that none deposited prodigious totals in NJ. Thus 3.37” fell, which is 0.48” below average. This ranks as the 55th driest December. Monthly statewide snowfall averaged 2.0”. This is 2.1” below the 1981–2010 average and ranks 45th least snowy. The northern seven counties averaged 5.5”, the central six counties averaged 1.8”, and the eight southern counties 0.2”, all below average.

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.