Spring

As was seen earlier this spring, rainfall was quite persistent during a good portion of May. However, unlike April, it was not just a matter of frequency but ultimately, quantity that made for soggy conditions in the fifth month of 2019. The statewide average precipitation was 6.70”, which is 2.71” above the 1981–2010 mean. This made for the 9th wettest May since records commenced in 1895. The northern half of NJ was wettest, averaging 8.69” (+4.35”), making it the 3rd wettest on record. Only May 1989 (10.13”) and 1984 (9.79”) saw more rain. The south averaged 5.52” (+1.72”), ranking 17th wettest.

Based on observations from 62 NJWxNet stations, there were only two calendar days (22nd and 25th) without measurable (0.01”) rainfall at any location. Three days saw a maximum of 0.01”–0.10” at one or more stations, nine with a maximum between 0.11”–0.25”, and eleven topping out from 0.26”–0.99”, while on six days one or more station received an inch or greater.

The wet conditions were accompanied by above average temperatures. The 62.7° statewide average was 2.1° above the 1981–2010 mean. This ranked as the 19th mildest May on record (tied with 1985). However, it is only the 8th warmest May since 2004. Ten of the past 12 months have been above average.

Much like last month, March 2019 had a wide variety of weather conditions across the Garden State. The month came in like a lion, with a week of wintry weather, which was particularly snowy in northern and central regions. More snow fell than in any other month this season and the temperature fell below zero in one location and down to single digits at a number of others. The remainder of the month was often lamb-like, including four days with high temperatures exceeding 70° at many locations and six in the 60°s. Several inch-plus rain events occurred, along with the first lightning-filled squall line of the year, which, in some locations, included hail and strong winds.

The statewide monthly temperature averaged 39.7°. This is 1.1° below the 1981–2010 average and is the 58th mildest (66th coolest) since 1895. The statewide average rain and melted snow totaled 3.91”. This is 0.20” below the 1981–2010 average. It was the 61st wettest (65th driest) March since 1895.

Statewide snowfall averaged 6.3”. This was 1.9” above average. Northern counties averaged 13.0” (6.7” above average), the central region 8.6” (+3.5”), and south 1.6” (-1.5”). As a preview of the seasonal snow summary in next month’s report, statewide snowfall through March is 20.5”, 5.0” below average. Barring the unlikely case of April snowfall exceeding any other month of the season, this will mark the first time since records began in 1895 that March was NJ’s snowiest month of the season for three consecutive snow seasons (October–April).

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.

Following a March with the first substantially below-average monthly temperature anomaly in NJ in over a year, April brought a return to record warmth last seen in February. With a statewide average of 56.0°, the month was 5.1° above the 1981–2010 mean. This ranked as the warmest April since statewide records commenced in 1895. Five of the top 10 and nine of the top 20 mildest Aprils of the past 123 years have occurred since 2002. With the warmth of January, February, and April hardly balanced by the colder March, this year is off to the 4th warmest start on record. Only January–April averages in 2012, 1998, and 2002 were higher, and five of the eight mildest such intervals in the past 123 years have been since 2002. The 12-month period from May 2016 through April 2017 was the third warmest on record at 55.5°. It was only surpassed by May 2011–April 2012 (56.5°) and 2015–2016 (56.2°). Twelve of the 15 warmest such intervals of the past 123 years have occurred since 1999, the others being in 1931–1932 (#10), 1990–1991 (#11), and 1991–1992 (#14).

May had many weather faces. Cool, damp weeks to start things off, a blustery mid-month day with some frozen precipitation, a week of summer heat, and an early Memorial Day deluge up the New Jersey Turnpike corridor. When all was summed and averaged, the mean monthly statewide temperature came in at 60.0°. This was 0.8° below normal and ranked as the 55th coolest of the past 122 Mays. Precipitation averaged 5.01”, which is 1.01” above average and 23rd wettest.

Rain fell on a number of May days across NJ, keeping vegetation green and fire danger down. It was most plentiful in the southern half of the state, where Mount Laurel Township (Burlington County) totaled 7.74”. This was followed by Mount Ephraim (Camden) with 7.68”, Washington Township (Gloucester) 7.54”, Salem (Salem) 7.41”, Cinnaminson (Burlington) 7.02”, and Estell Manor (Atlantic) and Merchantville (Camden) each with 7.00”. The northwest corner had the least rainfall in May, with just 3.01” in Andover (Sussex) and North Arlington (Bergen), along with Mount Olive (Morris) at 3.04”, Hackettstown (Warren) 3.05”, and Franklin (Sussex) and Wantage (Sussex) each with 3.06”.