Spring

As has been the case for the past several months, weather patterns have been reluctant to persist for more than several days to about a week. While climatologically rather common as winter transitions to summer, this season has seemingly been consistently inconsistent beyond the norm. April saw temperatures reach well into the 80°s on several days, followed a short time later by a hard freeze in most inland locations. Rainfall was above normal, more than twice so in the northwest, which is a reversal of the general pattern since late fall. Precipitation fell every few days, including multiple squally episodes that briefly delivered small hail, graupel, and bursts of snow at some locations. There was one event that brought some flash flooding and minor river flooding. Many residents are impatiently waiting for some mild conditions to lock in, getting summer underway. Patience….summer will arrive!

The good news is the rainfall that arrived quite often. Increasing concerns for drought encroaching on NJ were washed away by multiple storms that “performed” up to or exceeded expectations, something that was often not the case for multiple underperforming events in past months. Statewide rainfall averaged 5.10”. This is 1.40” above the 1991–2020 normal and ranks as the 24th wettest April since records commenced in 1895. As the monthly map shows, the northwest was wettest and south driest, yet still above normal. The north average 6.34” (+2.44”, 11th wettest), south 4.37” (+0.79”, 32nd wettest), and coast 4.09” (+0.54”, 42nd wettest).

Weather often varies from week-to-week and even day-to-day during the spring transition season. Such was certainly the case in spring 2021, as will be recapped later in this report. However, when it came to such “weather indecision,” May 2021 took the cake. Starting off somewhat damp with seasonable temperatures, a prolonged period of exceedingly dry weather ensued, first accompanied by cooler-than-normal temperatures and frosty mornings, and later by summer-like heat. As several wildfires broke out and soil moisture vanished, concerns of early-summer drought arose. Then along came one of the coolest Memorial Day weekends on record, accompanied by more than an average May’s worth of rain in some locations. This led to frequent decision making amongst farmers, gardeners, water resource managers, utility companies and customers, and day trippers. All were left wondering what might come next! Cicadas perhaps?

With the thermometer up and down throughout May, the statewide average temperature of 61.0° was just 0.2° below the new 1991–2020 normal. This ranked as the 47th mildest May since 1895. The average maximum of 73.0° was 0.7° above normal, while the 49.0° average minimum was 1.2° below normal. This is illustrative of a month that had many clear days and cool nights with low humidity. Despite dry conditions for most of the month, monthly precipitation came in close to normal, averaging 3.95” across NJ. This is 0.20” above normal, ranking 48th wettest of the past 127 years. Far south and west central areas were driest, while the central coast and northeast saw the most rain. Unlike last May, no snow was observed.

With March being a transitional weather and climate month, there are often pronounced differences in conditions from one day or week to the next. The third month of 2021 did not disappoint in several such respects. Swings in barometric pressure as storms and high pressure systems swung through the Northeast led to 16 days with one or more Rutgers NJ Weather Network stations gusting to 40 mph or higher, with 11 of those days exceeding 50 mph. Maximum temperatures exceeded 65° on 12 days (two days had record highs in some locations), while minimum temperatures fell below 19° on 13 days. Walpack, situated in a Sussex County valley, recorded the state’s lowest (21°) and highest (67°) temperatures on a single day (22nd) and just missed this again on the 30th. There was a two-week interval with virtually no precipitation, culminating in several wildfires on the 14th, yet five events occurred where rain accumulated to 0.98” in one or more locations. Finally, a record of sorts was tied as the statewide average snowfall totaled 0.0”, something observed eight other Marches in the past 127 years. The past two Marches are the only ones with back-to-back zero totals.

Statewide precipitation averaged 4.03”, which is 0.18” below the 1991–2020 average*. This made for the 58th wettest (70th driest) since 1895. Northern NJ was driest, coming in at 3.28” (-0.73, 48th driest), the south averaged 4.47” (+0.15”, 42nd wettest), and the coast 4.68” (+0.26”, 38th wettest). The southeast saw the most rain and northeast and central regions the least (Figure 1).

March temperature average 43.9°, which is 2.9° above the 1991–2020 average and the 14th mildest on record. The average high was 54.7° (+3.8°, 13th mildest) and average low was 33.0° (+1.8°, 19th mildest). The north averaged 41.2° (+2.4°, 19th mildest), south 45.6° (+3.2°, 13th mildest), and the coast 45.1° (+2.9°, 13th mildest).

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).