Spring

As spring turns to summer, all in Jersey can be pleased that water supplies are in good shape. Also, while it took some time to become established, by late May, warmer temperatures brought out summer wardrobes. Spring (March–May) conditions will be covered later in this report, but first a look at May. As the title of the monthly portion of this narrative suggests, May 2024 never established a consistent atmospheric pattern. There were plenty of episodes where light to moderate showers dotted the state, but never a broad soaker. Temperatures fluctuated on a weekly basis, without a persistent leaning until warmth prevailed later in the month. Put it all together and May ended on a green note born of somewhat below-normal precipitation and above-normal temperatures. The statewide average temperature of 63.9° was 2.7° above the 1991–2020 normal. This ranks as the 11th mildest May dating back to 1895. This anomaly was driven by elevated minimum temperatures that averaged 54.0° which is 3.8° above normal and ranks as the 4th warmest on record. This no doubt due to persistent nighttime cloud cover. The average high temperature of 73.7° was 1.4° above normal, ranking 35th warmest. The northern climate division averaged 63.0° (+3.1°, 7th warmest). Across the southern division the average temperature was 64.5° (+2.3°, 13th warmest). The coastal division averaged 63.1° (+2.1°, 11th warmest).

So much for March flipping from lion to lamb or vice versa. March 2024 was often a lion throughout, with frequent roaring winds and multiple rain events producing a near-record monthly precipitation total and occasional flooding. The first half of the month ran at a record-warm pace, the monthly average later to be tempered by a second half that was cooler than the first. Still, the month emerged as the 9th mildest on record. Befitting the overall mild conditions, snowfall was scarce to non-existent.

Winds gusted to 35 mph or higher at one or more Rutgers NJ Weather Network (NJWxNet) station on 16 days, exceeding 40 mph on 11 of those days. Precipitation (rain and the water equivalent of the very little snow that fell) averaged 7.76” across the state. This is 3.56” above the 1991–2020 normal and ranks as the third wettest March since records commenced in 1895. The northwest was least wet with 6.00”–7.00” falling. Totals increased to the southeast where near coastal areas received 9.00”–10.00”. The northern climate division averaged 7.01” (+3.00, 6th wettest), the southern division 8.15” (+3.83”, 3rd wettest), and the coastal division 8.98” (+4.56, 2nd wettest).

The statewide average March temperature was 46.0°. This is 5.0° above normal and ranks as the 9th mildest of the past 130 years. The average high temperature of 55.6° was 4.7° above normal and ranks 10th mildest. The average low of 36.3° was 5.1° above normal and ranks 4th mildest. The northern division averaged 43.9° (+5.1°, 9th mildest), southern division 47.2° (+4.8°, 8th mildest), and coastal division 47.0° (+4.8°, 7th mildest).

What can you say about a month that began with a swarm of tornadoes, finished with flooding rain, and in between, featured record heat, wildfires, and increasing drought concerns? Best to say that it was an odd one! Fitting this theme, the statewide average temperature of 55.4° was 3.9° above the 1991–2020 normal. This ranks as the third warmest April on record (since 1895) only behind 2017 and 2010 for top honors. April was the fifth month of the past ten ranking in the top 10, joining July (#7), August (#1), January (#1), and February (#5). The first four months of 2023 come in as the warmest start of the year on record with an average of 44.4°. This exceeds the previous record of 44.2° in 2012, with seven of the 10 warmest January–April periods (1895–present) occurring since 2002. The average April maximum temperature across NJ was 67.4° (+4.7°, 3rd warmest) and the average minimum was 43.4° (+3.1°, 5th warmest). Northern counties averaged 53.5° in April (+3.6°, 5th warmest), southern counties 56.6° (+4.0, 2nd warmest), and the coastal zone 55.8° (+4.1°, 2nd warmest).

April precipitation averaged 5.84” across New Jersey. This was 2.14” above normal, ranking as the 10th wettest on record. It was the wettest April since 2007 and second wettest since 1983. All but scattered areas in the northwest received above-normal precipitation, the greatest amounts falling near the Atlantic and Delaware Bay coasts. Northern counties averaged 5.55” (+1.65”, 26th wettest), southern counties 6.04” (+2.49”, 7th wettest), and the coastal zone 5.94” (+2.39”, 10th wettest). It is important to note that these totals and those for individual stations in the next section, do not include heavy rain that fell after standard early morning observation times at CoCoRaHS and National Weather Service Cooperative stations on April 30th. These rains were reported in morning observations on May 1st, thus will be included in May totals.

Many across NJ wondered if the incessant back and forth of weather conditions from early spring into May would ever cease and the more consistent warmth of late spring would arrive and persist. It took time this year, with a cool, damp start to May that included a nine-day interval of almost continuous onshore easterly flow. Come mid-month the seasonal transition was finally complete, and daytime highs mostly remained above 70° away from the coast and higher elevations. This included two episodes where temperatures exceeded 90°. Whether it was cool or warm, rainfall was rather plentiful through most of the month. Seven events produced an inch or more at multiple locations, two of which found some spots exceeding 3.00”.

The statewide average temperature was 63.3°. This is 2.1° over the 1991–2020 normal and ties as the 14th mildest May since 1895. The average maximum of 73.6° was 1.3° above normal and ranked 35th mildest while the average minimum of 53.0° was 2.8° above normal, ranking 7th mildest. Regionally, the north division came in at 62.0° (+2.1°, 15th mildest), the south 64.3° (+2.1°, tied with two others at 13th), and coast 62.4° (+1.4°, tied with one other at 20th).

Rainfall averaged 5.37” across NJ. This is 1.62” above normal and ranks as the 23rd wettest May of the past 128 years. Even with the Highlands being somewhat dry, the north was wettest at 5.98” (+1.96”, 18th wettest). The south averaged 5.03” (+1.43”, 25th), despite the far south being on the dry side. The coast came in with 4.77” (+1.26”, 26th).

When it comes to shedding the winter coat and thinking of warm weather to come, March is known to have its early spring teases. Then, along comes some late winter cold to remind us winter is not quite ready to disappear. This spring foolery was on exceptional display this month. High temperatures jumped into the 70°s on the 6th and 7th, then back to the cold until the 70° mark was again eclipsed during four of the five days from the 15th–19th. Next came some more seasonable temperatures before a polar blast brought mid-winter frigid conditions from the 28th–30th, only to be followed by another day of 70°s to end the month. Interspersed with these wild fluctuations were episodes of thunderstorms, snow and rain, and 13 days where winds gusted to greater than 40 mph at some locations.

When all was said and done, the statewide average temperature of 43.6° was 2.6° above the 1991–2020 normal. This ranked as the 16th mildest March since 1895, with the end-of-month cold spell keeping the month out of the top 10 for warmth. The average maximum of 54.0° was 3.1° above normal, ranking 17th mildest. The average minimum of 33.3° was 2.1° above normal, also ranking 17th. The north averaged 41.1° (+2.3°, 21st warmest), south 45.3° (+2.9°, 15th), and coast 44.9° (+2.7°, 13th).

Precipitation averaged 2.72” across NJ, which was 1.48” below normal and ranks as the 26th driest March since 1895. The north caught 2.54” (-1.47”, 26th driest), south 2.80” (-1.52”, 30th), and coast 3.06” (-1.36”, 34th). In particular, a zone from Hunterdon to Bergen counties was driest and the coast from Atlantic to Monmouth counties was wettest.