Monthly Summaries

Unprecedented: September 2021 Recap

October 11, 2021 - 4:38pm -- Dave Robinson

A flooded TD Bank Ballpark in Bridgewater (Somerset County) on September 2nd following the staggering rainfall caused by the remnants of Ida. Photo by Thomas P. Costello and Tariq Zehawi/USA Today Network.

Post-tropical storm Ida. The title of this month’s report speaks to this momentous weather extreme that will forever be the defining event of this month and likely the entire year. The storm delivered the most powerful tornado to strike the Garden State since 1990, demolishing multiple homes in Gloucester County. Rainfall exceeding 3.00” per hour led to the most widespread flash flood event on record for the state, resulting in the tragic deaths of 30 individuals in central and northeastern locales. A separate report on Ida has been prepared and may be accessed in the "News" menu.

There were 29 other days of weather this month that fortunately were not as dramatic as Ida on the 1st. All told, monthly precipitation averaged 6.20” across NJ. This was 2.04” above the 1991–2020 normal and ranks as the 15th wettest September since 1895. The north, where the bulk of Ida’s rain fell, averaged 8.92”, which was 4.46” above normal and ranks 7th wettest. The south averaged 4.61”, which was 0.62” above normal and ties as the 31st wettest. Along the coast, only 3.81” fell, some 0.08” below normal and ranking 44th wettest.

Sticky: August 2021 and Summer 2021 Recaps

September 10, 2021 - 6:30pm -- Dave Robinson

Flash flooding and residential evacuations in Helmetta on August 22

Whether the thermometer was reading high or low this August or whether rain was falling or not, one factor that most always had to be considered was the high level of humidity. The “Dog Days” of summer indeed. Of course, there was much else to consider this month, including contributions of rain from two tropical storms, one of which brought the largest crests on some rivers since May 1, 2014, 11 days where one or more locations received at least 2.00” of rain, and 16 days where the high temperature reached 90° or higher somewhere in the state.

Adding up all the rainfall, the statewide monthly average was 6.87”. This is 2.30” above the 1991–2020 normal and ranks as the 15th wettest August since 1895. The northern climate division led the way with 7.89” (+3.33”, 11th wettest), followed by the coastal area with 6.65” (+2.05”, 21st wettest), and the southern division at 6.21” (+1.64”, 27th wettest).

The statewide average temperature of 75.9° is 2.3° degrees above normal and ranks 4th warmest. Seven of the top 10 and 13 of the warmest 20 have occurred this century. The warmth was most strongly a function of elevated nighttime temperatures, which, for NJ, averaged 66.9°. This is 3.6° above normal and ranks 2nd warmest. The maximum temperature averaged 84.9°, some 1.1° above normal and ranks 18th warmest.

Everything but the Kitchen Sink: July 2021 Recap

August 5, 2021 - 7:55pm -- Dave Robinson

Tornado damage

Wow, what a month. July 2021 provided a never-ending cascade of weather events, including a tropical storm, a record-tying number of tornadoes, large hail, flash floods, hot days, chilly nights, smoke-filled skies, and on the last day of the month, perhaps the nicest day of the summer. The statewide average precipitation of 7.59” was 2.88” above the 1991–2020 normal and ranked 8th wettest of all Julys back to 1895. It was the wettest July since 1975 and second wettest in almost 50 years. The northern portion of the state averaged 8.16” which was 3.44” above normal. The south averaged 7.36” which was 2.62” above normal.

The average temperature of 75.8° was 0.4° above the 1991–2020 normal, but 1.9° above the 1895–2021 average. This ranked as the 24th warmest July since 1895. 13 of the 25 warmest Julys in the past 127 years have occurred since 2002. The nine July tornadoes is the most in a month since official records began in 1950. Tropical Storm Elsa was the earliest fifth storm of any season on record in the Atlantic basin. Read on for details on this potpourri of weather happenings.

Hit or Miss: June 2021 Recap

July 8, 2021 - 7:32pm -- Dave Robinson

A weir immediately downstream of the confluence of the Raritan and Millstone rivers in Somerset County on June 16th, as taken from the towpath of the Delaware-Raritan Canal

June was a hit or miss month when it came to rainfall, even within counties. Of course, this is not all that uncommon during the warm season, where much of the rainfall arrives courtesy of localized showers and thunderstorms. There were also ups and downs of the thermometer during the month, including some chilly mornings. Overall, the balance was weighted towards the warm side of the ledger, resulting in a top 10 ranking for June temperature.

The statewide average temperature of 71.9° was 1.6° above the 1991–2020 normal (3.0° greater than the 1895–2021 average). This ties the month with 2011 as the 8th warmest since records commenced in 1895. Seven of the 16 warmest Junes of the past 127 years have occurred in just the past 17 years. The average high of 82.7° was 1.7° above normal and ties as the 11th warmest, while the average low of 61.0° was 1.4° above normal and ranks 8th warmest.

Decision-Making Dilemma: May & Spring 2021 Recaps

June 6, 2021 - 4:03pm -- Dave Robinson

A waterspout over Barnegat Bay on May 8th near Seaside Heights

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.

Spring Mix: April 2021 Recap

May 6, 2021 - 3:56pm -- Dave Robinson

Daffodils gardens in Colonial Park in Franklin Township on April 25th

While April 2021 did not have a flare for the dramatic, it did provide a bit of a last look at winter and a glimpse ahead to summer. Overall, it was milder and drier than normal, but not exceedingly so for either variable. The statewide average temperature of 52.6° was 1.1° above the 1991–2020 normal*. Compared to an average over the 1895–present period, the temperature was 2.9° on the plus side, thus explaining the 2021 ranking as the 17th warmest April since 1895. Precipitation averaged 2.47”, which was 1.23” below normal and ranks as the 22nd driest. Coastal areas were wettest with approximately 3.50”–4.50” of rain, a good portion of the state received 2.50”–3.50”, while scattered areas were under 2.50” (Figure 1). Statewide and divisional snowfall came in at a trace.

The Wind Doth Blow: March 2021 Recap

April 8, 2021 - 11:17am -- Dave Robinson

An aerial view of a wildfire in Lakewood on March 14th

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).

Anything but Boring: February 2021 and Winter 2020/21 Recaps

March 8, 2021 - 3:51pm -- Dave Robinson

Wintry scene

Fate was clearly tempted when last month’s report was entitled: “Pretty Darn Boring.” Not that this wasn’t a truthful statement from both meteorological and climatological perspectives. So now this month’s title, being just as legitimate as January’s. The turnaround began in the waning hours of January 31st when what proved to be an impactful, long-lasting coastal storm began to invade the Garden State. This major event was followed by a series of storms that resulted in record or near record-setting monthly snowfall totals in northern and central regions and quite wet conditions in the south.

Statewide precipitation (rain and melted snowfall) averaged 4.89” in February. This was 2.03” above the 1991–2020 average and ranks as the 14th wettest February in 127 years of record keeping. The coastal south averaged 5.91” (+2.84”), ranking as 6th wettest. The remainder of the south came in with 5.09” (+2.20”, 11th) and the north 4.44” (+1.65”, 19th). More specifically, the southeast and central areas were wettest and the southwest and far north least wet.

While plenty of precipitation fell throughout the state, it was more often than not in the form of rain across the southern third of NJ, while central and northern areas were visited by one major snowstorm and a series of modest ones. All told, the statewide average snowfall was 23.5”. This is 15.3” above the 1991–2020 average and ranked as the 7th snowiest February.

Pretty Darn Boring: January 2021 Recap

February 9, 2021 - 10:04pm -- Dave Robinson

Snowfall map for January 3rd-4th

The first month of 2021 lacked major storms, whether wet or white, and temperatures rarely were either quite mild or very cold. Thus the title of this report. Yes, the last day of the month turned snowy, the harbinger of anything but a boring start to February, but that’s to be covered next month. The January statewide average temperature was 33.7°. This was 3.0° above the 1981–2010 normal and ranks as the 26th mildest January in the past 127 years. The average high was 41.1°, which is 1.8° above normal and ranks 34th mildest, while the average low of 26.3° was 4.2° above normal, ranking 20th mildest.

January precipitation (rain and melted snow) averaged 1.99” across the state, which is 1.41” below normal and ranks 13th driest since 1895. The north averaged 1.93” (-1.48”, 18th driest), the south 2.02” (-1.37”, 13th driest), and the coast 2.19” (-1.25”, 17th driest). Generally, the eastern half of the state was wetter (particularly the northeast) than the west.

A Mixed Bag, and A Blow Torch Year: December & Annual 2020 Recaps

January 7, 2021 - 4:43pm -- Dave Robinson

Drone photos of tidal flooding near the morning high tide on December 17th

The statewide average temperature during this last month of 2020 averaged 37.0°. This was 1.8° above the 1981–2010 normal and ranks as the 22nd mildest December in the 126-year record that dates back to 1895. Northern and southern portions of NJ had similar departures and rankings.

December precipitation (rain and the liquid equivalent of snow and sleet) averaged 6.24”. This includes rain measured at National Weather Service Cooperative Observing stations on the morning of December 1st but does not include rain measured at these stations for the 24 hours ending on the morning of January 1st. See an explanation of the November 30th–December 1st measurement in the November report. The monthly value is 2.39” above average and ranks as the 11th highest December precipitation total on record. North Jersey averaged 6.73”, which is 2.78” above average and ranks 7th wettest. The south came in at 5.89”, which is 2.10” above average and ranks 17th wettest. The coast averaged 6.43”, which is 2.67” above average and ranks 11th wettest.


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