Persistent Warmth
June and First Half of 2010 Overview

Dr. David A. Robinson
New Jersey State Climatologist
Center for Environmental Prediction, School of Environmental and Biological Sciences/NJAES, Rutgers University
July 4, 2010

June Overview

What a run of abnormal warmth across the Garden State. As discussed later in this report, temperatures have been above normal since March. June was no exception, as it goes into the record books as the warmest since records commenced in 1895. The statewide temperature of 74.4° is 5.0° above average. This surpasses the previous warmest June (1943) by 0.3° (table 1). Three of the six warmest Junes have occurred in the past six years.

Rank Year June Temp
1 2010 74.4°
2 1943 74.1°
3 2008 73.6°
4 1925 73.3°
5 1994 72.7°
6 2005 72.7°
7 1957 72.5°
8 1934 72.3°
9 1923 72.2°
10 1899 72.0°

Table 1. Ten warmest Junes across New Jersey since 1895

The maximum daily temperature equaled or surpassed 90° at one or more location on fifteen days. The 2nd to 6th saw daily maximums of 90° at Sicklerville (Camden County) on the 2nd, 91° at Sicklerville and Hammonton (Atlantic) on the 3rd, 91° at Hammonton on the 5th, 92° at four eastern Ocean and Monmouth county stations on the 5th, and 94° at Berkeley Township (Ocean) on the 6th. Woodbine (Cape May) topped out at 96° on the 13th.

The 90°s returned on nine of eleven days between the 19th and 29th. Eastampton (Burlington) hit 90° on the 19th, three stations reached 92° on the 21st, Hammonton was 93° on 22nd, eight stations maxed out at 94° on the 23rd, and Hammonton sizzled at 99° with seven other stations at 98° on the 24th. Wall Township (Monmouth) topped out at 93° on the 26th and three stations reached 96° on the 27th. The 28th was the warmest day of the month, with Point Pleasant (Ocean) reaching 100°, Berkeley Township 99° and 23 stations between 95° and 98°. Just like the 5th, it was stations at or near the coast in southeast Monmouth and northeast Ocean counties that were hottest, thanks in part to less cloud cover overspreading this area later in the afternoon than elsewhere in NJ. The heat continued at Point Pleasant on the 29th with a maximum of 95°.

On these fifteen hottest June days the lowest maximum temperatures were most often in the upper 70s to low 80s and occurred at sea level (for instance at Harvey Cedars (Ocean) and the Atlantic City Marina (Atlantic)) or at High Point Monument (Sussex), the highest point in the state (1803 feet). The widest differences in daily highs occurred on the 13th (96° at Woodbine and 71° at both Sea Girt and High Point Monument) and the 22nd (93° at Hammonton and 71° at High Point Monument).

The 7th to the 19th saw seven nights when temperatures dropped into the 40s at several locations. The High Point Monument station fell to 44° on the 7th. Pequest (Warren) dipped to 40° on both the 8th and 9th. The morning of the 9th was the coolest of the month with 29 stations around the state in the 40°s. Basking Ridge (Somerset) dropped to 49° on the 11th, Berkeley Township (Ocean) to 48° on the 16th, Pequest to 48° on the 18th, and Basking Ridge and Berkeley Township to 49° on the 19th. The month ended on a cool note, with Pequest falling to 46° on the 30th, with three other stations at 49°.

Statewide, June precipitation averaged 2.27". This is 1.52" below average and ranks as the 18th driest of the past 116 years (tied with 1908). The five wettest locations included Buena Vista Township (Atlantic) with 4.56", Denville Township (Morris) 4.30", Washington (Warren) 4.10", Wayne Township (Passaic) 4.09" and Bethlehem Township (Hunterdon) 3.93". The five driest locations included Linwood (Atlantic) and Howell Township (Monmouth) each at 0.86", Ewing (Mercer) 0.90" and Hamilton Township (Mercer) and Woodbine (Cape May) each at 0.92". It is illustrative of the local nature of summer thunderstorms that the wettest and driest stations sit only 25 miles apart in Atlantic County and the 5th wettest and 3rd driest are only 35 miles apart in west central NJ.

As suggested previously, the majority of the significant rain events in June were in the form of thunderstorms. On the 1st, storms brought 1.45" to Ortley Beach (Ocean) and 1.25" to Fair Haven (Monmouth). A non-convective steady afternoon and evening rain on the 9th accumulated to 1.16" in Shrewsbury (Monmouth), 1.15" at Monmouth Beach (Monmouth) and 1.12" in New Brunswick (Middlesex). All of NJ saw some rain, with the most in the northern half. Storms returned on the 13th to the western half, with little to none near the Atlantic coast. Bethlehem Township (Hunterdon) was drenched with 2.36" and Washington (Warren) with 2.26". Twenty-seven CoCoRaHS observers measured more than 1.00" on the 13th.

Cape May County had an afternoon storm on the 16th, with 1.05" in Wildwood Crest. Early the next morning, storms moved through the northern third of the state, bringing 0.95" to Mendham (Morris) and 0.63" to Basking Ridge (Somerset). On the 22nd, several swaths of moderate to heavy rain fell in storms that raced across some regions. South Harrison (Gloucester) received 1.12", Middle Township (Cape May) 0.83" and Franklin Township (Somerset) 0.74". Winds gusted to 43 mph at Bivalve (Cumberland).

Severe storms struck portions of south Jersey on the afternoon of the 24th, dropping temperatures from the upper 90°s to the low 70°s. Woodstown (Salem) received a quick 1.55" with small hail, Sicklerville (Camden) 1.28" and Oswego Lake (Burlington) 1.27". Winds gusted to 47 mph at West Creek (Ocean), though locally were likely stronger. Trees and power lines came down, resulting in power outages, particularly in Camden and Atlantic counties. A final round of storms crossed the state on the 28th, with a storm that roughly followed Rt. 80 dropping as much as 1.31" in Little Falls (Bergen). Windy southern storms deposited 1.19" at Seaside Heights (Ocean), 1.17" at Oswego Lake and 1.13" in Clayton (Gloucester). Winds peaked at 71 mph in Bivalve, 53 mph at Harvey Cedars (Ocean) and 44 mph at Seaside Heights.

There were several windy days in June that saw winds gusting to 47 mph at Bivalve on the 5th, 45 mph at High Point Monument (Sussex) on the 6th and 48 mph at Wantage (Sussex) on the 17th. The early month winds were a result of a pressure differential between the lowest monthly pressures (29.65" to 29.70") on the 6th and highest pressures (30.15" to 30.20") on the 8th and 9th. Each of these extremes are rather unremarkable, another sign of summer well underway.

The heat and overall dry conditions across the state in June began to dry out fields and forests. This led to an approximate 900 acre forest fire in Barnegat Township (Ocean) on the 26th-27th and a 120 acre brush fire at Fort Dix (Burlington) on the 28th.

First Half of 2010 Overview

If you like variety in your weather and climate, the first half of 2010 certainly did not disappoint. About the only thing missing was brutal cold, though it was several degrees below average during a record snowy February. Otherwise, temperatures were above average during the other five months. The six-month average of 50.4° is 2.9° above average, making it the 4th warmest first half of the year on record (table 2).

Rank Year Jan-Jun Temp
1 1998 51.4°
2 2002 50.7°
3 1991 50.5°
4 2010 50.4°
5 1949 50.3°
6 2006 50.1°
7 1921 50.0°
8 1990 49.9°
9 1953 49.7°
10 2008 49.5°

Table 2. Ten warmest January-June intervals across New Jersey since 1895

The April to June average of 64.7° is 4.6° above average, which by a wide margin makes it the warmest such interval on record (table 3). It was the persistence of the warmth, rather than record maximum temperatures that made the past three months so noteworthy. However, temperatures on April 7 did break records and at some locations it was the warmest day on record for so early in the season.

Rank Year Apr-Jun Temp
1 2010 64.7°
2 1991 63.3°
3 2004 62.6°
4 1959 62.2°
5 1957 62.1°
6 1941 62.1°
7 1998 62.0°
8 2006 61.9°
9 1921 61.8°
10 2008 61.8°

Table 3. Ten warmest April-June intervals across New Jersey since 1895

A stormy period that began in the fall of 2009 continued through the first three months of 2010. Thus, despite the following three months each having below-average precipitation, the six-month total of 25.54" is 2.45" above average. This makes January-June 2010 the 19th wettest, while the April-June total of 8.17" is 3.85" below average, or 14th driest. In addition to several heavy February snowstorms, a major wind and rain storm in mid March brought the most rain from a two-day winter (December-March period) storm on record. This was just one wet event in the wettest March in the 116 year state record book.

For those seeking more detailed information on hourly, daily and monthly conditions, please visit the following Office of the NJ State Climatologist's websites:

NJ Weather and Climate Network
NJ Community Collaborative Rain, Hail and Snow Network
NJ Snow Event Reports

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