Wide Precipitation Variations Statewide and Top 10 Warmth:
June and First Half of 2011 Overview

Dr. David A. Robinson
New Jersey State Climatologist
Center for Environmental Prediction, School of Environmental and Biological Sciences/NJAES, Rutgers University
July 3, 2011

June Overview

Due to an early-month heat wave and overall persistent warmth, June ranked as the 9th warmest across New Jersey since records began in 1895 (Table 1). The 72.2° average temperature was 2.8° above the 1971-2000 mean. Remarkably, nine of the past sixteen months have ranked in the top ten for warmth. Only December 2010 and January 2011 had below-average temperatures during this period.

Rank Year June Temp.
1 2010 74.4°
2 1943 74.1°
3 2008 73.6°
4 1925 73.3°
5 1994 72.7°
5 2005 72.7°
7 1957 72.5°
8 1934 72.3°
9 2011 72.2°
9 1923 72.2°
11 1899 72.0°
12 1949 71.8°
12 1973 71.8°
14 1952 71.7°
15 1976 71.6°

Table 1. The fifteen warmest Junes across New Jersey since 1895.

Newark (Essex County) reached 102° on June 9th for the hottest official reading of the month. Only eight June days had a below-average daily temperature at this airport location, while at the Atlantic City Airport in Pomona (Atlantic) only four days came in below average. There were eight days where at least one of the 55 locations monitored across the state reached or exceeded 90°. The 1st saw Upper Deerfield (Cumberland) and Sicklerville (Camden) reach 95°. The heat wave of the 7th-10th began with seven locations, including coastal Point Pleasant (Ocean), reaching 90°. Six locations maxed out at 97° on the 8th, with only coastal (Harvey Cedars (Ocean) at 81°) and High Point Monument under 90°. The 10th was the hottest day of the month. Joining the aforementioned Newark 102° at or above the century mark were Hammonton (Atlantic) and Berkeley Township (Ocean) at 101°, and Oswego Lake (Burlington) at 100°. Only Bivalve (Cumberland) on the shore of Delaware Bay at 88° was below 90°, with most stations topping out at 95° or higher. The 11th brought less torrid temperatures, although Hammonton made it to 91° with five other south Jersey stations reaching 90°.

Highs frequently in the 80°s prevailed during much of the remainder of the month, although Eastampton (Burlington) and Hammonton reached 93° on the 22nd and Hammonton hit 90° on the 23rd and 24th.

On the cool side of the ledger, daily minimum temperatures fell below 50° on eleven mornings in one or more locations. The first run of these temperatures was from the 2nd to 7th. Walpack (Sussex) dropped to 43° on the 2nd, with Pequest (Warren) down to 48°. The 3rd was the coolest morning of the month statewide. Walpack fell to 37°, Oswego Lake (Burlington) to 41°, with many other stations in the 40°s. Atlantic City Marina was the warm spot at 58°. Walpack was 40° on the 4th and Pequest 42°. Walpack at 46° paired with Berkeley Township (Ocean) at 47° for the two coolest locations on the 5th. Basking Ridge (Somerset) took honors with 49° on the 6th and Walpack was 49° on the 7th.

Cool lows returned from the 13th to 16th, with 49° lows at High Point (Sussex) on the 13th and Walpack on the 14th. Basking Ridge and Berkeley Township fell to 47° on the 15th and Pequest to 49° on the 16th. Finally, the 30th saw Walpack fall to 49°.

Summer precipitation often varies from one location to another, as most often rain falls from localized systems, often convective in nature. June 2011 epitomized these variations, with the lowest and highest totals differing by over 8" and situated only about 100 miles apart. Ringwood (Passaic) took top honors with 9.46", followed close behind by West Milford (Passaic) at 9.39". Other notable totals included Oakland (Bergen) 8.27", Jefferson Township (Morris) 8.12", and Allamuchy Township (Warren) 7.27". On the dry side, Southampton Township (Burlington) received 0.96", Linwood (Atlantic) 1.11", Moorestown (Burlington) 1.28", Medford (Burlington) 1.29", and Greenwich Township (Cumberland) 1.34". Statewide, June precipitation averaged out to 3.43". This is 0.36" below normal and is the 56th driest June (62nd wettest) of the past 117 years.

Eight events brought more than an inch of rain to several locations, with at least 3" falling during three of them. Thunderstorms occurred on eleven days, with hail reported on seven of those days. The action started on the 1st with a strong storm along the north Jersey coast. It deposited 0.37" of rain at Fair Haven (Monmouth) and 0.33" in Red Bank (Monmouth), but it was the hail that was most notable. Brick Township (Ocean) had hail up to the size of a golf ball, Red Bank up to 0.5" and Howell to 0.25". Hail was also reported in Manalapan and Wall in Monmouth County and Barnegat Township (Ocean).

Heat wave-breaking storms arrived on the evening of the 9th, accompanied by rain, hail, and localized strong winds. Most of the state received several tenths of an inch of rain or a bit more, however again, the north coast saw the heaviest totals. This included Red Bank with 1.60" and Holmdel (Monmouth) with 1.58". Unofficial wind gusts included 72 mph in Pennsville (Salem), 64 mph at Millville (Cumberland), and 60 mph at Weymouth (Atlantic). Wantage (Sussex) saw a gust of 50 mph and Hillsborough (Somerset) 46 mph. The winds toppled trees and brought down wires in nine central and southern Jersey counties (including a mile of wires in Princeton (Mercer)). Hail was observed in five counties. The Cape May County communities of Woodbine, Middle Township, and Upper Township had pea- to quarter-size hail, Cumberland County hail of a quarter size or slightly larger fell in Bridgeton and Vineland, and the Atlantic County towns of Richland and Weymouth also saw quarter or larger ice falling from the sky. Further north the Hunterdon County towns of Clinton and Califon received pea-size hail and the Bergen County communities of Harrington Park and Norwood saw up to golf ball-sized hail.

Storms returned late on the 11th into the first half of the 12th. Mine Hill (1.84") and Rockaway Township (1.51") in Morris County received the largest totals, with lower amounts of various magnitudes scattered around the rest of the state. Clayton (Gloucester) had quarter-size hail. The heaviest rain again focused on Morris County on the 14th, with 1.10" in Morris Township and 1.06" at Harding Township. Most of the state saw at least several tenths of an inch of rain.

The 16th into the early hours of the 17th brought heavy rain and loud thunder (awakening many) to the northern half of NJ. Ringwood (Passaic) received 3.46", Harrison (Hudson) 3.40", Oakland (Bergen) 3.03", and Hardyston (Sussex) 2.72". A number of northern locations received more than an inch, while southern areas saw very little to as much as an inch. Quarter-sized hail fell in Montclair (Essex).

Two powerful thunderstorm cells impacted select portions of the state on the evening of the 22nd. Tragically, winds in one cell brought down a tree onto a car in Whiting (Ocean), killing one occupant. Structural damage to buildings and wires was caused by falling trees elsewhere in Ocean County as well as in Mercer County. A funnel cloud was spotted in the Jackson Township (Ocean) area, but apparently did not touch the ground as a tornado. Whiting also saw golf ball-sized hail. Winds also brought down trees and wires and produced some flash flooding in a cell that passed through Sussex, Warren, and Morris counties. Notable rains in this cell accumulated to 2.72" in Hardyston (Sussex), and 1.58" and 1.91" at two locations in Blairstown (Warren).

A moisture-rich atmosphere generated significant flash-flood producing downpours in the extreme northern tier of NJ during the mid-day hours of the 23rd. Rain quickly accumulated to 2-4" totals in areas north of Route 80, with a sharp decline to totals under an inch immediately south of the interstate. Little rain fell in the southern half of NJ. Ringwood (Passaic) saw 4.58", Sparta (Sussex) 4.47" (4.25" fell in two hours), West Milford (Passaic) 4.28", and Jefferson Township (Morris) 3.64". Roads flooded and streams briefly overflowed their banks, leading to the evacuation of 37 residents near the Pascack Brook in Hillsdale (Bergen).

A thunderstorm roared across the Route 195 corridor in central NJ on the 24th, bringing with it winds that downed trees, signs and wires in Mercer and Ocean counties. Rain accumulated to 1.88" in Brick (Ocean) and 1.72" in Stafford Township (Ocean). Half inch-diameter hail fell in Lawrence Township (Mercer), with pea-size hail in Woodland Township (Burlington) and Brick. The last major storm of the month was an isolated one in the region close to the intersections of Gloucester, Salem, Cumberland and Atlantic counties. 3.09" in less than three hours soaked Franklin Township (Gloucester), leading to flash flooding. 2.27" fell in Upper Deerfield (Cumberland). This storm helped to contain a 170 acre brush fire that ignited on the 27th in Shamong Township (Burlington).

In addition to the storm-produced winds mentioned earlier in this narrative, wind gusts exceeded 40 mph on two other June days. Gusts on the 2nd included 48 mph at Wantage (Sussex), and 43 mph at High Point Monument (Sussex) and Red Lion (Burlington). Seaside Heights saw a gust of 40 mph on the 29th. The maximum barometric pressure of the month was in the 30.20"-30.25" range on the 1st and the lowest was between 29.55" and 29.60" on the 24th.

First Half of 2011 Overview

As discussed in the June narrative, above-average warmth has prevailed throughout the past year, and the first six months of 2011 were no exception. Aside from a snowy, below-average January, temperatures were above average from February through June. The first half statewide average of 48.8° makes this the 14th warmest January-June (Table 2). This is 1.3° above the long-term average of 47.5°. Nine of the fourteen warmest first halves have occurred since 1990.

Rank Year Jan-Jul Avg 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°
11 2000 49.2°
12 1913 48.9°
12 1976 48.9°
14 2011 48.8°
15 1999 48.7°
15 1952 48.7°
15 1933 48.7°
18 1973 48.6°
19 1937 48.4°
19 1946 48.4°

Table 2. The twenty warmest first six months of the year across New Jersey since 1895.

The 24.99" of rain and melted snow that fell during the past six months is 1.90" above average and ranks as the 21st wettest on record. Surpluses of a little more than 10" are found in the north in Morris, Passaic, and Bergen counties. Above-average anomalies fall to 3-4" moving south to Mercer and Middlesex counties. South of there, totals are within about 2" of average, with Cape May County the driest at about 2" below average. Thus it is the southern half of the state that must be watched most carefully when considering water resources through the remainder of the summer and into the fall.

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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