Off Goes the Faucet: September 2019 Recap

October 7, 2019 - 5:26pm -- Mathieu Gerbush


No months prior to this past September have been drier across New Jersey since February 2009, a testament to how precipitation has leaned toward the wet side since the last major drought impacted the state in 2002. The 1.21” received this September was 2.84” below the 1981–2010 average. This ranked as the 7th driest September since records commenced in 1895 (Table 1). February 2009 saw only 0.66”, but since February is on average the driest month of the year (2.80”), the last time a monthly deficit was larger than this September was the 3.06” departure in September 2007. Since 2000, only six other months early in the century have been drier (February 2002: 0.75”, October 2000: 0.77”, March 2006: 0.82”, October 2001: 0.93”, November 2001: 1.00”, and September 2005: 1.19”).

Conditions were driest in the north, averaging 1.06”, which is 3.41” below normal and ranks as the 4th driest September on record. Southern NJ ranked 12th driest with 1.30”, which is 2.52” below normal. This “flash drought” depleted soil moisture, resulting in brown lawns and shallow-rooted trees losing leaves early. Fire danger also increased, resulting in a ban on open fires. At month’s end, the US Drought Monitor had most of NJ in the D0 (abnormally dry) category, with Salem County experiencing moderate drought (D1) conditions. Thanks to above-average precipitation earlier this year, northern NJ reservoir levels remained above early-fall averages. Certainly, a watchful eye will be kept on all water resources should this dry spell continue.

Rank Year Sept. Avg. Precip.
1 1941 0.29"
2 1914 0.38"
3 2007 0.99"
4 1895 1.06"
5 1948 1.13"
6 2005 1.19"
7 2019 1.21"
8 1939 1.43"
9 1953 1.51"
10 1970 1.70"
10 1968 1.70"

Table 1. The eleven driest Septembers across NJ since 1895.

Above-average temperatures helped to dry things out in September. The 69.1° statewide average was 3.3° above the 1981–2010 mean. This ranks as the 8th warmest September over the past 125 years (tied with 1921; Table 2). Southern areas were warmest, at 3.5° above normal, while the north was 2.8° above.

Rank Year Sept. Avg. Temp.
1 1961 70.8°
2 2015 70.7°
3 2018 70.2°
3 2005 70.2°
5 2016 69.7°
6 1931 69.6°
7 2010 69.2°
8 2019 69.1°
8 1921 69.1°
10 2011 68.9°

Table 2. The ten warmest Septembers across NJ since 1895.


Every week of September found multiple days with one or more of the 64 Rutgers NJ Weather Network stations equaling or exceeding 85° for a high temperature. The longest break in such conditions was from the 17th–20th. Seven days surpassed 90°, beginning on the 2nd when Berkeley Township (Ocean County) and Upper Deerfield (Cumberland) reached 90°. The 4th found Vineland (Cumberland), Sicklerville (Camden), Greenwich (Salem), and Upper Deerfield all topping out at 93°, with 27 NJWxNet stations from 90°–92°. Sicklerville hit 92° on the 11th, with 32 stations at 90° or 91°. The monthly maximum of 95° was achieved at Woodbine (Cape May) on the 12, with Cape May Court House (Cape May) and Dennis (Cape May) at 93°, and 16 other stations from 90°–92°. Meanwhile, High Point (Sussex) only made it to 72°.

Readings in the 90°s returned on the 22nd, with Hillsborough-Duke (Somerset) and Moorestown (Burlington) each at 91° and eight other sites at 90°. Moorestown, Upper Deerfield, and Mannington (Salem) hit 93° on the 23rd, with 33 stations from 90°–92°. Sicklerville reached 90° on the 26th.

Eleven September days found low temperatures falling to 45° or cooler. As is often the case, the Sussex County valley locations of Walpack and Sandyston were part of this mix on each of the days. The 45° minimum at Sandyston on the 7th was the only morning during the first half of the month meeting the 45° criterion. Next up was the 17th, with Walpack at 44° and Sandyston 45°. The first lows in the 30°s arrived in Walpack (36°) and Sandyston (39°) on the 18th, with four coastal locations only down to 62°. It was cooler still on the 19th, with Sandyston and Walpack at 35° and five stations from 37°–39°. The coldest morning of the month was the 20th with Sandyston at 34°, Walpack and Pequest (Warren) 35°, seven stations from 36°–39°, and 30 locations from 40°–45°. Sandyston and Pequest were 42° on the 21st and Hopewell Township (Mercer) 43°.

A five-day cool run began on the 24th, with Walpack down to 44°. Walpack and Sandyston were 40° on the 25th, Walpack 43° on the 26th, Sandyston 42° and Basking Ridge (Somerset) and Hopewell Township 43° on the 27th, and Walpack 42° on the 28th.

Precipitation and Storms

Only two NJ stations saw September precipitation totals exceed the long-term statewide average. Both are CoCoRaHS stations located in Stafford Township (Ocean), with one recording 6.06” and the other 4.35”. In recent months it seems as if it has wanted to rain in this community more than anywhere else in NJ! Such is the randomness of weather sometimes. The next “wettest” station was in Hammonton (Atlantic) with 3.48”, with two other stations in town catching 3.18” (an NJWxNet site) and 2.97”. Little Egg Harbor Township (Ocean) received 3.41” during September, Medford Lakes (Burlington) 2.85”, Lacey Township (Ocean) 2.81”, and Tabernacle (Burlington) 2.80”. On the dry side, two Salem County stations tied for low honors, with 0.34” in Woodstown and Mannington (NJWxNet). A mix of CoCoRaHS and NJWxNet stations in eight counties completed the low ranks, with Upper Deerfield receiving 0.40”, Pittsgrove (Salem) 0.44”, Vineland 0.46”, South Harrison (Gloucester) 0.49”, Middle Township (Cape May) 0.53”, Verona (Essex) 0.57”, Cape May Court House 0.60”, Franklin Township (Somerset) 0.61”, and Lebanon (Hunterdon) and Haworth (Bergen) each with 0.63”.

Normally, our monthly reports only discuss precipitation events that see rainfall of an inch or more deposited at one or more locations in the state. However, given that there were only three such events this September, attention will also be paid to the five occurrences where top totals were between 0.50” and 0.99”. The first event of the month was the wettest. A morning squall line in the north and scattered afternoon and evening showers and thunderstorms around the state on the 2nd brought a maximum of 2.38” to Westfield (Union). Three Stafford Township stations came in with 2.18”, 1.85”, and 1.82”, Long Branch (Monmouth) saw 1.87”, and Cranford (Union) 1.56”. Of 230 CoCoRaHS reports, 32 stations exceeded 1.00” and 81 caught from 0.50”–0.99” (Figure 1). The least rain fell in the southwest, in part explaining why this region became the state’s driest this month.

Precipitation map for September 3rd
Figure 1. Rainfall from approximately 7AM on September 2nd to 7AM on September 3rd. Observations are comprised of reports from CoCoRaHS stations.

Scattered afternoon and evening thunderstorms on the 4th brought 2.32” to Greenwich (Salem), 1.95”, 1.25”, and 1.02” to stations in (where else?) Stafford Township, Medford Lakes 1.33”, Washington Township (Gloucester) 1.26”, and Winslow Township (Camden) 1.23”. Winds felled trees, some onto homes, in Ocean and Camden counties, with a 45 mph gust observed in Lower Alloways Creek Township (Salem).

The northwestern fringe of Hurricane Dorian delivered some scattered rain to NJ from the afternoon of the 6th until early on the 7th. Carteret (Middlesex) received 0.89”, Sayreville (Middlesex) 0.75”, Lacey Township 0.75”, Woodbridge (Middlesex) 0.73”, and Frenchtown (Hunterdon) 0.66”. Harvey Cedars (Ocean) received a maximum wind gust of 44 mph, with Sea Girt (Monmouth) gusting to 42 mph.

Scattered evening showers on the 11th into the predawn hours of the 12th brought 0.77” to a station in Franklin Township (Somerset), 0.62” in Newton (Sussex), and 0.47” in Fredon Township (Sussex). The last inch plus rain event of the month occurred during the afternoon and evening of the 12th. Atlantic, Burlington, and Mercer counties received the most, with little to no rain falling in the far north, southwest and deep south (Figure 2). Burlington (Burlington) caught 1.47”, Mt. Laurel (Burlington) 1.37”, Egg Harbor City (Atlantic) 1.32” and 1.27” (two stations), Mansfield (Burlington) 1.26”, Southampton (Burlington) 1.20”, and Pennington (Mercer) 1.18”. Only 31 of 229 stations reported more than 0.50”.

Precipitation map for September 13th
Figure 2. Rainfall from approximately 7AM on September 12th to 7AM on September 13th. Observations are comprised of reports from CoCoRaHS stations.

Predawn rain on the 15th brought Buena Vista (Atlantic) 0.80”, Toms River (Ocean) 0.65”, Port Republic (Atlantic) 0.61”, and Surf City (Ocean) 0.59”. A week of dry weather followed until late evening showers on the 23rd deposited 0.60” in Washington Township (Morris) and 0.32” at two Randolph (Morris) stations. Afternoon showers in the north followed by a line of thunderstorms in the south on the 26th brought 0.85” to Little Egg Harbor Township (Ocean), Cedar Bridge (Burlington) 0.71”, Woodland Township (Atlantic) 0.64”, Winslow Township 0.61”, and Stafford Township 0.60” and 0.49” (two stations). Scattered evening showers and thundershowers on the 28th saw Winslow Township accumulate 0.65”, Egg Harbor Township and Sicklerville each 0.61”, and Evesham (Burlington) 0.51”.

Aside from the gusts exceeding 40 mph mentioned above on the 4th and 6th, there were no other gusts equaling or exceeding 40 mph at any NJWxNet station in September. It was an exceedingly calm month. Barometric pressure peaked at 30.40”–30.45” on the 13th and bottomed out at 29.70”–29.80” on the 7th.