Alert archive / New Jersey / Flash Flood Warnings in 2025

Flash Flood Warning 71, NWS Philadelphia/Mount Holly

July 16, 2025Middlesex County, Somerset County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 16, 2025, 6:46 PM EDT for Middlesex County, Somerset County, New Jersey. It was in force for 4 hr. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jul 16, 2025, 6:46 PM EDT (22:46 UTC)
Expired: Jul 16, 2025, 10:45 PM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Middlesex County, NJ, Somerset County, NJ

The radar

The Philadelphia radar (KDIX), 61 km from the middle of the area, began a volume at 22:50 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

Time	Report	Where	Remark
Jul 16, 9:00 PM EDT	FLOOD	North Brunswick, NJ	Minor flooding of a few roads in North Brunswick. Time estimated.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 10.8 hours before the alert went out and 148 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 1571 J/kg
Mixed-layer CIN: -19 J/kg
Mixed-layer LCL: 781 m above ground
0-6 km bulk shear: 8 kt
0-1 km storm-relative helicity: 7 m²/s²
0-3 km storm-relative helicity: 31 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

097 
WGUS51 KPHI 162246
FFWPHI
NJC023-035-170245-
/O.NEW.KPHI.FF.W.0071.250716T2246Z-250717T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
646 PM EDT Wed Jul 16 2025

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Northwestern Middlesex County in northern New Jersey...
  Southeastern Somerset County in northern New Jersey...

* Until 1045 PM EDT.

* At 646 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.5 and 1.5 inches of 
  rain have fallen. Additional rainfall amounts up to 1 inch are 
  possible in the warned area. Flash flooding is ongoing or expected 
  to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flooding of small creeks and streams, urban areas,
           highways, streets, and underpasses as well as other
           drainage and low lying areas.

* Some locations that may experience flash flooding include...
  New Brunswick, Somerset, East Brunswick, South Brunswick, North 
  Brunswick, Middlesex, Bound Brook, Manville, Rocky Hill, 
  Millstone, Kendall Park and North Brunswick Township.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around...don't drown when encountering flooded roads. Most 
flood deaths occur in vehicles.

&&

LAT...LON 4056 7453 4056 7452 4053 7442 4039 7447
      4039 7459 4039 7465 4053 7465

FLASH FLOOD...RADAR INDICATED

$$

AKL

1 follow-up statement

629 
WGUS71 KPHI 170235
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1035 PM EDT Wed Jul 16 2025

NJC023-035-170245-
/O.EXP.KPHI.FF.W.0071.000000T0000Z-250717T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Middlesex NJ-Somerset NJ-
1035 PM EDT Wed Jul 16 2025

...FLASH FLOOD WARNING WILL EXPIRE AT 1045 PM EDT THIS EVENING FOR 
NORTHWESTERN MIDDLESEX AND SOUTHEASTERN SOMERSET COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

A Flood Watch remains in effect until 300 AM EDT for portions of 
central, northern, and northwest New Jersey.

&&

LAT...LON 4056 7453 4056 7452 4053 7442 4039 7447
      4039 7459 4039 7465 4053 7465

$$

AKL

The office that day

Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 16, 1:55 AM EDT	Heat Advisory	PHI	Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester and 10 more	42 hr
Jul 16, 7:31 PM EDT	Severe Thunderstorm Warning	PHI	Monmouth, Ocean	29 min
Jul 16, 7:37 PM EDT	Special Marine Warning	PHI		38 min
Jul 16, 7:38 PM EDT	Flash Flood Warning	PHI	Mercer	4 hr
Jul 16, 7:54 PM EDT	Severe Thunderstorm Warning	PHI	Middlesex, Monmouth, Ocean	26 min

Nearby

Flash Flood Warnings in New Jersey, 2025 Every flash flood warning in 2025

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.