Alert archive / New Jersey / Flash Flood Warnings in 2025

Flash Flood Warning 84, NWS Philadelphia/Mount Holly

July 31, 2025Middlesex County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 31, 2025, 2:52 PM EDT for Middlesex County, New Jersey. It was in force for 4 hr. 3 reports 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 31, 2025, 2:52 PM EDT (18:52 UTC)
Expired: Jul 31, 2025, 7:00 PM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County Middlesex County, NJ

The radar

The Philadelphia radar (KDIX), 61 km from the middle of the area, began a volume at 18:52 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 31, 3:04 PM EDT	FLASH FLOOD	1 Sw Hopelawn, NJ	NJ DOT reports flooding on US 9 Northbound At North of CR 656/Smith St (Woodbridge Twp), 1 right lane of 2 lanes closed.
Jul 31, 4:14 PM EDT	FLASH FLOOD	South Amboy, NJ	NJ DOT reports flooding on US 9 & NJ 35 Southbound Ramp To Raritan St (South Amboy), All lanes closed.
Jul 31, 5:23 PM EDT	FLASH FLOOD	South Amboy, NJ	Roads flooded in South Amboy.

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, 6.9 hours before the alert went out and 130 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: 1000 J/kg
Mixed-layer CIN: -70 J/kg
Mixed-layer LCL: 970 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: -13 m²/s²
0-3 km storm-relative helicity: 82 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.4

Open this sounding in Storm Lab

The text

As transmitted.

393 
WGUS51 KPHI 311852
FFWPHI
NJC023-312300-
/O.NEW.KPHI.FF.W.0084.250731T1852Z-250731T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
252 PM EDT Thu Jul 31 2025

The National Weather Service in Mount Holly has issued a

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

* Until 700 PM EDT.

* At 252 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Up to 1 inch of rain has 
  fallen. Additional rainfall amounts of 1 to 2 inches 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, Perth Amboy, Somerset, Edison, Old Bridge, East 
  Brunswick, South Brunswick, Sayreville, North Brunswick, Carteret, 
  Middlesex and Jamesburg.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 4050 7445 4059 7448 4061 7430 4060 7431
      4059 7429 4060 7422 4059 7420 4056 7422
      4055 7425 4050 7426 4049 7427 4046 7426
      4045 7422 4043 7425 4041 7425 4028 7440
      4027 7441 4035 7463

FLASH FLOOD...RADAR INDICATED

$$

MPS

1 follow-up statement

325 
WGUS71 KPHI 312252
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
652 PM EDT Thu Jul 31 2025

NJC023-312302-
/O.EXP.KPHI.FF.W.0084.000000T0000Z-250731T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Middlesex NJ-
652 PM EDT Thu Jul 31 2025

...FLASH FLOOD WARNING WILL EXPIRE AT 7 PM EDT THIS EVENING FOR 
MIDDLESEX COUNTY...

Although the heaviest rain has ended, continue to heed any road 
closures that may be in effect due to earlier flooding.

A Flood Watch remains in effect until 1200 AM EDT for portions of 
northern Delaware, New Jersey, and southeast Pennsylvania.

&&

LAT...LON 4050 7445 4059 7448 4061 7430 4060 7431
      4059 7429 4060 7422 4059 7420 4056 7422
      4055 7425 4050 7426 4049 7427 4046 7426
      4045 7422 4043 7425 4041 7425 4028 7440
      4027 7441 4035 7463

$$

Kruzdlo

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 31, 2:24 AM EDT	Small Craft Advisory	PHI		70 hr
Jul 31, 3:56 AM EDT	Rip Current Statement	PHI	Atlantic, Cape May, Monmouth, Ocean	4 days
Jul 31, 1:27 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Middlesex, Morris, Somerset	48 min
Jul 31, 1:48 PM EDT	Flash Flood Warning	PHI	Morris, Somerset	4 hr
Jul 31, 1:49 PM EDT	Tornado Warning	PHI	Middlesex, Somerset	26 min
Jul 31, 1:55 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Mercer	18 min
Jul 31, 2:05 PM EDT	Severe Thunderstorm Warning	PHI	Gloucester, Salem	40 min
Jul 31, 2:27 PM EDT	Flash Flood Warning Considerable damage threat	PHI	Camden, Gloucester	4 hr
Jul 31, 2:30 PM EDT	Flash Flood Warning	PHI	Morris	4 hr
Jul 31, 2:38 PM EDT	Severe Thunderstorm Warning	PHI	Middlesex	52 min
Jul 31, 2:46 PM EDT	Flash Flood Warning Considerable damage threat	PHI	Gloucester, Salem	4 hr
Jul 31, 2:55 PM EDT	Severe Thunderstorm Warning	PHI	Camden, Gloucester, Salem	50 min
Jul 31, 2:57 PM EDT	Special Marine Warning	PHI		63 min
Jul 31, 3:03 PM EDT	Severe Thunderstorm Warning	PHI	Middlesex, Monmouth	42 min
Jul 31, 3:10 PM EDT	Flash Flood Warning Considerable damage threat	PHI	Burlington, Camden, Gloucester, Mercer, Monmouth, Ocean	4 hr
Jul 31, 3:10 PM EDT	Tornado Warning	PHI	Camden, Gloucester, Salem	35 min
Jul 31, 3:12 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Ocean	48 min
Jul 31, 3:49 PM EDT	Flash Flood Warning	PHI	Camden, Gloucester, Salem	4 hr
Jul 31, 4:31 PM EDT	Flash Flood Warning Considerable damage threat	PHI	Middlesex, Monmouth	3 hr
Jul 31, 4:36 PM EDT	Special Marine Warning	PHI		54 min
Jul 31, 4:39 PM EDT	Special Marine Warning	PHI		36 min
Jul 31, 4:43 PM EDT	Flash Flood Warning	PHI	Monmouth, Ocean	4 hr
Jul 31, 5:21 PM EDT	Flash Flood Warning	PHI	Cumberland	3 hr
Jul 31, 5:53 PM EDT	Flash Flood Warning	PHI	Atlantic, Burlington, Cape May, Ocean	4 hr
Jul 31, 6:17 PM EDT	Special Marine Warning	PHI		58 min
Jul 31, 6:42 PM EDT	Special Marine Warning	PHI		63 min
Jul 31, 7:29 PM EDT	Special Marine Warning	PHI		91 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.