Alert archive / New Jersey / Flash Flood Warnings in 2026

Flash Flood Warning 47, NWS Philadelphia/Mount Holly

July 18, 2026Middlesex County, Morris County, Somerset County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 18, 2026, 12:40 PM EDT for Middlesex County, Morris County, Somerset County, New Jersey. It was in force for 3 hr. 11 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 18, 2026, 12:40 PM EDT (16:40 UTC)
Expired
Jul 18, 2026, 3:34 PM EDT
In force
3 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Middlesex County, NJ, Morris County, NJ, Somerset County, NJ

The radar

The Philadelphia radar (KDIX), 76 km from the middle of the area, began a volume at 16:43 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

TimeReportWhereRemark
Jul 18, 12:45 PM EDTFLASH FLOODSomerville, NJFlooding at the intersection of West End Ave and West Main Street.
Jul 18, 12:55 PM EDTFLOOD1 Sse South Bound Brook, NJNJDOT reported flooding on I-287 southbound Exit 10 - CR 527/Easton Ave in Franklin Twp. 1 left lane of 3 lanes closed.
Jul 18, 12:55 PM EDTFLASH FLOOD1 Sse South Bound Brook, NJCorrects previous flash flood report from 1 SSE South Bound Brook. NJDOT reported flooding on I-287 southbound Exit 10 - CR 527/Easton Ave in Franklin Twp. 1 left lane of 3 lanes closed.
Jul 18, 1:00 PM EDTFLOOD2 Ene Somerville, NJNJDOT reported flooding on I-287 in both directions north of Exit 14/US 22 in Bridgewater Township. All lanes closed.
Jul 18, 1:00 PM EDTFLASH FLOOD2 Ene Somerville, NJCorrects previous flood report from 2 ENE Somerville. NJDOT reported flooding on I-287 in both directions north of Exit 14/US 22 in Bridgewater Township. All lanes closed.
Jul 18, 1:00 PM EDTFLASH FLOOD2 W Kendall Park, NJCorrects previous flash flood report location. Flooding on Linden Ave with water reaching the homes along the street.
Jul 18, 1:40 PM EDTFLOOD1 N Perth Amboy, NJNJDOT reported flooding on NJ 440 Southbound At CR 611/State St (Perth Amboy), ramp lane closed.
Jul 18, 1:40 PM EDTFLASH FLOOD1 N Perth Amboy, NJCorrects previous flood report from 1 N Perth Amboy. NJDOT reported flooding on NJ 440 Southbound At CR 611/State St (Perth Amboy), ramp lane closed.
Jul 18, 1:56 PM EDTFLOODMetuchen, NJNJDOT reported flooding on NJ 27 Both Directions North of CR 501/Amboy Ave (Metuchen), 1 right lane of 2 lanes closed northbound; 1 right lane of 2 lanes closed southbound.
Jul 18, 1:56 PM EDTFLASH FLOODMetuchen, NJCorrects previous flood report from Metuchen. NJDOT reported flooding on NJ 27 Both Directions North of CR 501/Amboy Ave (Metuchen), 1 right lane of 2 lanes closed northbound; 1 right lane of 2 lanes closed southbound.
Jul 18, 2:20 PM EDTFLASH FLOODDunellen, NJFlooding at the intersection of South Ave and Pulaski Street resulting in a road closure.

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, 4.7 hours before the alert went out and 144 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-pSkew-T log-p diagram, Brookhaven, NY at 12:00Z on 2026-07-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 5 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 12:00Z on 2026-07-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 131 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
5 J/kg
Mixed-layer CIN
-238 J/kg
Mixed-layer LCL
1076 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
131 m²/s²
0-3 km storm-relative helicity
157 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.0

Open this sounding in Storm Lab

The text

As transmitted.

391 
WGUS51 KPHI 181640
FFWPHI
NJC023-027-035-182045-
/O.NEW.KPHI.FF.W.0047.260718T1640Z-260718T2045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1240 PM EDT Sat Jul 18 2026

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Northeastern Middlesex County in northern New Jersey...
  Southern Morris County in northern New Jersey...
  Somerset County in northern New Jersey...

* Until 445 PM EDT.

* At 1240 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.5 and 1.5 inches of 
  rain have fallen. The expected rainfall rate is 1 to 3 inches in 1 
  hour. 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, Morristown, Somerville, Somerset, 
  Edison, East Brunswick, Bridgewater, Carteret, Dover, Madison and 
  Middlesex.

This includes the following highways...
	New Jersey Turnpike between exits 10 and 13.
	Interstate 287 in New Jersey between mile markers 0 and 44.
	Interstate 78 in New Jersey between mile markers 27 and 42.
	Interstate 80 in New Jersey between mile markers 40 and 47.
	Garden State Parkway between mile markers 126 and 134.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4050 7478 4058 7471 4062 7470 4067 7473
      4070 7472 4079 7489 4086 7481 4090 7434
      4072 7440 4067 7446 4066 7445 4066 7442
      4060 7446 4060 7421 4055 7425 4050 7426
      4049 7427 4049 7429 4041 7474 4051 7480

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...1-3 INCHES IN 1 HOUR

$$

Kruzdlo
2 follow-up statements
101 
WGUS71 KPHI 181728
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
128 PM EDT Sat Jul 18 2026

NJC023-027-035-182045-
/O.CON.KPHI.FF.W.0047.000000T0000Z-260718T2045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Middlesex NJ-Morris NJ-Somerset NJ-
128 PM EDT Sat Jul 18 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 445 PM EDT THIS 
AFTERNOON FOR NORTHEASTERN MIDDLESEX, SOUTHERN MORRIS AND SOMERSET 
COUNTIES...

At 128 PM EDT, the New Jersey Department of Transportation reported 
all lanes were closed, in both directions, on I-287 in the 
Bridgewater area.

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, Morristown, Somerville, Somerset, 
  Edison, East Brunswick, Bridgewater, Carteret, Dover, Madison and 
  Middlesex.

This includes the following highways...
	New Jersey Turnpike between exits 10 and 13.
	Interstate 287 in New Jersey between mile markers 0 and 44.
	Interstate 78 in New Jersey between mile markers 28 and 42.
	Interstate 80 in New Jersey between mile markers 40 and 47.
	Garden State Parkway between mile markers 126 and 134.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4050 7478 4058 7471 4062 7470 4067 7473
      4070 7472 4079 7489 4086 7481 4090 7434
      4072 7440 4067 7446 4066 7445 4066 7442
      4060 7446 4060 7421 4055 7425 4050 7426
      4049 7427 4049 7429 4041 7474 4051 7480

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...1-3 INCHES IN 1 HOUR

$$

Kruzdlo
718 
WGUS71 KPHI 181934
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
334 PM EDT Sat Jul 18 2026

NJC023-027-035-181944-
/O.CAN.KPHI.FF.W.0047.000000T0000Z-260718T2045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Middlesex NJ-Morris NJ-Somerset NJ-
334 PM EDT Sat Jul 18 2026

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHEASTERN MIDDLESEX, 
SOUTHERN MORRIS AND 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 200 AM EDT Sunday for portions 
of northern Delaware, New Jersey, and Pennsylvania.

&&

LAT...LON 4050 7478 4058 7471 4062 7470 4067 7473
      4070 7472 4079 7489 4086 7481 4090 7434
      4072 7440 4067 7446 4066 7445 4066 7442
      4060 7446 4060 7421 4055 7425 4050 7426
      4049 7427 4049 7429 4041 7474 4051 7480

$$

Kruzdlo

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 18, 10:39 AM EDTSevere Thunderstorm WarningPHISussex, Warren21 min
Jul 18, 1:52 PM EDTFlash Flood WarningPHIMercer, Middlesex, Somerset4 hr
Jul 18, 2:36 PM EDTFlash Flood WarningPHIHunterdon, Mercer, Middlesex, Monmouth4 hr
Jul 18, 3:13 PM EDTSevere Thunderstorm WarningPHIBurlington, Mercer, Middlesex, Monmouth, Ocean47 min
Jul 18, 3:14 PM EDTFlash Flood Warning Considerable damage threatPHIMercer4 hr
Jul 18, 3:16 PM EDTSpecial Marine WarningPHI59 min
Jul 18, 3:30 PM EDTSevere Thunderstorm WarningPHIBurlington, Camden45 min
Jul 18, 3:31 PM EDTSevere Thunderstorm WarningPHIBurlington, Monmouth, Ocean44 min
Jul 18, 3:36 PM EDTSevere Thunderstorm WarningPHIBurlington, Camden, Gloucester39 min
Jul 18, 3:44 PM EDTFlash Flood WarningPHIMiddlesex, Monmouth, Ocean4 hr
Jul 18, 4:02 PM EDTSpecial Marine WarningPHI118 min
Jul 18, 4:03 PM EDTSevere Thunderstorm WarningPHIBurlington, Ocean42 min
Jul 18, 4:34 PM EDTFlash Flood WarningPHIOcean4 hr
Jul 18, 4:46 PM EDTFlash Flood WarningPHIOcean4 hr
Jul 18, 5:14 PM EDTSevere Thunderstorm WarningPHICumberland, Salem61 min
Jul 18, 5:16 PM EDTSpecial Marine WarningPHI89 min
Jul 18, 5:47 PM EDTSpecial Marine WarningPHI118 min
Jul 18, 5:49 PM EDTSevere Thunderstorm WarningPHIMonmouth, Ocean41 min
Jul 18, 6:30 PM EDTSpecial Marine WarningPHI2 hr
Jul 18, 6:30 PM EDTSevere Thunderstorm WarningPHIMercer, Middlesex, Monmouth, Somerset45 min
Jul 18, 6:55 PM EDTAreal Flood WarningPHIMonmouth4 hr
Jul 18, 6:56 PM EDTSpecial Marine WarningPHI64 min
Jul 18, 7:13 PM EDTSevere Thunderstorm WarningPHICape May32 min
Jul 18, 7:47 PM EDTAreal Flood WarningPHIMonmouth, Ocean4 hr

Nearby

Flash Flood Warnings in New Jersey, 2026Every flash flood warning in 2026

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.