Alert archive / New Jersey / Flash Flood Warnings in 2026

Flash Flood Warning 83, NWS Philadelphia/Mount Holly

July 28, 2026Morris County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 28, 2026, 10:39 PM EDT for Morris County, New Jersey. It was in force for 4 hr. 2 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 28, 2026, 10:39 PM EDT (02:39 UTC)
Expired: Jul 29, 2026, 2:45 AM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County Morris County, NJ

The radar

The Philadelphia radar (KDIX), 111 km from the middle of the area, began a volume at 02:43 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

Time	Report	Where	Remark
Jul 28, 11:15 PM EDT	FLASH FLOOD	1 S Parsippany-Troy Hil, NJ	Reports of water rescues and cars stranded in Parsippany and Troy Hills. Time estimated.
Jul 28, 11:30 PM EDT	FLASH FLOOD	1 Ese Boonton Twp, NJ	Reports of water rescues and cars stranded in Boonton. 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 00:00Z, 2.7 hours before the alert went out and 125 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: 325 J/kg
Mixed-layer CIN: -8 J/kg
Mixed-layer LCL: 775 m above ground
0-6 km bulk shear: 17 kt
0-1 km storm-relative helicity: 99 m²/s²
0-3 km storm-relative helicity: 105 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

856 
WGUS51 KPHI 290239
FFWPHI
NJC027-290645-
/O.NEW.KPHI.FF.W.0083.260729T0239Z-260729T0645Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1039 PM EDT Tue Jul 28 2026

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Eastern Morris County in northern New Jersey...

* Until 245 AM EDT.

* At 1039 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have fallen. The expected rainfall rate is 1.5 to 2.5 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...
  Morristown, Dover, Madison, Lincoln Park, Kinnelon, Boonton, 
  Butler, Rockaway, Morris Plains, Mountain Lakes, Riverdale and 
  Victory Gardens.

This includes the following highways...
	Interstate 287 in New Jersey between mile markers 35 and 53.
	Interstate 80 in New Jersey between mile markers 37 and 48.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 4101 7439 4101 7436 4100 7435 4101 7434
      4100 7431 4100 7430 4099 7429 4098 7430
      4097 7428 4094 7428 4093 7429 4092 7428
      4091 7430 4091 7433 4088 7434 4087 7434
      4087 7433 4074 7443 4083 7459 4103 7442

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...1.5-2.5 INCHES IN 1 HOUR

$$

AKL

2 follow-up statements

638 
WGUS71 KPHI 290402
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1202 AM EDT Wed Jul 29 2026

NJC027-290645-
/O.CON.KPHI.FF.W.0083.000000T0000Z-260729T0645Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Morris NJ-
1202 AM EDT Wed Jul 29 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 245 AM EDT EARLY THIS 
MORNING FOR EASTERN MORRIS COUNTY...

At 1202 AM EDT, Doppler radar and automated rain gauges indicated 
thunderstorms producing heavy rain with the Whippany River at 
Morristown going into flood stage. Between 2 and 3 inches of rain 
have fallen. The expected rainfall rate is 0.5 inches in 1 hour. 
Additional rainfall amounts up to 0.5 inches are possible in the 
warned area. Flash flooding is already occurring.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar and automated gauges.

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

For Whippany River at Morristown:
At 11:40pm the stage was 6.09 feet.
Flood Stage is 6 feet.

This includes the following highways...
	Interstate 287 in New Jersey between mile markers 35 and 53.
	Interstate 80 in New Jersey between mile markers 37 and 48.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 4101 7439 4101 7436 4100 7435 4101 7434
      4100 7431 4100 7430 4099 7429 4098 7430
      4097 7428 4094 7428 4093 7429 4092 7428
      4091 7430 4091 7433 4088 7434 4087 7434
      4087 7433 4074 7443 4083 7459 4103 7442

FLASH FLOOD...RADAR AND GAUGE INDICATED
EXPECTED RAINFALL RATE...0.5 INCHES IN 1 HOUR

$$

Hoeflich

166 
WGUS71 KPHI 290636
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
236 AM EDT Wed Jul 29 2026

NJC027-290646-
/O.EXP.KPHI.FF.W.0083.000000T0000Z-260729T0645Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Morris NJ-
236 AM EDT Wed Jul 29 2026

...FLASH FLOOD WARNING WILL EXPIRE AT 245 AM EDT EARLY THIS MORNING 
FOR EASTERN MORRIS COUNTY...

Flood waters have receded. 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 800 PM EDT Wednesday for a 
portion of northern New Jersey.

&&

LAT...LON 4101 7439 4101 7436 4100 7435 4101 7434
      4100 7431 4100 7430 4099 7429 4098 7430
      4097 7428 4094 7428 4093 7429 4092 7428
      4091 7430 4091 7433 4088 7434 4087 7434
      4087 7433 4074 7443 4083 7459 4103 7442

$$

Hoeflich

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 28, 8:10 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon	39 min
Jul 28, 11:36 PM EDT	Areal Flood Warning	PHI	Hunterdon, Warren	4 hr
Jul 28, 11:59 PM EDT	Flash Flood Warning	PHI	Monmouth, Ocean	4 hr
Jul 29, 12:56 AM EDT	Flash Flood Warning	PHI	Ocean	3 hr

Nearby

Flash Flood Warnings in New Jersey, 2026 Every 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.