Alert archive / New Jersey / Flash Flood Warnings in 2026

Flash Flood Warning 149, NWS Philadelphia/Mount Holly

September 1, 2026Morris County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Sep 1, 2026, 7:13 PM EDT for Morris County, New Jersey. It was in force for 2 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Sep 1, 2026, 7:13 PM EDT (23:13 UTC)
Expired
Sep 1, 2026, 9:16 PM EDT
In force
2 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 23:16 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.

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 11.2 hours before the alert went out and 129 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 2026-09-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 17 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 12:00Z on 2026-09-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 127 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
17 J/kg
Mixed-layer CIN
-24 J/kg
Mixed-layer LCL
481 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
127 m²/s²
0-3 km storm-relative helicity
177 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

As transmitted.

181 
WGUS51 KPHI 012313
FFWPHI
NJC027-020315-
/O.NEW.KPHI.FF.W.0149.260901T2313Z-260902T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
713 PM EDT Tue Sep 1 2026

The National Weather Service in Mount Holly has issued a

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

* Until 1115 PM EDT.

* At 713 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 to 2 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 indicated.

  IMPACT...Flash flooding of small creeks and streams, urban areas,
           highways, streets and underpasses as well as other poor
           drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  Morristown, Madison, Florham Park, East Hanover, Lincoln Park,
  Kinnelon, Boonton, Butler, Rockaway, Morris Plains, Mountain Lakes
  and Riverdale.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 4071 7441 4098 7460 4103 7456 4109 7450
      4108 7449 4103 7450 4105 7445 4104 7443
      4102 7443 4100 7430 4098 7430 4097 7428
      4093 7429 4091 7427 4090 7428 4091 7433
      4087 7434 4086 7432 4083 7433

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...1-2 INCHES IN 1 HOUR

$$

MPS
1 follow-up statement
835 
WGUS71 KPHI 020116
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
916 PM EDT Tue Sep 1 2026

NJC027-020126-
/O.CAN.KPHI.FF.W.0149.000000T0000Z-260902T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Morris NJ-
916 PM EDT Tue Sep 1 2026

...FLASH FLOOD WARNING IS CANCELLED FOR EASTERN MORRIS COUNTY...

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

&&

LAT...LON 4071 7441 4098 7460 4103 7456 4109 7450
      4108 7449 4103 7450 4105 7445 4104 7443
      4102 7443 4100 7430 4098 7430 4097 7428
      4093 7429 4091 7427 4090 7428 4091 7433
      4087 7434 4086 7432 4083 7433

$$

MPS

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 1, 2:30 AM EDTHeat AdvisoryPHIBurlington, Camden, Gloucester, Mercer18 hr
Sep 1, 4:47 PM EDTSpecial Marine WarningPHI43 min
Sep 1, 5:45 PM EDTSevere Thunderstorm WarningPHIWarren45 min
Sep 1, 6:52 PM EDTSevere Thunderstorm WarningPHIMiddlesex, Monmouth, Morris, Somerset38 min
Sep 1, 6:56 PM EDTSpecial Marine WarningPHI64 min
Sep 1, 7:02 PM EDTSevere Thunderstorm WarningPHIMonmouth43 min
Sep 1, 7:28 PM EDTSevere Thunderstorm WarningPHIMiddlesex, Monmouth47 min

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.