Alert archive / New Jersey / Flash Flood Warnings in 2026

Flash Flood Warning 155, NWS Philadelphia/Mount Holly

September 13, 2026Morris County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Sep 13, 2026, 5:54 AM EDT for Morris County, New Jersey. It was in force for 6 hr. 17 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
Sep 13, 2026, 5:54 AM EDT (09:54 UTC)
Expired
Sep 13, 2026, 12:00 PM EDT
In force
6 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

County Morris County, NJ

The radar

The Philadelphia radar (KDIX), 101 km from the middle of the area, began a volume at 09:53 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
Sep 13, 6:30 AM EDTFLASH FLOODEast Hanover, NJWater rescue in East Hanover Township due to a vehicle stuck in flood waters. Time estimated.
Sep 13, 7:18 AM EDTRAIN 2.111 Sw Mountain Lakes, NJMesonet station DW1105 Denville.
Sep 13, 7:45 AM EDTRAIN 2.61 Nw Florham Park, NJMesonet station MSTN4 1.4 NW Florham Park.
Sep 13, 8:00 AM EDTFLASH FLOODMorris Twp, NJRoads flooded in Morris Township with some impassable. Time estimated.
Sep 13, 8:00 AM EDTRAIN 2.442 Wnw Morris Plains, NJMesonet station MSPN4 2.2 SW Denville.
Sep 13, 8:05 AM EDTRAIN 2.421 Sw Towaco, NJMesonet station FW2458 Montville.
Sep 13, 8:07 AM EDTRAIN 2.32Whippany, NJMesonet station FW7566 Whippany.
Sep 13, 8:09 AM EDTRAIN 2.08Boonton Twp, NJMesonet station AV873 Boonton.
Sep 13, 11:45 AM EDTRAIN 3.62 Wnw Morris Plains, NJMesonet station MSPN4 2.2 SW Denville.
Sep 13, 11:45 AM EDTRAIN 4.321 Nw Florham Park, NJMesonet station MSTN4 1.4 NW Florham Park.
Sep 13, 12:00 PM EDTRAIN 2.361 Se Boonton, NJCO-OP Observer station BOON4 0.9 SE Boonton.
Sep 13, 12:00 PM EDTRAIN 4.04Lincoln Park, NJMesonet station LNPN4 Lincoln Park.
Sep 13, 12:05 PM EDTRAIN 2.551 Ese Ironia, NJMesonet station EW6513 Randolph.
Sep 13, 12:06 PM EDTRAIN 2.95Boonton Twp, NJMesonet station AV873 Boonton.
Sep 13, 12:09 PM EDTRAIN 3.96Whippany, NJMesonet station FW7566 Whippany.
Sep 13, 12:09 PM EDTRAIN 4.281 Sw Towaco, NJMesonet station FW2458 Montville.
Sep 13, 12:10 PM EDTRAIN 2.51Morris Plains, NJMesonet station FW7545 Morris Plains.

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, 9.9 hours before the alert went out and 128 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 00:00Z on 2026-09-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 00:00Z on 2026-09-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 51 square meters per square second.1939Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1254 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
51 m²/s²
0-3 km storm-relative helicity
89 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

932 
WGUS51 KPHI 130954
FFWPHI
NJC027-131400-
/O.NEW.KPHI.FF.W.0155.260913T0954Z-260913T1400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
554 AM EDT Sun Sep 13 2026

The National Weather Service in Mount Holly has issued a

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

* Until 1000 AM EDT.

* At 554 AM EDT, Doppler radar and automated rain gauges indicated
  thunderstorms producing heavy rain across the warned area. Between
  1 and 1.5 inches of rain have fallen. The expected rainfall rate is
  1 to 2 inches in 1 hour. Additional rainfall amounts of 0.5 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 and automated gauges.

  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, Chatham, Boonton, Butler, Rockaway and Morris Plains.

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 4076 7466 4088 7455 4101 7438 4100 7430
      4098 7430 4097 7428 4093 7429 4091 7427
      4090 7427 4091 7433 4087 7434 4086 7432
      4085 7433 4082 7433 4080 7436 4076 7438
      4076 7436 4072 7439 4071 7442 4075 7448

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

$$
3 follow-up statements
787 
WGUS71 KPHI 131108
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
708 AM EDT Sun Sep 13 2026

NJC027-131400-
/O.CON.KPHI.FF.W.0155.000000T0000Z-260913T1400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Morris NJ-
708 AM EDT Sun Sep 13 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 10 AM EDT THIS MORNING
FOR SOUTHEASTERN MORRIS COUNTY...

At 708 AM EDT, Doppler radar and automated rain gauges indicated that
heavy rain was falling across the warned area. Between 2 and 2.5
inches of rain have fallen. The expected rainfall rate is 1 to 2
inches in 1 hour. Additional rainfall amounts of 0.5 to 1 inch are
possible in the warned area. Flash flooding is ongoing or expected to
begin shortly.

HAZARD...Flash flooding caused by heavy rain.

SOURCE...Radar and automated gauges.

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, Chatham, Boonton, Butler, Rockaway and Morris Plains.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4076 7466 4088 7455 4101 7438 4100 7430
      4098 7430 4097 7428 4093 7429 4091 7427
      4090 7427 4091 7433 4087 7434 4086 7432
      4085 7433 4082 7433 4080 7436 4076 7438
      4076 7436 4072 7439 4071 7442 4075 7448

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

$$
584 
WGUS51 KPHI 131331
FFWPHI
NJC027-131600-
/O.EXT.KPHI.FF.W.0155.000000T0000Z-260913T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
931 AM EDT Sun Sep 13 2026

The National Weather Service in Mount Holly has extended the

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

* Until noon EDT.

* At 931 AM EDT, Doppler radar and automated rain gauges indicated
  heavy rain falling across the warned area. Between 2 and 3 inches
  of rain have fallen across much of the warned area. The expected
  rainfall rate is 1 to 3 inches in 1 hour. Additional rainfall
  amounts of 0.5 to 1 inch are possible in the warned area. Flash
  flooding is ongoing or expected to begin shortly.

  HAZARD...Flash flooding caused by heavy rain.

  SOURCE...Radar and automated gauges.

  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, Chatham, Boonton, Butler, Rockaway and Morris Plains.

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.

&&

LAT...LON 4076 7466 4088 7455 4101 7438 4100 7430
      4098 7430 4097 7428 4093 7429 4091 7427
      4090 7427 4091 7433 4087 7434 4086 7432
      4085 7433 4082 7433 4080 7436 4076 7438
      4076 7436 4072 7439 4071 7442 4075 7448

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

$$

Gorse
911 
WGUS71 KPHI 131552
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1152 AM EDT Sun Sep 13 2026

NJC027-131602-
/O.EXP.KPHI.FF.W.0155.000000T0000Z-260913T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Morris NJ-
1152 AM EDT Sun Sep 13 2026

...FLASH FLOOD WARNING WILL EXPIRE AT NOON EDT TODAY FOR SOUTHEASTERN
MORRIS COUNTY...

Flood waters are receding, and the heaviest rain has ended. Flooding
is no longer expected to pose a threat. Please continue to heed any
remaining road closures.

&&

LAT...LON 4076 7466 4088 7455 4101 7438 4100 7430
      4098 7430 4097 7428 4093 7429 4091 7427
      4090 7427 4091 7433 4087 7434 4086 7432
      4085 7433 4082 7433 4080 7436 4076 7438
      4076 7436 4072 7439 4071 7442 4075 7448

$$

Gorse

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 13, 4:37 AM EDTSpecial Marine WarningPHI53 min
Sep 13, 8:06 AM EDTFlash Flood WarningPHIMercer, Middlesex4 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.