Alert archive / New Jersey / Flash Flood Warnings in 2026

Flash Flood Warning 56, NWS Philadelphia/Mount Holly

July 21, 2026Sussex County, Warren County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 21, 2026, 8:49 AM EDT for Sussex County, Warren County, New Jersey. It was in force for 2 hr. 1 report 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 21, 2026, 8:49 AM EDT (12:49 UTC)
Expired
Jul 21, 2026, 11:18 AM EDT
In force
2 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Sussex County, NJ, Warren County, NJ

The radar

The Philadelphia radar (KDIX), 119 km from the middle of the area, began a volume at 12:50 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 21, 9:30 AM EDTRAIN 3.021 Sw Sparta, NJ3.02 inches of rainfall fell from 800am through 930am.

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, 0.8 hours before the alert went out and 178 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 2026-07-21Temperature 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°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 12:00Z on 2026-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 135 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1211 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
135 m²/s²
0-3 km storm-relative helicity
172 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

As transmitted.

244 
WGUS51 KPHI 211249
FFWPHI
NJC037-041-211700-
/O.NEW.KPHI.FF.W.0056.260721T1249Z-260721T1700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
849 AM EDT Tue Jul 21 2026

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Southwestern Sussex County in northwestern New Jersey...
  Northern Warren County in northwestern New Jersey...

* Until 100 PM EDT.

* At 849 AM 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 2.5 inches in 
  1 hour. Additional rainfall amounts of 0.5 to 1.5 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...
  Newton, Blairstown, Franklin, Ogdensburg, Hope, Andover, 
  Greendell, Allamuchy-Panther Valley, Great Meadows-Vienna, Lake 
  Mohawk, Columbia and Portland.

This includes Interstate 80 in New Jersey between mile markers 3 and 
18.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4086 7505 4087 7505 4089 7507 4091 7508
      4092 7510 4095 7511 4114 7468 4107 7453
      4083 7503

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

$$

Kruzdlo
1 follow-up statement
021 
WGUS71 KPHI 211518
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1118 AM EDT Tue Jul 21 2026

NJC037-041-211528-
/O.CAN.KPHI.FF.W.0056.000000T0000Z-260721T1700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sussex NJ-Warren NJ-
1118 AM EDT Tue Jul 21 2026

...FLASH FLOOD WARNING IS CANCELLED FOR SOUTHWESTERN SUSSEX AND 
NORTHERN WARREN COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. But additional showers and thunderstorms are expected this 
afternoon and evening.

&&

LAT...LON 4086 7505 4087 7505 4089 7507 4091 7508
      4092 7510 4095 7511 4114 7468 4107 7453
      4083 7503

$$

Kruzdlo

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 21, 11:01 AM EDTSpecial Marine WarningPHI59 min
Jul 21, 11:14 AM EDTSpecial Marine WarningPHI46 min
Jul 21, 12:07 PM EDTSpecial Marine WarningPHI53 min
Jul 21, 1:52 PM EDTSevere Thunderstorm WarningPHIMorris, Sussex, Warren53 min
Jul 21, 2:00 PM EDTTornado WarningPHIMorris30 min
Jul 21, 2:25 PM EDTTornado WarningPHIMorris50 min
Jul 21, 2:49 PM EDTFlash Flood WarningPHIMorris3 hr
Jul 21, 2:57 PM EDTSevere Thunderstorm WarningPHIHunterdon37 min
Jul 21, 2:57 PM EDTTornado WarningPHIMorris, Somerset48 min
Jul 21, 3:13 PM EDTFlash Flood WarningPHIMorris, Somerset3 hr
Jul 21, 4:06 PM EDTSpecial Marine WarningPHI54 min
Jul 21, 4:38 PM EDTFlash Flood Warning Considerable damage threatPHIBurlington, Camden, Gloucester, Salem4 hr
Jul 21, 4:43 PM EDTSevere Thunderstorm WarningPHIGloucester, Salem47 min
Jul 21, 4:46 PM EDTSpecial Marine WarningPHI89 min
Jul 21, 4:50 PM EDTSevere Thunderstorm WarningPHIMercer, Middlesex, Monmouth, Somerset55 min
Jul 21, 5:14 PM EDTSevere Thunderstorm WarningPHIBurlington, Camden46 min
Jul 21, 5:30 PM EDTSpecial Marine WarningPHI2 hr
Jul 21, 5:30 PM EDTSevere Thunderstorm WarningPHIAtlantic, Burlington, Camden, Gloucester, Salem45 min
Jul 21, 5:43 PM EDTSpecial Marine WarningPHI2 hr
Jul 21, 5:49 PM EDTTornado WarningPHICape May26 min
Jul 21, 6:06 PM EDTSevere Thunderstorm WarningPHIBurlington, Ocean39 min
Jul 21, 6:07 PM EDTSpecial Marine WarningPHI53 min
Jul 21, 6:09 PM EDTTornado WarningPHICape May36 min
Jul 21, 6:18 PM EDTSpecial Marine WarningPHI57 min
Jul 21, 6:34 PM EDTSevere Thunderstorm WarningPHIAtlantic, Burlington, Ocean41 min
Jul 21, 6:41 PM EDTSpecial Marine WarningPHI94 min
Jul 21, 6:50 PM EDTSpecial Marine WarningPHI85 min
Jul 21, 7:06 PM EDTTornado WarningPHIOcean12 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.