Alert archive / New Jersey / Flash Flood Warnings in 2026

Flash Flood Warning 120, NWS Philadelphia/Mount Holly

August 17, 2026New Castle County, Delaware; Cumberland County, Salem County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 17, 2026, 4:43 AM EDT for New Castle County, Delaware; Cumberland County, Salem 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
Aug 17, 2026, 4:43 AM EDT (08:43 UTC)
Expired
Aug 17, 2026, 6:49 AM EDT
In force
2 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties New Castle County, DE, Cumberland County, NJ, Salem County, NJ

The radar

The Dover AFB radar (KDOX), 69 km from the middle of the area, began a volume at 08:47 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 00:00Z, 8.7 hours before the alert went out and 272 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 2026-08-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 28 joules per kilogram.LCLEL10008507005003002001001 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 2026-08-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 38 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
28 J/kg
Mixed-layer CIN
-2 J/kg
Mixed-layer LCL
851 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
38 m²/s²
0-3 km storm-relative helicity
63 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

777 
WGUS51 KPHI 170843
FFWPHI
DEC003-NJC011-033-171245-
/O.NEW.KPHI.FF.W.0120.260817T0843Z-260817T1245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
443 AM EDT Mon Aug 17 2026

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Southwestern New Castle County in northern Delaware...
  Central Cumberland County in southern New Jersey...
  Salem County in southern New Jersey...

* Until 845 AM EDT.

* At 443 AM EDT, Doppler radar indicated 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 heavy rain.

  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...
  Vineland, Millville, Bridgeton, Middletown, Cumberland, 
  Pennsville, Salem, Laurel Lake, Woodstown, Alloway, Quinton and 
  Delaware City.

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.

Be aware of your surroundings and do not drive on flooded roads.

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 3961 7576 3968 7526 3962 7515 3931 7489
      3933 7552 3935 7549 3937 7551 3935 7555
      3933 7557 3933 7575

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

$$

MPS
1 follow-up statement
316 
WGUS71 KPHI 171049
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
649 AM EDT Mon Aug 17 2026

DEC003-NJC011-033-171059-
/O.CAN.KPHI.FF.W.0120.000000T0000Z-260817T1245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Cumberland NJ-Salem NJ-
649 AM EDT Mon Aug 17 2026

...FLASH FLOOD WARNING IS CANCELLED FOR SOUTHWESTERN NEW CASTLE, 
CENTRAL CUMBERLAND AND SALEM COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat.

&&

LAT...LON 3961 7576 3968 7526 3962 7515 3931 7489
      3933 7552 3935 7549 3937 7551 3935 7555
      3933 7557 3933 7575

$$

Kruzdlo

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 17, 6:45 PM EDTSevere Thunderstorm WarningPHINew Castle32 min
Aug 17, 7:04 PM EDTSevere Thunderstorm WarningPHIKent20 min
Aug 16, 11:38 PM EDTFlash Flood WarningPHIBurlington, Camden, Gloucester4 hr
Aug 17, 6:09 PM EDTSpecial Marine WarningPHI81 min

Nearby

Flash Flood Warnings in New Jersey, 2026Flash Flood Warnings in Delaware, 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.