Alert archive / New Jersey / Flash Flood Warnings in 2026

Flash Flood Warning 101, NWS Philadelphia/Mount Holly

August 5, 2026Hunterdon County, Warren County, New Jersey; Bucks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 5, 2026, 3:33 PM EDT for Hunterdon County, Warren County, New Jersey; Bucks County, Pennsylvania. It was in force for 86 min. 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 5, 2026, 3:33 PM EDT (19:33 UTC)
Expired
Aug 5, 2026, 4:59 PM EDT
In force
86 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Hunterdon County, NJ, Warren County, NJ, Bucks County, PA

The radar

The Philadelphia radar (KDIX), 93 km from the middle of the area, began a volume at 19:33 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, 7.6 hours before the alert went out and 187 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 2026-08-05Temperature 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 12:00Z on 2026-08-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -20 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
1372 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
-20 m²/s²
0-3 km storm-relative helicity
-42 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

859 
WGUS51 KPHI 051933
FFWPHI
NJC019-041-PAC017-052330-
/O.NEW.KPHI.FF.W.0101.260805T1933Z-260805T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
333 PM EDT Wed Aug 5 2026

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Hunterdon County in northwestern New Jersey...
  Southwestern Warren County in northwestern New Jersey...
  North Central Bucks County in southeastern Pennsylvania...

* Until 730 PM EDT.

* At 333 PM EDT, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain just beginning to move into the 
  warned area. These storms have a history of producing 1 to 2 
  inches of rainfall within an hour and causing flash flooding. 
  Flash flooding is ongoing or expected to begin shortly.

  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.

* Some locations that may experience flash flooding include...
  Easton, Flemington, High Bridge, Clinton, Alpha, Glen Gardner, 
  Ferndale, Hampton, Frenchtown, Lebanon, Milford and Califon.

This includes Interstate 78 in New Jersey between mile markers 0 and 
23.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Move to higher ground now. Act quickly to protect your life.

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

&&

LAT...LON 4063 7519 4065 7520 4067 7518 4068 7520
      4071 7520 4073 7518 4074 7519 4074 7479
      4051 7477 4050 7478 4051 7480 4048 7478
      4047 7520 4062 7520

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

Fitzsimmons
1 follow-up statement
069 
WGUS71 KPHI 052059
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
459 PM EDT Wed Aug 5 2026

NJC019-041-PAC017-052109-
/O.CAN.KPHI.FF.W.0101.000000T0000Z-260805T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hunterdon NJ-Warren NJ-Bucks PA-
459 PM EDT Wed Aug 5 2026

...FLASH FLOOD WARNING IS CANCELLED FOR HUNTERDON, SOUTHWESTERN 
WARREN AND NORTH CENTRAL BUCKS COUNTIES...

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

&&

LAT...LON 4063 7519 4065 7520 4067 7518 4068 7520
      4071 7520 4073 7518 4074 7519 4074 7479
      4051 7477 4050 7478 4051 7480 4048 7478
      4047 7520 4062 7520

$$

Fitzsimmons

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 5, 12:58 PM EDTFlash Flood WarningPHIBurlington, Camden, Gloucester6 hr
Aug 5, 1:13 PM EDTFlash Flood WarningPHIGloucester5 hr
Aug 5, 1:23 PM EDTFlash Flood WarningPHIBurlington, Mercer4 hr
Aug 5, 1:50 PM EDTHeat AdvisoryPHIBurlington, Camden, Gloucester, Hunterdon, Mercer, Middlesex and 6 more3 days
Aug 5, 2:50 PM EDTFlash Flood Warning Considerable damage threatPHIHunterdon, Mercer4 hr
Aug 5, 5:29 PM EDTFlash Flood WarningPHIMiddlesex3 hr
Aug 5, 2:17 PM EDTFlash Flood WarningPHIBucks, Montgomery4 hr

Nearby

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