Alert archive / New Jersey / Flash Flood Warnings in 2026

Flash Flood Warning 73, NWS Philadelphia/Mount Holly

July 28, 2026Hunterdon County, Mercer County, Somerset County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 28, 2026, 2:11 PM EDT for Hunterdon County, Mercer County, Somerset County, New Jersey. It was in force for 4 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
Jul 28, 2026, 2:11 PM EDT (18:11 UTC)
Expired
Jul 28, 2026, 6:01 PM EDT
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Hunterdon County, NJ, Mercer County, NJ, Somerset County, NJ

The radar

The Philadelphia radar (KDIX), 64 km from the middle of the area, began a volume at 18:11 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, 6.2 hours before the alert went out and 164 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 2026-07-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1266 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 2026-07-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 41 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
1266 J/kg
Mixed-layer CIN
-16 J/kg
Mixed-layer LCL
637 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
41 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.

808 
WGUS51 KPHI 281811
FFWPHI
NJC019-021-035-282215-
/O.NEW.KPHI.FF.W.0073.260728T1811Z-260728T2215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
211 PM EDT Tue Jul 28 2026

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Northern Mercer County in central New Jersey...
  Southwestern Somerset County in northern New Jersey...
  Southeastern Hunterdon County in northwestern New Jersey...

* Until 615 PM EDT.

* At 211 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across portions of the warned area. Between 0.5 and 1.5 
  inches of rain have fallen. The expected rainfall rate is 1.5 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...
  Flemington, Hopewell, Cloverhill, Skillman and Flagtown.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4052 7468 4040 7466 4038 7479 4051 7486

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...1.5-2.5 INCHES IN 1 HOUR

$$

Kruzdlo
1 follow-up statement
034 
WGUS71 KPHI 282201
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
601 PM EDT Tue Jul 28 2026

NJC019-021-035-282211-
/O.CAN.KPHI.FF.W.0073.000000T0000Z-260728T2215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hunterdon NJ-Mercer NJ-Somerset NJ-
601 PM EDT Tue Jul 28 2026

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHERN MERCER, 
SOUTHWESTERN SOMERSET AND SOUTHEASTERN HUNTERDON COUNTIES...

Flood waters have receded. Please continue to heed remaining road 
closures.

A Flood Watch remains in effect until 800 PM EDT Wednesday for 
portions of New Jersey and Pennsylvania as additional rainfall is 
expected.

A Flood Watch remains in effect until 200 PM EDT Wednesday for 
portions of northern Delaware, New Jersey, and Pennsylvania.

&&

LAT...LON 4052 7468 4040 7466 4038 7479 4051 7486

$$

AKL

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 28, 1:22 PM EDTSevere Thunderstorm WarningPHIWarren38 min
Jul 28, 1:31 PM EDTSevere Thunderstorm WarningPHIHunterdon, Mercer, Middlesex, Morris, Somerset, Warren44 min
Jul 28, 1:49 PM EDTTornado WarningPHISussex, Warren26 min
Jul 28, 2:04 PM EDTFlash Flood WarningPHIWarren10 hr
Jul 28, 2:15 PM EDTSevere Thunderstorm WarningPHIHunterdon, Morris, Sussex, Warren45 min
Jul 28, 2:45 PM EDTFlash Flood WarningPHIHunterdon, Morris, Warren9 hr
Jul 28, 2:56 PM EDTSevere Thunderstorm WarningPHIHunterdon, Morris, Somerset, Sussex49 min
Jul 28, 3:04 PM EDTSevere Thunderstorm WarningPHIMiddlesex, Monmouth41 min
Jul 28, 3:43 PM EDTSevere Thunderstorm WarningPHIHunterdon, Morris, Sussex, Warren23 min
Jul 28, 4:02 PM EDTFlash Flood WarningPHIMiddlesex2 hr
Jul 28, 5:22 PM EDTSevere Thunderstorm WarningPHIHunterdon34 min
Jul 28, 5:47 PM EDTSevere Thunderstorm WarningPHIHunterdon, Warren43 min
Jul 28, 6:10 PM EDTSpecial Marine WarningPHI2 hr
Jul 28, 6:16 PM EDTSevere Thunderstorm WarningPHIHunterdon, Morris, Somerset25 min
Jul 28, 6:17 PM EDTFlash Flood WarningPHIHunterdon, Warren6 hr
Jul 28, 6:23 PM EDTSevere Thunderstorm WarningPHIGloucester, Salem67 min
Jul 28, 6:46 PM EDTTornado WarningPHIGloucester, Salem29 min
Jul 28, 6:55 PM EDTSevere Thunderstorm WarningPHICumberland, Gloucester, Salem50 min
Jul 28, 7:06 PM EDTSevere Thunderstorm WarningPHIBurlington, Camden, Cumberland, Gloucester, Salem54 min
Jul 28, 7:11 PM EDTFlash Flood WarningPHICamden, Gloucester, Salem3 hr
Jul 28, 7:23 PM EDTSpecial Marine WarningPHI2 hr
Jul 28, 7:37 PM EDTSevere Thunderstorm WarningPHIAtlantic, Cape May, Cumberland, Salem23 min
Jul 28, 7:55 PM EDTFlash Flood WarningPHIHunterdon4 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.