Alert archive / New Jersey / Flash Flood Warnings in 2026

Flash Flood Warning 74, NWS Philadelphia/Mount Holly

July 28, 2026Hunterdon County, Morris County, Warren County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 28, 2026, 2:45 PM EDT for Hunterdon County, Morris County, Warren County, New Jersey. It was in force for 9 hr. 3 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: Jul 28, 2026, 2:45 PM EDT (18:45 UTC)
Expired: Jul 28, 2026, 11:45 PM EDT
In force: 9 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Hunterdon County, NJ, Morris County, NJ, Warren County, NJ

The radar

The Philadelphia radar (KDIX), 97 km from the middle of the area, began a volume at 18:48 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

Time	Report	Where	Remark
Jul 28, 5:45 PM EDT	RAIN 4.5	Washington, NJ
Jul 28, 8:30 PM EDT	FLASH FLOOD	2 Wnw Schooleys Mountai, NJ	NJ DOT - STMC: Flooding on NJ 57 Both Directions West of Stephensburg Rd (Mansfield Twp), All lanes closed eastbound; All lanes closed westbound. Time given in report.
Jul 28, 11:19 PM EDT	RAIN 6	Washington, NJ

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, 6.8 hours before the alert went out and 171 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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.

680 
WGUS51 KPHI 281845
FFWPHI
NJC019-027-041-282245-
/O.NEW.KPHI.FF.W.0074.260728T1845Z-260728T2245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  West Central Morris County in northern New Jersey...
  Northeastern Hunterdon County in northwestern New Jersey...
  Southeastern Warren County in northwestern New Jersey...

* Until 645 PM EDT.

* At 245 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...
  Hackettstown, Washington, High Bridge, Clinton, Oxford, Glen 
  Gardner, Hampton, Lebanon, Califon, Annandale, Pleasant Valley and 
  Brass Castle.

This includes Interstate 78 in New Jersey between mile markers 11 
and 24.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4088 7491 4081 7480 4061 7475 4051 7493
      4071 7506

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

$$

Kruzdlo

5 follow-up statements

573 
WGUS71 KPHI 281917
FFSPHI

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

NJC019-027-041-282245-
/O.CON.KPHI.FF.W.0074.000000T0000Z-260728T2245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hunterdon NJ-Morris NJ-Warren NJ-
317 PM EDT Tue Jul 28 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 645 PM EDT THIS 
EVENING FOR WEST CENTRAL MORRIS, NORTHEASTERN HUNTERDON AND 
SOUTHEASTERN WARREN COUNTIES...

At 317 PM EDT, storm spotters reported flooding in Washington 
Borough. Flooding was occurring on State Route 57. All lanes were 
being impacted by water. In addition, the right lane was flooded on 
NJ-31.

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...
  Hackettstown, Washington, High Bridge, Clinton, Oxford, Glen 
  Gardner, Hampton, Lebanon, Califon, Annandale, Pleasant Valley and 
  Brass Castle.

This includes Interstate 78 in New Jersey between mile markers 11 
and 24.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4088 7491 4081 7480 4061 7475 4051 7493
      4071 7506

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

$$

Kruzdlo

749 
WGUS51 KPHI 282238
FFWPHI
NJC019-027-041-290015-
/O.EXT.KPHI.FF.W.0074.000000T0000Z-260729T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Mount Holly has extended the

* Flash Flood Warning for...
  West Central Morris County in northern New Jersey...
  Northeastern Hunterdon County in northwestern New Jersey...
  Southeastern Warren County in northwestern New Jersey...

* Until 815 PM EDT.

* At 638 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 3 and 4.5 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...
  Hackettstown, Washington, High Bridge, Clinton, Oxford, Glen 
  Gardner, Hampton, Lebanon, Califon, Annandale, Pleasant Valley and 
  Brass Castle.

This includes Interstate 78 in New Jersey between mile markers 11 
and 24.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4088 7491 4081 7480 4061 7475 4051 7493
      4071 7506

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

$$

AKL

212 
WGUS51 KPHI 290012
FFWPHI
NJC019-027-041-290145-
/O.EXT.KPHI.FF.W.0074.000000T0000Z-260729T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Mount Holly has extended the

* Flash Flood Warning for...
  West Central Morris County in northern New Jersey...
  Northeastern Hunterdon County in northwestern New Jersey...
  Southeastern Warren County in northwestern New Jersey...

* Until 945 PM EDT.

* At 812 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 3 and 4.5 inches of 
  rain have fallen over the last 6 hours. 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...
  Hackettstown, Washington, High Bridge, Clinton, Oxford, Glen 
  Gardner, Hampton, Lebanon, Califon, Annandale, Pleasant Valley and 
  Brass Castle.

This includes Interstate 78 in New Jersey between mile markers 11 
and 24.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4088 7491 4081 7480 4061 7475 4051 7493
      4071 7506

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

$$

AKL

658 
WGUS51 KPHI 290143
FFWPHI
NJC019-027-041-290345-
/O.EXT.KPHI.FF.W.0074.000000T0000Z-260729T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Mount Holly has extended the

* Flash Flood Warning for...
  West Central Morris County in northern New Jersey...
  Northeastern Hunterdon County in northwestern New Jersey...
  Southeastern Warren County in northwestern New Jersey...

* Until 1145 PM EDT.

* At 943 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 3 and 4.5 inches of 
  rain have fallen. 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...
  Hackettstown, Washington, High Bridge, Clinton, Oxford, Glen 
  Gardner, Hampton, Lebanon, Califon, Annandale, Pleasant Valley and 
  Brass Castle.

This includes Interstate 78 in New Jersey between mile markers 11 
and 24.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4088 7491 4081 7480 4061 7475 4051 7493
      4071 7506

FLASH FLOOD...RADAR INDICATED

$$

AKL

554 
WGUS71 KPHI 290338
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1138 PM EDT Tue Jul 28 2026

NJC019-027-041-290348-
/O.EXP.KPHI.FF.W.0074.000000T0000Z-260729T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hunterdon NJ-Morris NJ-Warren NJ-
1138 PM EDT Tue Jul 28 2026

...FLASH FLOOD WARNING WILL EXPIRE AT 1145 PM EDT THIS EVENING FOR 
WEST CENTRAL MORRIS, NORTHEASTERN HUNTERDON AND SOUTHEASTERN WARREN 
COUNTIES...

The heavy rain has ended. Flash flooding is no longer expected to 
pose a widespread threat. Areas of standing water, flooded creeks, 
and flooded streams will continue through the night. A new Flood 
Warning was issued to cover that threat. Refer to that bulletin for 
the updated information. 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.

&&

LAT...LON 4088 7491 4081 7480 4061 7475 4051 7493
      4071 7506

$$

Hoeflich

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 28, 1:22 PM EDT	Severe Thunderstorm Warning	PHI	Warren	38 min
Jul 28, 1:31 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Mercer, Middlesex, Morris, Somerset, Warren	44 min
Jul 28, 1:49 PM EDT	Tornado Warning	PHI	Sussex, Warren	26 min
Jul 28, 2:04 PM EDT	Flash Flood Warning	PHI	Warren	10 hr
Jul 28, 2:11 PM EDT	Flash Flood Warning	PHI	Hunterdon, Mercer, Somerset	4 hr
Jul 28, 2:15 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Morris, Sussex, Warren	45 min
Jul 28, 2:56 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Morris, Somerset, Sussex	49 min
Jul 28, 3:04 PM EDT	Severe Thunderstorm Warning	PHI	Middlesex, Monmouth	41 min
Jul 28, 3:43 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Morris, Sussex, Warren	23 min
Jul 28, 4:02 PM EDT	Flash Flood Warning	PHI	Middlesex	2 hr
Jul 28, 5:22 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon	34 min
Jul 28, 5:47 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Warren	43 min
Jul 28, 6:10 PM EDT	Special Marine Warning	PHI		2 hr
Jul 28, 6:16 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Morris, Somerset	25 min
Jul 28, 6:17 PM EDT	Flash Flood Warning	PHI	Hunterdon, Warren	6 hr
Jul 28, 6:23 PM EDT	Severe Thunderstorm Warning	PHI	Gloucester, Salem	67 min
Jul 28, 6:46 PM EDT	Tornado Warning	PHI	Gloucester, Salem	29 min
Jul 28, 6:55 PM EDT	Severe Thunderstorm Warning	PHI	Cumberland, Gloucester, Salem	50 min
Jul 28, 7:06 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Cumberland, Gloucester, Salem	54 min
Jul 28, 7:11 PM EDT	Flash Flood Warning	PHI	Camden, Gloucester, Salem	3 hr
Jul 28, 7:23 PM EDT	Special Marine Warning	PHI		2 hr
Jul 28, 7:37 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Cape May, Cumberland, Salem	23 min
Jul 28, 7:55 PM EDT	Flash Flood Warning	PHI	Hunterdon	4 hr

Nearby

Flash Flood Warnings in New Jersey, 2026 Every 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.