Alert archive / New Jersey / Flash Flood Warnings in 2024

Flash Flood Warning 30, NWS Philadelphia/Mount Holly

August 6, 2024Mercer County, Middlesex County, Monmouth County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 6, 2024, 4:13 PM EDT for Mercer County, Middlesex County, Monmouth County, New Jersey. It was in force for 8 hr. 12 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
Aug 6, 2024, 4:13 PM EDT (20:13 UTC)
Expired
Aug 7, 2024, 12:25 AM EDT
In force
8 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ

The radar

The Philadelphia radar (KDIX), 42 km from the middle of the area, began a volume at 20:13 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
Aug 6, 4:16 PM EDTFLOOD1 Ne Trenton Mercer Air, NJNJ DOT - TOC South: Flooding on I-295 both directions south of Exit 73 - Scotch Rd (Hopewell Twp) 3 Left lanes of 4 lanes closed. Also visible on traffic camera.
Aug 6, 4:39 PM EDTFLOOD2 Ese Hopewell Twp., NJNJ DOT - TOC South: Flooding on NJ 31 both directions South of CR 546/Washington Crossing Pennington Rd (Hopewell Twp) All lanes closed.
Aug 6, 4:39 PM EDTFLASH FLOOD2 Ese Hopewell Twp., NJNJ DOT - TOC South: Flooding on NJ 31 both directions South of CR 546/Washington Crossing Pennington Rd (Hopewell Twp) All lanes closed.
Aug 6, 4:45 PM EDTFLASH FLOOD1 W Trenton Mercer Airp, NJFlooding on I-295 in both directions ramps to/from Exit 75 - CR 579/Bear Tavern Rd in Ewing Twp.
Aug 6, 6:39 PM EDTFLASH FLOOD1 Ene Ewing, NJShabakunk Creek at Sylva Lake Dam is still rising and beginning to flood buildings.
Aug 6, 7:30 PM EDTFLASH FLOODYorketown, NJCommanck Lane is closed due to flooding.
Aug 6, 9:00 PM EDTRAIN 3Washington Crossing, PAMesonet station WASN4 Washington Crossing.
Aug 6, 9:46 PM EDTRAIN 4.842 Ese Washington Crossi, NJMesonet station GW1897 EWING.
Aug 6, 9:48 PM EDTRAIN 4.14Lawrenceville, NJMesonet station LWRTR Lawrenceville.
Aug 6, 9:49 PM EDTRAIN 3.05Trenton Mercer Airport, NJASOS station KTTN Trenton.
Aug 6, 9:50 PM EDTRAIN 3.391 N Edinburg, NJMesonet station GW1857 PRINCETON JUNCTION.
Aug 6, 9:50 PM EDTRAIN 3.442 Ese Yorketown, NJMesonet station ENGLS Englishtown (LaFayette Mills).

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, 8.2 hours before the alert went out and 155 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 2024-08-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1440 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 2024-08-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 57 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
1440 J/kg
Mixed-layer CIN
-50 J/kg
Mixed-layer LCL
797 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
57 m²/s²
0-3 km storm-relative helicity
99 m²/s²
Significant tornado parameter
0.4
Supercell composite
3.2

Open this sounding in Storm Lab

The text

As transmitted.

137 
WGUS51 KPHI 062013
FFWPHI
NJC021-023-025-070015-
/O.NEW.KPHI.FF.W.0030.240806T2013Z-240807T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
413 PM EDT Tue Aug 6 2024

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Central Mercer County in central New Jersey...
  Central Monmouth County in central New Jersey...
  Southwestern Middlesex County in northern New Jersey...

* Until 815 PM EDT.

* At 413 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.5 and 2.5 inches of 
  rain have fallen with the highest totals occuring near Washington 
  Crossing. 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 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...
  Trenton, Marlboro, Ewing, Holmdel, Princeton, Jamesburg, 
  Hightstown, Cranbury, Pennington, Twin Rivers, Clearbrook Park and 
  Princeton Meadows.

This includes the following highways...
	Interstate 295 in New Jersey between mile markers 64 and 76.
	New Jersey Turnpike between exits 8A and 9.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4037 7449 4036 7415 4028 7414 4027 7437
      4022 7477 4025 7484 4031 7488 4034 7469
      4035 7468

FLASH FLOOD...RADAR INDICATED

$$

Deal
6 follow-up statements
833 
WGUS71 KPHI 062059
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
459 PM EDT Tue Aug 6 2024

NJC021-023-025-070015-
/O.CON.KPHI.FF.W.0030.000000T0000Z-240807T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mercer NJ-Middlesex NJ-Monmouth NJ-
459 PM EDT Tue Aug 6 2024

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 815 PM EDT THIS 
EVENING FOR CENTRAL MERCER, CENTRAL MONMOUTH AND SOUTHWESTERN 
MIDDLESEX COUNTIES...

At 459 PM EDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 1 and 3 inches of rain have 
fallen. Additional rainfall amounts of 1 to 2 inches are possible in 
the warned area. Flash flooding is already occurring with road 
closures being reported Pennington and several on ramps to I295 in 
Ewing NJ.

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...
  Trenton, Marlboro, Ewing, Holmdel, Princeton, Jamesburg, 
  Hightstown, Cranbury, Pennington, Twin Rivers, Clearbrook Park and 
  Princeton Meadows.

This includes the following highways...
	Interstate 295 in New Jersey between mile markers 64 and 76.
	New Jersey Turnpike between exits 8A and 9.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4037 7449 4036 7415 4028 7414 4027 7437
      4022 7477 4025 7484 4031 7488 4034 7469
      4035 7468

FLASH FLOOD...RADAR INDICATED

$$

Deal
655 
WGUS71 KPHI 062124
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
524 PM EDT Tue Aug 6 2024

NJC021-023-025-070015-
/O.CON.KPHI.FF.W.0030.000000T0000Z-240807T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mercer NJ-Middlesex NJ-Monmouth NJ-
524 PM EDT Tue Aug 6 2024

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 815 PM EDT THIS 
EVENING FOR CENTRAL MERCER, CENTRAL MONMOUTH AND SOUTHWESTERN 
MIDDLESEX COUNTIES...

At 524 PM EDT, Doppler radar indicated thunderstorms producing heavy 
rain in between Ewing and Pennington . Between 2 and 4 inches of 
rain have fallen. Additional rainfall amounts of 1 to 2 inches are 
possible in the warned area. Flash flooding is already occurring 
with several road closures in the Pennington and Ewing areas.

HAZARD...Life threatening flash flooding caused by thunderstorms.

SOURCE...Radar.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets, and underpasses.

Some locations that may experience flash flooding include...
  Trenton, Marlboro, Ewing, Holmdel, Princeton, Jamesburg, 
  Hightstown, Cranbury, Pennington, Twin Rivers, Clearbrook Park and 
  Princeton Meadows.

This includes the following highways...
	Interstate 295 in New Jersey between mile markers 64 and 76.
	New Jersey Turnpike between exits 8A and 9.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4037 7449 4036 7415 4028 7414 4027 7437
      4022 7477 4025 7484 4031 7488 4034 7469
      4035 7468

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

Deal
055 
WGUS71 KPHI 062155
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
555 PM EDT Tue Aug 6 2024

NJC025-062205-
/O.CAN.KPHI.FF.W.0030.000000T0000Z-240807T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Monmouth NJ-
555 PM EDT Tue Aug 6 2024

...FLASH FLOOD WARNING IS CANCELLED FOR CENTRAL MONMOUTH COUNTY...

Flooding is no longer expected to pose a threat. Please continue to 
heed remaining road closures.

A Flood Watch remains in effect until 1200 PM EDT Wednesday for 
portions of northern Delaware, New Jersey, and Pennsylvania.

&&

LAT...LON 4025 7484 4027 7485 4028 7486 4029 7486
      4030 7487 4031 7488 4034 7469 4035 7468
      4035 7458 4025 7452 4022 7477

$$

NJC021-023-070015-
/O.CON.KPHI.FF.W.0030.000000T0000Z-240807T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mercer NJ-Middlesex NJ-
555 PM EDT Tue Aug 6 2024

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 815 PM EDT THIS 
EVENING FOR CENTRAL MERCER AND SOUTHWESTERN MIDDLESEX COUNTIES...

At 555 PM EDT, Doppler radar indicated thunderstorms producing heavy 
rain in between Ewing and Pennington . Between 2 and 4 inches of 
rain have fallen. Additional rainfall amounts up to 1 inch are 
possible in the warned area. Flash flooding is already occurring 
with several road closures in the Pennington and Ewing areas.

HAZARD...Life threatening flash flooding caused by thunderstorms.

SOURCE...Radar.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets, and underpasses.

Some locations that may experience flash flooding include...
  Trenton, Ewing, Princeton, Hightstown, Pennington, Lawrenceville, 
  Mercerville-Hamilton Square, Edinburg, Plainsboro Center, Windsor, 
  Princeton Meadows and Washington Crossing.

This includes Interstate 295 in New Jersey between mile markers 64 
and 76.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4025 7484 4027 7485 4028 7486 4029 7486
      4030 7487 4031 7488 4034 7469 4035 7468
      4035 7458 4025 7452 4022 7477

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

Deal
071 
WGUS51 KPHI 062345
FFWPHI
NJC021-023-070300-
/O.EXT.KPHI.FF.W.0030.000000T0000Z-240807T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
745 PM EDT Tue Aug 6 2024

The National Weather Service in Mount Holly has extended the

* Flash Flood Warning for...
  Central Mercer County in central New Jersey...
  Southwestern Middlesex County in northern New Jersey...

* Until 1100 PM EDT.

* At 745 PM EDT, emergency management reported numerous flooded 
  roadways due to excessive rainfall in between Ewing and 
  Pennington. Between 2 and 4 inches of rain have fallen. Additional 
  rounds of strong thunderstorms with rainfall rates of 1 to 2 
  inches per hour are expected over the next several hours. Flash 
  flooding is already occurring.

  HAZARD...Life threatening flash flooding caused by
           thunderstorms.

  SOURCE...Emergency management reported.

  IMPACT...Life threatening flash flooding of creeks and streams,
           urban areas, highways, streets, and underpasses.

* Some locations that may experience flash flooding include...
  Trenton, Ewing, Princeton, Hightstown, Pennington, Lawrenceville, 
  Mercerville-Hamilton Square, Edinburg, Plainsboro Center, Windsor, 
  Princeton Meadows and Washington Crossing.

This includes Interstate 295 in New Jersey between mile markers 64 
and 76.

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.

&&

LAT...LON 4025 7484 4027 7485 4028 7486 4029 7486
      4030 7487 4031 7488 4034 7469 4035 7468
      4035 7458 4025 7452 4022 7477

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL RATE...1-2 INCHES IN 1 HOUR

$$

MJL
834 
WGUS51 KPHI 070229
FFWPHI
NJC021-023-070500-
/O.EXT.KPHI.FF.W.0030.000000T0000Z-240807T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1029 PM EDT Tue Aug 6 2024

The National Weather Service in Mount Holly has extended the

* Flash Flood Warning for...
  Central Mercer County in central New Jersey...
  Southwestern Middlesex County in northern New Jersey...

* Until 100 AM EDT.

* At 1029 PM EDT, Emergency management reported thunderstorms 
  producing heavy rain in between Ewing and Pennington earlier. 
  Between 2 and 4 inches of rain have fallen, and additional 
  rainfall of 1 to 2 inches is possible with rainfall rates of 1 to 
  2 inches per hour. Flash flooding is already occurring.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Emergency management reported.

  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...
  Trenton, Ewing, Princeton, Hightstown, Pennington, Lawrenceville, 
  Mercerville-Hamilton Square, Edinburg, Plainsboro Center, Windsor, 
  Princeton Meadows and Washington Crossing.

This includes Interstate 295 in New Jersey between mile markers 64 
and 76.

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.

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 4025 7484 4027 7485 4028 7486 4029 7486
      4030 7487 4031 7488 4034 7469 4035 7468
      4035 7458 4025 7452 4022 7477

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

$$

MPS
695 
WGUS71 KPHI 070425 RRB
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1225 AM EDT Wed Aug 7 2024

NJC021-023-070435-
/O.CAN.KPHI.FF.W.0030.000000T0000Z-240807T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mercer NJ-Middlesex NJ-
1225 AM EDT Wed Aug 7 2024

...FLASH FLOOD WARNING IS CANCELLED FOR CENTRAL MERCER AND 
SOUTHWESTERN MIDDLESEX COUNTIES...

The heavy rain has ended. While the flash flood threat has ended, 
flooding remains an issue. A new Flood Warning will be issued. 
Please continue to heed remaining road closures.

A Flood Watch remains in effect until 1200 PM EDT Wednesday for 
portions of northern Delaware, New Jersey, and Pennsylvania.

&&

LAT...LON 4025 7484 4027 7485 4028 7486 4029 7486
      4030 7487 4031 7488 4034 7469 4035 7468
      4035 7458 4025 7452 4022 7477

$$

MPS

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 6, 9:37 AM EDTHeat AdvisoryPHIBurlington, Camden, Gloucester, Hunterdon, Mercer, Middlesex and 5 more9 hr
Aug 6, 9:39 AM EDTSmall Craft AdvisoryPHI10 hr
Aug 6, 2:04 PM EDTSpecial Marine WarningPHI56 min
Aug 6, 2:41 PM EDTSevere Thunderstorm WarningPHIOcean19 min
Aug 6, 2:55 PM EDTSpecial Marine WarningPHI65 min
Aug 6, 3:15 PM EDTSpecial Marine WarningPHI60 min
Aug 6, 3:18 PM EDTSevere Thunderstorm WarningPHIMonmouth27 min
Aug 6, 3:21 PM EDTSevere Thunderstorm WarningPHIBurlington23 min
Aug 6, 3:23 PM EDTSevere Thunderstorm WarningPHIMercer, Middlesex, Monmouth37 min
Aug 6, 3:45 PM EDTFlash Flood WarningPHIMiddlesex, Monmouth2 hr
Aug 6, 3:49 PM EDTSevere Thunderstorm WarningPHIMercer, Middlesex, Monmouth56 min
Aug 6, 4:10 PM EDTSpecial Marine WarningPHI65 min
Aug 6, 4:32 PM EDTSevere Thunderstorm WarningPHIHunterdon, Middlesex, Somerset43 min
Aug 6, 4:37 PM EDTSevere Thunderstorm WarningPHIHunterdon, Mercer, Middlesex, Somerset40 min
Aug 6, 4:55 PM EDTFlash Flood Warning Considerable damage threatPHIMonmouth6 hr
Aug 6, 4:56 PM EDTSevere Thunderstorm WarningPHIOcean49 min
Aug 6, 5:06 PM EDTSevere Thunderstorm WarningPHIHunterdon, Middlesex, Morris, Somerset54 min
Aug 6, 5:29 PM EDTFlash Flood WarningPHIHunterdon, Middlesex, Morris, Somerset6 hr
Aug 6, 5:36 PM EDTFlash Flood WarningPHIMonmouth, Ocean8 hr
Aug 6, 6:37 PM EDTFlash Flood WarningPHIWarren3 hr
Aug 6, 6:39 PM EDTFlash Flood WarningPHIBurlington, Camden, Gloucester5 hr
Aug 6, 6:46 PM EDTFlash Flood WarningPHIMorris, Somerset4 hr
Aug 6, 6:57 PM EDTFlash Flood WarningPHIWarren3 hr
Aug 6, 7:04 PM EDTFlash Flood WarningPHIBurlington5 hr
Aug 6, 7:24 PM EDTFlash Flood WarningPHIBurlington, Mercer, Middlesex, Monmouth, Ocean5 hr

Nearby

Flash Flood Warnings in New Jersey, 2024Every flash flood warning in 2024

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.