Alert archive / New Jersey / Flash Flood Warnings in 2020

Flash Flood Warning 25, NWS Philadelphia/Mount Holly

July 24, 20204 counties in New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 24, 2020, 1:28 AM EDT for 4 counties in New Jersey. It was in force for 4 hr. 13 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 24, 2020, 1:28 AM EDT (05:28 UTC)
Expired: Jul 24, 2020, 5:30 AM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

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

The radar

The Philadelphia radar (KDIX), 57 km from the middle of the area, began a volume at 05:28 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 24, 1:50 AM EDT	FLASH FLOOD	1 Se Atlantic Highlands, NJ	STATE HIGHWAY 36 AND VALLEY DRIVE BARRICADED AS A RESULT OF FLOODING. TIME BASED ON DISPATCH REPORT.
Jul 24, 1:51 AM EDT	FLASH FLOOD	1 Sw South River, NJ	FLASH FLOODING HAS CLOSED STATE HIGHWAY 18 NEAR CRANBURY ROAD IN EAST BRUNSWICK TWP. TIME BASED ON DISPATCH REPORT.
Jul 24, 2:00 AM EDT	FLASH FLOOD	Hazlet, NJ	STATE HIGHWAY 35 CLOSED AT HOLMDEL ROAD IN HAZLET TWP. TIME BASED ON DISPATCH REPORT.
Jul 24, 2:00 AM EDT	FLASH FLOOD	Kendall Park, NJ	REPORTS OF MULTIPLE ROAD CLOSURES FROM FLASH FLOODING IN THE FRANKLIN PARK AREA. TIME BASED ON DISPATCH REPORT.
Jul 24, 2:25 AM EDT	FLASH FLOOD	1 S Keyport, NJ	WATER RESCUE REPORTED ON CLARK STREET. TIME BASED ON DISPATCH REPORT.
Jul 24, 2:30 AM EDT	HEAVY RAIN 4.25	Spotswood, NJ	BETWEEN MIDNIGHT AND 2:30 AM. MULTIPLE ROADS FLOODED IN AREA.
Jul 24, 2:35 AM EDT	FLASH FLOOD	1 Nw New Brunswick, NJ	VEHICLE STUCK IN FLOOD WATERS ON COLLEGE AVENUE. TIME BASED ON DISPATCH REPORT.
Jul 24, 2:40 AM EDT	FLOOD	1 Ene Parlin, NJ	FLOODING ON GARDEN STATE PARKWAY NEAR EXIT 123. LANE RESTRICTIONS IN PLACE.
Jul 24, 2:41 AM EDT	FLOOD	1 Ssw Keyport, NJ	FLOODING ON GARDEN STATE PARKWAY NEAR EXIT 117. LANE RESTRICTIONS IN PLACE. TIME BASED ON DISPATCH REPORT.
Jul 24, 2:50 AM EDT	FLOOD	2 Nw Kendall Park, NJ	FLOODING DAMAGED A TRANSFORMER AND UTILITY POLES NEAR PEOPLES LINE ROAD. TIME BASED ON DISPATCH REPORT.
Jul 24, 3:00 AM EDT	HEAVY RAIN 3.06	2 Nnw South River, NJ	6-HOUR RAINFALL TOTAL ENDING AT 3 AM. NJWXNET SENSOR.
Jul 24, 3:07 AM EDT	FLOOD	2 S South River, NJ	FLOODING ON STATE HIGHWAY 18 NEAR RACETRACK ROAD. RAMP CLOSED. TIME BASED ON DISPATCH REPORT.
Jul 24, 3:48 AM EDT	HEAVY RAIN 3.23	1 Wnw Matawan, NJ	MESONET STATION.

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 00:00Z, 5.5 hours before the alert went out and 122 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: 1702 J/kg
Mixed-layer CIN: -49 J/kg
Mixed-layer LCL: 797 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 111 m²/s²
0-3 km storm-relative helicity: 116 m²/s²
Significant tornado parameter: 0.6
Supercell composite: 4.0

Open this sounding in Storm Lab

The text

As transmitted.

472 
WGUS51 KPHI 240528
FFWPHI
NJC021-023-025-035-240930-
/O.NEW.KPHI.FF.W.0025.200724T0528Z-200724T0930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
128 AM EDT Fri Jul 24 2020

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  Northeastern Mercer County in central New Jersey...
  Southern Somerset County in northern New Jersey...
  Northeastern Monmouth County in central New Jersey...
  Middlesex County in northern New Jersey...

* Until 530 AM EDT.

* At 128 AM EDT, Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. Up to two inches of rain have
  already fallen. Flash flooding is ongoing or expected to begin
  shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar indicated.

  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 could experience flooding include...
  New Brunswick, Perth Amboy, Long Branch, Sandy Hook, Somerset,
  Edison, Middletown, Old Bridge, East Brunswick, South Brunswick,
  Sayreville, North Brunswick, Marlboro, Tinton Falls, Holmdel,
  Princeton, Red Bank, Matawan, Jamesburg and Highlands.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

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 4026 7396 4030 7480 4052 7469 4054 7432
      4053 7425 4050 7426 4050 7428 4047 7427
      4044 7420 4046 7418 4041 7403 4041 7398
      4048 7402 4048 7401 4043 7397

FLASH FLOOD...RADAR INDICATED

$$

CMS

3 follow-up statements

170 
WGUS71 KPHI 240613
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
213 AM EDT Fri Jul 24 2020

NJC021-023-025-035-240930-
/O.CON.KPHI.FF.W.0025.000000T0000Z-200724T0930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mercer NJ-Somerset NJ-Monmouth NJ-Middlesex NJ-
213 AM EDT Fri Jul 24 2020

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 530 AM EDT FOR
NORTHEASTERN MERCER...SOUTHERN SOMERSET...NORTHEASTERN MONMOUTH AND
MIDDLESEX COUNTIES...

At 211 AM EDT, law enforcement reported flash flooding across the 
warning area. The most severe flooding was occurring in the East 
Brunswick and Franklin Park areas. Widespread two to four inch 
rainfall has occurred with locally up to five inch rainfall amounts 
reported near Spotswood. This is a dangerous situation.

HAZARD...Life threatening flash flooding. Heavy rain producing flash 
         flooding.

SOURCE...Law enforcement.

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

Some locations that could experience flooding include...
New Brunswick, Perth Amboy, Long Branch, Sandy Hook, Somerset,
Edison, Middletown, Old Bridge, East Brunswick, South Brunswick,
Sayreville, North Brunswick, Marlboro, Tinton Falls, Holmdel,
Princeton, Red Bank, Matawan, Jamesburg and Highlands.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

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 4026 7396 4030 7480 4052 7469 4054 7432
      4053 7425 4050 7426 4050 7428 4047 7427
      4044 7420 4046 7418 4041 7403 4041 7398
      4048 7402 4048 7401 4043 7397

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

Davis

778 
WGUS71 KPHI 240736
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
336 AM EDT Fri Jul 24 2020

NJC021-023-025-035-240930-
/O.CON.KPHI.FF.W.0025.000000T0000Z-200724T0930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mercer NJ-Somerset NJ-Monmouth NJ-Middlesex NJ-
336 AM EDT Fri Jul 24 2020

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 530 AM EDT FOR
NORTHEASTERN MERCER...SOUTHERN SOMERSET...NORTHEASTERN MONMOUTH AND
MIDDLESEX COUNTIES...

At 334 AM EDT, law enforcement continued to report flash flooding 
across the warned area. There have been reports of flooding from 
Franklin Park to East Brunswick to Hazlet, with numerous roads 
closed. Travel is discouraged in the warning area.

HAZARD...Life threatening flash flooding. Heavy rain producing flash 
         flooding.

SOURCE...Law enforcement.

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

Some locations that could experience flooding include...
New Brunswick, Perth Amboy, Long Branch, Sandy Hook, Somerset,
Edison, Middletown, Old Bridge, East Brunswick, South Brunswick,
Sayreville, North Brunswick, Marlboro, Tinton Falls, Holmdel,
Princeton, Red Bank, Matawan, Jamesburg and Highlands.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

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 4026 7396 4030 7480 4052 7469 4054 7432
      4053 7425 4050 7426 4050 7428 4047 7427
      4044 7420 4046 7418 4041 7403 4041 7398
      4048 7402 4048 7401 4043 7397

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

CMS

842 
WGUS71 KPHI 240928
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
528 AM EDT Fri Jul 24 2020

NJC021-023-025-035-240937-
/O.EXP.KPHI.FF.W.0025.000000T0000Z-200724T0930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mercer NJ-Somerset NJ-Monmouth NJ-Middlesex NJ-
528 AM EDT Fri Jul 24 2020

...THE FLASH FLOOD WARNING FOR NORTHEASTERN MERCER...SOUTHERN
SOMERSET...NORTHEASTERN MONMOUTH AND MIDDLESEX COUNTIES WILL EXPIRE
AT 530 AM EDT...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat, though lingering flood waters may take some time to recede. 
Please continue to heed any remaining road closures and never drive 
through flooded roadways.

LAT...LON 4026 7396 4030 7480 4052 7469 4054 7432
      4053 7425 4050 7426 4050 7428 4047 7427
      4044 7420 4046 7418 4041 7403 4041 7398
      4048 7402 4048 7401 4043 7397

$$

Davis

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 23, 8:04 PM EDT	Severe Thunderstorm Warning	PHI	Middlesex, Monmouth	26 min
Jul 23, 11:16 PM EDT	Severe Thunderstorm Warning	PHI	Gloucester, Salem	44 min
Jul 23, 11:27 PM EDT	Special Marine Warning	PHI		63 min
Jul 24, 12:14 AM EDT	Special Weather Statement	PHI	Middlesex	31 min
Jul 24, 12:23 AM EDT	Severe Thunderstorm Warning	PHI	Mercer, Middlesex, Monmouth, Somerset	52 min
Jul 24, 12:31 AM EDT	Areal Flood Advisory	PHI	Hunterdon, Mercer, Middlesex, Monmouth, Somerset	119 min
Jul 24, 12:51 AM EDT	Special Marine Warning	PHI		54 min
Jul 24, 1:13 AM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Mercer, Middlesex, Monmouth, Somerset	62 min
Jul 24, 1:36 AM EDT	Special Marine Warning	PHI		84 min
Jul 24, 2:18 AM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Middlesex, Morris, Somerset	42 min
Jul 24, 5:04 AM EDT	Special Marine Warning	PHI		56 min
Jul 24, 10:43 AM EDT	Flash Flood Warning	PHI	Camden	76 min
Jul 24, 11:42 AM EDT	Special Marine Warning	PHI		63 min
Jul 24, 12:43 PM EDT	Areal Flood Advisory	PHI	Ocean	3 hr
Jul 24, 1:09 PM EDT	Areal Flood Advisory	PHI	Monmouth, Ocean	110 min
Jul 24, 1:40 PM EDT	Special Weather Statement	PHI	Atlantic	35 min
Jul 24, 1:43 PM EDT	Areal Flood Advisory	PHI	Burlington, Mercer, Monmouth	3 hr
Jul 24, 2:02 PM EDT	Areal Flood Advisory	PHI	Atlantic, Burlington, Camden, Gloucester	3 hr
Jul 24, 2:19 PM EDT	Areal Flood Advisory	PHI	Burlington, Camden, Gloucester	2 hr
Jul 24, 2:26 PM EDT	Flash Flood Warning	PHI	Burlington	2 hr
Jul 24, 2:39 PM EDT	Areal Flood Advisory	PHI	Burlington, Ocean	3 hr
Jul 24, 2:42 PM EDT	Areal Flood Advisory	PHI	Burlington, Ocean	2 hr
Jul 24, 3:34 PM EDT	Flash Flood Warning	PHI	Atlantic, Burlington, Ocean	2 hr
Jul 24, 4:22 PM EDT	Areal Flood Advisory	PHI	Atlantic, Cape May	3 hr
Jul 24, 4:58 PM EDT	Areal Flood Advisory	PHI	Cape May	2 hr

Nearby

Flash Flood Warnings in New Jersey, 2020 Every flash flood warning in 2020

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.