Alert archive / New Jersey / Flash Flood Warnings in 2020
Flash Flood Warning 29, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 31, 2020, 1:29 AM EDT for Middlesex County, Somerset County, New Jersey. It was in force for 4 hr. 2 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 31, 2020, 1:29 AM EDT (05:29 UTC)
- Expired
- Jul 31, 2020, 5:30 AM EDT
- In force
- 4 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
Counties Middlesex County, NJ, Somerset County, NJ
The radar
The Philadelphia radar (KDIX), 64 km from the middle of the area, began a volume at 05:32 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 31, 1:33 AM EDT | FLASH FLOOD | 1 Ene Highland Park, NJ | U.S. HIGHWAY 1 CLOSED NEAR WOODBRIDGE AVENUE FROM FLASH FLOODING. TIME BASED ON DISPATCH REPORT. |
| Jul 31, 3:19 AM EDT | FLASH FLOOD | 1 Sw Hopelawn, NJ | U.S. HIGHWAY 9 CLOSED SOUTH OF STATE HIGHWAY 440 FROM FLOODING. TIME BASED ON DISPATCH REPORT. |
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 131 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.
- Mixed-layer CAPE
- 2515 J/kg
- Mixed-layer CIN
- -27 J/kg
- Mixed-layer LCL
- 895 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- 79 m²/s²
- 0-3 km storm-relative helicity
- 102 m²/s²
- Significant tornado parameter
- 0.8
- Supercell composite
- 4.9
The text
As transmitted.
833
WGUS51 KPHI 310529
FFWPHI
NJC023-035-310930-
/O.NEW.KPHI.FF.W.0029.200731T0529Z-200731T0930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
129 AM EDT Fri Jul 31 2020
The National Weather Service in Mount Holly NJ has issued a
* Flash Flood Warning for...
Southeastern Somerset County in northern New Jersey...
Northern 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, Somerville, Somerset, Edison, East
Brunswick, South Brunswick, Sayreville, North Brunswick, Carteret,
Middlesex, Bound Brook, Manville, Rocky Hill, Millstone, Colonia,
Kingston, Martinsville, North Brunswick Township and Kendall Park.
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 4056 7421 4055 7425 4050 7426 4050 7428
4046 7426 4045 7423 4044 7425 4037 7462
4039 7464 4061 7463 4061 7444 4060 7446
4061 7431 4059 7429 4059 7420
FLASH FLOOD...RADAR INDICATED
$$
CMS3 follow-up statements
942
WGUS71 KPHI 310627
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
227 AM EDT Fri Jul 31 2020
NJC023-035-310930-
/O.CON.KPHI.FF.W.0029.000000T0000Z-200731T0930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Somerset NJ-Middlesex NJ-
227 AM EDT Fri Jul 31 2020
...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 530 AM EDT FOR
SOUTHEASTERN SOMERSET AND NORTHERN MIDDLESEX COUNTIES...
At 224 AM EDT, law enforcement reported flash flooding in Edison.
U.S. Highway 1 southbound was closed from flooding near Woodbridge
Avenue. A spotter also reported flooding in Hillsborough Township in
Somerset County. Though the heavy rainfall has ended, runoff will
continue to pose problems in flood-prone areas for the next couple
of hours. Flash flooding is already occurring.
HAZARD...Flash flooding caused by heavy rain.
SOURCE...Law enforcement.
IMPACT...Flooding of small creeks and streams, urban areas,
highways, streets and underpasses as well as other drainage
and low lying areas.
Some locations that could experience flooding include...
New Brunswick, Perth Amboy, Somerville, Somerset, Edison, East
Brunswick, South Brunswick, Sayreville, North Brunswick, Carteret,
Middlesex, Bound Brook, Manville, Rocky Hill, Millstone, Colonia,
Kingston, Martinsville, North Brunswick Township and Kendall Park.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Protecting yourself from immediate threats to life and safety shall
take priority. Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.
Turn around...don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Be especially cautious at night when it is harder to recognize the
dangers of flooding.
&&
LAT...LON 4056 7421 4055 7425 4050 7426 4050 7428
4046 7426 4045 7423 4044 7425 4037 7462
4039 7464 4061 7463 4061 7444 4060 7446
4061 7431 4059 7429 4059 7420
FLASH FLOOD...OBSERVED
$$
CMS262
WGUS71 KPHI 310803
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
403 AM EDT Fri Jul 31 2020
NJC023-035-310930-
/O.CON.KPHI.FF.W.0029.000000T0000Z-200731T0930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Somerset NJ-Middlesex NJ-
403 AM EDT Fri Jul 31 2020
...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 530 AM EDT FOR
SOUTHEASTERN SOMERSET AND NORTHERN MIDDLESEX COUNTIES...
At 401 AM EDT, law enforcement reported flash flooding in Woodbridge
Township in Middlesex County. Flooding is occurring on U.S. Highway
9 near State Highway 440 with all lanes closed at this time. Though
the heavy rainfall has ended, flooding will likely continue for the
next 60 to 90 minutes.
HAZARD...Flash flooding caused by heavy rain.
SOURCE...Law enforcement.
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, Somerville, Somerset, Edison, East
Brunswick, South Brunswick, Sayreville, North Brunswick, Carteret,
Middlesex, Bound Brook, Manville, Rocky Hill, Millstone, Colonia,
Kingston, Martinsville, North Brunswick Township and Kendall Park.
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 4056 7421 4055 7425 4050 7426 4050 7428
4046 7426 4045 7423 4044 7425 4037 7462
4039 7464 4061 7463 4061 7444 4060 7446
4061 7431 4059 7429 4059 7420
FLASH FLOOD...OBSERVED
$$
CMS793
WGUS71 KPHI 310931
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
531 AM EDT Fri Jul 31 2020
NJC023-035-310941-
/O.EXP.KPHI.FF.W.0029.000000T0000Z-200731T0930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Somerset NJ-Middlesex NJ-
531 AM EDT Fri Jul 31 2020
...THE FLASH FLOOD WARNING FOR SOUTHEASTERN SOMERSET AND NORTHERN
MIDDLESEX COUNTIES HAS EXPIRED...
The heavy rain has ended. Flood waters have receded. Flooding is no
longer expected to pose a threat. Please continue to heed any
remaining road closures.
LAT...LON 4056 7421 4055 7425 4050 7426 4050 7428
4046 7426 4045 7423 4044 7425 4037 7462
4039 7464 4061 7463 4061 7444 4060 7446
4061 7431 4059 7429 4059 7420
$$
CMSThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 30, 10:15 PM EDT | Special Marine Warning | PHI | 60 min | |
| Jul 30, 10:36 PM EDT | Special Weather Statement | PHI | Atlantic, Camden, Cumberland, Gloucester, Salem | 39 min |
| Jul 30, 11:06 PM EDT | Severe Thunderstorm Warning | PHI | Atlantic, Burlington, Camden, Cumberland, Gloucester, Salem | 39 min |
| Jul 30, 11:35 PM EDT | Severe Thunderstorm Warning | PHI | Atlantic, Burlington, Camden, Mercer, Monmouth, Ocean | 40 min |
| Jul 30, 11:40 PM EDT | Special Weather Statement | PHI | Hunterdon | 50 min |
| Jul 30, 11:51 PM EDT | Severe Thunderstorm Warning | PHI | Hunterdon, Mercer, Somerset, Warren | 54 min |
| Jul 31, 12:10 AM EDT | Severe Thunderstorm Warning | PHI | Burlington, Mercer, Middlesex, Monmouth, Ocean, Somerset | 50 min |
| Jul 31, 12:21 AM EDT | Areal Flood Advisory | PHI | Hunterdon, Mercer | 4 hr |
| Jul 31, 12:33 AM EDT | Severe Thunderstorm Warning | PHI | Hunterdon, Mercer, Middlesex, Monmouth, Morris, Ocean and 1 more | 42 min |
| Jul 31, 12:54 AM EDT | Areal Flood Advisory | PHI | Hunterdon, Mercer, Middlesex, Monmouth, Somerset | 4 hr |
| Jul 31, 1:10 AM EDT | Severe Thunderstorm Warning | PHI | Middlesex, Monmouth, Morris, Somerset | 35 min |
Nearby
Flash Flood Warnings in New Jersey, 2020Every 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.