Alert archive / New Jersey / Flash Flood Warnings in 2021
Flash Flood Warning 50, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 22, 2021, 2:40 AM EDT for Hunterdon County, Morris County, Somerset County, New Jersey. It was in force for 5 hr. 10 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 22, 2021, 2:40 AM EDT (06:40 UTC)
- Expired
- Aug 22, 2021, 7:52 AM EDT
- In force
- 5 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
Counties Hunterdon County, NJ, Morris County, NJ, Somerset County, NJ
The radar
The Philadelphia radar (KDIX), 72 km from the middle of the area, began a volume at 06:42 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 |
|---|---|---|---|
| Aug 22, 3:30 AM EDT | FLASH FLOOD | 1 Nw North Plainfield, NJ | ALL LANES OF US 22 CLOSED IN NORTH PLAINFIELD DUE TO FLOODING. |
| Aug 22, 4:45 AM EDT | FLASH FLOOD | 1 Se Flemington, NJ | FLOODING REPORTED ON US 202 IN RARITAN TOWNSHIP. TIME ESTIMATED. |
| Aug 22, 5:15 AM EDT | FLASH FLOOD | 3 Nne Ringoes, NJ | THE NESHANIC RIVER GAUGE AT REAVILLE EXCEEDED FLOOD STAGE. |
| Aug 22, 5:30 AM EDT | FLASH FLOOD | 2 Ssw Somerset, NJ | MIDDLEBUSH ROAD CLOSED NEAR BLACKWELLS MILLS ROAD FROM FLOODING. TIME BASED ON NEARBY REPORTS. |
| Aug 22, 6:20 AM EDT | FLASH FLOOD | 1 S Rocky Hill, NJ | ROAD FLOODING AND CLOSURES NEAR THE MILLSTONE RIVER IN ROCKY HILL AND PRINCETON. TIME BASED ON DISPATCH REPORT. |
| Aug 22, 6:30 AM EDT | HEAVY RAIN 3.1 | Flemington, NJ | COCORAHS STATION NJ-HN-15 FLEMINGTON 0.3 E. |
| Aug 22, 7:00 AM EDT | HEAVY RAIN 1.37 | 1 Ne Chatham, NJ | COCORAHS STATION NJ-MS-102 CHATHAM 0.6 NE. |
| Aug 22, 7:30 AM EDT | HEAVY RAIN 4.85 | 3 Ssw Cloverhill, NJ | 4.85 INCHES OF RAIN MEASURED IN WERTSVILLE. |
| Aug 22, 7:35 AM EDT | HEAVY RAIN 2.06 | 1 Se Somerset, NJ | COCORAHS STATION NJ-SM-67 FRANKLIN TWP. 2.4 ENE. |
| Aug 22, 7:45 AM EDT | FLASH FLOOD | 1 Nw Skillman, NJ | HOLLOW ROAD COMPLETELY FLOODED NORTH OF GRANDVIEW ROAD. ROCK BROOK OVERFLOWING. |
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, 6.7 hours before the alert went out and 154 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
- 1163 J/kg
- Mixed-layer CIN
- -6 J/kg
- Mixed-layer LCL
- 543 m above ground
- 0-6 km bulk shear
- 21 kt
- 0-1 km storm-relative helicity
- 75 m²/s²
- 0-3 km storm-relative helicity
- 85 m²/s²
- Significant tornado parameter
- 0.3
- Supercell composite
- 1.7
The text
As transmitted.
218
WGUS51 KPHI 220640
FFWPHI
NJC019-027-035-221200-
/O.NEW.KPHI.FF.W.0050.210822T0640Z-210822T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
240 AM EDT Sun Aug 22 2021
The National Weather Service in Mount Holly has issued a
* Flash Flood Warning for...
Southern Morris County in northern New Jersey...
Somerset County in northern New Jersey...
Eastern Hunterdon County in northwestern New Jersey...
* Until 800 AM EDT.
* At 240 AM EDT, Doppler radar indicated heavy rain across the
warned area. Between 0.5 and 1 inch of rain has already fallen in
spots. Additional rainfall amounts of 2 to 4 inches are possible
in the warned area. Flash flooding is ongoing or expected to begin
shortly.
HAZARD...Flash flooding caused by heavy rain.
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 will experience flash flooding include...
Somerville, Somerset, Bridgewater, Madison, Middlesex, Bound
Brook, Manville, Hackettstown, Chatham, Mendham, and Flemington.
This includes the following highways...
Interstate 78 in New Jersey between mile markers 17 and 42.
Interstate 287 in New Jersey between mile markers 11 and 34.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Motorists should not attempt to drive around barricades or drive
cars through flooded areas.
&&
LAT...LON 4047 7492 4078 7490 4080 7485 4084 7482
4085 7482 4075 7436 4067 7446 4066 7445
4066 7440 4062 7443 4057 7452 4054 7451
4049 7446 4042 7458 4039 7459 4038 7461
4039 7465 4038 7472 4042 7475 4042 7480
FLASH FLOOD...RADAR INDICATED
$$
Iovino2 follow-up statements
344
WGUS71 KPHI 220909
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
509 AM EDT Sun Aug 22 2021
NJC027-220919-
/O.CAN.KPHI.FF.W.0050.000000T0000Z-210822T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Morris NJ-
509 AM EDT Sun Aug 22 2021
...FLASH FLOOD WARNING IS CANCELLED FOR SOUTHERN MORRIS COUNTY...
Flooding is no longer expected to pose a threat. Please continue to
heed remaining road closures.
A Flood Watch remains in effect until 800 AM Monday.
LAT...LON 4047 7492 4078 7490 4072 7473 4076 7456
4070 7451 4067 7453 4065 7452 4067 7446
4066 7445 4066 7440 4062 7443 4057 7452
4049 7446 4042 7458 4039 7459 4038 7461
4039 7465 4038 7472 4042 7475 4042 7480
$$
NJC019-035-221200-
/O.CON.KPHI.FF.W.0050.000000T0000Z-210822T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hunterdon NJ-Somerset NJ-
509 AM EDT Sun Aug 22 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 8 AM EDT THIS MORNING
FOR SOMERSET AND EASTERN HUNTERDON COUNTIES...
At 509 AM EDT, Doppler radar indicated heavy rain across the warned
area. Between 2 and 3 inches of rain have already fallen in parts of
the area. Additional rainfall amounts of 1 to 2 inches are possible.
Flash flooding is ongoing or expected to begin shortly.
HAZARD...Flash flooding caused by heavy rain.
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 will experience flash flooding include...
New Brunswick, Somerville, Somerset, Bridgewater, Middlesex, Bound
Brook, Manville, Flemington, High Bridge and Clinton.
This includes the following highways...
Interstate 78 in New Jersey between mile markers 17 and 42.
Interstate 287 in New Jersey between mile markers 11 and 30.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Motorists should not attempt to drive around barricades or drive
cars through flooded areas.
&&
LAT...LON 4047 7492 4078 7490 4072 7473 4076 7456
4070 7451 4067 7453 4065 7452 4067 7446
4066 7445 4066 7440 4062 7443 4057 7452
4049 7446 4042 7458 4039 7459 4038 7461
4039 7465 4038 7472 4042 7475 4042 7480
FLASH FLOOD...RADAR INDICATED
$$
Iovino554
WGUS71 KPHI 221152
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
752 AM EDT Sun Aug 22 2021
NJC019-035-221202-
/O.CAN.KPHI.FF.W.0050.000000T0000Z-210822T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hunterdon NJ-Somerset NJ-
752 AM EDT Sun Aug 22 2021
...FLASH FLOOD WARNING FOR SOMERSET AND EASTERN HUNTERDON COUNTIES
HAS BEEN REPLACED WITH A FLOOD WARNING...
Please continue to heed road closures.
LAT...LON 4047 7492 4078 7490 4072 7473 4076 7456
4070 7451 4067 7453 4065 7452 4067 7446
4066 7445 4066 7440 4062 7443 4057 7452
4049 7446 4042 7458 4039 7459 4038 7461
4039 7465 4038 7472 4042 7475 4042 7480
$$
CMSThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 21, 9:35 PM EDT | Areal Flood Advisory | PHI | Mercer, Middlesex, Monmouth, Ocean | 3 hr |
| Aug 21, 10:47 PM EDT | Areal Flood Advisory | PHI | Morris | 3 hr |
| Aug 21, 11:38 PM EDT | Areal Flood Advisory | PHI | Atlantic, Burlington, Monmouth, Ocean | 3 hr |
| Aug 22, 12:04 AM EDT | Areal Flood Advisory | PHI | Atlantic, Burlington, Camden, Monmouth, Ocean | 3 hr |
| Aug 22, 12:24 AM EDT | Flash Flood Warning | PHI | Morris | 3 hr |
| Aug 22, 1:30 AM EDT | Areal Flood Advisory | PHI | Middlesex, Monmouth | 4 hr |
| Aug 22, 1:35 AM EDT | Areal Flood Advisory | PHI | Morris, Somerset | 3 hr |
| Aug 22, 2:04 AM EDT | Flash Flood Warning | PHI | Middlesex, Monmouth | 9 hr |
| Aug 22, 2:09 AM EDT | Flash Flood Warning | PHI | Burlington, Ocean | 5 hr |
| Aug 22, 3:10 AM EDT | Flash Flood Warning | PHI | Burlington, Hunterdon, Mercer, Monmouth, Ocean | 8 hr |
| Aug 22, 4:21 AM EDT | Flash Flood Warning | PHI | Monmouth, Ocean | 3 hr |
| Aug 22, 5:36 AM EDT | Flash Flood Warning | PHI | Mercer, Middlesex, Monmouth, Somerset | 5 hr |
| Aug 22, 6:07 AM EDT | Flash Flood Warning | PHI | Hunterdon, Warren | 67 min |
| Aug 22, 7:52 AM EDT | Areal Flood Warning | PHI | Hunterdon, Somerset | 15 hr |
| Aug 22, 10:43 AM EDT | Special Marine Warning | PHI | 62 min | |
| Aug 22, 10:49 AM EDT | Areal Flood Warning | PHI | Middlesex, Monmouth, Somerset | 13 hr |
| Aug 22, 10:52 AM EDT | Areal Flood Warning | PHI | Hunterdon, Mercer, Monmouth | 13 hr |
| Aug 22, 11:06 AM EDT | Special Marine Warning | PHI | 54 min | |
| Aug 22, 1:35 PM EDT | Coastal Flood Advisory | PHI | Cape May | 10 hr |
| Aug 22, 1:53 PM EDT | Areal Flood Advisory | PHI | Morris | 6 hr |
| Aug 22, 3:21 PM EDT | River Flood Warning | PHI | Somerset | 54 hr |
| Aug 22, 5:07 PM EDT | Areal Flood Advisory | PHI | Morris, Sussex, Warren | 6 hr |
| Aug 22, 5:48 PM EDT | Flash Flood Warning | PHI | Morris, Sussex, Warren | 6 hr |
Nearby
Flash Flood Warnings in New Jersey, 2021Every flash flood warning in 2021
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.