Alert archive / New Jersey / Flash Flood Warnings in 2021

Flash Flood Warning 21, NWS Philadelphia/Mount Holly

July 17, 2021Hunterdon County, New Jersey; Bucks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 17, 2021, 5:25 PM EDT for Hunterdon County, New Jersey; Bucks County, Pennsylvania. It was in force for 6 hr. 11 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 17, 2021, 5:25 PM EDT (21:25 UTC)
Expired: Jul 17, 2021, 11:11 PM EDT
In force: 6 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Hunterdon County, NJ, Bucks County, PA

The radar

The Philadelphia radar (KDIX), 75 km from the middle of the area, began a volume at 21:27 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 17, 6:35 PM EDT	FLASH FLOOD	3 Ne Ringoes, NJ	FLOODING ALONG THE NESHANIC RIVER AT REAVILLE BASED ON THE RIVER GAUGE.
Jul 17, 7:00 PM EDT	FLASH FLOOD	Flemington, NJ	REPORTS OF SEVERAL ROADS FLOODED. TIME ESTIMATED.
Jul 17, 7:06 PM EDT	HEAVY RAIN 3.47	Flemington, NJ
Jul 17, 7:10 PM EDT	FLASH FLOOD	2 Ese Stanton, NJ	WATER RESCUE ON PLEASANT RUN ROAD.
Jul 17, 7:10 PM EDT	FLASH FLOOD	3 Sw Quakertown, NJ	WATER RESCUE IN THE AREA OF OAK GROVE AND LOWER OAK GROVE IN FRANKLIN TOWNSHIP.
Jul 17, 7:30 PM EDT	HEAVY RAIN 3.75	3 E Frenchtown, NJ	KINGWOOD TOWNSHIP - NEW JERSEY WEATHER NETWORK.
Jul 17, 8:00 PM EDT	HEAVY RAIN 4.55	2 Sse Stanton, NJ
Jul 17, 8:50 PM EDT	FLASH FLOOD	1 Ese Raritan Twp, NJ	FLOODING ON 202 SOUTHBOUND. ALL LANES CLOSED. TIME ESTIMATED.
Jul 17, 9:00 PM EDT	FLASH FLOOD	3 Nw Sand Brook, NJ	A FEW FEET OF WATER FLOODING WHISKEY LANE. TIME ESTIMATED FROM RADAR.
Jul 17, 9:20 PM EDT	HEAVY RAIN 5.41	Flemington, NJ	UPDATED TOTAL THROUGH 9 PM.
Jul 17, 10:30 PM EDT	FLASH FLOOD	2 Ne Ringoes, NJ	3 VEHICLES STRANDED IN FLOOD WATERS ON OLD YORK ROAD AT THE NESHANIC RIVER. TIME ESTIMATED.

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, 9.4 hours before the alert went out and 178 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: 1203 J/kg
Mixed-layer CIN: -55 J/kg
Mixed-layer LCL: 1054 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 35 m²/s²
0-3 km storm-relative helicity: 46 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 1.0

Open this sounding in Storm Lab

The text

As transmitted.

851 
WGUS51 KPHI 172125
FFWPHI
NJC019-PAC017-180200-
/O.NEW.KPHI.FF.W.0021.210717T2125Z-210718T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
525 PM EDT Sat Jul 17 2021

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Hunterdon County in northwestern New Jersey...
  Central Bucks County in southeastern Pennsylvania...

* Until 1000 PM EDT.

* At 525 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have already fallen in spots. 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...
  Perkasie, Doylestown, Byram, Bedminster, Flemington, Chalfont, 
  Tinicum, High Bridge, Clinton, New Hope, Dublin, and Glen Gardner.

This includes the following highways...
	Interstate 78 in New Jersey between mile markers 8 and 26.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Motorists should not attempt to drive around barricades or drive 
cars through flooded areas.

&&

LAT...LON 4034 7535 4060 7521 4059 7518 4071 7497
      4079 7489 4074 7483 4071 7472 4067 7473
      4062 7470 4058 7471 4050 7478 4051 7480
      4042 7475 4042 7481 4038 7480 4038 7487
      4035 7486 4034 7494 4032 7491 4017 7506

FLASH FLOOD...RADAR INDICATED

$$

Iovino

4 follow-up statements

874 
WGUS71 KPHI 172246
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
646 PM EDT Sat Jul 17 2021

NJC019-PAC017-180200-
/O.CON.KPHI.FF.W.0021.000000T0000Z-210718T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hunterdon NJ-Bucks PA-
646 PM EDT Sat Jul 17 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 10 PM EDT THIS 
EVENING FOR HUNTERDON AND CENTRAL BUCKS COUNTIES...

At 646 PM EDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. 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 ongoing or expected to begin 
shortly.

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...
  Perkasie, Doylestown, Byram, Bedminster, Flemington, Chalfont, 
  Tinicum, High Bridge, Clinton, New Hope, Dublin, and Glen Gardner.

This includes the following highways...
	Interstate 78 in New Jersey between mile markers 9 and 26.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Motorists should not attempt to drive around barricades or drive 
cars through flooded areas.

&&

LAT...LON 4034 7535 4060 7521 4059 7518 4071 7497
      4079 7489 4074 7483 4071 7472 4067 7473
      4062 7470 4058 7471 4050 7478 4051 7480
      4042 7475 4042 7481 4038 7480 4038 7487
      4035 7486 4034 7494 4032 7491 4017 7506

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

$$

Iovino

586 
WGUS51 KPHI 180107
FFWPHI
NJC019-PAC017-180400-
/O.EXT.KPHI.FF.W.0021.000000T0000Z-210718T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
907 PM EDT Sat Jul 17 2021

The National Weather Service in Mount Holly has extended the

* Flash Flood Warning for...
  Hunterdon County in northwestern New Jersey...
  Central Bucks County in southeastern Pennsylvania...

* Until midnight EDT.

* At 907 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 3 and 6 inches of rain 
  have already fallen in spots, especially southern Hunterdon 
  County. Additional rainfall amounts of 1 to 1.5 inches are 
  possible in the warned area. Flash flooding is ongoing.

  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 additional flash flooding 
  include...
  Perkasie, Doylestown, Byram, Bedminster, Flemington, Chalfont, 
  Tinicum, High Bridge, Clinton, New Hope, Dublin, and Glen Gardner.

This includes the following highways...
	Interstate 78 in New Jersey between mile markers 9 and 26.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Motorists should not attempt to drive around barricades or drive 
cars through flooded areas.

&&

LAT...LON 4034 7535 4060 7521 4059 7518 4071 7497
      4079 7489 4074 7483 4071 7472 4067 7473
      4062 7470 4058 7471 4050 7478 4051 7480
      4042 7475 4042 7481 4038 7480 4038 7487
      4035 7486 4034 7494 4032 7491 4017 7506

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

$$

Iovino

876 
WGUS71 KPHI 180228
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1028 PM EDT Sat Jul 17 2021

PAC017-180238-
/O.CAN.KPHI.FF.W.0021.000000T0000Z-210718T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bucks PA-
1028 PM EDT Sat Jul 17 2021

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

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


LAT...LON 4071 7497 4079 7489 4074 7483 4071 7472
      4063 7473 4062 7470 4050 7478 4051 7480
      4042 7475 4042 7481 4038 7480 4038 7487
      4035 7486 4034 7494 4040 7497 4042 7506
      4054 7507 4057 7512 4056 7517 4058 7519

$$

NJC019-180400-
/O.CON.KPHI.FF.W.0021.000000T0000Z-210718T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hunterdon NJ-
1028 PM EDT Sat Jul 17 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL MIDNIGHT EDT TONIGHT 
FOR HUNTERDON COUNTY...

At 1028 PM EDT, Between 3 and 6 inches of rain have already fallen. 
Additional rainfall amounts up to 0.5 inches are possible in the 
warned area. Flash flooding is ongoing.

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...
  Byram, Flemington, High Bridge, Clinton, New Hope, Glen Gardner, 
  Hampton, Frenchtown, Lebanon, Milford, Califon, and Stockton.

This includes the following highways...
	Interstate 78 in New Jersey between mile markers 9 and 26.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Motorists should not attempt to drive around barricades or drive 
cars through flooded areas.

&&

LAT...LON 4071 7497 4079 7489 4074 7483 4071 7472
      4063 7473 4062 7470 4050 7478 4051 7480
      4042 7475 4042 7481 4038 7480 4038 7487
      4035 7486 4034 7494 4040 7497 4042 7506
      4054 7507 4057 7512 4056 7517 4058 7519

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

$$

Iovino

293 
WGUS71 KPHI 180311
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1111 PM EDT Sat Jul 17 2021

NJC019-180321-
/O.CAN.KPHI.FF.W.0021.000000T0000Z-210718T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hunterdon NJ-
1111 PM EDT Sat Jul 17 2021

...FLASH FLOOD WARNING IS CANCELLED FOR HUNTERDON COUNTY...

Little additional rainfall is expected overnight in Hunterdon 
County. The Flash Flood Warning has been replaced with a Flood 
Warning. It is in effect until 9:00 AM Sunday.

LAT...LON 4071 7497 4079 7489 4074 7483 4071 7472
      4063 7473 4062 7470 4050 7478 4051 7480
      4042 7475 4042 7481 4038 7480 4038 7487
      4035 7486 4034 7494 4040 7497 4042 7506
      4054 7507 4057 7512 4056 7517 4058 7519

$$

Iovino

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 17, 12:55 PM EDT	Special Weather Statement	PHI	Hunterdon	50 min
Jul 17, 1:05 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Mercer	40 min
Jul 17, 1:31 PM EDT	Areal Flood Advisory	PHI	Hunterdon	97 min
Jul 17, 1:50 PM EDT	Special Marine Warning	PHI		40 min
Jul 17, 1:56 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Morris, Somerset, Warren	36 min
Jul 17, 2:02 PM EDT	Areal Flood Advisory	PHI	Monmouth, Ocean	92 min
Jul 17, 2:56 PM EDT	Severe Thunderstorm Warning	PHI	Middlesex, Somerset	49 min
Jul 17, 3:06 PM EDT	Severe Thunderstorm Warning	PHI	Warren	39 min
Jul 17, 3:09 PM EDT	Tornado Warning	PHI	Middlesex	21 min
Jul 17, 3:38 PM EDT	Areal Flood Advisory	PHI	Middlesex	40 min
Jul 17, 3:51 PM EDT	Severe Thunderstorm Warning	PHI	Middlesex	24 min
Jul 17, 4:55 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Somerset	50 min
Jul 17, 5:13 PM EDT	Areal Flood Advisory	PHI	Hunterdon	4 hr
Jul 17, 5:19 PM EDT	Tornado Warning	PHI	Hunterdon	14 min
Jul 17, 5:30 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Warren	19 min
Jul 17, 5:52 PM EDT	Areal Flood Advisory	PHI	Somerset	2 hr
Jul 17, 6:02 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Mercer, Somerset	43 min
Jul 17, 6:15 PM EDT	Flash Flood Warning	PHI	Morris, Somerset	5 hr
Jul 17, 6:39 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Mercer, Middlesex, Morris, Somerset	51 min
Jul 17, 6:51 PM EDT	Severe Thunderstorm Warning	PHI	Burlington	39 min
Jul 17, 6:59 PM EDT	Small Craft Advisory	PHI		7 hr
Jul 17, 7:01 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Somerset	44 min
Jul 17, 7:12 PM EDT	Areal Flood Advisory	PHI	Mercer, Somerset	3 hr
Jul 17, 7:26 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Mercer, Middlesex, Morris, Somerset	49 min
Jul 16, 8:14 PM EDT	Special Weather Statement	PHI	Montgomery	31 min
Jul 16, 8:41 PM EDT	Special Weather Statement	PHI	Bucks	34 min
Jul 16, 9:07 PM EDT	Special Weather Statement	PHI	Lehigh	23 min
Jul 16, 9:29 PM EDT	Special Weather Statement	PHI	Lehigh	31 min
Jul 16, 10:21 PM EDT	Special Weather Statement	PHI	Lehigh	24 min
Jul 17, 2:30 PM EDT	Special Weather Statement	PHI	Berks	45 min
Jul 17, 2:36 PM EDT	Severe Thunderstorm Warning	PHI	Berks	39 min
Jul 17, 7:36 PM EDT	Special Weather Statement	PHI	Carbon	54 min

Nearby

Flash Flood Warnings in New Jersey, 2021 Flash Flood Warnings in Pennsylvania, 2021 Every 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.