Alert archive / New Jersey / Flash Flood Warnings in 2023

Flash Flood Warning 40, NWS Philadelphia/Mount Holly

July 9, 20234 counties in New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 9, 2023, 2:34 PM EDT for 4 counties in New Jersey. It was in force for 6 hr. 6 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 9, 2023, 2:34 PM EDT (18:34 UTC)
Expired: Jul 9, 2023, 8:20 PM EDT
In force: 6 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Hunterdon County, NJ, Morris County, NJ, Somerset County, NJ, Warren County, NJ

The radar

The Philadelphia radar (KDIX), 101 km from the middle of the area, began a volume at 18:35 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 9, 3:15 PM EDT	FLASH FLOOD	2 Sw Oldwick, NJ	Public sent in video of fast moving water across Halls Mills Road near Pottersville, NJ. Time estimated from radar.
Jul 9, 3:32 PM EDT	FLOOD	2 S Califon, NJ	Corrects previous tstm wnd dmg report from 2 S Califon. Picture received of street flooding on Cokesbury Rd on border of Lebanon Borough and Tewksbury Township.
Jul 9, 3:42 PM EDT	RAIN 1.94	3 W Stanton, NJ	CO-OP observer reports 1.94 inches of rain has fallen since this morning.
Jul 9, 6:54 PM EDT	FLASH FLOOD	1 Ese Franklin Twp, NJ	Clinton Township Police have posted pictures of the Raritan River flooding the Camp Carr campgrounds. Police on scene.
Jul 9, 7:30 PM EDT	FLOOD	Clinton, NJ	Public sends in pictures of ongoing flooding in Clinton, NJ that appears to be a creek out of its banks.
Jul 9, 8:00 PM EDT	FLASH FLOOD	2 W Stanton, NJ	The Raritan River gauge at Stanton reached minor flood stage.

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, 6.6 hours before the alert went out and 179 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: 216 J/kg
Mixed-layer CIN: -64 J/kg
Mixed-layer LCL: 749 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 9 m²/s²
0-3 km storm-relative helicity: 32 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.2

Open this sounding in Storm Lab

The text

As transmitted.

854 
WGUS51 KPHI 091834
FFWPHI
NJC019-027-035-041-100030-
/O.NEW.KPHI.FF.W.0040.230709T1834Z-230710T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
234 PM EDT Sun Jul 9 2023

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Southwestern Morris County in northern New Jersey...
  Northwestern Somerset County in northern New Jersey...
  Hunterdon County in northwestern New Jersey...
  Central Warren County in northwestern New Jersey...

* Until 830 PM EDT.

* At 234 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1.5 and 2.5 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...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...
  Hackettstown, Washington, Flemington, High Bridge, Clinton, 
  Belvidere, Harmony, Oxford, Hope, Glen Gardner, Hampton, and 
  Frenchtown.

This includes the following highways...
	Interstate 78 in New Jersey between mile markers 12 and 28.
	Interstate 80 in New Jersey between mile markers 12 and 13.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 4091 7508 4093 7497 4088 7474 4081 7473
      4070 7468 4058 7470 4047 7479 4048 7506
      4054 7507 4057 7509 4064 7500 4067 7501
      4072 7506 4075 7515 4077 7515 4077 7513
      4082 7508 4085 7510 4085 7507 4086 7505

FLASH FLOOD...RADAR INDICATED

$$

Hoeflich

2 follow-up statements

547 
WGUS71 KPHI 091938
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
338 PM EDT Sun Jul 9 2023

NJC019-027-035-041-100030-
/O.CON.KPHI.FF.W.0040.000000T0000Z-230710T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hunterdon NJ-Morris NJ-Somerset NJ-Warren NJ-
338 PM EDT Sun Jul 9 2023

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 830 PM EDT THIS 
EVENING FOR SOUTHWESTERN MORRIS, NORTHWESTERN SOMERSET, HUNTERDON, 
AND CENTRAL WARREN COUNTIES...

At 338 PM EDT, the public reported thunderstorms producing heavy 
rain. At 3:30 PM, the public sent in video of fast moving water 
across Halls Mills Road near Potterstown, NJ. Between 2 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.

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

SOURCE...Public reported.

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

Some locations that may experience flash flooding include...
  Hackettstown, Washington, Flemington, High Bridge, Clinton, 
  Belvidere, Harmony, Oxford, Hope, Glen Gardner, Hampton, and 
  Frenchtown.

This includes the following highways...
	Interstate 78 in New Jersey between mile markers 12 and 28.
	Interstate 80 in New Jersey near mile marker 12.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 4091 7508 4093 7497 4088 7474 4081 7473
      4070 7468 4058 7470 4047 7479 4048 7506
      4054 7507 4057 7509 4064 7500 4067 7501
      4072 7506 4075 7515 4077 7515 4077 7513
      4082 7508 4085 7510 4085 7507 4086 7505

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

$$

Hoeflich

247 
WGUS71 KPHI 100020
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
820 PM EDT Sun Jul 9 2023

NJC019-027-035-041-100030-
/O.CAN.KPHI.FF.W.0040.000000T0000Z-230710T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hunterdon NJ-Morris NJ-Somerset NJ-Warren NJ-
820 PM EDT Sun Jul 9 2023

...FLASH FLOOD WARNING FOR SOUTHWESTERN MORRIS, NORTHWESTERN 
SOMERSET, HUNTERDON, AND CENTRAL WARREN COUNTIES HAS BEEN REPLACED 
WITH A FLOOD WARNING...

LAT...LON 4091 7508 4093 7497 4088 7474 4081 7473
      4070 7468 4058 7470 4047 7479 4048 7506
      4054 7507 4057 7509 4064 7500 4067 7501
      4072 7506 4075 7515 4077 7515 4077 7513
      4082 7508 4085 7510 4085 7507 4086 7505

$$

Hoeflich

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 9, 12:37 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Warren	2 hr
Jul 9, 1:02 PM EDT	Flash Flood Warning	PHI	Hunterdon, Warren	8 hr
Jul 9, 1:57 PM EDT	Areal Flood Advisory	PHI	Morris, Sussex, Warren	65 min
Jul 9, 2:05 PM EDT	Flash Flood Warning	PHI	Sussex	6 hr
Jul 9, 2:30 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Morris, Warren	4 min
Jul 9, 2:59 PM EDT	Special Weather Statement	PHI	Somerset	31 min
Jul 9, 3:00 PM EDT	Flash Flood Warning	PHI	Morris, Somerset, Sussex, Warren	6 hr
Jul 9, 4:12 PM EDT	Special Weather Statement	PHI	Somerset	33 min
Jul 9, 4:34 PM EDT	Special Marine Warning	PHI		86 min
Jul 9, 4:57 PM EDT	Special Marine Warning	PHI		93 min
Jul 9, 4:58 PM EDT	Special Weather Statement	PHI	Cumberland, Salem	47 min
Jul 9, 5:09 PM EDT	Flash Flood Warning	PHI	Salem	4 hr
Jul 9, 5:10 PM EDT	Severe Thunderstorm Warning	PHI	Gloucester, Salem	50 min
Jul 9, 5:15 PM EDT	Special Weather Statement	PHI	Hunterdon, Warren	30 min
Jul 9, 5:35 PM EDT	Severe Thunderstorm Warning	PHI	Camden, Gloucester, Salem	25 min
Jul 9, 5:49 PM EDT	Special Weather Statement	PHI	Cumberland	26 min
Jul 9, 5:59 PM EDT	Flash Flood Warning	PHI	Hunterdon, Mercer	4 hr
Jul 9, 5:59 PM EDT	Special Weather Statement	PHI	Cape May	46 min
Jul 9, 6:33 PM EDT	Special Marine Warning	PHI		87 min
Jul 9, 6:52 PM EDT	Flash Flood Warning	PHI	Hunterdon, Mercer, Middlesex, Morris, Somerset	4 hr
Jul 9, 7:11 PM EDT	Areal Flood Advisory	PHI	Burlington, Camden, Gloucester, Mercer, Salem	3 hr
Jul 9, 7:16 PM EDT	Special Weather Statement	PHI	Burlington	29 min
Jul 9, 7:21 PM EDT	Special Marine Warning	PHI		114 min
Jul 9, 7:29 PM EDT	River Flood Warning	PHI	Hunterdon, Somerset	10 hr

Nearby

Flash Flood Warnings in New Jersey, 2023 Every flash flood warning in 2023

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.