Alert archive / New Jersey / Flash Flood Warnings in 2023

Flash Flood Warning 50, NWS Philadelphia/Mount Holly

July 9, 20235 counties in New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 9, 2023, 6:52 PM EDT for 5 counties in New Jersey. It was in force for 4 hr. 1 report 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, 6:52 PM EDT (22:52 UTC)
Expired: Jul 9, 2023, 11:00 PM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Morris County, NJ, Somerset County, NJ

The radar

The Philadelphia radar (KDIX), 78 km from the middle of the area, began a volume at 22:55 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, 9:45 PM EDT	FLASH FLOOD	4 Ssw Bedminster Twp, NJ	The Lamington River gauge at Burnt Mills 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, 10.9 hours before the alert went out and 139 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.

732 
WGUS51 KPHI 092252
FFWPHI
NJC019-021-023-027-035-100300-
/O.NEW.KPHI.FF.W.0050.230709T2252Z-230710T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  North Central Mercer County in central New Jersey...
  Northwestern Middlesex County in northern New Jersey...
  Southeastern Morris County in northern New Jersey...
  Somerset County in northern New Jersey...
  East Central Hunterdon County in northwestern New Jersey...

* Until 1100 PM EDT.

* At 652 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have fallen. Additional rainfall amounts of 0.5 to 1.5 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...
  Somerville, Somerset, Bridgewater, Madison, Middlesex, Florham 
  Park, Bound Brook, Manville, Chatham, Peapack And Gladstone, Far 
  Hills, and Rocky Hill.

This includes the following highways...
	Interstate 78 in New Jersey between mile markers 27 and 42.
	Interstate 287 in New Jersey between mile markers 7 and 31.

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 4068 7471 4071 7462 4082 7438 4080 7436
      4079 7437 4076 7438 4076 7436 4074 7437
      4067 7446 4066 7445 4067 7440 4065 7441
      4061 7444 4060 7446 4060 7444 4054 7446
      4044 7454 4036 7468 4043 7481

FLASH FLOOD...RADAR INDICATED

$$

Hoeflich

1 follow-up statement

462 
WGUS71 KPHI 100250
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1050 PM EDT Sun Jul 9 2023

NJC019-021-023-027-035-100300-
/O.EXP.KPHI.FF.W.0050.000000T0000Z-230710T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hunterdon NJ-Mercer NJ-Middlesex NJ-Morris NJ-Somerset NJ-
1050 PM EDT Sun Jul 9 2023

...FLASH FLOOD WARNING WILL EXPIRE AT 11 PM EDT THIS EVENING FOR 
NORTH CENTRAL MERCER, NORTHWESTERN MIDDLESEX, SOUTHEASTERN MORRIS, 
SOMERSET, AND EAST CENTRAL HUNTERDON COUNTIES...

Flood waters have receded. The heavy rain has ended. Flooding is no 
longer expected to pose a threat.

LAT...LON 4068 7471 4071 7462 4082 7438 4080 7436
      4079 7437 4076 7438 4076 7436 4074 7437
      4067 7446 4066 7445 4067 7440 4065 7441
      4061 7444 4060 7446 4060 7444 4054 7446
      4044 7454 4036 7468 4043 7481

$$

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, 2:34 PM EDT	Flash Flood Warning	PHI	Hunterdon, Morris, Somerset, Warren	6 hr
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, 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.