Alert archive / New Jersey / Flash Flood Warnings in 2023

Flash Flood Warning 49, NWS Philadelphia/Mount Holly

July 9, 2023Hunterdon County, Mercer County, New Jersey; Bucks County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 9, 2023, 5:59 PM EDT for Hunterdon County, Mercer County, New Jersey; Bucks County, Montgomery County, Pennsylvania. It was in force for 4 hr. 3 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, 5:59 PM EDT (21:59 UTC)
Expired: Jul 9, 2023, 10:00 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, Bucks County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 63 km from the middle of the area, began a volume at 21:59 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, 6:15 PM EDT	FLASH FLOOD	1 Nnw Horsham, PA	Closed due to flooding in Horsham Twp on Horsham Rd NB/SB between PA-611/Easton Rd and Dresher Rd.
Jul 9, 7:35 PM EDT	FLOOD	1 E Solebury Twp, PA	Video of water over-running roadway on Upper York Road (Rte 263) in New Hope PA. Road was still drivable at time of report.
Jul 9, 8:15 PM EDT	FLASH FLOOD	3 Ne Ringoes, NJ	The Neshanic River at Reaville 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, 10.0 hours before the alert went out and 193 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.

073 
WGUS51 KPHI 092159
FFWPHI
NJC019-021-PAC017-091-100200-
/O.NEW.KPHI.FF.W.0049.230709T2159Z-230710T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Northwestern Mercer County in central New Jersey...
  Southeastern Hunterdon County in northwestern New Jersey...
  Central Bucks County in southeastern Pennsylvania...
  East Central Montgomery County in southeastern Pennsylvania...

* Until 1000 PM EDT.

* At 559 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.5 and 1 inch of rain 
  has fallen. Additional rainfall amounts of 1 to 3 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...
  Doylestown, Byram, Hatboro, Flemington, New Hope, Newtown, 
  Langhorne, Bryn Athyn, Ivyland, Stockton, and Lumberville.

This includes the following highways...
	Pennsylvania Turnpike between mile markers 345 and 352.

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 4027 7515 4038 7514 4050 7507 4050 7479
      4043 7477 4011 7496 4012 7496 4013 7499
      4013 7502 4021 7519

FLASH FLOOD...RADAR INDICATED

$$

Hoeflich

1 follow-up statement

515 
WGUS71 KPHI 100151
FFSPHI

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

NJC019-021-PAC017-091-100201-
/O.EXP.KPHI.FF.W.0049.000000T0000Z-230710T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hunterdon NJ-Mercer NJ-Bucks PA-Montgomery PA-
951 PM EDT Sun Jul 9 2023

...FLASH FLOOD WARNING WILL EXPIRE AT 10 PM EDT THIS EVENING FOR 
NORTHWESTERN MERCER, SOUTHEASTERN HUNTERDON, CENTRAL BUCKS, AND EAST 
CENTRAL MONTGOMERY COUNTIES...

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

A Flood Watch remains in effect until 1200 AM EDT for portions of 
east central Pennsylvania...northeast Pennsylvania...and southeast 
Pennsylvania.

A Flood Watch remains in effect until 1200 AM EDT for portions of 
northern Delaware...northeast Maryland...southern New Jersey...and 
southeast Pennsylvania.

A Flood Watch remains in effect until 600 AM EDT Monday for portions 
of central New Jersey...northern New Jersey...and northwest New 
Jersey.

LAT...LON 4027 7515 4038 7514 4050 7507 4050 7479
      4043 7477 4011 7496 4012 7496 4013 7499
      4013 7502 4021 7519

$$

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	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
Jul 9, 11:00 AM EDT	Special Weather Statement	PHI	Carbon	30 min
Jul 9, 11:33 AM EDT	Flash Flood Warning	PHI	Chester, Delaware, Montgomery	8 hr
Jul 9, 11:47 AM EDT	Special Weather Statement	PHI	Monroe	43 min
Jul 9, 11:49 AM EDT	Special Weather Statement	PHI	Montgomery	41 min
Jul 9, 11:54 AM EDT	Areal Flood Advisory	PHI	Berks, Bucks, Lehigh, Montgomery	33 min
Jul 9, 12:14 PM EDT	Special Weather Statement	PHI	Bucks	46 min
Jul 9, 12:15 PM EDT	Special Weather Statement	PHI	Monroe	30 min
Jul 9, 12:22 PM EDT	Special Weather Statement	PHI	Lebanon	38 min
Jul 9, 12:27 PM EDT	Flash Flood Warning	PHI	Berks, Bucks, Lehigh, Montgomery	8 hr
Jul 9, 12:43 PM EDT	Areal Flood Advisory	PHI	Berks	33 min
Jul 9, 12:51 PM EDT	Special Weather Statement	PHI	Northampton	24 min
Jul 9, 12:57 PM EDT	Areal Flood Advisory	PHI	Carbon, Monroe	6 hr
Jul 9, 1:16 PM EDT	Flash Flood Warning	PHI	Berks	6 hr
Jul 9, 1:17 PM EDT	Special Weather Statement	PHI	Berks	28 min
Jul 9, 1:32 PM EDT	Areal Flood Advisory	PHI	Carbon, Lehigh, Monroe, Northampton	4 hr
Jul 9, 2:16 PM EDT	Areal Flood Advisory	PHI	Berks, Lehigh	30 min
Jul 9, 2:41 PM EDT	Flash Flood Warning	PHI	Berks	4 hr
Jul 9, 2:46 PM EDT	Flash Flood Warning	PHI	Berks, Lehigh, Northampton	6 hr
Jul 9, 3:01 PM EDT	Special Weather Statement	PHI	Berks	29 min
Jul 9, 3:03 PM EDT	Special Weather Statement	PHI	Chester	27 min
Jul 9, 3:15 PM EDT	Severe Thunderstorm Warning	PHI	Berks	30 min
Jul 9, 3:20 PM EDT	Special Weather Statement	PHI	Berks	25 min
Jul 9, 3:27 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester	33 min
Jul 9, 3:41 PM EDT	Special Weather Statement	PHI	Berks	34 min
Jul 9, 3:51 PM EDT	Flash Flood Warning Considerable damage threat	PHI	Berks, Chester, Lehigh, Montgomery	6 hr
Jul 9, 3:59 PM EDT	Special Weather Statement	PHI	Chester	31 min
Jul 9, 4:03 PM EDT	Severe Thunderstorm Warning	PHI	Montgomery	27 min
Jul 9, 4:19 PM EDT	Special Weather Statement	PHI	Chester	26 min
Jul 9, 4:31 PM EDT	Flash Flood Warning	PHI	Chester, Montgomery	4 hr
Jul 9, 5:12 PM EDT	Flash Flood Warning	PHI	Bucks, Montgomery	5 hr
Jul 9, 5:31 PM EDT	Flash Flood Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	4 hr
Jul 9, 6:05 PM EDT	Special Weather Statement	PHI	Bucks	25 min
Jul 9, 7:04 PM EDT	Areal Flood Warning	PHI	Berks	9 hr
Jul 9, 7:27 PM EDT	River Flood Warning	PHI	Chester	4 hr

Nearby

Flash Flood Warnings in New Jersey, 2023 Flash Flood Warnings in Pennsylvania, 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.