Alert archive / Pennsylvania / Flash Flood Warnings in 2024

Flash Flood Warning 42, NWS Philadelphia/Mount Holly

August 6, 2024Burlington County, New Jersey; 4 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 6, 2024, 8:29 PM EDT for Burlington County, New Jersey; 4 counties in Pennsylvania. It was in force for 4 hr. 13 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 6, 2024, 8:29 PM EDT (00:29 UTC)
Expired
Aug 7, 2024, 12:03 AM EDT
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Burlington County, NJ, Bucks County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 64 km from the middle of the area, began a volume at 00:32 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

TimeReportWhereRemark
Aug 6, 8:42 PM EDTFLASH FLOOD1 Sw Delran, NJUS 130 at Manor Drive NJ 511 Webcam in Cinnaminson shows flash flooding on roadway. At least one car stuck in flooded waters.
Aug 6, 8:45 PM EDTFLASH FLOODEdgewater Park, NJPictures shared on social media of road flooding in Edgewater Park. Time estimated from nearby reports.
Aug 6, 9:45 PM EDTRAIN 2.052 Ese Tullytown, PAMesonet station CW7186 Chesterfield.
Aug 6, 9:45 PM EDTRAIN 2.44Lima, PAMesonet station GW2214 DES - TEST SITE DELCO.
Aug 6, 9:48 PM EDTRAIN 2.621 W Bristol, PAMesonet station DCBPA Bristol.
Aug 6, 9:49 PM EDTRAIN 2.28Bristol, PAMesonet station GW0358 Bristol.
Aug 6, 9:50 PM EDTRAIN 2.641 S Lima, PAMesonet station FW3096 Media.
Aug 6, 10:00 PM EDTRAIN 6.01New Albany, NJPWS station KNJCINNA11 in Cinnaminson Township.
Aug 6, 10:00 PM EDTRAIN 6.881 Sw Delran, NJPWS station KNJRIVER27.
Aug 6, 10:15 PM EDTRAIN 7.031 Sw Delran, NJUpdates previous rain report from 1 SW Delran. PWS station KNJRIVER27.
Aug 6, 10:30 PM EDTFLASH FLOODBensalem, PAPicture on social media of a street flooded in Bensalem.
Aug 6, 10:30 PM EDTRAIN 6.091 Sse Fairview, NJRainfall total so far in Delran closer to the Moorestown border.
Aug 6, 10:40 PM EDTFLASH FLOODBristol, PAMultiple reports of flooding in Bristol, including a roof collapse due to the water load.

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, 0.5 hours before the alert went out and 211 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-pSkew-T log-p diagram, Brookhaven, NY at 00:00Z on 2024-08-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 123 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 00:00Z on 2024-08-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 27 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
123 J/kg
Mixed-layer CIN
-52 J/kg
Mixed-layer LCL
553 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
27 m²/s²
0-3 km storm-relative helicity
68 m²/s²
Significant tornado parameter
-0.0
Supercell composite
-0.8

Open this sounding in Storm Lab

The text

As transmitted.

506 
WGUS51 KPHI 070029
FFWPHI
NJC005-PAC017-045-091-101-070415-
/O.NEW.KPHI.FF.W.0042.240807T0029Z-240807T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
829 PM EDT Tue Aug 6 2024

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Northwestern Burlington County in southern New Jersey...
  Southeastern Bucks County in southeastern Pennsylvania...
  Delaware County in southeastern Pennsylvania...
  Southeastern Montgomery County in southeastern Pennsylvania...
  Philadelphia County in southeastern Pennsylvania...

* Until 1215 AM EDT.

* At 829 PM EDT, Doppler radar and automated rain gauges indicated 
  thunderstorms produced heavy rain across the warned area. Between 
  0.5 and 1.5 inches of rain have fallen. Another round of strong 
  thunderstorms with rainfall rates 1 to 2 inches per hour is 
  expected. 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 and automated gauges.

  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...
  Philadelphia, Trenton, Camden, Bensalem, Ewing, Norristown, 
  Chester, Lansdale, West Norriton, East Norriton, Yeadon and 
  Burlington.

This includes the following highways...
	Interstate 476 in Pennsylvania between mile markers 0 and 19.
	Interstate 76 in Pennsylvania between mile markers 330 and 351.
	Interstate 95 in Pennsylvania between mile markers 1 and 10...and
	between mile markers 12 and 40.
	Interstate 676 in Pennsylvania between mile markers 0 and 1.
	Northeast Extension between mile markers 21 and 28.
	Pennsylvania Turnpike between mile markers 329 and 359.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 4033 7518 4039 7496 4034 7494 4030 7487
      4025 7484 4022 7477 4016 7472 4006 7492
      3998 7491 4000 7504 3996 7513 3988 7515
      3987 7521 3988 7526 3981 7541 3988 7559
      3992 7552 3994 7552 4004 7536 4020 7539

FLASH FLOOD...RADAR AND GAUGE INDICATED
EXPECTED RAINFALL RATE...1-2 INCHES IN 1 HOUR

$$

MJL
1 follow-up statement
053 
WGUS71 KPHI 070403 RRA
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1203 AM EDT Wed Aug 7 2024

NJC005-PAC017-045-091-101-070413-
/O.CAN.KPHI.FF.W.0042.000000T0000Z-240807T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Burlington NJ-Bucks PA-Delaware PA-Montgomery PA-Philadelphia PA-
1203 AM EDT Wed Aug 7 2024

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHWESTERN BURLINGTON, 
SOUTHEASTERN BUCKS, DELAWARE, SOUTHEASTERN MONTGOMERY AND 
PHILADELPHIA COUNTIES...

The heavy rain has ended. While the flash flood threat has ended, 
flooding remains an issue. A new Flood Warning will be issued. 
Please continue to heed remaining road closures.

A Flood Watch remains in effect until 1200 PM EDT Wednesday for 
portions of northern Delaware, New Jersey, and Pennsylvania.

&&

LAT...LON 4033 7518 4039 7496 4034 7494 4030 7487
      4025 7484 4022 7477 4016 7472 4006 7492
      3998 7491 4000 7504 3996 7513 3988 7515
      3987 7521 3988 7526 3981 7541 3988 7559
      3992 7552 3994 7552 4004 7536 4020 7539

$$

MPS

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 6, 8:49 PM EDTFlash Flood Warning Considerable damage threatPHIMiddlesex, Somerset4 hr
Aug 6, 9:12 PM EDTFlash Flood Warning Considerable damage threatPHIBurlington, Camden3 hr
Aug 6, 9:32 PM EDTSevere Thunderstorm WarningPHIBurlington, Camden27 min
Aug 6, 11:37 PM EDTAreal Flood WarningPHIHunterdon, Mercer, Middlesex, Morris, Somerset4 hr
Aug 7, 12:07 AM EDTAreal Flood WarningPHIBurlington, Camden, Gloucester4 hr
Aug 7, 12:27 AM EDTAreal Flood WarningPHIBurlington, Mercer, Middlesex, Monmouth5 hr
Aug 7, 2:29 AM EDTFlash Flood WarningPHICape May, Cumberland113 min
Aug 7, 8:49 AM EDTMarine Dense Fog AdvisoryPHI21 hr
Aug 7, 2:09 PM EDTGale WatchPHI13 hr
Aug 7, 2:09 PM EDTSmall Craft AdvisoryPHI40 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2024Flash Flood Warnings in New Jersey, 2024Every flash flood warning in 2024

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.