Alert archive / New Jersey / Flash Flood Warnings in 2021

Flash Flood Warning 16, NWS Philadelphia/Mount Holly

July 12, 2021Camden County, New Jersey; Philadelphia County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 12, 2021, 6:01 PM EDT for Camden County, New Jersey; Philadelphia County, Pennsylvania. It was in force for 102 min. 4 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 12, 2021, 6:01 PM EDT (22:01 UTC)
Expired: Jul 12, 2021, 7:43 PM EDT
In force: 102 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Camden County, NJ, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 64 km from the middle of the area, began a volume at 22:04 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 12, 6:38 PM EDT	FLASH FLOOD	1 Nne Rittenhouse Squar, PA	FLOODING ON THE VINE STREET EXPRESSWAY.
Jul 12, 7:30 PM EDT	FLASH FLOOD	Pennsauken, NJ	U.S. HIGHWAY 130 CLOSED NEAR BROWNING ROAD. TIME BASED ON DISPATCH REPORT.
Jul 12, 7:30 PM EDT	HEAVY RAIN 3.45	1 Ssw Palmyra, NJ	NJWXNET STATION AT PENNSAUKEN SANITARY LANDFILL.
Jul 12, 7:40 PM EDT	FLOOD	1 Se Center City, PA	RIGHT LANE FLOODED AND IMPASSABLE ON I-95 SOUTHBOUND NEAR FISHTOWN.

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 220 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: 857 J/kg
Mixed-layer CIN: -57 J/kg
Mixed-layer LCL: 697 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 85 m²/s²
0-3 km storm-relative helicity: 114 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 2.4

Open this sounding in Storm Lab

The text

As transmitted.

632 
WGUS51 KPHI 122201
FFWPHI
NJC007-PAC101-130215-
/O.NEW.KPHI.FF.W.0016.210712T2201Z-210713T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
601 PM EDT Mon Jul 12 2021

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Northwestern Camden County in southern New Jersey...
  Southwestern Philadelphia County in southeastern Pennsylvania...

* Until 1015 PM EDT.

* At 601 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 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 will experience flash flooding include...
  Philadelphia, Camden, Gloucester City, Yeadon, Palmyra, Center 
  City, Kensington, South Philadelphia, Roxborough, and Morris Park.

This includes the following highways...
	Interstate 95 in Pennsylvania between mile markers 12 and 26.
	Interstate 76 in Pennsylvania between mile markers 340 and 351.
	Interstate 76 in New Jersey near mile marker 3.
	Interstate 676 in Pennsylvania between mile markers 0 and 1.
	Interstate 676 in New Jersey between mile markers 1 and 4.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3988 7519 3987 7521 3988 7522 3987 7524
      3988 7526 3993 7524 3994 7524 3995 7525
      3996 7525 3997 7527 3997 7528 4004 7514
      4000 7507 4000 7505 3999 7506 4000 7503
      3998 7501 3997 7502 3996 7502 3989 7513

FLASH FLOOD...RADAR INDICATED

$$

Iovino

1 follow-up statement

324 
WGUS71 KPHI 122343
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
743 PM EDT Mon Jul 12 2021

NJC007-PAC101-122353-
/O.CAN.KPHI.FF.W.0016.000000T0000Z-210713T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Camden NJ-Philadelphia PA-
743 PM EDT Mon Jul 12 2021

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHWESTERN CAMDEN AND 
SOUTHWESTERN PHILADELPHIA COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.



LAT...LON 3988 7519 3987 7521 3988 7522 3987 7524
      3988 7526 3993 7524 3994 7524 3995 7525
      3996 7525 3997 7527 3997 7528 4004 7514
      4000 7507 4000 7505 3999 7506 4000 7503
      3998 7501 3997 7502 3996 7502 3989 7513

$$

Iovino

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 12, 1:59 PM EDT	Areal Flood Advisory	PHI	Burlington, Camden	3 hr
Jul 12, 2:12 PM EDT	Flash Flood Warning Emergency	PHI	Burlington	7 hr
Jul 12, 2:20 PM EDT	Areal Flood Advisory	PHI	Mercer, Middlesex, Monmouth	3 hr
Jul 12, 2:37 PM EDT	Flash Flood Warning	PHI	Mercer, Middlesex, Monmouth	93 min
Jul 12, 3:08 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Mercer, Middlesex, Monmouth, Ocean	67 min
Jul 12, 3:31 PM EDT	Severe Thunderstorm Warning	PHI	Middlesex, Monmouth	41 min
Jul 12, 4:26 PM EDT	Special Marine Warning	PHI		2 hr
Jul 12, 4:33 PM EDT	Severe Thunderstorm Warning	PHI	Monmouth, Ocean	42 min
Jul 12, 4:52 PM EDT	Areal Flood Advisory	PHI	Monmouth, Ocean	98 min
Jul 12, 5:08 PM EDT	Areal Flood Advisory	PHI	Sussex	5 hr
Jul 12, 5:08 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Mercer	67 min
Jul 12, 5:26 PM EDT	Areal Flood Advisory	PHI	Camden	2 hr
Jul 12, 5:36 PM EDT	Special Weather Statement	PHI	Sussex	24 min
Jul 12, 5:41 PM EDT	Areal Flood Advisory	PHI	Burlington	83 min
Jul 12, 5:57 PM EDT	Severe Thunderstorm Warning	PHI	Morris, Sussex	63 min
Jul 12, 6:08 PM EDT	Areal Flood Advisory	PHI	Morris	98 min
Jul 12, 6:43 PM EDT	Areal Flood Advisory	PHI	Burlington, Camden, Gloucester	93 min
Jul 12, 6:52 PM EDT	Severe Thunderstorm Warning	PHI	Morris, Sussex	34 min
Jul 12, 7:00 PM EDT	Areal Flood Advisory	PHI	Gloucester, Salem	112 min
Jul 12, 7:06 PM EDT	Severe Thunderstorm Warning	PHI	Salem	69 min
Jul 12, 7:11 PM EDT	Flash Flood Warning	PHI	Morris, Sussex	35 min
Jul 12, 7:33 PM EDT	Special Marine Warning	PHI		58 min
Jul 11, 10:21 PM EDT	Severe Thunderstorm Warning	PHI	Berks	24 min
Jul 11, 10:22 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Carbon, Lehigh, Monroe, Northampton	38 min
Jul 12, 2:28 PM EDT	Areal Flood Advisory	PHI	Chester	3 hr
Jul 12, 4:16 PM EDT	Areal Flood Advisory	PHI	Bucks, Montgomery, Philadelphia	114 min
Jul 12, 5:41 PM EDT	Severe Thunderstorm Warning	PHI	Chester	34 min
Jul 12, 6:18 PM EDT	Flash Flood Warning	PHI	Delaware	84 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.