Alert archive / Pennsylvania / Flash Flood Warnings in 2020

Flash Flood Warning 48, NWS Philadelphia/Mount Holly

August 7, 2020Montgomery County, Philadelphia County, Pennsylvania; Camden County, Gloucester County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 7, 2020, 5:43 PM EDT for Montgomery County, Philadelphia County, Pennsylvania; Camden County, Gloucester County, New Jersey. It was in force for 4 hr. 2 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 7, 2020, 5:43 PM EDT (21:43 UTC)
Expired
Aug 7, 2020, 9:51 PM EDT
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Camden County, NJ, Gloucester County, NJ, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 71 km from the middle of the area, began a volume at 21:47 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 7, 7:00 PM EDTFLASH FLOODLogan Twp., NJCARS STUCK IN FLOODED WATER, KNEE HIGH DEEP WATER IN SOME AREAS. TIME ESTIMATED RADAR.
Aug 7, 7:15 PM EDTFLASH FLOODWoolwich Twp, NJWIDESPREAD FLASH FLOODING OF ROADS AND PROPERTIES REPORTED IN SWEDESBORO.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 9.7 hours before the alert went out and 215 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, Washington/Dulle, VA at 12:00Z on 2020-08-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 301 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, Washington/Dulle, VA at 12:00Z on 2020-08-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -37 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
301 J/kg
Mixed-layer CIN
-67 J/kg
Mixed-layer LCL
665 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
-37 m²/s²
0-3 km storm-relative helicity
18 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

123 
WGUS51 KPHI 072143
FFWPHI
NJC007-015-PAC091-101-080345-
/O.NEW.KPHI.FF.W.0048.200807T2143Z-200808T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
543 PM EDT Fri Aug 7 2020

The National Weather Service in Mount Holly NJ has issued a

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

* Until 1145 PM EDT Friday.

* At 542 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain moving into the warned area. Flash flooding is expected 
  to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar indicated.

  IMPACT...Flooding of small creeks and streams, urban areas, 
           highways, streets and underpasses as well as other 
           poor drainage and low lying areas.

* Some locations that could experience flooding include...
  Philadelphia, Camden, Wilmington, Gloucester City, Cherry Hill,
  Norristown, Chester, Deptford, West Deptford, Phoenixville, West
  Norriton, East Norriton, Bellmawr, Yeadon, Woodbury, Pitman,
  Carneys Point, Conshohocken, Palmyra and Hatboro.

Additional rainfall amounts of 1 to 3 inches are possible in the 
warned area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, urban areas, highways, streets, and underpasses
as well as other poor drainage areas and low lying spots.

&&

LAT...LON 4022 7515 4012 7496 4005 7498 3999 7506
      3998 7501 3995 7502 3991 7495 3969 7519
      3969 7533 3976 7540 3978 7540 3970 7551
      3972 7551 3984 7536 3987 7521 3988 7526
      3996 7525 4007 7536 4010 7546 4019 7555

FLASH FLOOD...RADAR INDICATED

$$

Iovino
2 follow-up statements
878 
WGUS71 KPHI 080014
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
814 PM EDT Fri Aug 7 2020

NJC007-PAC091-101-080022-
/O.CAN.KPHI.FF.W.0048.000000T0000Z-200808T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Camden NJ-Montgomery PA-Philadelphia PA-
814 PM EDT Fri Aug 7 2020

...THE FLASH FLOOD WARNING FOR NORTHWESTERN CAMDEN...SOUTHERN
MONTGOMERY AND PHILADELPHIA COUNTIES IS CANCELLED...

Flooding is no longer expected to pose a threat. Please continue to
heed any remaining road closures.

LAT...LON 3984 7536 3985 7525 3989 7514 3984 7509
      3980 7507 3969 7519 3969 7533 3976 7540
      3974 7546 3972 7551

$$

NJC015-080345-
/O.CON.KPHI.FF.W.0048.000000T0000Z-200808T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Gloucester NJ-
814 PM EDT Fri Aug 7 2020

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1145 PM EDT FRIDAY
FOR NORTHWESTERN GLOUCESTER COUNTY...

At 812 PM EDT, runoff from today's heavy rain was continuing to 
produce flooding in parts of Gloucester Coounty.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar indicated.

IMPACT...Flooding of small creeks and streams, urban areas, 
         highways, streets and underpasses as well as other 
         poor drainage and low lying areas.

Some locations that will conitnue to experience flooding include...
Deptford, West Deptford, Bellmawr, Woodbury, Pitman, Paulsboro, 
Westville, Woodbury Heights, National Park, Swedesboro, Mullica 
Hill, Gibbstown and Wenonah.

Little additional rainfall is expected.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, urban areas, highways, streets, and underpasses
as well as other poor drainage areas and low lying spots.

&&

LAT...LON 3984 7536 3985 7525 3989 7514 3984 7509
      3980 7507 3969 7519 3969 7533 3976 7540
      3974 7546 3972 7551

FLASH FLOOD...RADAR INDICATED

$$

Iovino
717 
WGUS71 KPHI 080151 RRA
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
951 PM EDT Fri Aug 7 2020

NJC015-080201-
/O.CAN.KPHI.FF.W.0048.000000T0000Z-200808T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Gloucester NJ-
951 PM EDT Fri Aug 7 2020

...THE FLASH FLOOD WARNING FOR NORTHWESTERN GLOUCESTER COUNTY IS
CANCELLED...

Flood waters have receded. Flooding is no longer expected to pose a
threat. Please continue to heed any remaining road closures.

LAT...LON 3984 7536 3985 7525 3989 7514 3984 7509
      3980 7507 3969 7519 3969 7533 3976 7540
      3974 7546 3972 7551

$$

Iovino

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 7, 6:49 AM EDTAreal Flood AdvisoryPHIBerks4 hr
Aug 7, 9:22 AM EDTAreal Flood AdvisoryPHIBucks3 hr
Aug 7, 10:34 AM EDTSevere Thunderstorm WarningPHICarbon, Lehigh56 min
Aug 7, 11:28 AM EDTSpecial Weather StatementPHICarbon, Lehigh47 min
Aug 7, 2:34 PM EDTAreal Flood AdvisoryPHIBerks4 hr
Aug 7, 3:46 PM EDTAreal Flood AdvisoryPHICarbon, Lehigh, Northampton4 hr
Aug 7, 4:10 PM EDTFlash Flood WarningPHIBerks2 hr
Aug 7, 4:20 PM EDTAreal Flood AdvisoryPHIChester, Montgomery4 hr
Aug 7, 4:32 PM EDTFlash Flood WarningPHIChester3 hr
Aug 7, 4:47 PM EDTSpecial Weather StatementPHIChester28 min
Aug 7, 5:00 PM EDTSevere Thunderstorm WarningPHIChester60 min
Aug 7, 5:03 PM EDTFlash Flood WarningPHIChester, Delaware5 hr
Aug 7, 5:15 PM EDTAreal Flood AdvisoryPHIBucks3 hr
Aug 7, 5:25 PM EDTAreal Flood AdvisoryPHIBucks, Montgomery, Philadelphia3 hr
Aug 7, 5:38 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Montgomery, Philadelphia52 min
Aug 7, 5:49 PM EDTTornado WarningPHIChester, Delaware26 min
Aug 7, 5:57 PM EDTSevere Thunderstorm WarningPHIDelaware, Philadelphia48 min
Aug 7, 6:00 PM EDTTornado WarningPHIDelaware30 min
Aug 7, 6:39 PM EDTSevere Thunderstorm WarningPHIBucks27 min
Aug 7, 7:10 PM EDTRiver Flood WarningPHIDelaware7 hr
Aug 7, 7:17 PM EDTAreal Flood WarningPHIBucks, Montgomery3 hr
Aug 7, 6:08 PM EDTAreal Flood AdvisoryPHICumberland, Gloucester, Salem3 hr
Aug 7, 6:16 PM EDTAreal Flood AdvisoryPHIMercer2 hr
Aug 7, 6:24 PM EDTSpecial Marine WarningPHI66 min
Aug 7, 6:41 PM EDTSevere Thunderstorm WarningPHIAtlantic, Camden, Cumberland, Gloucester, Salem49 min
Aug 7, 6:57 PM EDTSevere Thunderstorm WarningPHIAtlantic, Camden, Cumberland, Gloucester, Salem48 min
Aug 7, 7:24 PM EDTSpecial Marine WarningPHI66 min
Aug 7, 7:25 PM EDTFlash Flood WarningPHIAtlantic, Cape May, Cumberland, Gloucester4 hr
Aug 7, 7:28 PM EDTSevere Thunderstorm WarningPHIAtlantic, Burlington, Camden, Cape May, Cumberland, Gloucester and 1 more62 min

Nearby

Flash Flood Warnings in Pennsylvania, 2020Flash Flood Warnings in New Jersey, 2020Every flash flood warning in 2020

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.