Alert archive / Pennsylvania / Flash Flood Warnings in 2017

Flash Flood Warning 50, NWS Philadelphia/Mount Holly

August 23, 2017Camden County, Gloucester County, New Jersey; 4 counties in Pennsylvania; New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 23, 2017, 12:06 AM EDT for Camden County, Gloucester County, New Jersey; 4 counties in Pennsylvania; New Castle County, Delaware. It was in force for 4 hr. 6 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 23, 2017, 12:06 AM EDT (04:06 UTC)
Expired: Aug 23, 2017, 4:00 AM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties New Castle County, DE, Camden County, NJ, Gloucester County, NJ, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 92 km from the middle of the area, began a volume at 04:10 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
Aug 23, 12:47 AM EDT	FLOOD	1 S Philadelphia Sports, PA	FLOODING ON I 95 NEAR EXIT 17 RESULTING IN A RAMP RESTRICITION.
Aug 23, 12:58 AM EDT	FLOOD	University City, PA	FLOODING RESULTING IN A LANE RESTRICTION ON I76 BETWEEN EXITS 345 AND 346A
Aug 23, 2:02 AM EDT	FLOOD	Locustwood, NJ	STATE HIGHWAY 70 EASTBOUND CLOSED AT HADDONFIELD ROAD IN CHERRY HILL TWP DUE TO FLOODING.
Aug 23, 2:29 AM EDT	FLOOD	Westville, NJ	STATE HIGHWAY 45 JUST SOUTH OF U.S. HIGHWAY 130 CLOSED DUE TO FLOODING.
Aug 23, 2:41 AM EDT	FLOOD	1 Wsw Deerbrook I, PA	FLOODING ON SMITHBRIDGE ROAD BETWEEN BROOK LANE AND RIDGE ROAD IN CHADDS FORD TOWNSHIP. ALL LANES CLOSED.
Aug 23, 4:00 AM EDT	HEAVY RAIN 3.1	West Deptford Twp, NJ

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 00:00Z, 4.1 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: 550 J/kg
Mixed-layer CIN: -36 J/kg
Mixed-layer LCL: 1559 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 134 m²/s²
0-3 km storm-relative helicity: 248 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 2.1

Open this sounding in Storm Lab

The text

As transmitted.

289 
WGUS51 KPHI 230406
FFWPHI
DEC003-NJC007-015-PAC029-045-091-101-230800-
/O.NEW.KPHI.FF.W.0050.170823T0406Z-170823T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1206 AM EDT WED AUG 23 2017

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  Northern New Castle County in northern Delaware...
  Northwestern Camden County in southern New Jersey...
  Northwestern Gloucester County in southern New Jersey...
  Southeastern Montgomery County in southeastern Pennsylvania...
  Southern Chester County in southeastern Pennsylvania...
  Philadelphia County in southeastern Pennsylvania...
  Delaware County in southeastern Pennsylvania...

* Until 400 AM EDT

* At 1206 AM EDT...Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. Up to two inches of rain have
  already fallen. Flash flooding is expected to begin shortly in the
  areas of heaviest rain.

* Some locations that could experience flooding include...
  Philadelphia, Camden, Wilmington, Newark, West Chester, Gloucester
  City, Chester, West Deptford, Pennsville, Bellmawr, Yeadon,
  Westtown, Woodbury, Carneys Point, Conshohocken, Palmyra, Folcroft,
  Swarthmore, Elsmere and Paulsboro.

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.

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

&&

LAT...LON 3982 7603 3987 7600 4012 7519 4002 7503
      3999 7506 3999 7503 3995 7502 3994 7498
      3972 7537 3978 7540 3978 7544 3967 7551
      3967 7579 3972 7579 3972 7604

$$

CMS

2 follow-up statements

434 
WGUS71 KPHI 230517
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
117 AM EDT WED AUG 23 2017

DEC003-NJC007-015-PAC029-045-091-101-230800-
/O.CON.KPHI.FF.W.0050.000000T0000Z-170823T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Camden NJ-Gloucester NJ-Montgomery PA-Chester PA-
Philadelphia PA-Delaware PA-
117 AM EDT WED AUG 23 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 400 AM EDT FOR
NORTHERN NEW CASTLE...NORTHWESTERN CAMDEN...NORTHWESTERN
GLOUCESTER...SOUTHEASTERN MONTGOMERY...SOUTHERN CHESTER...
PHILADELPHIA AND DELAWARE COUNTIES...

At 115 AM EDT...Doppler radar and automated rain gauges indicated up 
to three inches of rain have already fallen in a corridor from West 
Grove to Chester to southern portions of Philadelphia. Reports of 
street flooding have already come in from Chester, Delaware, and 
Philadelphia Counties. Flash flooding is imminent or occurring.

Some locations that could experience flooding include...
Philadelphia, Camden, Wilmington, Newark, West Chester, Gloucester
City, Chester, West Deptford, Pennsville, Bellmawr, Yeadon, Westtown,
Woodbury, Carneys Point, Conshohocken, Palmyra, Folcroft, Swarthmore,
Elsmere and Paulsboro.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3982 7603 3987 7600 4012 7519 4002 7503
      3999 7506 3999 7503 3995 7502 3994 7498
      3972 7537 3978 7540 3978 7544 3967 7551
      3967 7579 3972 7579 3972 7604

$$

CMS

968 
WGUS71 KPHI 230639
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
239 AM EDT WED AUG 23 2017

DEC003-NJC007-015-PAC029-045-091-101-230800-
/O.CON.KPHI.FF.W.0050.000000T0000Z-170823T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Camden NJ-Gloucester NJ-Montgomery PA-Chester PA-
Philadelphia PA-Delaware PA-
239 AM EDT WED AUG 23 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 400 AM EDT FOR
NORTHERN NEW CASTLE...NORTHWESTERN CAMDEN...NORTHWESTERN
GLOUCESTER...SOUTHEASTERN MONTGOMERY...SOUTHERN CHESTER...
PHILADELPHIA AND DELAWARE COUNTIES...

At 236 AM EDT...flooding was occurring in portions of Camden and 
Gloucester Counties. State Highway 70 was flooded near Haddonfield 
Road in Cherry Hill Township, and State Highway 45 was closed south 
of U.S. Highway 130 in Westville. Although the heavy rainfall has 
ended, flooding is expected to continue for the next couple of hours.

Some locations that could experience flooding include...
Philadelphia, Camden, Wilmington, Newark, West Chester, Gloucester
City, Chester, West Deptford, Pennsville, Bellmawr, Yeadon, Westtown,
Woodbury, Carneys Point, Conshohocken, Palmyra, Folcroft, Swarthmore,
Elsmere and Paulsboro.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Please report flooding to your local law enforcement agency when you
can do so safely.

&&

LAT...LON 3982 7603 3987 7600 4012 7519 4002 7503
      3999 7506 3999 7503 3995 7502 3994 7498
      3972 7537 3978 7540 3978 7544 3967 7551
      3967 7579 3972 7579 3972 7604

$$

CMS

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 22, 8:12 PM EDT	Severe Thunderstorm Warning	PHI	Sussex, Warren	48 min
Aug 22, 8:15 PM EDT	Tornado Warning	PHI	Warren	30 min
Aug 22, 8:20 PM EDT	Special Weather Statement	PHI	Sussex	40 min
Aug 22, 8:45 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Somerset, Warren	60 min
Aug 22, 8:58 PM EDT	Severe Thunderstorm Warning	PHI	Sussex, Warren	24 min
Aug 22, 9:42 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Mercer, Middlesex, Morris, Somerset, Warren	48 min
Aug 22, 10:07 PM EDT	Severe Thunderstorm Warning	PHI	Gloucester, Salem	53 min
Aug 22, 10:13 PM EDT	Special Marine Warning	PHI		92 min
Aug 22, 10:27 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Mercer, Middlesex, Monmouth, Somerset	48 min
Aug 22, 10:37 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Mercer, Middlesex, Monmouth, Somerset	4 hr
Aug 22, 10:40 PM EDT	Areal Flood Advisory	PHI	Mercer	4 hr
Aug 22, 10:58 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Cumberland, Gloucester, Mercer, Middlesex and 1 more	62 min
Aug 22, 11:39 PM EDT	Special Marine Warning	PHI		66 min
Aug 22, 11:42 PM EDT	Flash Flood Warning	PHI	Hunterdon, Middlesex, Somerset	4 hr
Aug 22, 11:46 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Camden, Gloucester, Ocean, Salem	44 min
Aug 23, 12:29 AM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Gloucester, Ocean	46 min
Aug 23, 12:37 AM EDT	Areal Flood Advisory	PHI	Burlington, Camden, Gloucester, Mercer, Middlesex, Monmouth and 1 more	4 hr
Aug 23, 1:56 AM EDT	Areal Flood Advisory	PHI	Salem	4 hr
Aug 23, 2:43 AM EDT	Areal Flood Advisory	PHI	Atlantic, Burlington, Camden, Cumberland, Gloucester, Ocean and 1 more	4 hr
Aug 23, 3:37 AM EDT	Areal Flood Warning	PHI	Hunterdon, Middlesex, Somerset	4 hr
Aug 23, 4:02 AM EDT	Areal Flood Warning	PHI	Camden, Gloucester	4 hr
Aug 22, 9:18 PM EDT	Areal Flood Advisory	PHI	Berks, Montgomery	4 hr
Aug 22, 9:23 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester, Montgomery	52 min
Aug 22, 9:40 PM EDT	Tornado Warning	PHI	Berks, Chester, Montgomery	20 min

Nearby

Flash Flood Warnings in Pennsylvania, 2017 Flash Flood Warnings in New Jersey, 2017 Flash Flood Warnings in Delaware, 2017 Every flash flood warning in 2017

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.