Alert archive / Pennsylvania / Flash Flood Warnings in 2019

Flash Flood Warning 80, NWS Philadelphia/Mount Holly

August 7, 20194 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 7, 2019, 4:44 PM EDT for 4 counties in Pennsylvania. It was in force for 3 hr. 21 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, 2019, 4:44 PM EDT (20:44 UTC)
Expired: Aug 7, 2019, 7:45 PM EDT
In force: 3 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 83 km from the middle of the area, began a volume at 20:48 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 7, 5:10 PM EDT	FLASH FLOOD	1 Sse Newtown Square, PA	WATER RESCUE IN PROGRESS ON TROOP FARM DRIVE AND SOUTH NEWTOWN STREET ROAD.
Aug 7, 5:13 PM EDT	FLASH FLOOD	2 Ssw Newtown Square, PA	WATER RESCUE IN PROGRESS ON GRADYVILLE ROAD AND BISHOP HOLLOW ROAD.
Aug 7, 5:19 PM EDT	FLASH FLOOD	2 Ssw Whitemarsh Twp, PA	ADDS LOCATION DETAIL TO PREVIOUS FLASH FLOOD REPORT FROM WHITEMARSH TWP. WATER RESCUE ONGOING ON HARTS LN IN WHITEMARSH.
Aug 7, 5:19 PM EDT	FLASH FLOOD	Whitemarsh Twp, PA	WATER RESCUE ONGOING IN WHITEMARSH.
Aug 7, 5:20 PM EDT	FLASH FLOOD	2 Nne Gladwyne, PA	WATER RESCUE IN PROGRESS ON HARTS LANE.
Aug 7, 5:29 PM EDT	FLASH FLOOD	Ardmore, PA	WATER RESCUE REPORTED ON E COUNTY LINE RD AT SIMPSON RD.
Aug 7, 5:30 PM EDT	FLASH FLOOD	2 Wsw Newtown Twp, PA	THE GAUGE ON CRUM CREEK NEAR NEWTOWN SQUARE REACHED FLOOD STAGE.
Aug 7, 5:35 PM EDT	FLASH FLOOD	1 Ssw Ardmore, PA	WATER RESCUE IN PROGRESS ON EAST COUNTY LINE ROAD.
Aug 7, 5:40 PM EDT	FLASH FLOOD	1 Sw Shawmont, PA	WATER RESCUE IN PROGRESS ON HOLLOW ROAD NEAR INTERSTATE 76.
Aug 7, 5:40 PM EDT	FLASH FLOOD	Wynnewood, PA	WATER RESCUE IN PROGRESS ON PENN ROAD.
Aug 7, 5:43 PM EDT	FLOOD	1 Nne Lawrence Park, PA	FLOODING ON I-476.
Aug 7, 5:44 PM EDT	FLASH FLOOD	1 W Villanova, PA	WATER RESCUE IN PROGRESS ON CONESTOGA ROAD.
Aug 7, 5:44 PM EDT	FLASH FLOOD	Wynnewood, PA	WATER RESCUE AT THE INTERSECTION OF PENN RD AND E WYNNEWOOD RD.
Aug 7, 5:45 PM EDT	FLASH FLOOD	1 W Media, PA	THE GAUGE AT RIDLEY CREEK NEAR MEDIA REACHED FLOOD STAGE.
Aug 7, 5:50 PM EDT	FLASH FLOOD	1 Sse Manayunk, PA	INTERSTATE 76 WEST BOUND AT CITY AVE CLOSED DUE TO FLOODING.
Aug 7, 5:54 PM EDT	FLOOD	1 Ene Roxborough, PA	FLOODING ON I-76.
Aug 7, 6:00 PM EDT	FLASH FLOOD	1 N Lawrence Park, PA	I476 NORTH BOUND AT ROUTE 3 BLOCKED DUE TO FLOODING. STRANDED VEHICLE IN THE FLOOD WATERS.
Aug 7, 6:01 PM EDT	FLASH FLOOD	Green Ridge, PA	THE GAUGE AT CHESTER CREEK NEAR CHESTER REACHED FLOOD STAGE.
Aug 7, 6:19 PM EDT	FLOOD	1 Sse Lawrence Park, PA	STANDING WATER ON W ROLLING ROAD ALONG DARBY CREEK.
Aug 7, 6:50 PM EDT	FLASH FLOOD	1 N Springfield Twp, PA	FLOODING ON W ROLLING RD WEST OF STATE RD. MULTIPLE CARS STRANDED.
Aug 7, 7:15 PM EDT	FLASH FLOOD	1 Ssw Ardmore, PA	18 HOMES ARE BEING EVACUATED DUE TO FLOODING ALONG PANTREADING CREEK.

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, 8.7 hours before the alert went out and 212 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: 371 J/kg
Mixed-layer CIN: -114 J/kg
Mixed-layer LCL: 1115 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 11 m²/s²
0-3 km storm-relative helicity: 70 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

As transmitted.

230 
WGUS51 KPHI 072044
FFWPHI
PAC029-045-091-101-072345-
/O.NEW.KPHI.FF.W.0080.190807T2044Z-190807T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
444 PM EDT Wed Aug 7 2019

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  Southeastern Montgomery County in southeastern Pennsylvania...
  East central Chester County in southeastern Pennsylvania...
  Northwestern Philadelphia County in southeastern Pennsylvania...
  Delaware County in southeastern Pennsylvania...

* Until 745 PM EDT.

* At 444 PM EDT, Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. Up to one inch of rain has
  already fallen. Flash flooding is expected to begin shortly in the
  areas of heaviest rain.

* Some locations that could experience flooding include...
  Philadelphia, West Chester, Norristown, West Norriton, East
  Norriton, Yeadon, Westtown, Conshohocken, Hatboro, Ambler,
  Swarthmore, Narberth, East Lansdowne, Cheyney, Morris Park, Bryn
  Mawr, Trout Lake, Chelsea, Radnor Township and Gradyville.

LAT...LON 3998 7564 4007 7549 4016 7531 4024 7518
      4018 7509 3995 7523 3983 7546

$$

NC

2 follow-up statements

545 
WGUS71 KPHI 072154
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
554 PM EDT Wed Aug 7 2019

PAC029-045-091-101-072345-
/O.CON.KPHI.FF.W.0080.000000T0000Z-190807T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Montgomery PA-Chester PA-Philadelphia PA-Delaware PA-
554 PM EDT Wed Aug 7 2019

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 745 PM EDT FOR
SOUTHEASTERN MONTGOMERY...EAST CENTRAL CHESTER...NORTHWESTERN
PHILADELPHIA AND DELAWARE COUNTIES...

At 530 PM EDT, local law enforcement reported water rescues due to 
flash flooding in Newtown Square and Whitemarsh townships. This 
flooding is a result of over 2 inches of rain which fell earlier. 

Some locations that could experience flooding include...
Philadelphia, West Chester, Norristown, West Norriton, East Norriton,
Yeadon, Westtown, Conshohocken, Hatboro, Ambler, Swarthmore,
Narberth, East Lansdowne, Cheyney, Morris Park, Bryn Mawr, Trout
Lake, Chelsea, Radnor Township and Gradyville.

LAT...LON 3998 7564 4007 7549 4016 7531 4024 7518
      4018 7509 3995 7523 3983 7546

$$

NC

905 
WGUS71 KPHI 072343
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
743 PM EDT Wed Aug 7 2019

PAC029-045-091-101-072352-
/O.EXP.KPHI.FF.W.0080.000000T0000Z-190807T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Montgomery PA-Chester PA-Philadelphia PA-Delaware PA-
743 PM EDT Wed Aug 7 2019

...THE FLASH FLOOD WARNING FOR SOUTHEASTERN MONTGOMERY...EAST CENTRAL
CHESTER...NORTHWESTERN PHILADELPHIA AND DELAWARE COUNTIES WILL EXPIRE
AT 745 PM EDT...

The heavy rain has ended and flash flooding is beginning to 
decrease. However, an Areal Flood Warning remains in effect for the 
area as small stream flooding may continue. Please continue to heed 
any remaining road closures.

LAT...LON 3998 7564 4007 7549 4016 7531 4024 7518
      4018 7509 3995 7523 3983 7546

$$

NC

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 7, 10:02 AM EDT	Flash Flood Watch	PHI	Bucks, Delaware, Montgomery, Philadelphia	11 hr
Aug 7, 1:02 PM EDT	Areal Flood Advisory	PHI	Bucks	4 hr
Aug 7, 1:22 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	38 min
Aug 7, 1:26 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	49 min
Aug 7, 1:46 PM EDT	Severe Thunderstorm Warning	PHI	Berks	44 min
Aug 7, 2:01 PM EDT	Areal Flood Advisory	PHI	Bucks	97 min
Aug 7, 2:59 PM EDT	Special Weather Statement	PHI	Bucks, Montgomery	31 min
Aug 7, 3:01 PM EDT	Areal Flood Advisory	PHI	Berks	2 hr
Aug 7, 3:02 PM EDT	Special Weather Statement	PHI	Berks, Lehigh	43 min
Aug 7, 3:18 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	42 min
Aug 7, 3:24 PM EDT	Flash Flood Warning	PHI	Berks	106 min
Aug 7, 3:24 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Lehigh, Monroe, Northampton	51 min
Aug 7, 3:30 PM EDT	Special Weather Statement	PHI	Delaware, Montgomery	30 min
Aug 7, 3:31 PM EDT	Special Weather Statement	PHI	Philadelphia	44 min
Aug 7, 3:41 PM EDT	Areal Flood Advisory	PHI	Berks, Lehigh, Northampton	91 min
Aug 7, 3:54 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Northampton	51 min
Aug 7, 4:03 PM EDT	Special Weather Statement	PHI	Philadelphia	42 min
Aug 7, 4:06 PM EDT	Areal Flood Advisory	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	4 hr
Aug 7, 4:09 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Delaware, Montgomery, Philadelphia	66 min
Aug 7, 4:14 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Monroe, Northampton	46 min
Aug 7, 4:20 PM EDT	Flash Flood Warning	PHI	Bucks, Montgomery, Philadelphia	4 hr
Aug 7, 4:27 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	63 min
Aug 7, 5:16 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Delaware, Montgomery, Philadelphia	59 min
Aug 7, 5:57 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	78 min
Aug 7, 6:01 PM EDT	Areal Flood Advisory	PHI	Bucks, Delaware, Philadelphia	3 hr
Aug 7, 6:10 PM EDT	River Flood Warning	PHI	Delaware	119 min
Aug 7, 7:42 PM EDT	Areal Flood Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	3 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2019 Every flash flood warning in 2019

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.