Alert archive / Pennsylvania / Flash Flood Warnings in 2012

Flash Flood Warning 26, NWS Philadelphia/Mount Holly

August 1, 2012Montgomery County, Philadelphia County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 1, 2012, 5:09 PM EDT for Montgomery County, Philadelphia County, Pennsylvania. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Aug 1, 2012, 5:09 PM EDT (21:09 UTC)
Expired: Aug 1, 2012, 8:14 PM EDT
In force: 3 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 60 km from the middle of the area, began a volume at 21:10 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.

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 9.2 hours before the alert went out and 107 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: 897 J/kg
Mixed-layer CIN: -5 J/kg
Mixed-layer LCL: 643 m above ground
0-6 km bulk shear: 17 kt
0-1 km storm-relative helicity: 16 m²/s²
0-3 km storm-relative helicity: -2 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

491 
WGUS51 KPHI 012109
FFWPHI
PAC091-101-020115-
/O.NEW.KPHI.FF.W.0026.120801T2109Z-120802T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
509 PM EDT WED AUG 1 2012

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHEASTERN MONTGOMERY COUNTY...
  PHILADELPHIA COUNTY...

* UNTIL 915 PM EDT...

* AT 505 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN FROM A THUNDERSTORM OVER PHILADELPHIA AND   
  SOUTHEASTERN MONTGOMERY COUNTIES. RADAR HAS INDICATED AS MUCH AS 
  TWO AND ONE INCHES OF RAIN HAS FALLEN SO FAR.  

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  CONSHOHOCKEN...JENKINTOWN...NARBERTH...PHILADELPHIA...ROCKLEDGE...
  GERMANTOWN...CENTER CITY...CHESTNUT HILL...HOLMESBURG...
  KENSINGTON...MORRIS PARK...NORTHEAST PHILADELPHIA...ROXBOROUGH...
  TACONY AND WISSINOMING.

ADDITIONAL RAINFALL AMOUNTS OF 1 TO 2 INCHES ARE POSSIBLE IN THE 
WARNED AREA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

PLEASE REPORT FLOODING...HAIL OR WIND DAMAGE TO THE NATIONAL WEATHER
SERVICE BY CALLING TOLL FREE...1-877-633-6772.

&&

LAT...LON 4005 7498 3995 7514 3997 7526 4001 7530
      4010 7536 4012 7497 4012 7496 4009 7495

$$

HAYES

2 follow-up statements

025 
WGUS71 KPHI 012336
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
736 PM EDT WED AUG 1 2012

PAC091-101-020115-
/O.CON.KPHI.FF.W.0026.000000T0000Z-120802T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
MONTGOMERY PA-PHILADELPHIA PA-
736 PM EDT WED AUG 1 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 915 PM EDT FOR
PHILADELPHIA AND SOUTHEASTERN MONTGOMERY COUNTIES...

AT 731 PM EDT...THE HEAVIEST RAIN HAS EXITED THE AREA. HOWEVER... 
CREEKS AND STREAMS CONTINUE TO RISE DUE TO THE EARLIER HEAVY RAIN. 
THE RUNOFF COULD STILL PUSH CREEKS AND STREAMS TO NEAR OR JUST OVER 
BANKFULL. 

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
CONSHOHOCKEN...JENKINTOWN...NARBERTH...PHILADELPHIA...ROCKLEDGE...
GERMANTOWN...CENTER CITY...CHESTNUT HILL...HOLMESBURG...KENSINGTON...
MORRIS PARK...NORTHEAST PHILADELPHIA...ROXBOROUGH...TACONY AND
WISSINOMING.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY. MOVE TO HIGHER GROUND.

PLEASE REPORT FLOODING...HAIL OR WIND DAMAGE BY CALLING YOUR LOCAL
LAW ENFORCEMENT OFFICIALS OR BY CALLING THE NATIONAL WEATHER SERVICE
TOLL FREE AT...1-877-633-6772.

&&

LAT...LON 4005 7498 3995 7514 3997 7526 4001 7530
      4010 7536 4012 7497 4012 7496 4009 7495

$$

HAYES

123 
WGUS71 KPHI 020014
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
814 PM EDT WED AUG 1 2012

PAC091-101-020024-
/O.CAN.KPHI.FF.W.0026.000000T0000Z-120802T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
MONTGOMERY PA-PHILADELPHIA PA-
814 PM EDT WED AUG 1 2012

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR PHILADELPHIA AND
SOUTHEASTERN MONTGOMERY COUNTIES...

THE WATERS FROM THE EARLIER HEAVY RAINS ARE RECEDING AND FLOOD WATERS
NO LONGER POSE A THREAT TO LIFE OR PROPERTY. THEREFORE...THE FLASH
FLOOD WARNING HAS BEEN CANCELLED.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO PHILADELPHIA.

LAT...LON 4005 7498 3995 7514 3997 7526 4001 7530
      4010 7536 4012 7497 4012 7496 4009 7495

$$

HAYES

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 31, 8:11 PM EDT	Special Weather Statement	PHI	Berks	64 min
Jul 31, 9:12 PM EDT	Special Weather Statement	PHI	Berks, Lehigh	63 min
Jul 31, 9:51 PM EDT	Coastal Flood Statement	PHI	Delaware, Philadelphia	5 hr
Aug 1, 1:02 AM EDT	Special Weather Statement	PHI	Chester	58 min
Aug 1, 2:03 PM EDT	Special Weather Statement	PHI	Chester	57 min
Aug 1, 2:27 PM EDT	Special Weather Statement	PHI	Bucks	63 min
Aug 1, 2:47 PM EDT	Areal Flood Advisory	PHI	Bucks	3 hr
Aug 1, 3:03 PM EDT	Special Weather Statement	PHI	Monroe	57 min
Aug 1, 3:31 PM EDT	Coastal Flood Statement	PHI	Delaware, Philadelphia	11 hr
Aug 1, 3:35 PM EDT	Special Weather Statement	PHI	Philadelphia	55 min
Aug 1, 4:07 PM EDT	Flash Flood Warning	PHI	Bucks, Montgomery	3 hr
Aug 1, 4:16 PM EDT	Special Weather Statement	PHI	Carbon, Monroe	59 min
Aug 1, 4:51 PM EDT	Areal Flood Advisory	PHI	Monroe	36 min
Aug 1, 4:53 PM EDT	Special Weather Statement	PHI	Philadelphia	67 min
Aug 1, 5:06 PM EDT	Areal Flood Advisory	PHI	Montgomery, Philadelphia	12 min
Aug 1, 5:22 PM EDT	Flash Flood Warning	PHI	Monroe	106 min
Aug 1, 5:34 PM EDT	Special Weather Statement	PHI	Carbon	56 min
Aug 1, 5:43 PM EDT	Special Weather Statement	PHI	Delaware, Montgomery	62 min
Aug 1, 5:46 PM EDT	Severe Thunderstorm Warning	PHI	Philadelphia	31 min
Aug 1, 5:50 PM EDT	Special Weather Statement	PHI	Montgomery	55 min
Aug 1, 5:53 PM EDT	Areal Flood Advisory	PHI	Carbon, Monroe	100 min
Aug 1, 5:55 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Monroe, Northampton	65 min
Aug 1, 6:08 PM EDT	Flash Flood Warning	PHI	Chester, Montgomery	2 hr
Aug 1, 6:16 PM EDT	Areal Flood Advisory	PHI	Philadelphia	46 min
Aug 1, 6:22 PM EDT	Special Weather Statement	PHI	Lehigh	53 min
Aug 1, 6:30 PM EDT	Areal Flood Advisory	PHI	Chester, Delaware	64 min
Aug 1, 6:53 PM EDT	Areal Flood Advisory	PHI	Lehigh, Northampton	69 min
Aug 1, 6:59 PM EDT	Special Weather Statement	PHI	Northampton	61 min
Aug 1, 7:32 PM EDT	Special Weather Statement	PHI	Chester	58 min
Aug 1, 7:49 PM EDT	Areal Flood Advisory	PHI	Chester	52 min

Nearby

Flash Flood Warnings in Pennsylvania, 2012 Every flash flood warning in 2012

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.