Alert archive / Pennsylvania / Flash Flood Warnings in 2009

Flash Flood Warning 67, NWS Philadelphia/Mount Holly

October 24, 2009Bucks County, Philadelphia County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Oct 24, 2009, 8:01 PM EDT for Bucks County, Philadelphia County, Pennsylvania. It was in force for 4 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
Oct 24, 2009, 8:01 PM EDT (00:01 UTC)
Expired
Oct 25, 2009, 12:00 AM EDT
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Bucks County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 58 km from the middle of the area, began a volume at 00:04 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.

The nearest sounding before it

Brookhaven, NY (KOKX), launched 00:00Z, 0.0 hours before the alert went out and 203 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, Brookhaven, NY at 00:00Z on 2009-10-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 534 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, Brookhaven, NY at 00:00Z on 2009-10-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 462 square meters per square second.1939587897Sfc1 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
534 J/kg
Mixed-layer CIN
-17 J/kg
Mixed-layer LCL
447 m above ground
0-6 km bulk shear
62 kt
0-1 km storm-relative helicity
462 m²/s²
0-3 km storm-relative helicity
486 m²/s²
Significant tornado parameter
1.6
Supercell composite
11.4

Open this sounding in Storm Lab

The text

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

000 
WGUS51 KPHI 250001
FFWPHI
PAC017-101-250400-
/O.NEW.KPHI.FF.W.0067.091025T0001Z-091025T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
801 PM EDT SAT OCT 24 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHEASTERN BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...
  NORTHEASTERN PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA...
  THIS INCLUDES THE CITY OF PHILADELPHIA...

* UNTIL MIDNIGHT EDT

* AT 758 PM EDT...POOR DRAINAGE FLOODING WAS REPORTED IN BUCKS 
  COUNTY AND THE FRANKFORD CREEK WAS FLOODING IN PHILADELPHIA. 
  THE HEAVIEST RAIN HAS MOVED OUT OF THE AREA, BUT POOR DRAINAGE
  WILL PERSIST. SIGNIFICANT BUT WITHIN BANKFULL RISES ARE EXPECTED
  ALONG THE MAIN STEM OF THE NESHAMINY CREEK.  
 
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 4007 7492 4006 7495 4003 7498 3996 7513
      4003 7519 4008 7519 4005 7512 4013 7502
      4022 7517 4024 7520 4026 7520 4040 7503
      4016 7477

$$

TFG
3 follow-up statements
215 
WGUS51 KPHI 250005 CCA
FFWPHI
PAC017-101-250400-
/O.COR.KPHI.FF.W.0067.091025T0001Z-091025T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING...CORRECTED
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
801 PM EDT SAT OCT 24 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHEASTERN BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...
  NORTHEASTERN PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA...
  THIS INCLUDES THE CITY OF PHILADELPHIA...

* UNTIL MIDNIGHT EDT

* AT 758 PM EDT...POOR DRAINAGE FLOODING WAS REPORTED IN BUCKS 
  COUNTY AND THE FRANKFORD CREEK WAS FLOODING IN PHILADELPHIA. 
  THE HEAVIEST RAIN HAS MOVED OUT OF THE AREA, BUT POOR DRAINAGE     
  FLOODING WILL PERSIST AS WELL AS FLOODING ALONG SOME OF THE SMALLER
  STREAMS. SIGNIFICANT BUT WITHIN BANKFULL RISES ARE EXPECTED 
  ALONG THE MAIN STEM OF THE NESHAMINY CREEK. IF THIS PROJECTION
  CHANGES, AN UPDATED STATEMENT WILL BE ISSUED.  
  
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 4007 7492 4006 7495 4003 7498 3996 7513
      4003 7519 4008 7519 4005 7512 4013 7502
      4022 7517 4024 7520 4026 7520 4040 7503
      4016 7477

$$

TFG
000 
WGUS71 KPHI 250104
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
904 PM EDT SAT OCT 24 2009

PAC101-250111-
/O.CAN.KPHI.FF.W.0067.000000T0000Z-091025T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
PHILADELPHIA PA-
904 PM EDT SAT OCT 24 2009

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR NORTHEASTERN
PHILADELPHIA COUNTY...

THE FRANKFORD CREEK WAS NO LONGER FLOODING. PLEASE REFER TO THE
FLOOD WARNING STATEMENT CONCERNING FLOODING ALONG THE WISSAHICKON 
CREEK.


LAT...LON 4006 7495 4003 7498 4004 7499 4008 7497
      4011 7497 4013 7499 4014 7504 4024 7520
      4026 7520 4040 7503 4016 7477

$$

PAC017-250400-
/O.CON.KPHI.FF.W.0067.000000T0000Z-091025T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BUCKS PA-
904 PM EDT SAT OCT 24 2009

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL MIDNIGHT EDT FOR
SOUTHEASTERN BUCKS COUNTY...

AT 900 PM EDT...THUNDERSTORMS THAT PRODUCED FLASH FLOODING WERE ALL 
IN NEW JERSEY. ANY SMALL CREAK AND POOR DRAINAGE FLOODING SHOULD 
CONTINUE TO DECREASE ACROSS THE COUNTY. FLOODING IS NOT EXPECTED 
ALONG THE MAIN STEM OF THE NESHAMINY CREEK.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO 
WOODSIDE...TULLYTOWN...RICHBORO...NEWTOWN...LEVITTOWN...LANGHORNE... 
IVYLAND...FEASTERVILLE AND DOYLESTOWN

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 4006 7495 4003 7498 4004 7499 4008 7497
      4011 7497 4013 7499 4014 7504 4024 7520
      4026 7520 4040 7503 4016 7477

$$
 
TFG
000 
WGUS71 KPHI 250116
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
916 PM EDT SAT OCT 24 2009

PAC017-250400-
/O.CON.KPHI.FF.W.0067.000000T0000Z-091025T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BUCKS PA-
916 PM EDT SAT OCT 24 2009

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL MIDNIGHT EDT FOR
SOUTHEASTERN BUCKS COUNTY...

AT 908 PM EDT...THE HEAVY RAIN IS OVER, BUT RISES ARE CONTINUING ON 
SOME AREA STREAMS. THE NESHAMINY CREEK AT PENNS PARK IS CONTINUING 
TO RISE AND THIS INCREASES THE CHANCES FOR SOME MAIN STEM FLOODING 
FARTHER DOWNSTREAM ON THE NESHAMINY CREEK AT LANGHORNE. PLEASE LOOK 
FOR A POSSIBLE FLOOD WARNING FOR THE NESHAMINY CREEK.

ELSEWHERE POOR DRAINAGE FLOODING WILL CONTINUE TO RECEDE AS THE 
HEAVY RAIN IS OVER.
  
LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO 
WOODSIDE...TULLYTOWN...RICHBORO...NEWTOWN...LEVITTOWN...LANGHORNE... 
IVYLAND...FEASTERVILLE AND DOYLESTOWN

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 4006 7495 4003 7498 4004 7499 4008 7497
      4011 7497 4013 7499 4014 7504 4024 7520
      4026 7520 4040 7503 4016 7477

$$
 
TFG

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 24, 9:01 PM EDTAreal Flood WarningPHIMontgomery, Philadelphia9 hr
Oct 24, 9:25 PM EDTRiver Flood WarningPHIBucks5 hr
Oct 24, 9:26 PM EDTAreal Flood WarningPHIDelaware5 hr
Oct 24, 9:58 PM EDTAreal Flood WarningPHIMontgomery4 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2009Every flash flood warning in 2009

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.