Alert archive / Pennsylvania / Flash Flood Warnings in 2009

Flash Flood Warning 12, NWS Philadelphia/Mount Holly

June 30, 2009Bucks County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jun 30, 2009, 3:13 PM EDT for Bucks County, Montgomery County, Pennsylvania. It was in force for 114 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jun 30, 2009, 3:13 PM EDT (19:13 UTC)
Expired
Jun 30, 2009, 5:07 PM EDT
In force
114 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Bucks County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 78 km from the middle of the area, began a volume at 19:15 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, 7.2 hours before the alert went out and 118 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, Phillips Aaf/Abe, MD at 12:00Z on 2009-06-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 161 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Phillips Aaf/Abe, MD at 12:00Z on 2009-06-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 53 square meters per square second.19395878Sfc1 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
161 J/kg
Mixed-layer CIN
-86 J/kg
Mixed-layer LCL
1704 m above ground
0-6 km bulk shear
51 kt
0-1 km storm-relative helicity
53 m²/s²
0-3 km storm-relative helicity
95 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.8

Open this sounding in Storm Lab

The text

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

000 
WGUS51 KPHI 301913
FFWPHI
PAC017-091-302315-
/O.NEW.KPHI.FF.W.0012.090630T1913Z-090630T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
313 PM EDT TUE JUN 30 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...
  MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 715 PM EDT

* AT 311 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  TORRENTIAL DOWNPOURS WITH THUNDERSTORMS OVER CENTRAL BUCKS AND 
  MONTGOMERY COUNTIES. IN ADDITION TO FLOODING, THE HEAVY DOWNPOURS
  WILL MAKE IT EASIER FOR TREES TO BE KNOCKED ESPECIALLY BECAUSE
  OF ALL THE RAIN THIS PAST MONTH. 

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO TINICUM...
  REVERE...PIPERSVILLE...OTTSVILLE...GARDENVILLE...FRICKS...
  ERWINNA...BEDMINSTER...SOUDERTON...QUAKERTOWN...PERKASIE...NEW
  HOPE...DUBLIN AND DOYLESTOWN

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.

&&

LAT...LON 4007 7538 4007 7541 4010 7543 4009 7545
      4024 7556 4043 7540 4056 7511 4050 7506
      4042 7506 4040 7502 4041 7497 4034 7495
      4029 7487

$$
 
TFG
1 follow-up statement
000 
WGUS71 KPHI 302107
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
507 PM EDT TUE JUN 30 2009

PAC017-091-302117-
/O.CAN.KPHI.FF.W.0012.000000T0000Z-090630T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
MONTGOMERY PA-BUCKS PA-
507 PM EDT TUE JUN 30 2009

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

THE HEAVY RAIN AND FLOODING HAS ENDED ACROSS BUCKS AND MONTGOMERY
COUNTIES.

LAT...LON 4007 7538 4007 7541 4010 7543 4009 7545
      4024 7556 4043 7540 4056 7511 4050 7506
      4042 7506 4040 7502 4041 7497 4034 7495
      4029 7487

$$
 
TFG

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 30, 1:15 PM EDTSevere Thunderstorm WarningPHIBerks75 min
Jun 30, 2:31 PM EDTSevere Thunderstorm WarningPHIBerks, Chester, Montgomery44 min
Jun 30, 2:51 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery54 min
Jun 30, 3:12 PM EDTSevere Thunderstorm WarningPHIBucks63 min

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.