Alert archive / Pennsylvania / Flash Flood Warnings in 2006

Flash Flood Warning 67, NWS Philadelphia/Mount Holly

August 29, 2006Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 29, 2006, 3:39 PM EDT for Chester 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 29, 2006, 3:39 PM EDT (19:39 UTC)
Expired
Aug 29, 2006, 6:30 PM EDT
In force
3 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Counties, with a storm outline in the text

County Chester County, PA

The radar

The Philadelphia radar (KDIX), 119 km from the middle of the area, began a volume at 19:42 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, 7.7 hours before the alert went out and 75 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 2006-08-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 21 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, Phillips Aaf/Abe, MD at 12:00Z on 2006-08-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 98 square meters per square second.193958Sfc1 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
21 J/kg
Mixed-layer CIN
-132 J/kg
Mixed-layer LCL
934 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
98 m²/s²
0-3 km storm-relative helicity
185 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

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

000 
WGUS51 KPHI 291939
FFWPHI
PAC029-292230-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
339 PM EDT TUE AUG 29 2006

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHERN CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA

* UNTIL 630 PM EDT

* AT 337 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  TORRENTIAL RAIN FROM A THUNDERSTORM. DOPPLER RADAR PRECIPITATION
  ESTIMATES OF 2 TO 3 INCHES PER HOUR IS OCCURRING WITH THE 
  THUNDERSTORM. THIS SAME THUNDERSTORM PRODUCED NEARLY 3 INCHES OF
  RAIN IN AN HOUR IN SOUTHEASTERN BERKS COUNTY, IN THE TOWN OF
  SHILLINGTON, WITH SIGNIFICANT STREET FLOODING REPORTED.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  PHOENIXVILLE...HONEY BROOK AND ELVERSON

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.
RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE
PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO CROSS
SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR BY
AUTOMOBILE.

LAT...LON 4002 7595 4010 7547 4026 7568 4011 7594

$$

GORSE
2 follow-up statements
000 
WGUS71 KPHI 292006
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
404 PM EDT TUE AUG 29 2006

PAC029-292230-
CHESTER PA-
405 PM EDT TUE AUG 29 2006

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 630 PM EDT FOR
NORTHERN CHESTER COUNTY...

AT 400 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
FOLLOW A TORRENTIAL RAIN PRODUCING THUNDERSTORM OVER THE WARNED
AREA. SOME STREET, HIGHWAY AND POOR DRAINAGE FLOODING HAS BEEN REPORTED
AROUND THE VALLEY FORGE AREA WITH RAINFALL RATES AROUND 2 INCHES PER
HOUR.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO PHOENIXVILLE
AND LIONVILLE.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.
RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE
PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO CROSS
SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR BY
AUTOMOBILE.

LAT...LON 3993 7554 4006 7539 4022 7563 4009 7585

$$

GORSE
000 
WGUS71 KPHI 292125
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
525 PM EDT TUE AUG 29 2006

PAC029-292230-
CHESTER PA-
525 PM EDT TUE AUG 29 2006

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 630 PM EDT FOR
NORTHERN CHESTER COUNTY...

AT 520 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING
ANOTHER CLUSTER OF SHOWERS AND THUNDERSTORMS MOVING ACROSS THE 
COUNTY. TORRENTIAL RAINFALL COUPLED WITH CONTINUED RUNOFF FROM THE 
EARLIER RAINFALL WILL RESULT IN AREAS OF FLASH FLOODING. THE
VALLEY CREEK GAGE AT VALLEY FORGE IS EXPERIENCING A RAPID RISE WITH 
A STAGE AT 6.48 FEET AND RISING. FLOOD STAGE IS 7 FEET. 

THIS IS A POTENTIALLY DANGEROUS SITUATION. DO NOT DRIVE THROUGH 
FLOODED ROADS. IF YOU LIVE NEAR A STREAM OR CREEK, MOVE TO HIGHER 
GROUND NOW

LAT...LON 3993 7554 4006 7539 4022 7563 4009 7585

$$

GORSE

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 29, 2:14 PM EDTSevere Thunderstorm WarningPHIBerks61 min
Aug 29, 2:42 PM EDTFlash Flood WarningPHIBerks3 hr
Aug 29, 2:53 PM EDTSevere Thunderstorm WarningPHIChester, Montgomery52 min
Aug 29, 3:37 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Montgomery, Philadelphia68 min
Aug 29, 3:50 PM EDTFlash Flood WarningPHIMontgomery3 hr
Aug 29, 4:15 PM EDTFlash Flood WarningPHIPhiladelphia3 hr
Aug 29, 5:43 PM EDTFlash Flood WarningPHIBerks2 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2006Every flash flood warning in 2006

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.