Alert archive / Pennsylvania / Flash Flood Warnings in 2008

Flash Flood Warning 10, NWS Philadelphia/Mount Holly

June 14, 2008Chester County, Pennsylvania; Cecil County, Maryland

NWS Philadelphia/Mount Holly issued this flash flood warning at Jun 14, 2008, 6:28 PM EDT for Chester County, Pennsylvania; Cecil County, Maryland. It was in force for 60 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 14, 2008, 6:28 PM EDT (22:28 UTC)
Expired
Jun 14, 2008, 7:28 PM EDT
In force
60 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Cecil County, MD, Chester County, PA

The radar

The Dover AFB radar (KDOX), 103 km from the middle of the area, began a volume at 22:29 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

Washington/Dulle, VA (KIAD), launched 12:00Z, 10.5 hours before the alert went out and 136 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, Washington/Dulle, VA at 12:00Z on 2008-06-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 92 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, Washington/Dulle, VA at 12:00Z on 2008-06-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 125 square meters per square second.1939Sfc1 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
92 J/kg
Mixed-layer CIN
-205 J/kg
Mixed-layer LCL
1369 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
125 m²/s²
0-3 km storm-relative helicity
139 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.

000 
WGUS51 KPHI 142230
FFWPHI
MDC015-PAC029-150230-
/O.NEW.KPHI.FF.W.0010.080614T2228Z-080615T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
628 PM EDT SAT JUN 14 2008

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  WESTERN CECIL COUNTY IN NORTHEAST MARYLAND...
  SOUTHWESTERN CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 1030 PM EDT

* AT 625 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
  THUNDERSTORMS WITH TORRENTIAL DOWNPOURS HEADING FOR LOCATIONS
  THAT HAVE ALREADY RECEIVED IN EXCESS OF TWO INCHES OF RAIN
  IN EXTREME SOUTHWEST CHESTER COUNTY AND NORTHWEST CECIL COUNTY.
  THE HEAVIEST RAIN HAS FALLEN OVER PARTS OF THE OCTORARO CREEK
  BASIN. 

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO MOUNT
  VERNON AND GLEN ROY

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...AS WELL AS FARMLAND ALONG THE
BANKS OF CREEKS AND STREAMS.

FLOODING IS OCCURRING OR IS IMMINENT. MOST FLOOD RELATED DEATHS OCCUR
IN AUTOMOBILES. DO NOT ATTEMPT TO CROSS WATER COVERED BRIDGES...
DIPS...OR LOW WATER CROSSINGS. NEVER TRY TO CROSS A FLOWING STREAM...
EVEN A SMALL ONE...ON FOOT. TO ESCAPE RISING WATER MOVE UP TO HIGHER
GROUND.

LAT...LON 3973 7615 3975 7610 3988 7600 3944 7594
      3944 7600 3946 7602 3954 7598 3956 7599
      3954 7599 3953 7600 3955 7609 3965 7617
      3968 7622 3972 7623
TIME...MOT...LOC 2228Z 180DEG 0KT 3974 7604

$$
 
TFG
1 follow-up statement
000 
WGUS71 KPHI 142328
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
727 PM EDT SAT JUN 14 2008

MDC015-PAC029-142337-
/O.CAN.KPHI.FF.W.0010.000000T0000Z-080615T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CECIL MD-CHESTER PA-
727 PM EDT SAT JUN 14 2008

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR SOUTHWESTERN
CHESTER AND WESTERN CECIL COUNTIES...

THE SECOND CLUSTER OF THUNDERSTORMS WITH HEAVY RAIN MISSED THE WARNING
AREA AND FLASH FLOODING IS NO LONGER EXPECTED IN THOSE PARTS OF CECIL
AND CHESTER COUNTIES.


LAT...LON 3973 7615 3975 7610 3988 7600 3944 7594
      3944 7600 3946 7602 3954 7598 3956 7599
      3954 7599 3953 7600 3955 7609 3965 7617
      3968 7622 3972 7623
TIME...MOT...LOC 2327Z 180DEG 0KT 3974 7604

$$
 
TFG

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 14, 2:23 PM EDTFlash Flood WarningPHIMonroe3 hr
Jun 14, 3:02 PM EDTSevere Thunderstorm WarningPHIMonroe58 min
Jun 14, 4:26 PM EDTSevere Thunderstorm WarningPHICarbon, Monroe, Northampton64 min
Jun 14, 4:49 PM EDTFlash Flood WarningPHICarbon5 hr
Jun 14, 5:07 PM EDTSevere Thunderstorm WarningPHICarbon, Monroe53 min
Jun 14, 5:18 PM EDTSevere Thunderstorm WarningPHICarbon, Monroe57 min
Jun 14, 6:15 PM EDTSevere Thunderstorm WarningPHIChester75 min
Jun 14, 6:48 PM EDTFlash Flood WarningPHICarbon, Monroe3 hr
Jun 14, 7:05 PM EDTSevere Thunderstorm WarningPHIBerks, Chester, Montgomery70 min
Jun 14, 7:42 PM EDTSevere Thunderstorm WarningPHIBucks, Chester, Montgomery63 min
Jun 14, 7:56 PM EDTSevere Thunderstorm WarningPHIBucks, Delaware, Philadelphia79 min

Nearby

Flash Flood Warnings in Pennsylvania, 2008Flash Flood Warnings in Maryland, 2008Every flash flood warning in 2008

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.