Alert archive / Pennsylvania / Flash Flood Warnings in 2011

Flash Flood Warning 22, NWS Philadelphia/Mount Holly

August 14, 2011Chester County, Pennsylvania; Cecil County, Maryland

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 14, 2011, 1:12 AM EDT for Chester County, Pennsylvania; Cecil County, Maryland. 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
Aug 14, 2011, 1:12 AM EDT (05:12 UTC)
Expired
Aug 14, 2011, 5:15 AM EDT
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Cecil County, MD, Chester County, PA

The radar

The Philadelphia radar (KDIX), 116 km from the middle of the area, began a volume at 05:15 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

Washington/Dulle, VA (KIAD), launched 00:00Z, 5.2 hours before the alert went out and 175 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 00:00Z on 2011-08-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.1000850700500300200100-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 00:00Z on 2011-08-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 28 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
7399 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
28 m²/s²
0-3 km storm-relative helicity
54 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.

521 
WGUS51 KPHI 140512
FFWPHI
MDC015-PAC029-140915-
/O.NEW.KPHI.FF.W.0022.110814T0512Z-110814T0915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
112 AM EDT SUN AUG 14 2011

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHERN CECIL COUNTY...
  CHESTER COUNTY...

* UNTIL 515 AM EDT...

* AT 106 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR ESTIMATED   
  OVER FOUR INCHES OF RAIN HAS FALLEN OVER PORTIONS OF THE WARNED    
  AREA SINCE SATURDAY AFTERNOON. IN ADDITION...HEAVY RAIN HAS BEEN   
  TRAINING OVER PORTIONS OF CECIL AND SOUTHERN CHESTER COUNTY FOR    
  THE PAST FEW HOURS. WITH EVEN MORE RAIN ON THE WAY...FLASH         
  FLOODING IS EXPECTED IN PARTS OF CECIL COUNTY AND IN CHESTER       
  COUNTY DURING THE NEXT FEW HOURS. THIS MEANS THAT ROADWAY FLOODING 
  AND FLOODING ALONG SMALL WATERWAYS CAN BE EXPECTED. 

  NO FLOODING IS EXPECTED ALONG THE BRANDYWINE RIVER.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLASH FLOODING IS OBSERVED ACT QUICKLY. MOVE
UP TO HIGHER GROUND TO ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS
SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

&&

LAT...LON 3975 7612 3987 7601 3992 7601 4003 7595
      4011 7595 4026 7566 4020 7556 4013 7551
      4009 7545 4010 7543 4007 7541 3996 7548
      3987 7562 3984 7560 3982 7570 3972 7579
      3953 7578 3950 7580 3954 7607 3964 7616

$$

FORECASTER:JJM
1 follow-up statement
817 
WGUS71 KPHI 140645
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
245 AM EDT SUN AUG 14 2011

PAC029-140654-
/O.CAN.KPHI.FF.W.0022.000000T0000Z-110814T0915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CHESTER PA-
245 AM EDT SUN AUG 14 2011

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR CHESTER COUNTY...

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 FOR CHESTER COUNTY.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO WEST CHESTER.

LAT...LON 3965 7615 3971 7613 3972 7579 3953 7578
      3950 7580 3953 7600 3955 7603 3954 7607
      3964 7616

$$

MDC015-140915-
/O.CON.KPHI.FF.W.0022.000000T0000Z-110814T0915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CECIL MD-
245 AM EDT SUN AUG 14 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 515 AM EDT FOR
NORTHERN CECIL COUNTY...

WHILE THE HEAVY RAIN HAS MOVED OUT OF CECIL COUNTY...WATER REMAINS 
HIGH IN SOME SPOTS. THEREFORE THE FLASH FLOOD WARNING REMAIN IN 
EFFECT FOR THE TIME BEING.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3965 7615 3971 7613 3972 7579 3953 7578
      3950 7580 3953 7600 3955 7603 3954 7607
      3964 7616

$$

FORECASTER: JJM

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 13, 9:39 PM EDTAreal Flood AdvisoryPHICarbon, Lehigh, Monroe, Northampton4 hr
Aug 13, 9:56 PM EDTFlash Flood WarningPHIBerks, Lehigh, Northampton4 hr
Aug 13, 11:33 PM EDTAreal Flood AdvisoryPHIBucks4 hr
Aug 14, 12:37 AM EDTAreal Flood AdvisoryPHIChester3 hr
Aug 14, 3:42 AM EDTFlash Flood WatchPHIBerks, Carbon, Delaware, Lehigh, Monroe, Northampton and 1 more25 hr
Aug 14, 3:55 AM EDTFlash Flood WarningPHIBucks, Delaware, Montgomery, Philadelphia4 hr
Aug 14, 4:45 AM EDTSpecial Weather StatementPHIPhiladelphia60 min
Aug 14, 6:24 AM EDTAreal Flood AdvisoryPHIBucks3 hr
Aug 14, 7:43 AM EDTFlash Flood WarningPHIBucks, Delaware, Montgomery, Philadelphia4 hr
Aug 14, 9:21 AM EDTAreal Flood WarningPHINorthampton3 hr
Aug 14, 12:37 PM EDTAreal Flood WarningPHIBucks, Lehigh, Northampton7 hr
Aug 14, 1:00 PM EDTAreal Flood WarningPHIBucks, Chester, Delaware, Montgomery, Philadelphia8 hr
Aug 14, 1:51 AM EDTAreal Flood AdvisoryPHICaroline, Kent, Queen Anne's, Talbot6 hr
Aug 14, 2:27 AM EDTFlash Flood WarningPHICaroline, Kent, Queen Anne's4 hr
Aug 14, 5:03 AM EDTFlash Flood WarningPHICecil, Kent, Queen Anne's4 hr
Aug 14, 8:41 AM EDTFlash Flood WarningPHICecil, Kent, Queen Anne's4 hr
Aug 14, 12:16 PM EDTAreal Flood WarningPHICecil, Kent4 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2011Flash Flood Warnings in Maryland, 2011Every flash flood warning in 2011

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.