Alert archive / Pennsylvania / Flash Flood Warnings in 2011

Flash Flood Warning 52, NWS Philadelphia/Mount Holly

September 7, 2011Berks County, Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Sep 7, 2011, 3:33 PM EDT for Berks County, Chester 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
Sep 7, 2011, 3:33 PM EDT (19:33 UTC)
Expired
Sep 7, 2011, 7:30 PM EDT
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Berks County, PA, Chester County, PA

The radar

The Philadelphia radar (KDIX), 116 km from the middle of the area, began a volume at 19:35 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, 7.6 hours before the alert went out and 199 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 2011-09-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 2011-09-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 154 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
1 J/kg
Mixed-layer CIN
-270 J/kg
Mixed-layer LCL
448 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
154 m²/s²
0-3 km storm-relative helicity
184 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.

518 
WGUS51 KPHI 071933
FFWPHI
PAC011-029-072330-
/O.NEW.KPHI.FF.W.0052.110907T1933Z-110907T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
333 PM EDT WED SEP 7 2011

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CHESTER COUNTY...
  EASTERN BERKS COUNTY...

* UNTIL 730 PM EDT...

* AT 330 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  VERY HEAVY RAIN FROM A CLUSTER OF STRONG THUNDERSTORMS OVER THE 
  AREA. BETWEEN 1 AND 2 INCHES OF RAIN IS EXPECTED ACROSS THE AREA
  RESULTING IN FLASH FLOODING.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4066 7594 4068 7589 4046 7568 4033 7562
      4025 7569 4026 7566 4022 7560 4020 7559
      4020 7556 4000 7547 3983 7566 3979 7574
      3973 7578 3972 7582 3999 7589 4044 7594

$$

HAYES
2 follow-up statements
258 
WGUS71 KPHI 072208
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
608 PM EDT WED SEP 7 2011

PAC011-029-072330-
/O.CON.KPHI.FF.W.0052.000000T0000Z-110907T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CHESTER PA-BERKS PA-
608 PM EDT WED SEP 7 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 730 PM EDT FOR
EASTERN BERKS AND CHESTER COUNTIES...

RAIN GAGE REPORTS IN THE AREA INDICATE THAT UP TO 1.25 INCHES OF 
RAIN HAS FALLEN IN THE LAST COUPLE OF HOURS. RAIN HAS MOSTLY ENDED 
FOR THE TIME BEING...BUT FLOODING HAS BEEN REPORTED IN SOME AREAS 
AND WILL LIKELY CONTINUE A WHILE LONGER. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

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 4066 7594 4068 7589 4046 7568 4033 7562
      4025 7569 4026 7566 4022 7560 4020 7559
      4020 7556 4000 7547 3983 7566 3979 7574
      3973 7578 3972 7582 3999 7589 4044 7594

$$

FORECASTER: AMC
321 
WGUS71 KPHI 072324
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
724 PM EDT WED SEP 7 2011

PAC011-029-072333-
/O.EXP.KPHI.FF.W.0052.000000T0000Z-110907T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CHESTER PA-BERKS PA-
724 PM EDT WED SEP 7 2011

...THE FLASH FLOOD WARNING WILL EXPIRE AT 730 PM EDT FOR EASTERN
BERKS AND CHESTER COUNTIES...

ALTHOUGH THE IMMEDIATE THREAT OF FLASH FLOODING HAS ENDED FOR THE 
TIME BEING...OTHER FLOOD WARNINGS ARE IN EFFECT FOR AREA RIVERS AND 
STREAMS. 

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

LAT...LON 4066 7594 4068 7589 4046 7568 4033 7562
      4025 7569 4026 7566 4022 7560 4020 7559
      4020 7556 4000 7547 3983 7566 3979 7574
      3973 7578 3972 7582 3999 7589 4044 7594

$$

FORECASTER: AMC

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 6, 10:31 PM EDTAreal Flood WarningPHIBerks, Lehigh15 hr
Sep 6, 11:13 PM EDTRiver Flood WarningPHIChester, Montgomery, Philadelphia3 days
Sep 6, 11:19 PM EDTRiver Flood WarningPHIMontgomery17 hr
Sep 7, 12:59 AM EDTRiver Flood WarningPHIChester, Delaware41 hr
Sep 7, 3:40 AM EDTRiver Flood WarningPHIMontgomery, Philadelphia54 hr
Sep 7, 3:47 AM EDTRiver Flood WarningPHIDelaware4 hr
Sep 7, 4:26 AM EDTRiver Flood WarningPHIBerks, Montgomery6 hr
Sep 7, 4:26 AM EDTRiver Flood WarningPHIMontgomery3 days
Sep 7, 9:48 AM EDTRiver Flood WarningPHILehigh, Northampton5 hr
Sep 7, 10:05 AM EDTRiver Flood WarningPHIMonroe, Northampton60 hr
Sep 7, 10:05 AM EDTRiver Flood WarningPHINorthampton67 hr
Sep 7, 10:05 AM EDTRiver Flood WarningPHIBucks68 hr
Sep 7, 10:05 AM EDTRiver Flood WarningPHIBucks67 hr
Sep 7, 10:05 AM EDTRiver Flood WarningPHIBucks67 hr
Sep 7, 10:05 AM EDTRiver Flood WarningPHIBucks64 hr
Sep 7, 10:05 AM EDTRiver Flood WarningPHIBucks67 hr
Sep 7, 10:05 AM EDTRiver Flood WarningPHIBucks68 hr
Sep 7, 11:48 AM EDTCoastal Flood AdvisoryPHIDelaware, Philadelphia18 hr
Sep 7, 1:32 PM EDTSpecial Weather StatementPHIBerks58 min
Sep 7, 1:38 PM EDTSpecial Weather StatementPHILebanon52 min
Sep 7, 1:50 PM EDTAreal Flood AdvisoryPHIBerks17 min
Sep 7, 2:05 PM EDTFlash Flood WarningPHIBerks4 hr
Sep 7, 2:36 PM EDTSpecial Weather StatementPHIBerks54 min
Sep 7, 2:39 PM EDTSpecial Weather StatementPHIChester66 min
Sep 7, 3:06 PM EDTFlash Flood WarningPHIChester4 hr
Sep 7, 3:49 PM EDTSpecial Weather StatementPHIBerks, Chester56 min
Sep 7, 4:06 PM EDTRiver Flood WarningPHIBerks, Montgomery41 hr
Sep 7, 4:06 PM EDTRiver Flood WarningPHIBerks45 hr
Sep 7, 4:09 PM EDTSpecial Weather StatementPHIBucks, Delaware, Lehigh, Montgomery, Northampton, Philadelphia66 min
Sep 7, 5:10 PM EDTAreal Flood AdvisoryPHIBerks, Bucks, Carbon, Lehigh, Monroe, Montgomery and 1 more3 hr
Sep 7, 6:07 PM EDTRiver Flood WarningPHIChester10 hr
Sep 7, 7:14 PM EDTAreal Flood AdvisoryPHIBerks65 min
Sep 7, 7:21 PM EDTAreal Flood WarningPHIBerks, Chester14 hr
Sep 7, 7:32 PM EDTSpecial Weather StatementPHIBerks58 min
Sep 7, 7:39 PM EDTCoastal Flood WarningPHIDelaware, Philadelphia6 hr

Nearby

Flash Flood Warnings in Pennsylvania, 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.