Alert archive / Pennsylvania / Flash Flood Warnings in 2015

Flash Flood Warning 35, NWS Philadelphia/Mount Holly

July 15, 20157 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 15, 2015, 4:27 AM EDT for 7 counties in Pennsylvania. It was in force for 4 hr. 4 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Jul 15, 2015, 4:27 AM EDT (08:27 UTC)
Expired
Jul 15, 2015, 8:30 AM EDT
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Berks County, PA, Bucks County, PA, Chester County, PA, Delaware County, PA, Lehigh County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 69 km from the middle of the area, began a volume at 08:27 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.

What was reported inside it

TimeReportWhereRemark
Jul 15, 4:30 AM EDTFLASH FLOODPottstown, PACARS STALLED IN HIGH WATER IN POTTSTOWN. ALSO... COLLEGE DRIVE WAS CLOSED DUE TO HIGH WATER.
Jul 15, 4:40 AM EDTFLOOD1 Ne Broomall, PAFLOODING REPORTED ON I476 NEAR BROOMALL
Jul 15, 6:28 AM EDTFLOODAmity Gardens, PAROADS CLOSED IN AMITY GARDENS DUE TO FLOODING.
Jul 15, 7:59 AM EDTHEAVY RAIN 2.131 W Limerick, PA

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Brookhaven, NY (KOKX), launched 00:00Z, 8.5 hours before the alert went out and 215 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, Brookhaven, NY at 00:00Z on 2015-07-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 623 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, Brookhaven, NY at 00:00Z on 2015-07-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 66 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
623 J/kg
Mixed-layer CIN
-11 J/kg
Mixed-layer LCL
582 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
66 m²/s²
0-3 km storm-relative helicity
104 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.

083 
WGUS51 KPHI 150827
FFWPHI
PAC011-017-029-045-077-091-101-151230-
/O.NEW.KPHI.FF.W.0035.150715T0827Z-150715T1230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
427 AM EDT WED JUL 15 2015

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ  HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHEASTERN DELAWARE COUNTY IN SOUTHEASTERN PENNSYLVANIA...
  NORTHEASTERN CHESTER COUNTY IN SOUTHEASTERN PENNSYLVANIA...
  SOUTHWESTERN BUCKS COUNTY IN SOUTHEASTERN PENNSYLVANIA...
  SOUTHEASTERN BERKS COUNTY IN EASTERN PENNSYLVANIA...
  SOUTHEASTERN LEHIGH COUNTY IN EASTERN PENNSYLVANIA...
  PHILADELPHIA COUNTY IN SOUTHEASTERN PENNSYLVANIA...
  MONTGOMERY COUNTY IN SOUTHEASTERN PENNSYLVANIA...

* UNTIL 830 AM EDT
    
* AT 426 AM EDT...DOPPLER RADAR INDICATED THUNDERSTORMS PRODUCING 
  HEAVY RAIN ACROSS THE WARNED AREA. UP TO ONE TO ONE AND HALF 
  INCHES OF RAIN HAS ALREADY FALLEN WITHIN THE PAST 20 TO 30 
  MINUTES. FLASH FLOODING IS EXPECTED TO BEGIN SHORTLY.

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  PHILADELPHIA...READING...CAMDEN...BENSALEM...NORRISTOWN...
  POTTSTOWN...PHOENIXVILLE...LANSDALE...WEST NORRITON...EAST
  NORRITON...YEADON...EMMAUS...QUAKERTOWN...PERKASIE...
  CONSHOHOCKEN...HATBORO...SOUDERTON...FOLCROFT...AMBLER AND
  PAULSBORO.

ADDITIONAL RAINFALL AMOUNTS OF ONE INCH ARE POSSIBLE IN THE WARNED 
AREA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOVE TO HIGHER GROUND NOW. ACT QUICKLY TO PROTECT YOUR LIFE.

TURN AROUND...DON'T DROWN WHEN ENCOUNTERING FLOODED ROADS. MOST FLOOD
DEATHS OCCUR IN VEHICLES.

&&

LAT...LON 4056 7553 4009 7488 4007 7491 4005 7497
      4002 7501 4002 7504 3998 7508 3996 7513
      3995 7514 3992 7513 3986 7522 3985 7526
      4034 7591

$$

HEAVENER
3 follow-up statements
041 
WGUS71 KPHI 151031
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
631 AM EDT WED JUL 15 2015

PAC011-017-029-045-077-091-101-151230-
/O.CON.KPHI.FF.W.0035.000000T0000Z-150715T1230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
DELAWARE PA-CHESTER PA-BUCKS PA-BERKS PA-LEHIGH PA-PHILADELPHIA PA-
MONTGOMERY PA-
631 AM EDT WED JUL 15 2015

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 830 AM EDT FOR
NORTHEASTERN DELAWARE...NORTHEASTERN CHESTER...SOUTHWESTERN BUCKS...
SOUTHEASTERN BERKS...SOUTHEASTERN LEHIGH...PHILADELPHIA AND
MONTGOMERY COUNTIES...

AT 625 AM EDT...DOPPLER RADAR INDICATED MODERATE TO HEAVY RAIN 
SHOWERS ACROSS THE WARNED AREA. THOUGH THE INTENSITY OF THE CURRENT 
STORMS HAS DECREASED THERE ARE MORE SHOWERS AND THUNDERSTORMS JUST 
UPWIND OF THE CURRENT ACTIVITY. THESE SHOWERS MAY EXACERBATE ANY 
CURRENT FLASH FLOOD THREATS.  

SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
PHILADELPHIA...READING...CAMDEN...BENSALEM...NORRISTOWN...
POTTSTOWN...PHOENIXVILLE...LANSDALE...WEST NORRITON...EAST
NORRITON...YEADON...EMMAUS...QUAKERTOWN...PERKASIE...CONSHOHOCKEN...
HATBORO...SOUDERTON...FOLCROFT...AMBLER AND PAULSBORO.

ADDITIONAL RAINFALL AMOUNTS OF ONE-HALF OF AN INCH ARE POSSIBLE IN 
THE WARNED AREA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOVE TO HIGHER GROUND NOW. ACT QUICKLY TO PROTECT YOUR LIFE.

&&

LAT...LON 4056 7553 4009 7488 4007 7491 4005 7497
      4002 7501 4002 7504 3998 7508 3996 7513
      3995 7514 3992 7513 3986 7522 3985 7526
      4034 7591

$$

HEAVENER
113 
WGUS71 KPHI 151140
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
740 AM EDT WED JUL 15 2015

PAC011-077-151146-
/O.CAN.KPHI.FF.W.0035.000000T0000Z-150715T1230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BERKS PA-LEHIGH PA-
740 AM EDT WED JUL 15 2015

...THE FLASH FLOOD WARNING FOR SOUTHEASTERN BERKS AND SOUTHEASTERN
LEHIGH COUNTIES IS CANCELLED...

THE HEAVY RAIN HAS ENDED...AND FLOODING IS NO LONGER EXPECTED TO 
POSE A THREAT. PERIODS OF LIGHT TO MODERATE RAIN WILL CONTINUE 
THROUGH THE MORNING. PLEASE CONTINUE TO HEED ALL ROAD CLOSURES.

LAT...LON 4009 7488 4007 7491 4005 7497 4002 7501
      4002 7504 3998 7508 3996 7513 3995 7514
      3992 7513 3986 7522 3985 7526 4012 7562
      4034 7523

$$

PAC017-029-045-091-101-151230-
/O.CON.KPHI.FF.W.0035.000000T0000Z-150715T1230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
DELAWARE PA-CHESTER PA-BUCKS PA-PHILADELPHIA PA-MONTGOMERY PA-
740 AM EDT WED JUL 15 2015

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 830 AM EDT FOR
NORTHEASTERN DELAWARE...NORTHEASTERN CHESTER...SOUTH CENTRAL BUCKS...
PHILADELPHIA AND MONTGOMERY COUNTIES...

AT 736 AM EDT...DOPPLER RADAR INDICATED THUNDERSTORMS PRODUCING 
HEAVY RAIN ACROSS THE URBANIZED AREA OF SOUTHEAST PENNSYLVANIA WITH 
RAIN RATES OF AN INCH OR MORE PER HOUR. THE FLASH FLOOD THREAT 
CONTINUES THIS MORNING.

SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
PHILADELPHIA...CAMDEN...BENSALEM...NORRISTOWN...PHOENIXVILLE...
LANSDALE...WEST NORRITON...EAST NORRITON...YEADON...CONSHOHOCKEN...
HATBORO...FOLCROFT...AMBLER...PAULSBORO...COLLEGEVILLE...
JENKINTOWN...NARBERTH...CHALFONT...TRAPPE AND HATFIELD.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE 
INTO AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE 
USUALLY DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS 
POWERFUL ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING 
FLOODED ROADS MAKE THE SMART CHOICE...TURN AROUND...DON'T DROWN.

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE PONDING OF WATER IN 
URBAN AREAS...HIGHWAYS...STREETS AND UNDERPASSES AS WELL AS OTHER 
POOR DRAINAGE AREAS AND LOW LYING SPOTS. DO NOT ATTEMPT TO TRAVEL 
ACROSS FLOODED ROADS. FIND ALTERNATE ROUTES.

&&

LAT...LON 4009 7488 4007 7491 4005 7497 4002 7501
      4002 7504 3998 7508 3996 7513 3995 7514
      3992 7513 3986 7522 3985 7526 4012 7562
      4034 7523

$$

ROBERTSON
556 
WGUS71 KPHI 151228
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
828 AM EDT WED JUL 15 2015

PAC017-029-045-091-101-151234-
/O.EXP.KPHI.FF.W.0035.000000T0000Z-150715T1230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
DELAWARE PA-CHESTER PA-BUCKS PA-PHILADELPHIA PA-MONTGOMERY PA-
828 AM EDT WED JUL 15 2015

...THE FLASH FLOOD WARNING FOR NORTHEASTERN DELAWARE...NORTHEASTERN
CHESTER...SOUTH CENTRAL BUCKS...PHILADELPHIA AND MONTGOMERY COUNTIES
WILL EXPIRE AT 830 AM EDT...

COUNTY EMERGENCY OFFICIALS INDICATED THE FLOODING THAT OCCURRED 
EARLIER THIS MORNING HAS RECEDED. THEREFORE, THE WARNING WILL BE 
ALLOWED TO EXPIRE.

MORE RAIN IS EXPECTED THIS MORNING. ADDITIONAL FLOODING IS POSSIBLE. 

LAT...LON 4009 7488 4007 7491 4005 7497 4002 7501
      4002 7504 3998 7508 3996 7513 3995 7514
      3992 7513 3986 7522 3985 7526 4012 7562
      4034 7523

$$

KRUZDLO

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 15, 2:36 AM EDTSpecial Weather StatementPHIBerks, Chester24 min
Jul 15, 3:11 AM EDTSpecial Weather StatementPHIBerks, Chester64 min
Jul 15, 3:39 AM EDTSevere Thunderstorm WarningPHIChester, Delaware, Montgomery, Philadelphia66 min
Jul 15, 3:50 AM EDTAreal Flood AdvisoryPHIBerks, Chester, Delaware, Montgomery4 hr
Jul 15, 4:11 AM EDTSpecial Weather StatementPHIBucks, Lehigh, Montgomery64 min
Jul 15, 4:48 AM EDTSpecial Weather StatementPHIBucks27 min
Jul 15, 5:36 AM EDTFlash Flood WarningPHIBucks, Chester, Philadelphia4 hr
Jul 15, 6:51 AM EDTAreal Flood AdvisoryPHIMonroe, Northampton4 hr
Jul 15, 7:22 AM EDTFlash Flood WarningPHIMonroe, Northampton4 hr
Jul 15, 9:12 AM EDTAreal Flood AdvisoryPHIBucks, Chester, Delaware, Montgomery, Philadelphia4 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2015Every flash flood warning in 2015

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.