Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2015

Severe Thunderstorm Warning 74, NWS Philadelphia/Mount Holly

June 30, 2015Chester County, Delaware County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 30, 2015, 2:52 PM EDT for Chester County, Delaware County, Montgomery County, Pennsylvania. It was in force for 38 min. 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
Jun 30, 2015, 2:52 PM EDT (18:52 UTC)
Expired
Jun 30, 2015, 3:30 PM EDT
In force
38 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Chester County, PA, Delaware County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 105 km from the middle of the area, began a volume at 18:53 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
Jun 30, 3:17 PM EDTTSTM WND DMGWest Goshen, PATREES AND WIRES REPORTED DOWN IN WEST GOSHEN.
Jun 30, 3:20 PM EDTTSTM WND GST 63West Chester, PA
Jun 30, 3:34 PM EDTTSTM WND DMG3 S Phoenixville, PATREES AND WIRES REPORTED DOWN IN PHOENIXVILLE.
Jun 30, 3:34 PM EDTTSTM WND DMGPhoenixville, PATREES AND WIRES REPORTED DOWN IN PHOENIXVILLE.

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

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jun 30, 1:21 PM EDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 6.9 hours before the alert went out and 72 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 2015-06-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 600 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 2015-06-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 128 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
600 J/kg
Mixed-layer CIN
-45 J/kg
Mixed-layer LCL
728 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
128 m²/s²
0-3 km storm-relative helicity
128 m²/s²
Significant tornado parameter
0.3
Supercell composite
2.9

Open this sounding in Storm Lab

The text

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

628 
WUUS51 KPHI 301852
SVRPHI
PAC029-045-091-301930-
/O.NEW.KPHI.SV.W.0074.150630T1852Z-150630T1930Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
252 PM EDT TUE JUN 30 2015

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ  HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTH CENTRAL DELAWARE COUNTY IN SOUTHEASTERN PENNSYLVANIA...
  CENTRAL CHESTER COUNTY IN SOUTHEASTERN PENNSYLVANIA...
  SOUTHWESTERN MONTGOMERY COUNTY IN SOUTHEASTERN PENNSYLVANIA...

* UNTIL 330 PM EDT

* AT 251 PM EDT...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM
  CAPABLE OF PRODUCING QUARTER SIZE HAIL AND DAMAGING WINDS IN EXCESS
  OF 60 MPH. THIS STORM WAS LOCATED OVER COATESVILLE...OR 8 MILES
  WEST OF WEST CHESTER...AND MOVING NORTHEAST AT 25 MPH.

* LOCATIONS IMPACTED INCLUDE...
  WEST CHESTER...NORRISTOWN...PHOENIXVILLE...WEST NORRITON...EAST
  NORRITON...COATESVILLE...DOWNINGTOWN...CONSHOHOCKEN...
  COLLEGEVILLE...ROYERSFORD...TRAPPE...SCHWENKSVILLE...VALLEY
  FORGE...MARSHALLTON...GLENMOORE...BRYN MAWR...KING OF PRUSSIA...
  CHESTER SPRINGS...RADNOR TOWNSHIP AND TROUT LAKE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WINDS...LARGE HAIL...DEADLY
LIGHTNING AND VERY HEAVY RAIN. FOR YOUR PROTECTION...MOVE TO AN
INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR HOME OR BUSINESS. HEAVY
RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE INTO AREAS WHERE WATER
COVERS THE ROAD.

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...FREQUENT CLOUD TO
GROUND LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS
IMMEDIATELY. REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE
ENOUGH TO BE STRUCK BY LIGHTNING.

TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD
TO FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED
ROADWAYS.

&&

LAT...LON 3986 7580 4003 7591 4027 7547 4003 7525
TIME...MOT...LOC 1851Z 236DEG 22KT 3999 7577 

$$

HEAVENER
1 follow-up statement
800 
WWUS51 KPHI 301905
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
305 PM EDT TUE JUN 30 2015

PAC029-045-091-301930-
/O.CON.KPHI.SV.W.0074.000000T0000Z-150630T1930Z/
DELAWARE PA-CHESTER PA-MONTGOMERY PA-
305 PM EDT TUE JUN 30 2015

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 330 PM EDT
FOR NORTH CENTRAL DELAWARE...NORTHEASTERN CHESTER AND SOUTHWESTERN
MONTGOMERY COUNTIES...

AT 305 PM EDT...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE
OF PRODUCING QUARTER SIZE HAIL AND DAMAGING WINDS IN EXCESS OF 60
MPH. THIS STORM WAS LOCATED OVER LIONVILLE...OR NEAR WEST CHESTER...
MOVING NORTHEAST AT 25 MPH.

LOCATIONS IMPACTED INCLUDE...
WEST CHESTER...NORRISTOWN...PHOENIXVILLE...WEST NORRITON...EAST
NORRITON...DOWNINGTOWN...CONSHOHOCKEN...COLLEGEVILLE...ROYERSFORD...
TRAPPE...SCHWENKSVILLE...VALLEY FORGE...MARSHALLTON...BRYN MAWR...
KING OF PRUSSIA...CHESTER SPRINGS...RADNOR TOWNSHIP...PAOLI...
LIONVILLE-MARCHWOOD AND LIONVILLE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WINDS...DESTRUCTIVE HAIL...
DEADLY LIGHTNING AND VERY HEAVY RAIN. FOR YOUR PROTECTION MOVE TO AN
INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR HOME OR BUSINESS. HEAVY
RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE INTO AREAS WHERE WATER
COVERS THE ROAD.

IF YOU ARE IN THE PATH OF THIS STORM...PREPARE IMMEDIATELY FOR LARGE
HAIL AND DAMAGING WINDS. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING AND AWAY FROM WINDOWS.

TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD
TO FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED
ROADWAYS.

&&

LAT...LON 3992 7571 4008 7578 4027 7547 4003 7525
TIME...MOT...LOC 1905Z 236DEG 22KT 4005 7565 

$$

HEAVENER

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 30, 10:01 AM EDTAreal Flood AdvisoryPHICarbon, Monroe4 hr
Jun 30, 12:37 PM EDTAreal Flood AdvisoryPHIBerks4 hr
Jun 30, 12:47 PM EDTSpecial Weather StatementPHIBerks43 min
Jun 30, 1:08 PM EDTSevere Thunderstorm WarningPHIBerks, Lehigh52 min
Jun 30, 1:47 PM EDTSpecial Weather StatementPHILehigh43 min
Jun 30, 1:48 PM EDTFlash Flood WarningPHIBerks4 hr
Jun 30, 1:55 PM EDTSpecial Weather StatementPHIChester50 min
Jun 30, 2:00 PM EDTTornado WarningPHIBerks, Chester30 min
Jun 30, 2:05 PM EDTSevere Thunderstorm WarningPHIBerks, Carbon, Lehigh, Monroe, Northampton55 min
Jun 30, 2:13 PM EDTTornado WarningPHILehigh32 min
Jun 30, 2:19 PM EDTSpecial Weather StatementPHIChester26 min
Jun 30, 2:26 PM EDTAreal Flood AdvisoryPHIBerks, Chester4 hr
Jun 30, 2:34 PM EDTSevere Thunderstorm WarningPHIBerks, Chester, Montgomery56 min
Jun 30, 2:41 PM EDTSevere Thunderstorm WarningPHIChester49 min
Jun 30, 2:42 PM EDTTornado WarningPHILehigh, Northampton33 min
Jun 30, 2:48 PM EDTSpecial Weather StatementPHIChester57 min
Jun 30, 2:55 PM EDTFlash Flood WarningPHIBerks, Lehigh, Northampton4 hr
Jun 30, 3:00 PM EDTAreal Flood AdvisoryPHIBucks, Monroe, Northampton4 hr
Jun 30, 3:00 PM EDTSevere Thunderstorm WarningPHILehigh, Northampton60 min
Jun 30, 3:08 PM EDTAreal Flood AdvisoryPHIChester4 hr
Jun 30, 3:22 PM EDTTornado WarningPHIChester, Delaware, Montgomery23 min
Jun 30, 3:25 PM EDTSevere Thunderstorm WarningPHIChester37 min
Jun 30, 3:31 PM EDTSpecial Weather StatementPHILehigh44 min
Jun 30, 3:37 PM EDTAreal Flood AdvisoryPHICarbon, Lehigh, Monroe, Northampton4 hr
Jun 30, 3:43 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Philadelphia47 min
Jun 30, 3:45 PM EDTSevere Thunderstorm WarningPHIBucks, Chester, Delaware, Montgomery, Philadelphia45 min
Jun 30, 3:47 PM EDTSevere Thunderstorm WarningPHINorthampton43 min
Jun 30, 3:54 PM EDTFlash Flood WatchPHIBerks, Bucks, Carbon, Chester, Delaware, Lehigh and 4 more13 hr
Jun 30, 3:57 PM EDTAreal Flood AdvisoryPHIBucks, Chester, Delaware, Montgomery, Philadelphia4 hr
Jun 30, 4:22 PM EDTSpecial Weather StatementPHIMonroe23 min
Jun 30, 4:29 PM EDTSpecial Weather StatementPHIDelaware, Philadelphia31 min
Jun 30, 4:31 PM EDTSpecial Weather StatementPHICarbon29 min
Jun 30, 4:58 PM EDTAreal Flood AdvisoryPHIDelaware, Montgomery, Philadelphia3 hr
Jun 30, 4:59 PM EDTSpecial Weather StatementPHIPhiladelphia61 min
Jun 30, 5:03 PM EDTSpecial Weather StatementPHIMonroe27 min
Jun 30, 5:51 PM EDTSpecial Weather StatementPHIMonroe24 min
Jun 30, 6:03 PM EDTFlash Flood WarningPHICarbon, Monroe11 hr
Jun 30, 6:28 PM EDTSevere Thunderstorm WarningPHIMonroe, Northampton47 min
Jun 30, 7:13 PM EDTSevere Thunderstorm WarningPHIMonroe62 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2015Every severe thunderstorm 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.