Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2015

Severe Thunderstorm Warning 102, NWS Philadelphia/Mount Holly

July 15, 20154 counties in Pennsylvania; New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 15, 2015, 3:39 AM EDT for 4 counties in Pennsylvania; New Castle County, Delaware. It was in force for 66 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
Jul 15, 2015, 3:39 AM EDT (07:39 UTC)
Expired
Jul 15, 2015, 4:45 AM EDT
In force
66 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties New Castle County, DE, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 92 km from the middle of the area, began a volume at 07:39 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, 7.7 hours before the alert went out and 195 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 2015-07-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 858 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 00:00Z on 2015-07-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 73 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
858 J/kg
Mixed-layer CIN
-55 J/kg
Mixed-layer LCL
1163 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
73 m²/s²
0-3 km storm-relative helicity
109 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.1

Open this sounding in Storm Lab

The text

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

531 
WUUS51 KPHI 150739
SVRPHI
DEC003-PAC029-045-091-101-150845-
/O.NEW.KPHI.SV.W.0102.150715T0739Z-150715T0845Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
339 AM EDT WED JUL 15 2015

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ  HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTH CENTRAL NEW CASTLE COUNTY IN NORTHERN DELAWARE...
  DELAWARE COUNTY IN SOUTHEASTERN PENNSYLVANIA...
  SOUTHEASTERN CHESTER COUNTY IN SOUTHEASTERN PENNSYLVANIA...
  SOUTHWESTERN PHILADELPHIA COUNTY IN SOUTHEASTERN PENNSYLVANIA...
  SOUTH CENTRAL MONTGOMERY COUNTY IN SOUTHEASTERN PENNSYLVANIA...

* UNTIL 445 AM EDT

* AT 338 AM EDT...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM
  CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM
  WAS LOCATED NEAR ELAM...OR NEAR WEST CHESTER...AND MOVING NORTHEAST
  AT 25 MPH.

* LOCATIONS IMPACTED INCLUDE...
  PHILADELPHIA...WEST CHESTER...NORRISTOWN...CHESTER...WEST
  NORRITON...EAST NORRITON...YEADON...WESTTOWN...CONSHOHOCKEN...
  FOLCROFT...SWARTHMORE...KENNETT SQUARE...NARBERTH...EAST
  LANSDOWNE...MORRIS PARK...SOUTH PHILADELPHIA...MARSHALLTON...
  ROXBOROUGH...ELAM AND RADNOR TOWNSHIP.

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 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 3980 7569 3991 7575 4015 7533 3993 7514
      3984 7536
TIME...MOT...LOC 0738Z 243DEG 23KT 3986 7562 

$$

HEAVENER
2 follow-up statements
412 
WWUS51 KPHI 150804
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
404 AM EDT WED JUL 15 2015

DEC003-150813-
/O.CAN.KPHI.SV.W.0102.000000T0000Z-150715T0845Z/
NEW CASTLE DE-
404 AM EDT WED JUL 15 2015

...THE SEVERE THUNDERSTORM WARNING FOR NORTH CENTRAL NEW CASTLE
COUNTY IS CANCELLED...
    
THE SEVERE THUNDERSTORM WHICH PROMPTED THE WARNING HAS MOVED OUT OF 
THE WARNED AREA. THEREFORE THE WARNING HAS BEEN CANCELLED.

LAT...LON 3983 7547 3999 7561 4015 7533 3993 7514
      3984 7536
TIME...MOT...LOC 0803Z 243DEG 23KT 3994 7543 

$$

PAC029-045-091-101-150845-
/O.CON.KPHI.SV.W.0102.000000T0000Z-150715T0845Z/
DELAWARE PA-CHESTER PA-PHILADELPHIA PA-MONTGOMERY PA-
404 AM EDT WED JUL 15 2015

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 445 AM EDT
FOR DELAWARE...EAST CENTRAL CHESTER...SOUTHWESTERN PHILADELPHIA AND
SOUTH CENTRAL MONTGOMERY COUNTIES...

AT 403 AM EDT...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE
OF PRODUCING DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS
LOCATED OVER LIMA...OR 9 MILES EAST OF WEST CHESTER...MOVING
NORTHEAST AT 25 MPH.

LOCATIONS IMPACTED INCLUDE...
PHILADELPHIA...NORRISTOWN...CHESTER...WEST NORRITON...EAST
NORRITON...YEADON...WESTTOWN...CONSHOHOCKEN...FOLCROFT...
SWARTHMORE...NARBERTH...EAST LANSDOWNE...MORRIS PARK...SOUTH
PHILADELPHIA...ROXBOROUGH...RADNOR TOWNSHIP...TROUT LAKE...
BROOMALL...PAOLI AND NETHER PROVIDENCE TOWNSHIP.

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.

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

&&

LAT...LON 3983 7547 3999 7561 4015 7533 3993 7514
      3984 7536
TIME...MOT...LOC 0803Z 243DEG 23KT 3994 7543 

$$

HEAVENER
151 
WWUS51 KPHI 150840
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
440 AM EDT WED JUL 15 2015

PAC029-045-091-101-150849-
/O.EXP.KPHI.SV.W.0102.000000T0000Z-150715T0845Z/
DELAWARE PA-CHESTER PA-PHILADELPHIA PA-MONTGOMERY PA-
440 AM EDT WED JUL 15 2015

...THE SEVERE THUNDERSTORM WARNING FOR DELAWARE...EAST CENTRAL
CHESTER...SOUTHWESTERN PHILADELPHIA AND SOUTH CENTRAL MONTGOMERY
COUNTIES WILL EXPIRE AT 445 AM EDT...
                
LAT...LON 3983 7547 3999 7561 4015 7533 3993 7514
      3984 7536
TIME...MOT...LOC 0836Z 243DEG 23KT 3994 7543 

$$

HEAVENER

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, 3:50 AM EDTAreal Flood AdvisoryPHIBerks, Chester, Delaware, Montgomery4 hr
Jul 15, 4:11 AM EDTSpecial Weather StatementPHIBucks, Lehigh, Montgomery64 min
Jul 15, 4:27 AM EDTFlash Flood WarningPHIBerks, Bucks, Chester, Delaware, Lehigh, Montgomery and 1 more4 hr
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
Jul 15, 6:04 AM EDTSpecial Weather StatementPHINew Castle56 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2015Severe Thunderstorm Warnings in Delaware, 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.