Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2013

Severe Thunderstorm Warning 7, NWS Philadelphia/Mount Holly

April 10, 20135 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Apr 10, 2013, 7:44 PM EDT for 5 counties in Pennsylvania. It was in force for 46 min. 2 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
Apr 10, 2013, 7:44 PM EDT (23:44 UTC)
Expired
Apr 10, 2013, 8:30 PM EDT
In force
46 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

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

The radar

The Philadelphia radar (KDIX), 100 km from the middle of the area, began a volume at 23:45 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
Apr 10, 7:50 PM EDTTSTM WND DMG3 Ne Pottsgrove, PATREES AND WIRES DOWN
Apr 10, 8:15 PM EDTTSTM WND DMGValley Green, PATREES AND WIRES DOWN

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

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 11.7 hours before the alert went out and 91 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 2013-04-10Temperature 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°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 2013-04-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 180 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
-437 J/kg
Mixed-layer LCL
1938 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
180 m²/s²
0-3 km storm-relative helicity
181 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.

353 
WUUS51 KPHI 102344
SVRPHI
PAC011-017-029-045-091-110030-
/O.NEW.KPHI.SV.W.0007.130410T2344Z-130411T0030Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
744 PM EDT WED APR 10 2013

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHEASTERN BERKS COUNTY IN EASTERN PENNSYLVANIA...
  SOUTHERN BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...
  NORTHERN CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
  NORTH CENTRAL DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA...
  MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 830 PM EDT

* AT 740 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING QUARTER SIZE
  HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH.  THESE STORMS WERE
  LOCATED ALONG A LINE EXTENDING FROM GREEN LANE TO HONEY BROOK...OR
  ALONG A LINE EXTENDING FROM 15 MILES SOUTH OF ALLENTOWN TO 9 MILES
  EAST OF NEW HOLLAND...AND MOVING EAST AT 45 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  PERKASIE...SCHWENKSVILLE...PUGHTOWN AND GLENMOORE AROUND 750 PM
  EDT...
  TRAPPE...SOUDERTON...ROYERSFORD AND HATFIELD AROUND 755 PM EDT...
  DUBLIN AND PHOENIXVILLE AROUND 800 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE
IMMEDIATELY FOR DAMAGING WINDS...LARGE HAIL...AND DEADLY CLOUD TO
GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

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.

&&

LAT...LON 4018 7595 4043 7546 4029 7486 4026 7485
      4009 7523 3994 7540 4007 7594 4009 7595
      4014 7589
TIME...MOT...LOC 2344Z 287DEG 40KT 4035 7543 4012 7587

$$

MPD
2 follow-up statements
300 
WWUS51 KPHI 102355
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
755 PM EDT WED APR 10 2013

PAC011-110006-
/O.CAN.KPHI.SV.W.0007.000000T0000Z-130411T0030Z/
BERKS PA-
755 PM EDT WED APR 10 2013

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN BERKS COUNTY IS
CANCELLED...

LAT...LON 4021 7574 4041 7536 4029 7486 4026 7485
      4009 7523 3994 7540 4004 7579
TIME...MOT...LOC 2356Z 287DEG 40KT 4031 7526 4008 7570

$$

PAC017-029-045-091-110030-
/O.CON.KPHI.SV.W.0007.000000T0000Z-130411T0030Z/
BUCKS PA-MONTGOMERY PA-DELAWARE PA-CHESTER PA-
755 PM EDT WED APR 10 2013

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 830 PM EDT
FOR NORTHEASTERN CHESTER...NORTH CENTRAL DELAWARE...MONTGOMERY AND
SOUTHERN BUCKS COUNTIES...

AT 753 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING QUARTER
SIZE HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH.  THESE STORMS
WERE LOCATED ALONG A LINE EXTENDING FROM SOUDERTON TO GLENMOORE...OR
ALONG A LINE EXTENDING FROM 21 MILES SOUTHEAST OF ALLENTOWN TO 12
MILES NORTHWEST OF WEST CHESTER...MOVING EAST AT 45 MPH.

SEVERE THUNDERSTORMS WILL BE NEAR...
  DOYLESTOWN...ROBESONIA...TROOPER AND NORTH WALES BY 805 PM EDT...
  SPRING HOUSE...PAOLI...MALVERN AND KING OF PRUSSIA BY 810 PM EDT...
  NEWTOWN GRANT AND WEST CONSHOHOCKEN BY 815 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

&&

LAT...LON 4021 7574 4041 7536 4029 7486 4026 7485
      4009 7523 3994 7540 4004 7579
TIME...MOT...LOC 2356Z 287DEG 40KT 4031 7526 4008 7570

$$

MPD
984 
WWUS51 KPHI 110025
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
825 PM EDT WED APR 10 2013

PAC029-110034-
/O.CAN.KPHI.SV.W.0007.000000T0000Z-130411T0030Z/
CHESTER PA-
825 PM EDT WED APR 10 2013

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN CHESTER COUNTY IS
CANCELLED...

LAT...LON 4010 7521 3995 7540 4002 7543 4002 7541
      4005 7540 4007 7536 4007 7537 4006 7540
      4009 7543 4009 7544 4022 7537 4034 7504
      4029 7486 4026 7485
TIME...MOT...LOC 0024Z 287DEG 40KT 4022 7487 3999 7531

$$

PAC017-045-091-110030-
/O.CON.KPHI.SV.W.0007.000000T0000Z-130411T0030Z/
BUCKS PA-MONTGOMERY PA-DELAWARE PA-
825 PM EDT WED APR 10 2013

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 830 PM EDT
FOR NORTH CENTRAL DELAWARE...SOUTHEASTERN MONTGOMERY AND CENTRAL
BUCKS COUNTIES...

AT 819 PM EDT...A LINE OF SEVERE THUNDERSTORMS WAS REPORTED CAPABLE
OF PRODUCING DAMAGING WINDS IN EXCESS OF 60 MPH.  THESE STORMS WERE 
LOCATED ALONG A LINE EXTENDING FROM 15 MILES WEST OF TRENTON TO 8 
MILES EAST OF WEST CHESTER...MOVING EAST AT 45 MPH.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

&&

LAT...LON 4010 7521 3995 7540 4002 7543 4002 7541
      4005 7540 4007 7536 4007 7537 4006 7540
      4009 7543 4009 7544 4022 7537 4034 7504
      4029 7486 4026 7485
TIME...MOT...LOC 0024Z 287DEG 40KT 4022 7487 3999 7531

$$

MPD

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 10, 4:53 PM EDTSpecial Weather StatementPHICarbon, Monroe112 min
Apr 10, 5:25 PM EDTSevere Thunderstorm WarningPHICarbon, Monroe65 min
Apr 10, 6:21 PM EDTSevere Thunderstorm WarningPHILehigh, Northampton54 min
Apr 10, 6:56 PM EDTSevere Thunderstorm WarningPHIBucks, Northampton49 min
Apr 10, 7:41 PM EDTSpecial Weather StatementPHIBucks, Chester, Montgomery64 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2013Every severe thunderstorm warning in 2013

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.