Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 128, NWS Philadelphia/Mount Holly

July 26, 20126 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 26, 2012, 6:46 PM EDT for 6 counties in Pennsylvania. It was in force for 89 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
Jul 26, 2012, 6:46 PM EDT (22:46 UTC)
Expired
Jul 26, 2012, 8:15 PM EDT
In force
89 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, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 99 km from the middle of the area, began a volume at 22:47 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 26, 7:04 PM EDTTSTM WND GST 64Elverson, PA
Jul 26, 7:30 PM EDTTSTM WND GST 50Oreland, PA

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
Jul 26, 3:57 PM EDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 10.8 hours before the alert went out and 76 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 2012-07-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 59 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 2012-07-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 238 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
59 J/kg
Mixed-layer CIN
-282 J/kg
Mixed-layer LCL
1017 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
238 m²/s²
0-3 km storm-relative helicity
239 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.

648 
WUUS51 KPHI 262246
SVRPHI
PAC011-017-029-045-091-101-270015-
/O.NEW.KPHI.SV.W.0128.120726T2246Z-120727T0015Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
646 PM EDT THU JUL 26 2012

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...
  CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
  THIS INCLUDES THE CITY OF WEST CHESTER...
  DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA...
  MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...
  PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA...
  THIS INCLUDES THE CITY OF PHILADELPHIA...

* UNTIL 815 PM EDT

* AT 645 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WINDS IN
  EXCESS OF 60 MPH.  THESE STORMS WERE LOCATED ALONG A LINE EXTENDING
  ACROSS WESTERN BERKS COUNTY...AND MOVING EAST AT 55 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  MOUNT VERNON...GLEN ROY...NEW MORGAN AND HONEY BROOK AROUND 655 PM
  EDT...
  HOMEVILLE...COCHRANVILLE...PARKESBURG AND OXFORD AROUND 700 PM
  EDT...
  WEST GROVE AND COATESVILLE AROUND 705 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DOPPLER RADAR HAS INDICATED SOME ROTATION WITHIN THIS STORM. WHILE
NOT IMMEDIATELY LIKELY...A TORNADO MAY STILL DEVELOP. IF A TORNADO IS
SPOTTED...ACT QUICKLY AND MOVE TO A PLACE OF SAFETY IN A STURDY
STRUCTURE...SUCH AS A BASEMENT OR SMALL INTERIOR ROOM.

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.

PLEASE REPORT HAIL OR STRONG WINDS TO THE NATIONAL WEATHER SERVICE BY
CALLING TOLL FREE...1-877-633-6772...WHEN YOU CAN DO SO SAFELY.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 1100 PM EDT 
THURSDAY EVENING FOR EASTERN PENNSYLVANIA.

&&

LAT...LON 3972 7614 3987 7600 4011 7594 4013 7589
      4026 7606 4025 7572 4045 7556 4042 7548
      4044 7546 4037 7496 4016 7472 3997 7511
      3989 7513 3986 7523 3985 7533 3980 7541
      3984 7553 3983 7563 3981 7570 3972 7578
TIME...MOT...LOC 2245Z 285DEG 53KT 4055 7569 4018 7613

$$

IOVINO
1 follow-up statement
955 
WWUS51 KPHI 262340
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
740 PM EDT THU JUL 26 2012

PAC011-262349-
/O.CAN.KPHI.SV.W.0128.000000T0000Z-120727T0015Z/
BERKS PA-
740 PM EDT THU JUL 26 2012

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

PLEASE REPORT HAIL OR STRONG WINDS TO THE NATIONAL WEATHER SERVICE BY
CALLING TOLL FREE...1-877-633-6772...WHEN YOU CAN DO SO SAFELY.

LAT...LON 3974 7610 3988 7600 4011 7594 4041 7521
      4037 7496 4016 7472 3997 7512 3989 7514
      3985 7533 3980 7541 3983 7549 3984 7560
      3981 7570 3972 7578 3972 7614
TIME...MOT...LOC 2339Z 285DEG 53KT 4027 7488 3990 7532

$$

PAC017-029-045-091-101-270015-
/O.CON.KPHI.SV.W.0128.000000T0000Z-120727T0015Z/
BUCKS PA-MONTGOMERY PA-PHILADELPHIA PA-DELAWARE PA-CHESTER PA-
740 PM EDT THU JUL 26 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 815 PM EDT
FOR CHESTER...DELAWARE...PHILADELPHIA...MONTGOMERY AND SOUTHERN BUCKS
COUNTIES...

AT 735 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 NEW HOPE TO KING OF PRUSSIA 
TO COATESVILLE...MOVING EAST AT 55 MPH.

SEVERE THUNDERSTORMS WILL BE NEAR...
  WISSINOMING...TACONY...SOUTH PHILADELPHIA AND PHILADELPHIA
  INTERNATIONAL AIRPORT BY 745 PM EDT...
  TULLYTOWN...CROYDON AND BRISTOL BY 750 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

PLEASE REPORT HAIL OR STRONG WINDS TO THE NATIONAL WEATHER SERVICE BY
CALLING TOLL FREE...1-877-633-6772...WHEN YOU CAN DO SO SAFELY.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 1100 PM EDT 
THURSDAY EVENING FOR EASTERN PENNSYLVANIA.

&&

LAT...LON 3974 7610 3988 7600 4011 7594 4041 7521
      4037 7496 4016 7472 3997 7512 3989 7514
      3985 7533 3980 7541 3983 7549 3984 7560
      3981 7570 3972 7578 3972 7614
TIME...MOT...LOC 2339Z 285DEG 53KT 4027 7488 3990 7532

$$

IOVINO

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 26, 7:41 AM EDTSpecial Weather StatementPHICarbon, Lehigh, Monroe, Northampton64 min
Jul 26, 5:21 PM EDTSevere Thunderstorm WarningPHICarbon, Monroe54 min
Jul 26, 5:46 PM EDTSevere Thunderstorm WarningPHICarbon, Lehigh, Northampton74 min
Jul 26, 6:03 PM EDTSevere Thunderstorm WarningPHIMonroe42 min
Jul 26, 6:10 PM EDTSevere Thunderstorm WarningPHIBerks, Lehigh, Northampton95 min
Jul 26, 6:22 PM EDTSevere Thunderstorm WarningPHIBucks83 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2012Every severe thunderstorm warning in 2012

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.