Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 53, NWS Philadelphia/Mount Holly

June 29, 20126 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 29, 2012, 4:14 AM EDT for 6 counties in Pennsylvania. It was in force for 76 min. 10 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 29, 2012, 4:14 AM EDT (08:14 UTC)
Expired: Jun 29, 2012, 5:30 AM EDT
In force: 76 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties Berks County, PA, Bucks County, PA, Chester County, PA, Lehigh County, PA, Montgomery County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 127 km from the middle of the area, began a volume at 08:17 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

Time	Report	Where	Remark
Jun 29, 4:30 AM EDT	TSTM WND DMG	Elverson, PA	LARGE LIMBS DOWN
Jun 29, 4:36 AM EDT	HAIL 0.75	Dublin, PA
Jun 29, 4:50 AM EDT	HAIL 1	West Chester, PA
Jun 29, 5:00 AM EDT	HAIL 0.75	Boyertown, PA
Jun 29, 5:00 AM EDT	HAIL 0.88	Pottstown, PA
Jun 29, 5:03 AM EDT	TSTM WND GST 60	Spring City, PA
Jun 29, 5:05 AM EDT	TSTM WND DMG	Coatesville, PA	LARGE LIMBS DOWN
Jun 29, 5:10 AM EDT	TSTM WND DMG	Paoli, PA	LARGE LIMBS DOWN IN PAOLI
Jun 29, 5:15 AM EDT	TSTM WND DMG	Eagleville, PA	TREE AND TREE LIMBS TOOK DOWN WIRES.
Jun 29, 5:15 AM EDT	TSTM WND DMG	Norristown, PA	LARGE LIMBS DOWN

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

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 8.2 hours before the alert went out and 211 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2494 m above ground
0-6 km bulk shear: 56 kt
0-1 km storm-relative helicity: 132 m²/s²
0-3 km storm-relative helicity: 317 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.

544 
WUUS51 KPHI 290814
SVRPHI
PAC011-017-029-077-091-095-290930-
/O.NEW.KPHI.SV.W.0053.120629T0814Z-120629T0930Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
414 AM EDT FRI JUN 29 2012

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  BERKS COUNTY IN EASTERN PENNSYLVANIA...
  THIS INCLUDES THE CITY OF READING...
  LEHIGH COUNTY IN EASTERN PENNSYLVANIA...
  THIS INCLUDES THE CITY OF ALLENTOWN...
  SOUTH CENTRAL NORTHAMPTON COUNTY IN EASTERN PENNSYLVANIA...
  WESTERN BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...
  CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
  THIS INCLUDES THE CITY OF WEST CHESTER...
  MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 530 AM EDT

* AT 413 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING QUARTER SIZE
  HAIL...AND DESTRUCTIVE WINDS UP TO 70 MPH.  THESE STORMS
  WERE LOCATED ALONG A LINE EXTENDING FROM 12 MILES NORTH OF
  STRAUSSTOWN TO 8 MILES SOUTHWEST OF WOMELSDORF TO 33 MILES
  SOUTHWEST OF WOMELSDORF...OR ALONG A LINE EXTENDING FROM 28 MILES
  NORTHWEST OF READING TO 17 MILES NORTH OF LANCASTER TO 17 MILES
  WEST OF LANCASTER...AND MOVING EAST AT 50 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  WOMELSDORF AND STRAUSSTOWN AROUND 420 AM EDT...
  WERNERSVILLE AND BERNVILLE AROUND 425 AM EDT...
  SINKING SPRING...SHOEMAKERSVILLE...LEESPORT AND HAMBURG AROUND 430
  AM EDT...
  WANAMAKERS AND WYOMISSING AROUND 435 AM 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.

WIND DAMAGE WITH THIS LINE WAS REPORTED IN THE LOWER SUSQUEHANNA 
VALLEY. THIS IS A DANGEROUS STORM...SEEK SAFE SHELTER AND STAY 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.

&&

LAT...LON 4051 7638 4052 7624 4058 7602 4065 7599
      4070 7583 4063 7519 4057 7518 4058 7513
      4056 7510 4022 7517 3985 7572 3994 7600
      4003 7594 4011 7595 4014 7589 4047 7640
TIME...MOT...LOC 0814Z 274DEG 44KT 4067 7622 4029 7628
          4002 7660

$$

TFG

2 follow-up statements

143 
WWUS51 KPHI 290849
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
449 AM EDT FRI JUN 29 2012

PAC011-017-029-077-091-095-290930-
/O.CON.KPHI.SV.W.0053.000000T0000Z-120629T0930Z/
BERKS PA-BUCKS PA-LEHIGH PA-MONTGOMERY PA-NORTHAMPTON PA-CHESTER PA-
449 AM EDT FRI JUN 29 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 530 AM EDT
FOR CHESTER...SOUTH CENTRAL NORTHAMPTON...MONTGOMERY...LEHIGH...
WESTERN BUCKS AND BERKS COUNTIES...

AT 447 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING QUARTER
SIZE HAIL...AND DESTRUCTIVE WINDS TO AROUND 75 MPH.  THESE STORMS
WERE LOCATED ALONG A LINE EXTENDING FROM LENHARTSVILLE TO AMITY
GARDENS TO PARKESBURG...OR ALONG A LINE EXTENDING FROM 17 MILES NORTH
OF READING TO 11 MILES SOUTHEAST OF READING TO 17 MILES WEST OF WEST
CHESTER...MOVING EAST AT 50 MPH.

SEVERE THUNDERSTORMS WILL BE NEAR...
  PUGHTOWN...CEDARVILLE...TOPTON AND THORNDALE BY 455 AM EDT...
  CLAUSSVILLE...CHESTER SPRINGS...SPRING CITY AND LIONVILLE BY 500 AM
  EDT...
  WEST CHESTER AND TRAPPE BY 505 AM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

THIS LINE HAS A HISTORY OF PRODUCING WIND DAMAGE IN THE 
LOWER SUSQUEHANNA VALLEY. THIS IS AN EXTREMELY DANGEROUS SITUATION.
SEEK SHELTER NOW INSIDE A STURDY STRUCTURE AND STAY 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 800 AM EDT FRIDAY
MORNING FOR NORTHERN DELAWARE AND NORTHEASTERN MARYLAND AND SOUTHERN
NEW JERSEY AND SOUTHEAST PENNSYLVANIA.

&&

LAT...LON 4058 7602 4065 7599 4070 7583 4063 7519
      4057 7519 4058 7513 4056 7510 4022 7517
      3985 7572 3994 7600 4003 7594 4011 7595
      4014 7589 4026 7607 4033 7611 4051 7615
TIME...MOT...LOC 0848Z 274DEG 44KT 4057 7588 4026 7574
          3996 7592

$$

TFG

459 
WWUS51 KPHI 290908
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
508 AM EDT FRI JUN 29 2012

PAC011-017-029-077-091-095-290930-
/O.CON.KPHI.SV.W.0053.000000T0000Z-120629T0930Z/
BERKS PA-BUCKS PA-LEHIGH PA-MONTGOMERY PA-NORTHAMPTON PA-CHESTER PA-
508 AM EDT FRI JUN 29 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 530 AM EDT
FOR EASTERN CHESTER...SOUTH CENTRAL NORTHAMPTON...MONTGOMERY...
SOUTHERN LEHIGH...WESTERN BUCKS AND EASTERN BERKS COUNTIES...

AT 504 AM EDT...A LINE OF SEVERE THUNDERSTORMS WAS REPORTED CAPABLE
OF PRODUCING QUARTER SIZE HAIL...AND DAMAGING WINDS IN EXCESS OF 60
MPH.  THESE STORMS WERE LOCATED ALONG A LINE EXTENDING FROM ANCIENT
OAKS TO SCHWENKSVILLE TO MARSHALLTON...OR ALONG A LINE EXTENDING FROM
8 MILES WEST OF ALLENTOWN TO 20 MILES NORTH OF WEST CHESTER TO WEST
CHESTER...MOVING EAST AT 50 MPH.

SEVERE THUNDERSTORMS WILL BE NEAR...
  ALLENTOWN...FOUNTAIN HILL...COOPERSBURG AND WEST NORRITON BY 515 AM
  EDT...
  HELLERTOWN...FOUNTAIN HILL...FRICKS AND SPRING HOUSE BY 520 AM
  EDT...
  SPRINGTOWN AND PLEASANT VALLEY BY 525 AM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...CONTINUOUS CLOUD TO
GROUND LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS
IMMEDIATELY! LIGHTNING IS ONE OF NATURES NUMBER ONE KILLERS.
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 800 AM EDT FRIDAY
MORNING FOR NORTHERN DELAWARE AND NORTHEASTERN MARYLAND AND SOUTHERN
NEW JERSEY AND SOUTHEAST PENNSYLVANIA.

&&

LAT...LON 4050 7586 4053 7579 4062 7577 4065 7560
      4063 7519 4057 7519 4057 7516 4058 7513
      4056 7510 4022 7517 3985 7572 3990 7582
      4002 7572 4017 7572 4032 7575 4039 7586
TIME...MOT...LOC 0908Z 274DEG 44KT 4055 7556 4024 7542
          3994 7560

$$
  
TFG

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 29, 3:51 AM EDT	Special Weather Statement	PHI	Berks, Bucks, Chester, Delaware, Lehigh, Montgomery and 1 more	54 min
Jun 29, 4:46 AM EDT	Severe Thunderstorm Warning	PHI	Chester	48 min
Jun 29, 5:00 AM EDT	Severe Thunderstorm Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	75 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2012 Every 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.