Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2008

Severe Thunderstorm Warning 70, NWS Philadelphia/Mount Holly

June 14, 2008Bucks County, Chester County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 14, 2008, 7:42 PM EDT for Bucks County, Chester County, Montgomery County, Pennsylvania. It was in force for 63 min. 3 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 14, 2008, 7:42 PM EDT (23:42 UTC)
Expired: Jun 14, 2008, 8:45 PM EDT
In force: 63 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties Bucks County, PA, Chester County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 73 km from the middle of the area, began a volume at 23:42 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 14, 8:05 PM EDT	TSTM WND DMG	North Wales, PA	TREE LIMBS DOWN.
Jun 14, 8:25 PM EDT	TSTM WND DMG	Doylestown, PA	FEW TREES KNOCKED DOWN IN BUCKS COUNTY.
Jun 14, 8:30 PM EDT	TSTM WND DMG	5 E Doylestown, PA	TREES DOWN IN BUCKINGHAM TOWNSHIP AND WRIGHTSTOWN TOWNSHIP.

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

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 11.7 hours before the alert went out and 210 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: 29 J/kg
Mixed-layer CIN: -177 J/kg
Mixed-layer LCL: 1159 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 42 m²/s²
0-3 km storm-relative helicity: 72 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.

000 
WUUS51 KPHI 142343
SVRPHI
PAC017-029-091-150045-
/O.NEW.KPHI.SV.W.0070.080614T2342Z-080615T0045Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
742 PM EDT SAT JUN 14 2008

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CENTRAL BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...
  NORTHEASTERN CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
  CENTRAL MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 845 PM EDT

* AT 737 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING PENNY SIZE HAIL...AND
  DAMAGING WINDS TO 60 MPH.  THIS STORM WAS LOCATED NEAR
  COLLEGEVILLE...OR ABOUT 23 MILES SOUTHEAST OF READING...AND MOVING
  EAST AT 20 MPH. THIS STORM HAS DOWNED TREES IN CHESTER COUNTY.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  7 MILES SOUTH OF SOUDERTON BY 810 PM...
  LANSDALE BY 815 PM...
  AMBLER AND 7 MILES SOUTH OF FRICKS BY 825 PM...
  CHALFONT BY 830 PM...
  WILLOW GROVE BY 840 PM...
  IVYLAND...6 MILES WEST OF RICHBORO...7 MILES SOUTH OF DOYLESTOWN
  AND 8 MILES NORTHWEST OF FEASTERVILLE BY 845 PM...

THUNDERSTORMS ARE CAPABLE OF PRODUCING HEAVY RAINFALL WHICH MAY
RESULT IN LOCALIZED AREAS OF FLOODING. DO NOT DRIVE IN AREAS WHERE
WATER IS CROSSING THE ROAD.

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.

SEEK SHELTER NOW INSIDE A STURDY STRUCTURE AND STAY AWAY FROM 
WINDOWS

LAT...LON 4028 7551 4049 7509 4011 7489 4011 7497
      4013 7501 4012 7505 4014 7553
TIME...MOT...LOC 2342Z 268DEG 16KT 4021 7549

$$
 
TFG

1 follow-up statement

000 
WWUS51 KPHI 150020
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
819 PM EDT SAT JUN 14 2008

PAC029-150029-
/O.CAN.KPHI.SV.W.0070.000000T0000Z-080615T0045Z/
CHESTER PA-
819 PM EDT SAT JUN 14 2008

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

THE SEVERE STORM HAS MOVED EAST OF THE COUNTY.

LAT...LON 4011 7489 4011 7497 4012 7498 4013 7502
      4013 7522 4013 7525 4014 7526 4014 7535
      4029 7537 4049 7509
TIME...MOT...LOC 0019Z 268DEG 16KT 4023 7526

$$

PAC017-091-150045-
/O.CON.KPHI.SV.W.0070.000000T0000Z-080615T0045Z/
MONTGOMERY PA-BUCKS PA-
819 PM EDT SAT JUN 14 2008

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 845 PM EDT
FOR CENTRAL BUCKS AND CENTRAL MONTGOMERY COUNTIES...

AT 814 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE
HAIL...AND DAMAGING WINDS TO AROUND 60 MPH.  THIS STORM WAS
LOCATED NEAR LANSDALE...OR 17 MILES NORTHWEST OF PHILADELPHIA...
MOVING EAST AT 20 MPH. THIS STORM HAS ALREADY CAUSED TREE DAMAGE.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  BRITTANY FARMS-HIGHLANDS...SPRING HOUSE AND AMBLER BY 825 PM EDT...
  MAPLE GLEN BY 830 PM EDT...
  NEW BRITAIN BY 835 PM EDT...
  HORSHAM BY 840 PM EDT...
  IVYLAND BY 845 PM EDT...

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.

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.

LAT...LON 4011 7489 4011 7497 4012 7498 4013 7502
      4013 7522 4013 7525 4014 7526 4014 7535
      4029 7537 4049 7509
TIME...MOT...LOC 0019Z 268DEG 16KT 4023 7526

$$

TFG

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 14, 2:23 PM EDT	Flash Flood Warning	PHI	Monroe	3 hr
Jun 14, 3:02 PM EDT	Severe Thunderstorm Warning	PHI	Monroe	58 min
Jun 14, 4:26 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Monroe, Northampton	64 min
Jun 14, 4:49 PM EDT	Flash Flood Warning	PHI	Carbon	5 hr
Jun 14, 5:07 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Monroe	53 min
Jun 14, 5:18 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Monroe	57 min
Jun 14, 6:15 PM EDT	Severe Thunderstorm Warning	PHI	Chester	75 min
Jun 14, 6:28 PM EDT	Flash Flood Warning	PHI	Chester	60 min
Jun 14, 6:48 PM EDT	Flash Flood Warning	PHI	Carbon, Monroe	3 hr
Jun 14, 7:05 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester, Montgomery	70 min
Jun 14, 7:56 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Delaware, Philadelphia	79 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2008 Every severe thunderstorm warning in 2008

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.