Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2008

Severe Thunderstorm Warning 59, NWS Philadelphia/Mount Holly

June 10, 2008Bucks County, Chester County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 10, 2008, 7:36 PM EDT for Bucks County, Chester County, Montgomery County, Pennsylvania. It was in force for 54 min. 4 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 10, 2008, 7:36 PM EDT (23:36 UTC)
Expired: Jun 10, 2008, 8:30 PM EDT
In force: 54 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), 90 km from the middle of the area, began a volume at 23:40 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 10, 7:45 PM EDT	TSTM WND GST 70	Collegeville, PA	60 TO 70 MPH WIND GUSTS IN COLLEGEVILLE.
Jun 10, 7:45 PM EDT	TSTM WND GST 70	N Collegeville, PA	60 TO 70 MPH WIND GUSTS IN COLLEGEVILLE.
Jun 10, 7:49 PM EDT	TSTM WND DMG	Eagleville, PA	TREE DOWN IN EAGLEVILLE.
Jun 10, 8:00 PM EDT	TSTM WND DMG	Eagleville, PA	TREE DOWN IN EAGLEVILLE.

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.

Issued	Product	Office	Lasted
Jun 10, 5:47 PM EDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 11.6 hours before the alert went out and 121 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: 1286 J/kg
Mixed-layer CIN: -135 J/kg
Mixed-layer LCL: 1568 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 6 m²/s²
0-3 km storm-relative helicity: 20 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.3

Open this sounding in Storm Lab

The text

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

000 
WUUS51 KPHI 102337
SVRPHI
PAC017-029-091-110030-
/O.NEW.KPHI.SV.W.0059.080610T2336Z-080611T0030Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
736 PM EDT TUE JUN 10 2008

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

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

* UNTIL 830 PM EDT

* AT 732 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING PENNY SIZE HAIL...AND
  DESTRUCTIVE WINDS IN EXCESS OF 70 MPH.  THIS STORM WAS LOCATED 9
  MILES SOUTH OF CEDARVILLE...OR ABOUT 21 MILES SOUTHEAST OF
  READING...AND MOVING NORTHEAST AT 50 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  SPRING MOUNT BY 745 PM...
  SOUDERTON AND LANSDALE BY 750 PM...
  PERKASIE...FRICKS AND CHALFONT BY 755 PM...
  BEDMINSTER...DUBLIN AND GARDENVILLE BY 800 PM...
  TINICUM BY 805 PM...

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.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 100 AM WEDNESDAY
MORNING FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW JERSEY AND
EASTERN PENNSYLVANIA.

LAT...LON 4043 7554 4041 7548 4054 7531 4058 7525
      4055 7520 4053 7509 4045 7511 4024 7484
      4008 7528 4006 7543 4024 7569
TIME...MOT...LOC 2336Z 231DEG 45KT 4015 7560

$$

GORSE

1 follow-up statement

000 
WWUS51 KPHI 102351
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
750 PM EDT TUE JUN 10 2008

PAC017-029-091-110030-
/O.CON.KPHI.SV.W.0059.000000T0000Z-080611T0030Z/
CHESTER PA-MONTGOMERY PA-BUCKS PA-
750 PM EDT TUE JUN 10 2008

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

AT 745 PM EDT...TRAINED WEATHER SPOTTERS REPORTED 60 TO 70 MPH WINDS
IN COLLEGEVILLE IN MONTGOMERY COUNTY. THIS STORM WAS LOCATED NEAR 
PHOENIXVILLE...OR 23 MILES SOUTHEAST OF READING...MOVING NORTHEAST 
AT 52 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  SKIPPACK...EVANSBURG...SCHWENKSVILLE AND SPRING MOUNT BY 755 PM
  EDT...
  HARLEYSVILLE AND KULPSVILLE BY 800 PM EDT...
  SOUDERTON...HATFIELD...TELFORD AND LANSDALE BY 805 PM EDT...

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...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.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 100 AM EDT
WEDNESDAY MORNING FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW
JERSEY AND EASTERN PENNSYLVANIA.

LAT...LON 4043 7554 4041 7548 4054 7531 4058 7525
      4055 7520 4053 7509 4045 7511 4024 7484
      4008 7528 4006 7543 4024 7569
TIME...MOT...LOC 2349Z 231DEG 45KT 4018 7551

$$

GORSE

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 10, 5:47 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Monroe	58 min
Jun 10, 5:51 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh	54 min
Jun 10, 6:20 PM EDT	Severe Thunderstorm Warning	PHI	Monroe	40 min
Jun 10, 6:42 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh	59 min
Jun 10, 6:47 PM EDT	Flash Flood Warning	PHI	Berks, Lehigh	3 hr
Jun 10, 6:57 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Monroe, Northampton	48 min
Jun 10, 7:02 PM EDT	Severe Thunderstorm Warning	PHI	Chester	58 min
Jun 10, 7:13 PM EDT	Severe Thunderstorm Warning	PHI	Monroe, Northampton	77 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.