Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2007

Severe Thunderstorm Warning 67, NWS Philadelphia/Mount Holly

June 12, 2007Bucks County, Montgomery County, Philadelphia County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 12, 2007, 3:20 PM EDT for Bucks County, Montgomery County, Philadelphia County, Pennsylvania. It was in force for 40 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 12, 2007, 3:20 PM EDT (19:20 UTC)
Expired
Jun 12, 2007, 4:00 PM EDT
In force
40 min
Issued by
NWS Philadelphia/Mount Holly
Area
Counties, with a storm outline in the text

Counties Bucks County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 67 km from the middle of the area, began a volume at 19:21 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
Jun 12, 3:20 PM EDTHAIL 0.5Fort Washington, PADIME SIZE HAIL REPORTED IN FORT WASHINGTON.
Jun 12, 3:20 PM EDTHAIL 0.5Warminster Heights, PADIME SIZE HAIL REPORTED IN WARMINSTER.
Jun 12, 3:35 PM EDTHAIL 0.5Fort Washington, PADIME SIZE HAIL REPORTED IN FORT WASHINGTON.

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
Jun 12, 12:55 PM EDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 7.3 hours before the alert went out and 107 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 2007-06-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 186 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 2007-06-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 25 square meters per square second.1939Sfc1 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
186 J/kg
Mixed-layer CIN
-92 J/kg
Mixed-layer LCL
1120 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
25 m²/s²
0-3 km storm-relative helicity
34 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 121921
SVRPHI
PAC017-091-101-122000-
/O.NEW.KPHI.SV.W.0067.070612T1920Z-070612T2000Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
320 PM EDT TUE JUN 12 2007

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTH CENTRAL BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...
  SOUTHEASTERN MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...
  WESTERN PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 400 PM EDT

* AT 317 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING NICKEL SIZE HAIL...AND
  DAMAGING WINDS NEAR 60 MPH. THIS STORM WAS LOCATED NEAR WILLOW
  GROVE...OR ABOUT 9 MILES NORTH OF PHILADELPHIA...AND MOVING
  SOUTHWEST AT 15 TO 20 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  CHESTNUT HILL AND PLYMOUTH MEETING BY 330 PM EDT...
  GERMANTOWN AND 6 MILES SOUTHEAST OF NORRISTOWN BY 335 PM EDT...
  ROXBOROUGH AND 7 MILES SOUTHEAST OF KING OF PRUSSIA BY 340 PM
  EDT...
  BRYN MAWR BY 345 PM EDT...

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 4021 7502 4029 7516 4010 7543 3999 7528
      3998 7518 4005 7514 4007 7512

$$

JRP

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 12, 12:56 PM EDTSevere Thunderstorm WarningPHIMonroe64 min
Jun 12, 1:12 PM EDTSevere Thunderstorm WarningPHILehigh26 min
Jun 12, 1:18 PM EDTSevere Thunderstorm WarningPHIBerks42 min
Jun 12, 2:00 PM EDTSevere Thunderstorm WarningPHICarbon, Lehigh, Northampton30 min
Jun 12, 2:15 PM EDTSevere Thunderstorm WarningPHIMontgomery, Philadelphia30 min
Jun 12, 2:25 PM EDTSevere Thunderstorm WarningPHIBucks35 min
Jun 12, 2:48 PM EDTSevere Thunderstorm WarningPHIPhiladelphia42 min
Jun 12, 4:00 PM EDTFlash Flood WarningPHIMontgomery3 hr
Jun 12, 4:08 PM EDTSevere Thunderstorm WarningPHIBucks37 min
Jun 12, 5:46 PM EDTFlash Flood WarningPHIBucks119 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2007Every severe thunderstorm warning in 2007

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.