Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 77, NWS Philadelphia/Mount Holly

June 15, 2009Bucks County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 15, 2009, 5:13 PM EDT for Bucks County, Montgomery County, Pennsylvania. It was in force for 62 min. 1 report 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 15, 2009, 5:13 PM EDT (21:13 UTC)
Expired
Jun 15, 2009, 6:15 PM EDT
In force
62 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Bucks County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 75 km from the middle of the area, began a volume at 21:16 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 15, 5:20 PM EDTHAIL 1Lansdale, PA

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

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 9.2 hours before the alert went out and 103 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 2009-06-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 196 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 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 2009-06-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 41 square meters per square second.19395878Sfc1 km3 km6 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
196 J/kg
Mixed-layer CIN
-80 J/kg
Mixed-layer LCL
943 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
41 m²/s²
0-3 km storm-relative helicity
92 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.7

Open this sounding in Storm Lab

The text

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

000 
WUUS51 KPHI 152113
SVRPHI
PAC017-091-152215-
/O.NEW.KPHI.SV.W.0077.090615T2113Z-090615T2215Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
513 PM EDT MON JUN 15 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CENTRAL BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...
  EASTERN MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...
  THIS INCLUDES THE CITY OF WILLOW GROVE...

* UNTIL 615 PM EDT

* AT 510 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  A SEVERE THUNDERSTORM CAPABLE OF PRODUCING NICKEL SIZE HAIL...AND  
  DAMAGING WINDS UP TO 60 MPH.  THIS STORM WAS LOCATED NEAR          
  SOUDERTON...OR 14 MILES NORTHWEST OF WILLOW GROVE...AND MOVING     
  SOUTHEAST AT 20 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  LANSDALE AND CHALFONT AROUND 520 PM EDT...
  8 MILES NORTHEAST OF NORRISTOWN AROUND 535 PM EDT...
  AMBLER AROUND 540 PM EDT...
  6 MILES NORTHEAST OF PLYMOUTH MEETING AROUND 545 PM EDT...
  WILLOW GROVE AROUND 555 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS STORM HAS A HISTORY OF PRODUCING LARGE HAIL AND STRONG WINDS.
SEEK SHELTER NOW INSIDE A STURDY STRUCTURE AND STAY AWAY FROM 
WINDOWS

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...FREQUENT 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 7506 4007 7512 4009 7522 4002 7534
      4007 7537 4007 7540 4032 7546 4034 7525
TIME...MOT...LOC 2112Z 325DEG 17KT 4028 7530

$$

GORSE/DEFINO
2 follow-up statements
000 
WWUS51 KPHI 152126
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
526 PM EDT MON JUN 15 2009

PAC017-152134-
/O.CAN.KPHI.SV.W.0077.000000T0000Z-090615T2215Z/
BUCKS PA-
526 PM EDT MON JUN 15 2009

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL BUCKS COUNTY IS
CANCELLED...

THE SEVERE THUNDERSTORM HAS EXITED THE COUNTY, THEREFORE THE WARNING 
HAS BEEN CANCELLED.

LAT...LON 4008 7511 4009 7523 4002 7534 4007 7537
      4007 7540 4026 7543 4028 7526 4011 7506
TIME...MOT...LOC 2124Z 325DEG 17KT 4021 7529

$$

PAC091-152215-
/O.CON.KPHI.SV.W.0077.000000T0000Z-090615T2215Z/
MONTGOMERY PA-
526 PM EDT MON JUN 15 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 615 PM EDT
FOR SOUTHEASTERN MONTGOMERY COUNTY...

AT 520 PM EDT...A TRAINED WEATHER SPOTTER REPORTED A SEVERE 
THUNDERSTORM PRODUCING QUARTER SIZE HAIL IN LANSDALE. THIS STORM WAS 
LOCATED NEAR NORTH WALES...OR 10 MILES NORTHWEST OF WILLOW 
GROVE...MOVING SOUTHEAST AT 20 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  EAST NORRITON BY 530 PM EDT...
  SPRING HOUSE AND BLUE BELL BY 535 PM EDT...
  AMBLER...MAPLE GLEN AND PLYMOUTH MEETING BY 540 PM EDT...
  FORT WASHINGTON AND PLYMOUTH MEETING BY 545 PM EDT...
  FLOURTOWN AND ORELAND BY 550 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS STORM HAS A LONG HISTORY OF PRODUCING LARGE HAIL. SEEK SHELTER 
NOW INSIDE A STURDY STRUCTURE AND STAY AWAY FROM WINDOWS

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...FREQUENT 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 4008 7511 4009 7523 4002 7534 4007 7537
      4007 7540 4026 7543 4028 7526 4011 7506
TIME...MOT...LOC 2124Z 325DEG 17KT 4021 7529

$$

GORSE/DEFINO
000 
WWUS51 KPHI 152149
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
549 PM EDT MON JUN 15 2009

PAC091-152215-
/O.CON.KPHI.SV.W.0077.000000T0000Z-090615T2215Z/
MONTGOMERY PA-
549 PM EDT MON JUN 15 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 615 PM EDT
FOR SOUTH CENTRAL MONTGOMERY COUNTY...

AT 547 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING NICKEL SIZE 
HAIL...AND DAMAGING WINDS UP TO 60 MPH. THIS STORM WAS LOCATED NEAR 
FLOURTOWN...OR 7 MILES WEST OF WILLOW GROVE...MOVING SOUTHEAST AT 20 
MPH.

THIS STORM HAS A LONG HISTORY OF PRODUCING LARGE HAIL AND STRONG 
WINDS. SEEK SHELTER NOW INSIDE A STURDY STRUCTURE AND STAY AWAY FROM 
WINDOWS

THE SEVERE THUNDERSTORM WILL BE NEAR...
  GLENSIDE BY 555 PM EDT...
  WYNCOTE BY 600 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...FREQUENT 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 4008 7513 4009 7523 4002 7534 4007 7537
      4008 7539 4014 7541 4020 7523
TIME...MOT...LOC 2148Z 325DEG 17KT 4010 7524

$$

GORSE/DEFINO

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 15, 2:33 PM EDTSevere Thunderstorm WarningPHICarbon57 min
Jun 15, 3:16 PM EDTSevere Thunderstorm WarningPHICarbon, Lehigh, Northampton59 min
Jun 15, 4:15 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Lehigh, Montgomery60 min
Jun 15, 5:55 PM EDTSevere Thunderstorm WarningPHIDelaware, Montgomery, Philadelphia65 min
Jun 15, 6:37 PM EDTSevere Thunderstorm WarningPHIDelaware, Philadelphia53 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2009Every severe thunderstorm warning in 2009

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.