Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 78, NWS Philadelphia/Mount Holly

June 15, 2009Delaware County, Montgomery County, Philadelphia County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 15, 2009, 5:55 PM EDT for Delaware County, Montgomery County, Philadelphia County, Pennsylvania. It was in force for 65 min. 2 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 15, 2009, 5:55 PM EDT (21:55 UTC)
Expired
Jun 15, 2009, 7:00 PM EDT
In force
65 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 65 km from the middle of the area, began a volume at 21:55 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, 6:05 PM EDTHAIL 0.25Roxborough, PAPEA SIZE HAIL REPORTED IN THE ROXBOROUGH SECTION OF PHILADELPHIA.
Jun 15, 6:08 PM EDTTSTM WND DMGNw Roxborough, PATREE REPORTED DOWN ON NIXON AVENUE.

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, 9.9 hours before the alert went out and 97 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 152155
SVRPHI
PAC045-091-101-152300-
/O.NEW.KPHI.SV.W.0078.090615T2155Z-090615T2300Z/

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

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHEASTERN DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA...
  SOUTHEASTERN MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...
  PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA...
  THIS INCLUDES THE CITY OF PHILADELPHIA...

* UNTIL 700 PM EDT

* AT 551 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           
  CHESTNUT HILL...OR 8 MILES SOUTHWEST OF WILLOW GROVE...AND         
  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...
  CHESTNUT HILL AND BRYN MAWR AROUND 600 PM EDT...
  GERMANTOWN AROUND 605 PM EDT...
  ROXBOROUGH AROUND 610 PM EDT...
  TEMPLE UNIVERSITY...KENSINGTON...PHILADELPHIA AND YEADON AROUND 620
  PM EDT...
  CENTER CITY AROUND 625 PM EDT...
  SOUTH PHILADELPHIA AROUND 630 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 4000 7506 3998 7511 3995 7515 3989 7514
      3987 7520 3985 7526 4007 7537 4012 7517
TIME...MOT...LOC 2153Z 330DEG 16KT 4009 7525

$$

GORSE/DEFINO
1 follow-up statement
000 
WWUS51 KPHI 152222
SVSPHI

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

PAC045-101-152300-
/O.CON.KPHI.SV.W.0078.000000T0000Z-090615T2300Z/
DELAWARE PA-PHILADELPHIA PA-
622 PM EDT MON JUN 15 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 700 PM EDT
FOR SOUTHERN PHILADELPHIA AND EAST CENTRAL DELAWARE COUNTIES...

AT 619 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 
TEMPLE UNIVERSITY...OR NEAR PHILADELPHIA...MOVING SOUTHEAST AT 20 
MPH.

THIS STORM HAS HAD 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...
  SOUTH PHILADELPHIA AND 6 MILES NORTHEAST OF PHILADELPHIA
  INTERNATIONAL AIRPORT BY 630 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...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 3989 7514 3987 7521 3986 7525 3986 7527
      3997 7531 4005 7513 4000 7506 3998 7511
      3995 7515
TIME...MOT...LOC 2221Z 330DEG 16KT 3996 7519

$$

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, 5:13 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery62 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.