Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2015

Severe Thunderstorm Warning 36, NWS Philadelphia/Mount Holly

June 12, 2015Berks County, Chester County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 12, 2015, 4:57 PM EDT for Berks County, Chester County, Montgomery County, Pennsylvania. It was in force for 48 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jun 12, 2015, 4:57 PM EDT (20:57 UTC)
Expired
Jun 12, 2015, 5:45 PM EDT
In force
48 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Berks County, PA, Chester County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 115 km from the middle of the area, began a volume at 20:57 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.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 9.0 hours before the alert went out and 202 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, Washington/Dulle, VA at 12:00Z on 2015-06-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 325 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, Washington/Dulle, VA at 12:00Z on 2015-06-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 38 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
325 J/kg
Mixed-layer CIN
-121 J/kg
Mixed-layer LCL
1369 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
38 m²/s²
0-3 km storm-relative helicity
67 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

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

855 
WUUS51 KPHI 122057
SVRPHI
PAC011-029-091-122145-
/O.NEW.KPHI.SV.W.0036.150612T2057Z-150612T2145Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
457 PM EDT FRI JUN 12 2015

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ  HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHEASTERN CHESTER COUNTY IN SOUTHEASTERN PENNSYLVANIA...
  SOUTHEASTERN BERKS COUNTY IN EASTERN PENNSYLVANIA...
  MONTGOMERY COUNTY IN SOUTHEASTERN PENNSYLVANIA...

* UNTIL 545 PM EDT

* AT 455 PM EDT...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM
  CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM
  WAS LOCATED OVER GLENMOORE...OR 11 MILES NORTHWEST OF WEST
  CHESTER...AND MOVING EAST AT 25 MPH.

* LOCATIONS IMPACTED INCLUDE...
  POTTSTOWN...PHOENIXVILLE...LANSDALE...WEST NORRITON...EAST
  NORRITON...SOUDERTON...BIRDSBORO...COLLEGEVILLE...ROYERSFORD...
  TRAPPE...HATFIELD...EAST GREENVILLE...SCHWENKSVILLE...ELVERSON...
  BALLY...BECHTELSVILLE...GREEN LANE...NEW MORGAN...GLENMOORE AND
  CEDARVILLE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WINDS...LARGE HAIL...DEADLY 
LIGHTNING AND VERY HEAVY RAIN. HEAVY RAINS ASSOCIATED WITH THIS 
STORM COULD FLOOD ROADS QUICKLY SO DO NOT DRIVE INTO AREAS WHERE 
WATER COVERS THE ROAD.

&&

LAT...LON 4046 7556 4022 7516 4000 7581 4013 7589
      4014 7588 4017 7592 4019 7593
TIME...MOT...LOC 2055Z 253DEG 18KT 4009 7573 

$$

JJM
2 follow-up statements
994 
WWUS51 KPHI 122110
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
510 PM EDT FRI JUN 12 2015

PAC011-029-091-122145-
/O.CON.KPHI.SV.W.0036.000000T0000Z-150612T2145Z/
CHESTER PA-BERKS PA-MONTGOMERY PA-
510 PM EDT FRI JUN 12 2015

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 545 PM EDT
FOR NORTHEASTERN CHESTER...SOUTHEASTERN BERKS AND MONTGOMERY
COUNTIES...

AT 510 PM EDT...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE
OF PRODUCING DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS
LOCATED NEAR PUGHTOWN...OR 13 MILES NORTH OF WEST CHESTER...MOVING
NORTHEAST AT 25 MPH.

LOCATIONS IMPACTED INCLUDE...
POTTSTOWN...PHOENIXVILLE...LANSDALE...WEST NORRITON...EAST
NORRITON...SOUDERTON...BIRDSBORO...COLLEGEVILLE...ROYERSFORD...
TRAPPE...HATFIELD...EAST GREENVILLE...SCHWENKSVILLE...ELVERSON...
BALLY...BECHTELSVILLE...GREEN LANE...GLENMOORE...CEDARVILLE AND
CHESTER SPRINGS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WINDS...DESTRUCTIVE HAIL...
DEADLY LIGHTNING AND VERY HEAVY RAIN. FOR YOUR PROTECTION MOVE TO AN
INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR HOME OR BUSINESS. HEAVY
RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE INTO AREAS WHERE WATER
COVERS THE ROAD.

&&

LAT...LON 4046 7556 4022 7517 4004 7570 4002 7575
      4023 7587
TIME...MOT...LOC 2110Z 242DEG 23KT 4015 7560 

$$

JJM
904 
WWUS51 KPHI 122136
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
536 PM EDT FRI JUN 12 2015

PAC011-029-091-122146-
/O.EXP.KPHI.SV.W.0036.000000T0000Z-150612T2145Z/
CHESTER PA-BERKS PA-MONTGOMERY PA-
536 PM EDT FRI JUN 12 2015

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN CHESTER...
SOUTHEASTERN BERKS AND MONTGOMERY COUNTIES WILL EXPIRE AT 545 PM
EDT...
    
THE SEVERE THUNDERSTORM WHICH PROMPTED THE WARNING HAS WEAKENED. 
THEREFORE THE WARNING WILL BE ALLOWED TO EXPIRE.

LAT...LON 4046 7556 4022 7517 4004 7570 4002 7575
      4023 7587
TIME...MOT...LOC 2133Z 253DEG 18KT 4015 7560 

$$

JJM

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 11, 8:57 PM EDTSpecial Weather StatementPHISchuylkill48 min
Jun 11, 9:23 PM EDTSpecial Weather StatementPHILehigh, Northampton52 min
Jun 11, 9:33 PM EDTSpecial Weather StatementPHIBerks27 min
Jun 11, 9:41 PM EDTAreal Flood AdvisoryPHILehigh, Northampton4 hr
Jun 11, 9:54 PM EDTSpecial Weather StatementPHIBerks51 min
Jun 12, 4:38 PM EDTSpecial Weather StatementPHIMontgomery52 min
Jun 12, 5:07 PM EDTSevere Thunderstorm WarningPHILehigh, Northampton38 min
Jun 12, 5:41 PM EDTSevere Thunderstorm WarningPHINorthampton49 min
Jun 12, 6:13 PM EDTSevere Thunderstorm WarningPHIMonroe, Northampton28 min
Jun 12, 6:53 PM EDTSevere Thunderstorm WarningPHILehigh, Northampton52 min
Jun 12, 7:27 PM EDTSevere Thunderstorm WarningPHINorthampton33 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2015Every severe thunderstorm warning in 2015

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.