Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2015

Severe Thunderstorm Warning 90, NWS Philadelphia/Mount Holly

July 9, 20155 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 9, 2015, 6:57 PM EDT for 5 counties in Pennsylvania. It was in force for 48 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: Jul 9, 2015, 6:57 PM EDT (22:57 UTC)
Expired: Jul 9, 2015, 7:45 PM EDT
In force: 48 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties Berks County, PA, Bucks County, PA, Chester County, PA, Lehigh County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 103 km from the middle of the area, began a volume at 22:59 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
Jul 9, 7:30 PM EDT	TSTM WND DMG	Downingtown, PA	NUMEROUS TREES AND WIRES DOWN AROUND THE COUNTY.
Jul 9, 7:30 PM EDT	TSTM WND DMG	Norristown, PA	LARGE TREE BRANCHES DOWN AT THE INTERSECTION OF DEKALB PIKE AND GERMANTOWN PIKE
Jul 9, 7:30 PM EDT	TSTM WND DMG	Plymouth Meeting, PA	TREES AND WIRES DOWN AROUND THE COUNTY.

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
Jul 9, 4:57 PM EDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 11.0 hours before the alert went out and 204 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: 1 J/kg
Mixed-layer CIN: -194 J/kg
Mixed-layer LCL: 1091 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: -19 m²/s²
0-3 km storm-relative helicity: -2 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.

001 
WUUS51 KPHI 092257
SVRPHI
PAC011-017-029-077-091-092345-
/O.NEW.KPHI.SV.W.0090.150709T2257Z-150709T2345Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
657 PM EDT THU JUL 9 2015

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ  HAS ISSUED A

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

* UNTIL 745 PM EDT

* AT 655 PM EDT...DOPPLER RADAR INDICATED A LINE OF SEVERE
  THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS OF 60
  MPH. THESE STORMS WERE LOCATED ALONG A LINE EXTENDING FROM NEAR
  FLEETWOOD TO NEAR CEDARVILLE TO NEAR GLENMOORE TO PARKESBURG TO
  QUARRYVILLE...AND MOVING NORTHEAST AT 50 MPH.

  THIS LINE OF STORMS HAS HAD A HISTORY OF WIND DAMAGE.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  POTTSTOWN AROUND 700 PM EDT.
  BALLY...BECHTELSVILLE...PUGHTOWN...GILBERTSVILLE AND CEDARVILLE
  AROUND 705 PM EDT.
  DOWNINGTOWN...ROYERSFORD...EAST GREENVILLE AND GREEN LANE AROUND
  710 PM EDT.
  TRAPPE...SCHWENKSVILLE...LIONVILLE-MARCHWOOD...LIONVILLE AND
  GERYVILLE AROUND 715 PM EDT.
  QUAKERTOWN...SPRING MOUNT AND MARSHALLTON AROUND 720 PM EDT.
  PHOENIXVILLE...SOUDERTON...HATFIELD AND VALLEY FORGE AROUND 725 PM
  EDT.
  WEST NORRITON...PERKASIE...COLLEGEVILLE...CHESTER SPRINGS...
  OTTSVILLE AND FRICKS AROUND 730 PM EDT.
  EAST NORRITON...DUBLIN...FERNDALE...REVERE...ERWINNA...PAOLI AND
  PLYMOUTH MEETING AROUND 735 PM EDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WINDS...LARGE 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.

THESE STORMS HAVE A HISTORY OF PRODUCING WIND DAMAGE. THIS IS A VERY
DANGEROUS SITUATION. SEEK SHELTER NOW INSIDE A STURDY STRUCTURE AND
STAY AWAY FROM WINDOWS.
 
&&

LAT...LON 3987 7599 3995 7600 4004 7593 4011 7594
      4014 7588 4017 7592 4020 7591 4039 7596
      4055 7510 4049 7506 4042 7506 4041 7500
      4022 7487 4004 7534 4006 7536 4004 7541
      4001 7543 3980 7604
TIME...MOT...LOC 2255Z 242DEG 46KT 4042 7581 4028 7571 4013 7579 3997
7594 3990 7612

$$

GORSE

2 follow-up statements

580 
WWUS51 KPHI 092316
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
716 PM EDT THU JUL 9 2015

PAC011-017-029-077-091-092345-
/O.CON.KPHI.SV.W.0090.000000T0000Z-150709T2345Z/
CHESTER PA-BUCKS PA-BERKS PA-LEHIGH PA-MONTGOMERY PA-
716 PM EDT THU JUL 9 2015

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 745 PM EDT
FOR CHESTER...BUCKS...SOUTHEASTERN BERKS...SOUTHEASTERN LEHIGH AND
MONTGOMERY COUNTIES...

AT 713 PM EDT...DOPPLER RADAR INDICATED A LINE OF SEVERE
THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS OF 60
MPH. THESE STORMS WERE LOCATED ALONG A LINE EXTENDING FROM BALLY TO
SCHWENKSVILLE TO PHOENIXVILLE TO NEAR COATESVILLE TO NEAR 
PARKESBURG...MOVING EAST AT 50 MPH. DOPPLER RADAR IS INDICATING THE 
STRONGEST WIND IS ACROSS NORTHERN CHESTER COUNTY AND INTO NORTHERN 
MONTGOMERY COUNTY. THIS WILL MOVE INTO PORTIONS OF BUCKS COUNTY.

THESE SEVERE STORMS WILL BE NEAR...
  PHOENIXVILLE...WEST NORRITON...COLLEGEVILLE...TRAPPE...EAST
GREENVILLE...SCHWENKSVILLE...GREEN LANE...GERYVILLE...VALLEY FORGE
AND SPRING MOUNT AROUND 720 PM EDT.
  NORRISTOWN...LANSDALE...EAST NORRITON...CONSHOHOCKEN...SOUDERTON...
HATFIELD...KING OF PRUSSIA...RADNOR TOWNSHIP AND CHESTER SPRINGS
AROUND 725 PM EDT.
  QUAKERTOWN...CHALFONT...PLYMOUTH MEETING AND FRICKS AROUND 730 PM
EDT.
  PERKASIE...DOYLESTOWN...AMBLER...DUBLIN AND PAOLI AROUND 735 PM
EDT.
  HATBORO...BEDMINSTER...BRYN ATHYN...IVYLAND...PIPERSVILLE...WILLOW
GROVE...OTTSVILLE AND REVERE AROUND 740 PM EDT.
  PHILADELPHIA...BYRAM...TINICUM...NEW HOPE...NEWTOWN...RICHBORO...
GARDENVILLE...LUMBERVILLE...ERWINNA AND WOODSIDE AROUND 745 PM EDT.

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.

THESE STORMS HAVE A HISTORY OF PRODUCING WIND DAMAGE. THIS IS A VERY
DANGEROUS SITUATION. SEEK SHELTER NOW INSIDE A STURDY STRUCTURE AND
STAY AWAY FROM WINDOWS.
 
&&

LAT...LON 3987 7599 3995 7600 4004 7593 4014 7588
      4041 7584 4055 7510 4049 7506 4042 7506
      4041 7500 4022 7487 4004 7534 4006 7536
      4004 7541 4001 7543 3980 7604
TIME...MOT...LOC 2313Z 269DEG 43KT 4040 7559 4026 7549 4012 7552 3998
7577 3993 7593

$$

GORSE

314 
WWUS51 KPHI 092329
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
729 PM EDT THU JUL 9 2015

PAC011-017-029-077-091-092345-
/O.CON.KPHI.SV.W.0090.000000T0000Z-150709T2345Z/
CHESTER PA-BUCKS PA-BERKS PA-LEHIGH PA-MONTGOMERY PA-
729 PM EDT THU JUL 9 2015

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 745 PM EDT
FOR NORTHEASTERN CHESTER...BUCKS...EAST CENTRAL BERKS...SOUTHEASTERN
LEHIGH AND MONTGOMERY COUNTIES...

AT 728 PM EDT...DOPPLER RADAR INDICATED A LINE OF SEVERE
THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS OF 60
MPH. THESE STORMS WERE LOCATED ALONG A LINE EXTENDING FROM NEAR
QUAKERTOWN TO NEAR FRICKS TO NEAR LANSDALE TO KING OF PRUSSIA TO
DOWNINGTOWN...MOVING NORTHEAST AT 50 MPH.

THESE SEVERE STORMS WILL BE NEAR...
  LANSDALE...QUAKERTOWN...PERKASIE...DOYLESTOWN...BEDMINSTER...
CHALFONT...HATFIELD...DUBLIN...GARDENVILLE AND PIPERSVILLE AROUND 735
PM EDT.
  BYRAM...AMBLER...ROYERSFORD...TINICUM...FERNDALE...LUMBERVILLE...
REVERE AND OTTSVILLE AROUND 740 PM EDT.
  PHILADELPHIA...HATBORO...COLLEGEVILLE...TRAPPE...NEW HOPE...
NEWTOWN...BRYN ATHYN...IVYLAND...WILLOW GROVE AND RICHBORO AROUND 745
PM EDT.

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.

IN ADDITION TO DAMAGING WINDS...FREQUENT CLOUD TO GROUND LIGHTNING 
IS OCCURRING WITH THESE STORMS.  MOVE INDOORS IMMEDIATELY.  
REMEMBER... IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE 
STRUCK BY LIGHTNING.

&&

LAT...LON 4015 7569 4046 7555 4055 7510 4049 7506
      4042 7506 4041 7500 4022 7487 4004 7534
      4006 7536 4004 7541 4001 7543 3986 7588
      4003 7580
TIME...MOT...LOC 2328Z 243DEG 49KT 4048 7536 4034 7526 4020 7530 4009
7537 4001 7571

$$

GORSE

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 9, 6:15 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester, Montgomery	45 min
Jul 9, 6:35 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh	40 min
Jul 9, 6:46 PM EDT	Areal Flood Advisory	PHI	Carbon, Lehigh, Monroe, Northampton	4 hr
Jul 9, 6:50 PM EDT	Severe Thunderstorm Warning	PHI	Chester	40 min
Jul 9, 7:12 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Lehigh, Northampton	48 min
Jul 9, 7:21 PM EDT	Areal Flood Advisory	PHI	Berks, Lehigh	4 hr
Jul 9, 7:29 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware	46 min
Jul 9, 7:39 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	66 min
Jul 9, 7:55 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware, Philadelphia	40 min
Jul 9, 7:56 PM EDT	Areal Flood Advisory	PHI	Bucks, Delaware, Montgomery, Philadelphia	4 hr

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2015 Every 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.