Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2013

Severe Thunderstorm Warning 64, NWS Philadelphia/Mount Holly

July 7, 2013Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 7, 2013, 6:29 PM EDT for Chester County, Pennsylvania. It was in force for 61 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: Jul 7, 2013, 6:29 PM EDT (22:29 UTC)
Expired: Jul 7, 2013, 7:30 PM EDT
In force: 61 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

County Chester County, PA

The radar

The Dover AFB radar (KDOX), 122 km from the middle of the area, began a volume at 22:29 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 7, 6:50 PM EDT	TSTM WND DMG	Sadsbury Twp, PA	TREES AND WIRES DOWN

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 7, 4:45 PM EDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 10.5 hours before the alert went out and 160 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: 285 J/kg
Mixed-layer CIN: -180 J/kg
Mixed-layer LCL: 1178 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 16 m²/s²
0-3 km storm-relative helicity: 55 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.

101 
WUUS51 KPHI 072229
SVRPHI
PAC029-072330-
/O.NEW.KPHI.SV.W.0064.130707T2229Z-130707T2330Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
629 PM EDT SUN JUL 7 2013

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHERN CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 730 PM EDT

* AT 627 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS. THESE SEVERE STORMS EXTENDED FROM
  PARADISE TO GLEN ROY TO ROCK SPRINGS...MOVING EAST AT 20 MPH. THESE
  STORMS ARE CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS OF 60 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  MOUNT VERNON AND GLEN ROY AROUND 640 PM EDT...
  HOMEVILLE AROUND 645 PM EDT...
  OXFORD AROUND 650 PM EDT...
  COCHRANVILLE AROUND 655 PM EDT...
  PARKESBURG AROUND 700 PM EDT...
  WEST GROVE AROUND 710 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE WINDS OF MORE THAN 57 MPH...OR HAIL ONE
INCH OR LARGER.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 1000 PM EDT
SUNDAY EVENING FOR NORTHEAST MARYLAND AND NORTHERN NEW JERSEY AND
EASTERN PENNSYLVANIA.

&&

LAT...LON 3974 7612 3977 7607 3983 7603 3985 7603
      3988 7599 3997 7600 4006 7594 4006 7555
      3985 7566 3972 7579 3972 7613
TIME...MOT...LOC 2229Z 269DEG 19KT 3996 7612 3981 7610
          3971 7618

$$

FORECASTER:  DRAG

2 follow-up statements

845 
WWUS51 KPHI 072257
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
657 PM EDT SUN JUL 7 2013

PAC029-072330-
/O.CON.KPHI.SV.W.0064.000000T0000Z-130707T2330Z/
CHESTER PA-
657 PM EDT SUN JUL 7 2013

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 730 PM EDT
FOR SOUTHERN CHESTER COUNTY...

AT 654 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING
WINDS TO NEAR 60 MPH. THESE STORMS WERE LOCATED ALONG A LINE 
EXTENDING FROM 6 MILES NORTHWEST OF COATESVILLE TO COCHRANVILLE TO 
OXFORD...MOVING EAST AT 20 MPH.

SEVERE THUNDERSTORMS WILL BE NEAR...
WEST GROVE AND SOUTH COATESVILLE AROUND 705 PM EDT...
TOUGHKENAMON AND THORNDALE AROUND 715 PM EDT...
DOWNINGTOWN AND LADENBERG AROUND 720 PM EDT...
LIONVILLE AND KENNETT SQUARE AROUND 725 PM EDT...
EXTON AND WEST CHESTER AROUND 730 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! REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE
ENOUGH TO BE STRUCK BY LIGHTNING.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 1000 PM EDT
SUNDAY EVENING FOR NORTHEAST MARYLAND AND NORTHERN NEW JERSEY AND
EASTERN PENNSYLVANIA.

&&

LAT...LON 3972 7604 3979 7600 3983 7599 3997 7600
      4004 7594 4006 7594 4006 7555 3985 7566
      3972 7579
TIME...MOT...LOC 2257Z 269DEG 19KT 4005 7587 3988 7586
          3973 7596

$$

FORECASTER:  DRAG

585 
WWUS51 KPHI 072315
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
715 PM EDT SUN JUL 7 2013

PAC029-072330-
/O.CON.KPHI.SV.W.0064.000000T0000Z-130707T2330Z/
CHESTER PA-
715 PM EDT SUN JUL 7 2013

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 730 PM EDT
FOR SOUTHERN CHESTER COUNTY...

AT 711 PM EDT...A LINE OF SEVERE THUNDERSTORMS WAS REPORTED CAPABLE 
OF PRODUCING DAMAGING WINDS NEAR 60 MPH. THESE STORMS WERE LOCATED 
ALONG A LINE EXTENDING FROM DOWNINGTOWN TO WEST GROVE TO 
KEMBLESVILLE...MOVING EAST AT 20 MPH.

THE STRONGEST STORMS WERE ALONG THE SOUTHERN PART OF THE LINE 
APPROACHING KEMBLESVILLE.   

SEVERE THUNDERSTORMS WILL BE NEAR...
AVONDALE AND KEMBLESVILLE AROUND 720 PM EDT...
TOUGHKENAMON AND LIONVILLE AROUND 725 PM EDT...
KENNETT SQUARE AND WEST CHESTER AROUND 730 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 1000 PM EDT
SUNDAY EVENING FOR NORTHEAST MARYLAND AND NEW JERSEY AND EASTERN
PENNSYLVANIA.

&&

LAT...LON 3979 7592 3983 7589 3993 7585 4006 7578
      4006 7555 3985 7566 3972 7579 3973 7595
TIME...MOT...LOC 2314Z 252DEG 17KT 4005 7570 3983 7580
          3974 7585

$$

FORECASTER:  DRAG

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 7, 3:57 PM EDT	Special Weather Statement	PHI	Berks, Carbon, Lehigh, Monroe	3 hr
Jul 7, 4:41 PM EDT	Special Weather Statement	PHI	Berks, Carbon, Chester, Lehigh, Northampton	2 hr
Jul 7, 5:11 PM EDT	Special Weather Statement	PHI	Berks, Carbon	64 min
Jul 7, 5:31 PM EDT	Special Weather Statement	PHI	Berks, Carbon	59 min
Jul 7, 5:56 PM EDT	Special Weather Statement	PHI	Carbon, Monroe	49 min
Jul 7, 6:12 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Monroe	48 min
Jul 7, 6:20 PM EDT	Special Weather Statement	PHI	Berks, Chester	40 min
Jul 7, 6:51 PM EDT	Special Weather Statement	PHI	Montgomery	39 min
Jul 7, 7:08 PM EDT	Special Weather Statement	PHI	Montgomery	37 min
Jul 7, 7:22 PM EDT	Special Weather Statement	PHI	Delaware	38 min
Jul 7, 7:27 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware	48 min
Jul 7, 7:34 PM EDT	Special Weather Statement	PHI	Bucks	41 min
Jul 7, 7:53 PM EDT	Special Weather Statement	PHI	Delaware, Philadelphia	52 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2013 Every severe thunderstorm warning in 2013

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.