Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2013

Severe Thunderstorm Warning 65, NWS Philadelphia/Mount Holly

July 7, 2013Chester County, Delaware County, Pennsylvania; New Castle County, Delaware; Salem County, New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 7, 2013, 7:27 PM EDT for Chester County, Delaware County, Pennsylvania; New Castle County, Delaware; Salem County, New Jersey. 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
Jul 7, 2013, 7:27 PM EDT (23:27 UTC)
Expired
Jul 7, 2013, 8:15 PM EDT
In force
48 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties New Castle County, DE, Salem County, NJ, Chester County, PA, Delaware County, PA

The radar

The Philadelphia radar (KDIX), 100 km from the middle of the area, began a volume at 23:28 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jul 7, 4:45 PM EDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 11.5 hours before the alert went out and 183 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 2013-07-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 285 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 2013-07-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 16 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
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.

443 
WUUS51 KPHI 072327
SVRPHI
DEC003-NJC033-PAC029-045-080015-
/O.NEW.KPHI.SV.W.0065.130707T2327Z-130708T0015Z/

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

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHWESTERN DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA...
  NORTHERN NEW CASTLE COUNTY IN NORTHERN DELAWARE...
  CENTRAL CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
  NORTHWESTERN SALEM COUNTY IN SOUTHERN NEW JERSEY...

* UNTIL 815 PM EDT

* AT 725 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS. THESE SEVERE STORMS EXTENDED FROM
  KENNETT SQUARE TO GLEN WESTOVER...MOVING EAST AT 20 MPH. THESE
  STORMS ARE CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS OF 60 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  PIKE CREEK AND HOCKESSIN AROUND 735 PM EDT...
  ASHLAND AROUND 740 PM EDT...
  STANTON AROUND 745 PM EDT...
  WESTTOWN AND WILMINGTON MANOR AROUND 750 PM EDT...
  CONCORDVILLE AND CHEYNEY AROUND 755 PM EDT...
  WILMINGTON AROUND 800 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

THIS LINE OF SEVERE THUNDERSTORMS HAS A HISTORY OF PRODUCING WIND 
DAMAGE IN WESTERN CHESTER COUNTY. DO NOT STAY OUTDOORS.

VERY HEAVY RAIN WILL ALSO OCCUR WITH THIS LINE OF SEVERE
THUNDERSTORMS...WHICH COULD FLOOD LOW LYING AREAS QUICKLY AND COVER
ROADS WITH WATER. DO NOT DRIVE INTO AREAS WHERE WATER COVERS THE
ROAD.

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS LINE OF
SEVERE THUNDERSTORMS. WHEN THUNDER ROARS...MOVE INDOORS! 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 NEW JERSEY AND EASTERN
PENNSYLVANIA.

&&

LAT...LON 3992 7575 3996 7535 3981 7540 3979 7542
      3978 7541 3966 7545 3967 7553 3969 7552
      3968 7554 3967 7554 3971 7579 3973 7580
TIME...MOT...LOC 2326Z 269DEG 18KT 3987 7571 3972 7576

$$

FORECASTER: DRAG
2 follow-up statements
577 
WWUS51 KPHI 072348
SVSPHI

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

PAC029-072356-
/O.CAN.KPHI.SV.W.0065.000000T0000Z-130708T0015Z/
CHESTER PA-
748 PM EDT SUN JUL 7 2013

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

THE STORM THAT PROMPTED THE SEVERE THUNDERSTORM WARNING HAS MOVED OUT
OF THE AREA...THEREFORE THE SEVERE THUNDERSTORM WARNING HAS BEEN
CANCELLED.

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

LAT...LON 3975 7565 3985 7557 3995 7545 3996 7535
      3981 7540 3979 7542 3978 7541 3966 7545
      3967 7553 3969 7552 3968 7554 3967 7554
      3969 7567
TIME...MOT...LOC 2346Z 286DEG 18KT 3982 7552 3970 7563

$$

DEC003-NJC033-PAC045-080015-
/O.CON.KPHI.SV.W.0065.000000T0000Z-130708T0015Z/
DELAWARE PA-NEW CASTLE DE-SALEM NJ-
748 PM EDT SUN JUL 7 2013

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 815 PM EDT
FOR NORTHWESTERN SALEM...NORTHEASTERN NEW CASTLE AND SOUTHWESTERN
DELAWARE COUNTIES...

AT 743 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING
WINDS OF NEAR 60 MPH. THESE STORMS WERE LOCATED ALONG A LINE 
EXTENDING FROM TALLEYVILLE TO STANTON...MOVING EAST AT 20 MPH AND
WEAKENING A BIT.

SEVERE THUNDERSTORMS WILL BE NEAR...
BOOTHWYN AND LIMA AROUND 755 PM EDT...
MARCUS HOOK AND LINWOOD AROUND 800 PM EDT...
TRAINER AND PENNS GROVE AROUND 805 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF YOU ARE IN THE PATH OF THIS STORM...PREPARE FOR POTENTIALLY 
DAMAGING WINDS...BRIEF HEAVY RAIN AND DEADLY CLOUD TO GROUND 
LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...PREFERABLY 
INSIDE A STRONG BUILDING.

&&

LAT...LON 3975 7565 3985 7557 3995 7545 3996 7535
      3981 7540 3979 7542 3978 7541 3966 7545
      3967 7553 3969 7552 3968 7554 3967 7554
      3969 7567
TIME...MOT...LOC 2346Z 286DEG 18KT 3982 7552 3970 7563

$$

FORECASTER:  DRAG
473 
WWUS51 KPHI 072356
SVSPHI

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

DEC003-NJC033-PAC045-080005-
/O.CAN.KPHI.SV.W.0065.000000T0000Z-130708T0015Z/
DELAWARE PA-NEW CASTLE DE-SALEM NJ-
756 PM EDT SUN JUL 7 2013

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN SALEM...
NORTHEASTERN NEW CASTLE AND SOUTHWESTERN DELAWARE COUNTIES IS
CANCELLED...

THE LINE OF STORMS HAVE WEAKENED TO BELOW SEVERE LIMITS...THEREFORE 
THE SEVERE THUNDERSTORM WARNING HAS BEEN CANCELLED.

WEST TO NORTHWEST WIND GUSTS OF 45 MPH ARE STILL POSSIBLE BUT NOT 60 
MPH. 

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

LAT...LON 3975 7565 3985 7557 3995 7545 3996 7535
      3981 7540 3979 7542 3978 7541 3966 7545
      3967 7553 3969 7552 3968 7554 3967 7554
      3969 7567
TIME...MOT...LOC 2355Z 286DEG 18KT 3981 7546 3969 7557

$$

FORECASTER:  DRAG

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 7, 3:57 PM EDTSpecial Weather StatementPHIBerks, Carbon, Lehigh, Monroe3 hr
Jul 7, 4:41 PM EDTSpecial Weather StatementPHIBerks, Carbon, Chester, Lehigh, Northampton2 hr
Jul 7, 5:11 PM EDTSpecial Weather StatementPHIBerks, Carbon64 min
Jul 7, 5:31 PM EDTSpecial Weather StatementPHIBerks, Carbon59 min
Jul 7, 5:56 PM EDTSpecial Weather StatementPHICarbon, Monroe49 min
Jul 7, 6:12 PM EDTSevere Thunderstorm WarningPHICarbon, Monroe48 min
Jul 7, 6:20 PM EDTSpecial Weather StatementPHIBerks, Chester40 min
Jul 7, 6:29 PM EDTSevere Thunderstorm WarningPHIChester61 min
Jul 7, 6:51 PM EDTSpecial Weather StatementPHIMontgomery39 min
Jul 7, 7:08 PM EDTSpecial Weather StatementPHIMontgomery37 min
Jul 7, 7:22 PM EDTSpecial Weather StatementPHIDelaware38 min
Jul 7, 7:34 PM EDTSpecial Weather StatementPHIBucks41 min
Jul 7, 7:53 PM EDTSpecial Weather StatementPHIDelaware, Philadelphia52 min
Jul 7, 2:01 PM EDTAreal Flood AdvisoryPHISussex119 min
Jul 7, 2:32 PM EDTSpecial Weather StatementPHISussex13 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2013Severe Thunderstorm Warnings in Delaware, 2013Severe Thunderstorm Warnings in New Jersey, 2013Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.