Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2013

Severe Thunderstorm Warning 101, NWS Philadelphia/Mount Holly

September 2, 2013Bucks County, Montgomery County, Philadelphia County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Sep 2, 2013, 10:29 AM EDT for Bucks County, Montgomery County, Philadelphia County, Pennsylvania. It was in force for 76 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
Sep 2, 2013, 10:29 AM EDT (14:29 UTC)
Expired
Sep 2, 2013, 11:45 AM EDT
In force
76 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Bucks County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 52 km from the middle of the area, began a volume at 14:30 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

Brookhaven, NY (KOKX), launched 12:00Z, 2.5 hours before the alert went out and 203 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, Brookhaven, NY at 12:00Z on 2013-09-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 791 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, Brookhaven, NY at 12:00Z on 2013-09-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 79 square meters per square second.193958Sfc1 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
791 J/kg
Mixed-layer CIN
-32 J/kg
Mixed-layer LCL
538 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
79 m²/s²
0-3 km storm-relative helicity
75 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.1

Open this sounding in Storm Lab

The text

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

721 
WUUS51 KPHI 021429
SVRPHI
PAC017-091-101-021545-
/O.NEW.KPHI.SV.W.0101.130902T1429Z-130902T1545Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1029 AM EDT MON SEP 2 2013

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHEASTERN BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...
  SOUTHEASTERN MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...
  NORTHEASTERN PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 1145 AM EDT

* AT 1026 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM. THE STORM WAS NEAR PHILADELPHIA...MOVING
  NORTHEAST AT 10 MPH. THIS STORM IS CAPABLE OF PRODUCING DAMAGING
  WINDS IN EXCESS OF 60 MPH. 

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  WISSINOMING AROUND 1035 AM EDT...
  TACONY AROUND 1045 AM EDT...
  HOLMESBURG AND ROCKLEDGE AROUND 1050 AM EDT...
  NORTHEAST PHILADELPHIA AND ANDALUSIA AROUND 1110 AM EDT...
  BRYN ATHYN AROUND 1115 AM EDT...
  BENSALEM AROUND 1125 AM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE WINDS OF MORE THAN 57 MPH...OR HAIL ONE
INCH OR LARGER. SEEK SHELTER INDOORS IMMEDIATELY.

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

&&

LAT...LON 4007 7491 4007 7494 4002 7502 4001 7505
      3999 7506 3998 7508 3997 7510 4003 7516
      4024 7502 4012 7482
TIME...MOT...LOC 1429Z 222DEG 9KT 4001 7509

$$
 
TFG
2 follow-up statements
365 
WWUS51 KPHI 021506
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1106 AM EDT MON SEP 2 2013

PAC017-091-101-021545-
/O.CON.KPHI.SV.W.0101.000000T0000Z-130902T1545Z/
BUCKS PA-MONTGOMERY PA-PHILADELPHIA PA-
1106 AM EDT MON SEP 2 2013

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1145 AM EDT
FOR NORTHEASTERN PHILADELPHIA...SOUTHEASTERN MONTGOMERY AND SOUTH
CENTRAL BUCKS COUNTIES...

AT 1100 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS UP
TO 60 MPH. TREE DAMAGE HAS OCCURRED IN PHILADELPHIA. 
THIS STORM WAS LOCATED NEAR ROCKLEDGE...OR 7 MILES
NORTHEAST OF PHILADELPHIA...MOVING NORTHEAST AT 10 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
NORTHEAST PHILADELPHIA AROUND 1110 AM EDT...
BRYN ATHYN AROUND 1120 AM EDT...
BENSALEM AROUND 1125 AM EDT...
FEASTERVILLE AROUND 1140 AM EDT...
CHURCHVILLE AND VILLAGE SHIRES AROUND 1145 AM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO 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.

&&

LAT...LON 4012 7491 4008 7495 4006 7501 4004 7504
      4005 7507 4005 7510 4007 7514 4024 7502
      4014 7486
TIME...MOT...LOC 1505Z 210DEG 9KT 4009 7505

$$

TFG
489 
WWUS51 KPHI 021516
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1116 AM EDT MON SEP 2 2013

PAC017-091-101-021527-
/O.CAN.KPHI.SV.W.0101.000000T0000Z-130902T1545Z/
BUCKS PA-MONTGOMERY PA-PHILADELPHIA PA-
1116 AM EDT MON SEP 2 2013

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN PHILADELPHIA...
SOUTHEASTERN MONTGOMERY AND SOUTH CENTRAL BUCKS COUNTIES IS
CANCELLED...

THE STORM HAS WEAKENED TO BELOW SEVERE LIMITS...THEREFORE THE SEVERE
THUNDERSTORM WARNING HAS BEEN CANCELLED.

LAT...LON 4012 7491 4008 7495 4006 7501 4004 7504
      4005 7507 4005 7510 4007 7514 4024 7502
      4014 7486
TIME...MOT...LOC 1517Z 210DEG 9KT 4012 7503

$$

TFG

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 2, 4:56 AM EDTSpecial Weather StatementPHICarbon49 min
Sep 2, 5:34 AM EDTSevere Thunderstorm WarningPHICarbon, Monroe56 min
Sep 2, 7:09 AM EDTAreal Flood AdvisoryPHINorthampton4 hr
Sep 2, 9:37 AM EDTAreal Flood AdvisoryPHIPhiladelphia113 min
Sep 2, 9:52 AM EDTFlash Flood WarningPHIPhiladelphia4 hr
Sep 2, 10:50 AM EDTAreal Flood AdvisoryPHIDelaware3 hr
Sep 2, 11:27 AM EDTAreal Flood AdvisoryPHIDelaware, Montgomery, Philadelphia3 hr
Sep 2, 12:37 PM EDTFlash Flood WarningPHIDelaware3 hr
Sep 2, 12:44 PM EDTFlash Flood WarningPHIBucks4 hr
Sep 2, 3:06 PM EDTAreal Flood AdvisoryPHICarbon, Monroe114 min
Sep 2, 3:14 PM EDTSpecial Weather StatementPHINorthampton61 min
Sep 2, 4:02 PM EDTSpecial Weather StatementPHILehigh, Northampton43 min
Sep 2, 4:44 PM EDTSpecial Weather StatementPHILehigh46 min
Sep 2, 4:52 PM EDTSpecial Weather StatementPHIBucks38 min
Sep 2, 5:05 PM EDTAreal Flood AdvisoryPHILehigh115 min
Sep 2, 5:39 PM EDTFlash Flood WarningPHILehigh2 hr
Sep 2, 5:46 PM EDTSpecial Weather StatementPHILehigh44 min
Sep 2, 6:57 PM EDTSpecial Weather StatementPHIMontgomery48 min
Sep 2, 7:59 PM EDTSpecial Weather StatementPHIChester46 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 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.