Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2013

Severe Thunderstorm Warning 73, NWS Philadelphia/Mount Holly

July 20, 2013Bucks County, Northampton County, Pennsylvania; Hunterdon County, Warren County, New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 20, 2013, 7:16 PM EDT for Bucks County, Northampton County, Pennsylvania; Hunterdon County, Warren County, New Jersey. It was in force for 59 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 20, 2013, 7:16 PM EDT (23:16 UTC)
Expired
Jul 20, 2013, 8:15 PM EDT
In force
59 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Hunterdon County, NJ, Warren County, NJ, Bucks County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 101 km from the middle of the area, began a volume at 23:16 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, 11.3 hours before the alert went out and 199 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 2013-07-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1324 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 2013-07-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 91 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
1324 J/kg
Mixed-layer CIN
-126 J/kg
Mixed-layer LCL
1201 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
91 m²/s²
0-3 km storm-relative helicity
146 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.7

Open this sounding in Storm Lab

The text

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

149 
WUUS51 KPHI 202316
SVRPHI
NJC019-041-PAC017-095-210015-
/O.NEW.KPHI.SV.W.0073.130720T2316Z-130721T0015Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
716 PM EDT SAT JUL 20 2013

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHWESTERN WARREN COUNTY IN NORTHWEST NEW JERSEY...
  CENTRAL HUNTERDON COUNTY IN NORTHWEST NEW JERSEY...
  NORTH CENTRAL BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...
  SOUTH CENTRAL NORTHAMPTON COUNTY IN EASTERN PENNSYLVANIA...

* UNTIL 815 PM EDT

* AT 712 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM. THE STORM WAS NEAR FREEMANSBURG...MOVING EAST
  AT 25 MPH. THIS STORM IS CAPABLE OF PRODUCING DAMAGING WINDS IN
  EXCESS OF 60 MPH. 

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  OLD ORCHARD AND GLENDON AROUND 725 PM EDT...
  RIEGELSVILLE AND EASTON AROUND 730 PM EDT...
  ALPHA AROUND 735 PM EDT...
  BLOOMSBURY AND MILFORD AROUND 745 PM EDT...
  CLINTON AROUND 805 PM EDT...
  CLINTON AND ANNANDALE AROUND 810 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS SEVERE
THUNDERSTORM. WHEN THUNDER ROARS...MOVE INDOORS! REMEMBER...IF YOU
CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE STRUCK BY LIGHTNING.

&&

LAT...LON 4070 7484 4054 7484 4056 7537 4058 7540
      4061 7539 4062 7538 4064 7539 4069 7538
TIME...MOT...LOC 2316Z 270DEG 21KT 4062 7531

$$

FORECASTER: HEAVENER
2 follow-up statements
978 
WWUS51 KPHI 202338
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
738 PM EDT SAT JUL 20 2013

NJC041-PAC095-202347-
/O.CAN.KPHI.SV.W.0073.000000T0000Z-130721T0015Z/
WARREN NJ-NORTHAMPTON PA-
738 PM EDT SAT JUL 20 2013

...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL NORTHAMPTON AND
SOUTHWESTERN WARREN COUNTIES IS CANCELLED...

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

LAT...LON 4054 7484 4055 7508 4057 7511 4056 7517
      4058 7520 4063 7515 4064 7512 4067 7507
      4067 7484
TIME...MOT...LOC 2337Z 270DEG 21KT 4062 7515

$$

NJC019-210015-
/O.CON.KPHI.SV.W.0073.000000T0000Z-130721T0015Z/
HUNTERDON NJ-
738 PM EDT SAT JUL 20 2013

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 815 PM EDT
FOR CENTRAL HUNTERDON COUNTY...

AT 735 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS IN
EXCESS OF 60 MPH. THIS STORM WAS LOCATED NEAR BLOOMSBURY...OR NEAR
EASTON...MOVING EAST AT 25 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
BLOOMSBURY AND MILFORD AROUND 745 PM EDT...
CLINTON AROUND 805 PM EDT...
ANNANDALE AND HIGH BRIDGE AROUND 810 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF YOU ARE IN THE PATH OF THIS STORM...PREPARE FOR DAMAGING 
WINDS...AND DEADLY CLOUD TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD 
MOVE TO A SHELTER...PREFERABLY INSIDE A STRONG BUILDING...AWAY FROM 
WINDOWS OR EVEN BELOW GROUND LEVEL.

&&

LAT...LON 4054 7484 4055 7508 4057 7511 4056 7517
      4058 7520 4063 7515 4064 7512 4067 7507
      4067 7484
TIME...MOT...LOC 2337Z 270DEG 21KT 4062 7515

$$

FORECASTER: HEAVENER
161 
WWUS51 KPHI 202348
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
748 PM EDT SAT JUL 20 2013

NJC019-202358-
/O.CAN.KPHI.SV.W.0073.000000T0000Z-130721T0015Z/
HUNTERDON NJ-
748 PM EDT SAT JUL 20 2013

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

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

LAT...LON 4054 7484 4055 7508 4057 7511 4056 7517
      4058 7520 4063 7515 4064 7512 4067 7507
      4067 7484
TIME...MOT...LOC 2348Z 270DEG 21KT 4062 7507

$$

FORECASTER: HEAVENER

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 19, 8:24 PM EDTSpecial Weather StatementPHIBerks36 min
Jul 19, 8:33 PM EDTSevere Thunderstorm WarningPHIBerks42 min
Jul 19, 9:01 PM EDTSpecial Weather StatementPHIChester29 min
Jul 19, 9:07 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Lehigh, Northampton38 min
Jul 19, 9:41 PM EDTSpecial Weather StatementPHINorthampton34 min
Jul 20, 2:39 PM EDTSpecial Weather StatementPHIMonroe51 min
Jul 20, 3:31 PM EDTSpecial Weather StatementPHIMonroe59 min
Jul 20, 5:13 PM EDTSpecial Weather StatementPHILehigh62 min
Jul 19, 8:05 PM EDTSpecial Weather StatementPHIHunterdon25 min
Jul 19, 8:26 PM EDTSpecial Weather StatementPHIHunterdon34 min
Jul 19, 8:58 PM EDTSpecial Weather StatementPHIHunterdon, Somerset32 min
Jul 19, 9:24 PM EDTSpecial Weather StatementPHISomerset36 min
Jul 20, 4:18 PM EDTSpecial Weather StatementPHIMorris57 min
Jul 20, 5:47 PM EDTSpecial Weather StatementPHIMonmouth58 min
Jul 20, 6:36 PM EDTSpecial Weather StatementPHISomerset39 min
Jul 20, 6:41 PM EDTSevere Thunderstorm WarningPHIMiddlesex, Somerset64 min
Jul 20, 6:57 PM EDTSpecial Weather StatementPHIHunterdon63 min
Jul 20, 7:54 PM EDTSpecial Weather StatementPHISalem66 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 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.