Alert archive / New Jersey / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 4, NWS Philadelphia/Mount Holly

April 21, 2012Bucks County, Montgomery County, Philadelphia County, Pennsylvania; 8 counties in New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Apr 21, 2012, 9:38 PM EDT for Bucks County, Montgomery County, Philadelphia County, Pennsylvania; 8 counties in New Jersey. It was in force for 67 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
Apr 21, 2012, 9:38 PM EDT (01:38 UTC)
Expired
Apr 21, 2012, 10:45 PM EDT
In force
67 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Burlington County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Morris County, NJ, Somerset County, NJ, Warren County, NJ, Bucks County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 53 km from the middle of the area, began a volume at 01:39 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

TimeReportWhereRemark
Apr 21, 10:07 PM EDTTSTM WND DMGLebanon, NJWIRE DOWN

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Brookhaven, NY (KOKX), launched 00:00Z, 1.6 hours before the alert went out and 165 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 00:00Z on 2012-04-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 46 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 00:00Z on 2012-04-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 124 square meters per square second.19395878Sfc1 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
46 J/kg
Mixed-layer CIN
-47 J/kg
Mixed-layer LCL
687 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
124 m²/s²
0-3 km storm-relative helicity
93 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.

198 
WUUS51 KPHI 220138
SVRPHI
NJC005-019-021-023-025-027-035-041-PAC017-091-101-220245-
/O.NEW.KPHI.SV.W.0004.120422T0138Z-120422T0245Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
938 PM EDT SAT APR 21 2012

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  MERCER COUNTY IN CENTRAL NEW JERSEY...
  THIS INCLUDES THE CITY OF TRENTON...
  WESTERN MONMOUTH COUNTY IN CENTRAL NEW JERSEY...
  MIDDLESEX COUNTY IN NORTHERN NEW JERSEY...
  THIS INCLUDES THE CITY OF NEW BRUNSWICK...
  SOUTHWESTERN MORRIS COUNTY IN NORTHERN NEW JERSEY...
  THIS INCLUDES THE CITY OF MORRISTOWN...
  SOMERSET COUNTY IN NORTHERN NEW JERSEY...
  THIS INCLUDES THE CITY OF SOMERVILLE...
  HUNTERDON COUNTY IN NORTHWEST NEW JERSEY...
  SOUTHERN WARREN COUNTY IN NORTHWEST NEW JERSEY...
  EASTERN BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...
  SOUTHEASTERN MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...
  NORTHEASTERN PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA...
  NORTHWESTERN BURLINGTON COUNTY IN SOUTHERN NEW JERSEY...

* UNTIL 1045 PM EDT

* AT 935 PM EDT...NATIONAL WEATHER SERVICE 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 FERNDALE TO RICHBORO TO HOLMESBURG...OR ALONG A LINE EXTENDING
  FROM 10 MILES SOUTH OF EASTON TO 14 MILES WEST OF TRENTON TO 7
  MILES NORTHEAST OF PHILADELPHIA...AND MOVING EAST AT 30 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  BLOOMSBURY...MILFORD...BENSALEM AND NEWTOWN AROUND 945 PM EDT...
  SERGEANTSVILLE...WOODSIDE AND WILLINGBORO AROUND 950 PM EDT...
  SAND BROOK...YARDLEY AND LEVITTOWN AROUND 955 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE
IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD
TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

PLEASE REPORT HAIL OR STRONG WINDS TO THE NATIONAL WEATHER SERVICE BY
CALLING TOLL FREE...1-877-633-6772...WHEN YOU CAN DO SO SAFELY.

&&

LAT...LON 4017 7441 4008 7455 4005 7454 3997 7502
      3998 7501 4000 7504 3997 7511 4028 7510
      4058 7527 4062 7519 4066 7520 4093 7454
      4070 7442 4067 7445 4066 7439 4061 7443
      4060 7436 4045 7427 4017 7428
TIME...MOT...LOC 0138Z 255DEG 25KT 4056 7513 4030 7498
          4006 7500

$$

MPD
2 follow-up statements
553 
WWUS51 KPHI 220151
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
951 PM EDT SAT APR 21 2012

PAC091-101-220202-
/O.CAN.KPHI.SV.W.0004.000000T0000Z-120422T0245Z/
MONTGOMERY PA-PHILADELPHIA PA-
951 PM EDT SAT APR 21 2012

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

PLEASE REPORT HAIL OR STRONG WINDS TO THE NATIONAL WEATHER SERVICE BY
CALLING TOLL FREE...1-877-633-6772...WHEN YOU CAN DO SO SAFELY.

LAT...LON 4017 7428 4017 7441 4008 7455 4005 7454
      3999 7496 4012 7493 4031 7496 4054 7510
      4062 7519 4066 7520 4093 7454 4070 7442
      4067 7445 4066 7440 4061 7443 4060 7436
      4045 7427
TIME...MOT...LOC 0152Z 255DEG 25KT 4059 7501 4033 7486
          4009 7488

$$

NJC005-019-021-023-025-027-035-041-PAC017-220245-
/O.CON.KPHI.SV.W.0004.000000T0000Z-120422T0245Z/
WARREN NJ-HUNTERDON NJ-MERCER NJ-MORRIS NJ-SOMERSET NJ-BUCKS PA-
MIDDLESEX NJ-BURLINGTON NJ-MONMOUTH NJ-
951 PM EDT SAT APR 21 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1045 PM EDT
FOR WESTERN MONMOUTH...NORTHWESTERN BURLINGTON...MIDDLESEX...EASTERN
BUCKS...SOMERSET...SOUTHWESTERN MORRIS...MERCER...HUNTERDON AND
SOUTHERN WARREN COUNTIES...

AT 950 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING
WINDS IN EXCESS OF 60 MPH.  THESE STORMS WERE LOCATED ALONG A LINE
EXTENDING FROM MILFORD TO PENNINGTON TO CROYDON...OR ALONG A LINE
EXTENDING FROM 12 MILES SOUTHEAST OF EASTON TO 9 MILES NORTHWEST OF
TRENTON TO 12 MILES SOUTHWEST OF TRENTON...MOVING EAST AT 30 MPH.

SEVERE THUNDERSTORMS WILL BE NEAR...
  TULLYTOWN...MORRISVILLE...PENNINGTON AND FLORENCE BY 1000 PM EDT...
  CLINTON...ANNANDALE...HIGH BRIDGE AND JACKSONVILLE BY 1005 PM
  EDT...
  LEBANON AND JOBSTOWN BY 1010 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

PLEASE REPORT HAIL OR STRONG WINDS TO THE NATIONAL WEATHER SERVICE BY
CALLING TOLL FREE...1-877-633-6772...WHEN YOU CAN DO SO SAFELY.

&&

LAT...LON 4017 7428 4017 7441 4008 7455 4005 7454
      3999 7496 4012 7493 4031 7496 4054 7510
      4062 7519 4066 7520 4093 7454 4070 7442
      4067 7445 4066 7440 4061 7443 4060 7436
      4045 7427
TIME...MOT...LOC 0152Z 255DEG 25KT 4059 7501 4033 7486
          4009 7488

$$

MPD
531 
WWUS51 KPHI 220224
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1024 PM EDT SAT APR 21 2012

NJC005-019-021-025-041-PAC017-220234-
/O.CAN.KPHI.SV.W.0004.000000T0000Z-120422T0245Z/
WARREN NJ-HUNTERDON NJ-MERCER NJ-BUCKS PA-BURLINGTON NJ-MONMOUTH NJ-
1024 PM EDT SAT APR 21 2012

...THE SEVERE THUNDERSTORM WARNING FOR WESTERN MONMOUTH...
NORTHWESTERN BURLINGTON...EASTERN BUCKS...MERCER...HUNTERDON AND
SOUTHERN WARREN COUNTIES IS CANCELLED...

PLEASE REPORT HAIL OR STRONG WINDS TO THE NATIONAL WEATHER SERVICE BY
CALLING TOLL FREE...1-877-633-6772...WHEN YOU CAN DO SO SAFELY.

LAT...LON 4034 7434 4026 7448 4033 7462 4039 7462
      4038 7472 4051 7477 4062 7470 4064 7473
      4070 7471 4078 7489 4093 7454 4070 7442
      4067 7445 4066 7440 4061 7443 4060 7435
      4044 7427
TIME...MOT...LOC 0224Z 243DEG 44KT 4075 7476 4050 7460
          4026 7463

$$

NJC023-027-035-220245-
/O.CON.KPHI.SV.W.0004.000000T0000Z-120422T0245Z/
MORRIS NJ-SOMERSET NJ-MIDDLESEX NJ-
1024 PM EDT SAT APR 21 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1045 PM EDT
FOR MIDDLESEX...SOMERSET AND SOUTHWESTERN MORRIS COUNTIES...

AT 1024 PM EDT...A LINE OF SEVERE THUNDERSTORMS WAS REPORTED CAPABLE
OF PRODUCING DAMAGING WINDS IN EXCESS OF 60 MPH.  THESE STORMS WERE
LOCATED ALONG A LINE EXTENDING FROM LONG VALLEY TO MILLSTONE TO 8
MILES SOUTH OF KINGSTON...OR ALONG A LINE EXTENDING FROM 15 MILES
WEST OF MORRISTOWN TO SOMERVILLE TO 7 MILES EAST OF TRENTON...MOVING
NORTHEAST AT 50 MPH.

SEVERE THUNDERSTORMS WILL BE NEAR...
  CHESTER...SOUTH BRUNSWICK...MARTINSVILLE AND SOUTH BOUND BROOK BY
  1030 PM EDT...
  SUCCASUNNA...MILLINGTON...BASKING RIDGE AND SOUTH PLAINFIELD BY
  1035 PM EDT...
  VICTORY GARDENS AND DOVER BY 1040 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

PLEASE REPORT HAIL OR STRONG WINDS TO THE NATIONAL WEATHER SERVICE BY
CALLING TOLL FREE...1-877-633-6772...WHEN YOU CAN DO SO SAFELY.

&&

LAT...LON 4034 7434 4026 7448 4033 7462 4039 7462
      4038 7472 4051 7477 4062 7470 4064 7473
      4070 7471 4078 7489 4093 7454 4070 7442
      4067 7445 4066 7440 4061 7443 4060 7435
      4044 7427
TIME...MOT...LOC 0224Z 243DEG 44KT 4075 7476 4050 7460
          4026 7463

$$

MPD

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 21, 8:41 PM EDTSpecial Weather StatementPHIBerks, Bucks, Chester, Delaware, Lehigh, Monroe and 3 more109 min
Apr 21, 8:45 PM EDTSevere Thunderstorm WarningPHIBucks, Chester, Delaware, Montgomery, Philadelphia30 min
Apr 22, 3:45 AM EDTWind AdvisoryPHIDelaware, Philadelphia20 hr
Apr 22, 4:14 AM EDTCoastal Flood AdvisoryPHIDelaware, Philadelphia20 hr

Nearby

Severe Thunderstorm Warnings in New Jersey, 2012Severe Thunderstorm Warnings in Pennsylvania, 2012Every severe thunderstorm warning in 2012

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.