Alert archive / New Jersey / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 20, NWS Philadelphia/Mount Holly

May 7, 20094 counties in New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 7, 2009, 1:43 PM EDT for 4 counties in New Jersey. It was in force for 62 min. 2 reports 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
May 7, 2009, 1:43 PM EDT (17:43 UTC)
Expired
May 7, 2009, 2:45 PM EDT
In force
62 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Somerset County, NJ

The radar

The Philadelphia radar (KDIX), 61 km from the middle of the area, began a volume at 17:46 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
May 7, 1:45 PM EDTTSTM WND DMG4 Ne Pennington, NJWIRES REPORTED DOWN IN HOPEWELL.
May 7, 2:25 PM EDTHAIL 0.5New Brunswick, NJPEA TO DIME SIZE HAIL WAS REPORTED IN NEW BRUNSWICK, SOUTH BRUNSWICK AND EDISON.

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 12:00Z, 5.7 hours before the alert went out and 134 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 2009-05-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2009-05-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 62 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
523 m above ground
0-6 km bulk shear
51 kt
0-1 km storm-relative helicity
62 m²/s²
0-3 km storm-relative helicity
215 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.

000 
WUUS51 KPHI 071743
SVRPHI
NJC019-021-023-035-071845-
/O.NEW.KPHI.SV.W.0020.090507T1743Z-090507T1845Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
143 PM EDT THU MAY 7 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHERN MERCER COUNTY IN CENTRAL NEW JERSEY...
  MIDDLESEX COUNTY IN NORTHERN NEW JERSEY...
  THIS INCLUDES THE CITIES OF...PERTH AMBOY...NEW BRUNSWICK...
  SOUTHERN SOMERSET COUNTY IN NORTHERN NEW JERSEY...
  SOUTHEASTERN HUNTERDON COUNTY IN NORTHWEST NEW JERSEY...

* UNTIL 245 PM EDT

* AT 143 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING NICKEL SIZE HAIL...AND
  DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR
  PENNINGTON...OR 10 MILES NORTH OF TRENTON...AND MOVING NORTHEAST AT
  25 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  HOPEWELL AND LAWRENCEVILLE BY 150 PM EDT...
  SKILLMAN AND PRINCETON BY 200 PM EDT...
  ROCKY HILL BY 205 PM EDT...
  BELLE MEAD BY 210 PM EDT...
  KENDALL PARK BY 215 PM EDT...
  SOUTH BRUNSWICK...MILLSTONE AND DAYTON BY 220 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.

&&

LAT...LON 4045 7422 4042 7425 4040 7425 4026 7479
      4041 7488 4062 7443 4059 7444 4060 7431
      4059 7429 4059 7426 4055 7423 4047 7427
TIME...MOT...LOC 1743Z 247DEG 21KT 4036 7481

$$
 
TFG
1 follow-up statement
000 
WWUS51 KPHI 071836
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
236 PM EDT THU MAY 7 2009

NJC035-071846-
/O.CAN.KPHI.SV.W.0020.000000T0000Z-090507T1845Z/
SOMERSET NJ-
236 PM EDT THU MAY 7 2009

...THE SEVERE THUNDERSTORM WARNING FOR EXTREME EAST CENTRAL SOMERSET
COUNTY IS CANCELLED...

THE SEVERE STORM HAS MOVED EAST OF THE AREA.

LAT...LON 4046 7425 4045 7428 4044 7429 4044 7437
      4056 7445 4059 7444 4060 7431 4059 7429
      4059 7426 4055 7423 4047 7427
TIME...MOT...LOC 1836Z 235DEG 37KT 4055 7430

$$

NJC023-071845-
/O.CON.KPHI.SV.W.0020.000000T0000Z-090507T1845Z/
MIDDLESEX NJ-
236 PM EDT THU MAY 7 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 245 PM EDT
FOR NORTHEASTERN MIDDLESEX COUNTY...

AT 235 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING PENNY SIZE
HAIL...AND WINDS UP TO 60 MPH.  THIS STORM WAS
LOCATED NEAR FORDS...OR NEAR PERTH AMBOY...MOVING NORTHEAST AT 40
MPH. THERE HAVE BEEN NUMEROUS REPORTS OF PEA TO MARBLE SIZE HAIL IN
THE NEW BRUNSWICK AREA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO LARGE HAIL AND POSSIBLY DAMAGING WINDS...CONTINUOUS
CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS
IMMEDIATELY LIGHTNING IS ONE OF NATURES NUMBER ONE KILLERS.
REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE
STRUCK BY LIGHTNING.

&&

LAT...LON 4046 7425 4045 7428 4044 7429 4044 7437
      4056 7445 4059 7444 4060 7431 4059 7429
      4059 7426 4055 7423 4047 7427
TIME...MOT...LOC 1836Z 235DEG 37KT 4055 7430

$$

TFG

The office that day

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

IssuedProductOfficeCountiesLasted
May 6, 9:01 PM EDTFlood WatchPHIHunterdon, Mercer, Middlesex, Monmouth, Somerset19 hr
May 7, 3:09 AM EDTAreal Flood AdvisoryPHIHunterdon, Morris2 hr
May 7, 1:22 PM EDTAreal Flood AdvisoryPHIBurlington, Camden, Gloucester, Salem4 hr
May 7, 1:42 PM EDTAreal Flood AdvisoryPHIHunterdon, Mercer, Middlesex, Somerset4 hr
May 7, 2:01 PM EDTSpecial Marine WarningPHI89 min
May 7, 2:05 PM EDTSevere Thunderstorm WarningPHIAtlantic, Camden, Cumberland, Gloucester, Salem40 min
May 7, 2:34 PM EDTAreal Flood AdvisoryPHIBurlington, Camden, Mercer, Middlesex, Monmouth3 hr
May 7, 2:53 PM EDTSpecial Marine WarningPHI97 min
May 7, 4:05 PM EDTSpecial Marine WarningPHI67 min

Nearby

Severe Thunderstorm Warnings in New Jersey, 2009Every severe thunderstorm warning in 2009

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.