Alert archive / New Jersey / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 234, NWS Philadelphia/Mount Holly

October 24, 2009Hunterdon County, Somerset County, New Jersey; Bucks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Oct 24, 2009, 6:28 PM EDT for Hunterdon County, Somerset County, New Jersey; Bucks County, Pennsylvania. It was in force for 47 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
Oct 24, 2009, 6:28 PM EDT (22:28 UTC)
Expired
Oct 24, 2009, 7:15 PM EDT
In force
47 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Hunterdon County, NJ, Somerset County, NJ, Bucks County, PA

The radar

The Philadelphia radar (KDIX), 66 km from the middle of the area, began a volume at 22:29 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, 10.5 hours before the alert went out and 178 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 2009-10-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 74 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 2009-10-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 282 square meters per square second.1939587897Sfc1 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
74 J/kg
Mixed-layer CIN
-42 J/kg
Mixed-layer LCL
485 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
282 m²/s²
0-3 km storm-relative helicity
325 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.6

Open this sounding in Storm Lab

The text

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

000 
WUUS51 KPHI 242228
SVRPHI
NJC019-035-PAC017-242315-
/O.NEW.KPHI.SV.W.0234.091024T2228Z-091024T2315Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
628 PM EDT SAT OCT 24 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  WEST CENTRAL SOMERSET COUNTY IN NORTHERN NEW JERSEY...
  THIS INCLUDES THE CITY OF SOMERVILLE...
  HUNTERDON COUNTY IN NORTHWEST NEW JERSEY...
  CENTRAL BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 715 PM EDT

* AT 627 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS
  OF 60 MPH.  THIS STORM WAS LOCATED NEAR STOCKTON...OR 17 MILES
  NORTHWEST OF TRENTON...AND MOVING NORTHEAST AT 45 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  SERGEANTSVILLE...SAND BROOK...FLEMINGTON...CLOVERHILL...
  ANNANDALE...LEBANON...FLAGTOWN...WHITE HOUSE STATION AND
  BRIDGEWATER

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DOPPLER RADAR HAS INDICATED SOME WEAK ROTATION WITHIN THIS STORM.
WHILE NOT IMMEDIATELY LIKELY...A TORNADO MAY STILL DEVELOP. IF A
TORNADO IS SPOTTED...ACT QUICKLY AND MOVE TO A PLACE OF SAFETY IN A
STURDY STRUCTURE...SUCH AS A BASEMENT OR SMALL INTERIOR ROOM.

&&

LAT...LON 4034 7490 4033 7493 4032 7492 4019 7503
      4054 7505 4071 7479 4056 7459
TIME...MOT...LOC 2228Z 229DEG 38KT 4039 7498

$$

RNS
2 follow-up statements
000 
WWUS51 KPHI 242243
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
643 PM EDT SAT OCT 24 2009

PAC017-242254-
/O.CAN.KPHI.SV.W.0234.000000T0000Z-091024T2315Z/
BUCKS PA-
643 PM EDT SAT OCT 24 2009

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

LAT...LON 4036 7489 4038 7491 4036 7490 4041 7493
      4064 7486 4071 7479 4056 7459
TIME...MOT...LOC 2244Z 229DEG 38KT 4050 7481

$$

NJC019-035-242315-
/O.CON.KPHI.SV.W.0234.000000T0000Z-091024T2315Z/
HUNTERDON NJ-SOMERSET NJ-
643 PM EDT SAT OCT 24 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 715 PM EDT
FOR WEST CENTRAL SOMERSET AND EASTERN HUNTERDON COUNTIES...

AT 642 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 FLEMINGTON...OR 13
MILES SOUTHWEST OF SOMERVILLE...MOVING NORTHEAST AT 45 MPH.

OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
LEBANON...FLAGTOWN...WHITE HOUSE STATION...RARITAN AND BRIDGEWATER

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 4036 7489 4038 7491 4036 7490 4041 7493
      4064 7486 4071 7479 4056 7459
TIME...MOT...LOC 2244Z 229DEG 38KT 4050 7481

$$

RNS
000 
WWUS51 KPHI 242256
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
656 PM EDT SAT OCT 24 2009

NJC019-242306-
/O.CAN.KPHI.SV.W.0234.000000T0000Z-091024T2315Z/
HUNTERDON NJ-
656 PM EDT SAT OCT 24 2009

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

LAT...LON 4056 7460 4048 7471 4056 7470 4065 7472
      4056 7459
TIME...MOT...LOC 2256Z 229DEG 38KT 4058 7469

$$

NJC035-242315-
/O.CON.KPHI.SV.W.0234.000000T0000Z-091024T2315Z/
SOMERSET NJ-
656 PM EDT SAT OCT 24 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 715 PM EDT
FOR CENTRAL SOMERSET COUNTY...

AT 656 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 RARITAN...OR NEAR
SOMERVILLE...MOVING NORTHEAST AT 45 MPH.

THE SEVERE THUNDERSTORM WILL OTHERWISE REMAIN OVER MAINLY RURAL AREAS
OF THE INDICATED COUNTY.

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 4056 7460 4048 7471 4056 7470 4065 7472
      4056 7459
TIME...MOT...LOC 2256Z 229DEG 38KT 4058 7469

$$

RNS

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 24, 4:49 PM EDTAreal Flood AdvisoryPHIHunterdon, Mercer, Somerset, Sussex, Warren4 hr
Oct 24, 6:19 PM EDTSevere Thunderstorm WarningPHISalem26 min
Oct 24, 6:31 PM EDTTornado WarningPHIHunterdon10 min
Oct 24, 7:16 PM EDTFlash Flood WarningPHIHunterdon, Morris, Somerset3 hr
Oct 24, 7:24 PM EDTAreal Flood AdvisoryPHIBurlington, Camden, Gloucester, Middlesex, Monmouth, Ocean and 1 more3 hr
Oct 24, 3:30 PM EDTAreal Flood AdvisoryPHIBerks, Carbon, Chester, Lehigh, Monroe, Northampton4 hr
Oct 24, 4:55 PM EDTAreal Flood AdvisoryPHIBucks, Montgomery4 hr
Oct 24, 5:41 PM EDTFlash Flood WarningPHIChester, Delaware3 hr
Oct 24, 6:02 PM EDTFlash Flood WarningPHIMontgomery3 hr

Nearby

Severe Thunderstorm Warnings in New Jersey, 2009Severe Thunderstorm Warnings in Pennsylvania, 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.