Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2008

Severe Thunderstorm Warning 258, NWS Philadelphia/Mount Holly

September 9, 20084 states

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Sep 9, 2008, 9:21 AM EDT for 4 states. It was in force for 39 min. 4 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: Sep 9, 2008, 9:21 AM EDT (13:21 UTC)
Expired: Sep 9, 2008, 10:00 AM EDT
In force: 39 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties New Castle County, DE, Cecil County, MD, Gloucester County, NJ, Hunterdon County, NJ, Mercer County, NJ, Morris County, NJ, Salem County, NJ, Somerset County, NJ, Sussex County, NJ, Warren County, NJ, Berks County, PA, Bucks County, PA, Chester County, PA, Delaware County, PA, Lehigh County, PA, Monroe County, PA, Montgomery County, PA, Northampton County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 98 km from the middle of the area, began a volume at 13:22 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

Time	Report	Where	Remark
Sep 9, 9:30 AM EDT	TSTM WND GST 43	Wind Gap, PA	A 43 MPH THUNDERSTORM WIND GUST WAS MEASURED IN WIND GAP.
Sep 9, 9:45 AM EDT	TSTM WND DMG	Mount Arlington, NJ	MULTIPLE TREES AND WIRES DOWN IN MOUNT ARLINGTON. A FEW TREES AND WIRES ALSO DOWN IN MENDHAM.
Sep 9, 9:48 AM EDT	TSTM WND DMG	High Bridge, NJ	TREES DOWN ON CHARLESTON ROAD IN BETHLEHEM TOWNSHIP
Sep 9, 10:00 AM EDT	TSTM WND DMG	2 Sw Morris Park, PA	A FEW TREES AND WIRES DOWN MAINLY IN THE UPPER PART OF THE COUNTY.

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

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 1.4 hours before the alert went out and 109 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1988 J/kg
Mixed-layer CIN: -21 J/kg
Mixed-layer LCL: 557 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: 118 m²/s²
0-3 km storm-relative helicity: 109 m²/s²
Significant tornado parameter: 1.0
Supercell composite: 5.3

Open this sounding in Storm Lab

The text

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

000 
WUUS51 KPHI 091321
SVRPHI
DEC003-MDC015-NJC015-019-021-027-033-035-037-041-PAC011-017-029-045-
077-089-091-095-101-091400-
/O.NEW.KPHI.SV.W.0258.080909T1321Z-080909T1400Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
921 AM EDT TUE SEP 9 2008

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EXTREME NORTHWESTERN MERCER COUNTY IN CENTRAL NEW JERSEY...
  SOUTHEASTERN BERKS COUNTY IN EASTERN PENNSYLVANIA...
  EASTERN LEHIGH COUNTY IN EASTERN PENNSYLVANIA...
  NORTHAMPTON COUNTY IN EASTERN PENNSYLVANIA...
  NORTHERN CECIL COUNTY IN NORTHEAST MARYLAND...
  SOUTHEASTERN MONROE COUNTY IN NORTHEAST PENNSYLVANIA...
  NORTHERN NEW CASTLE COUNTY IN NORTHERN DELAWARE...
  WESTERN MORRIS COUNTY IN NORTHERN NEW JERSEY...
  NORTHWESTERN SOMERSET COUNTY IN NORTHERN NEW JERSEY...
  HUNTERDON COUNTY IN NORTHWEST NEW JERSEY...
  SOUTHERN SUSSEX COUNTY IN NORTHWEST NEW JERSEY...
  WARREN COUNTY IN NORTHWEST NEW JERSEY...
  BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...
  CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
  DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA...
  MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...
  WESTERN PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA...
  NORTHWESTERN GLOUCESTER COUNTY IN SOUTHERN NEW JERSEY...
  NORTHWESTERN SALEM COUNTY IN SOUTHERN NEW JERSEY...

* UNTIL 1000 AM EDT

* AT 918 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WINDS 
  OF AROUND 60 MPH.  THESE STORMS WERE LOCATED ALONG A LINE
  EXTENDING FROM ECHO LAKE TO OCTORARO...OR ALONG A LINE EXTENDING
  FROM 15 MILES SOUTHEAST OF MOUNT POCONO TO 20 MILES WEST OF
  ELKTON...AND MOVING EAST AT AROUND 40 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  SPRINGTOWN...PLEASANT VALLEY...CHESTER SPRINGS AND ROXBURG BY 930
  AM...
  LADENBERG...KEMBLESVILLE...PLEASANT VALLEY AND PLEASANT HILL BY 935
  AM...
  NEWTON AND VALLEY FORGE BY 940 AM...

THUNDERSTORMS ARE CAPABLE OF PRODUCING HEAVY RAINFALL WHICH MAY
RESULT IN LOCALIZED AREAS OF FLOODING. DO NOT DRIVE IN AREAS WHERE
WATER IS CROSSING THE ROAD.

IN ADDITION TO LARGE HAIL AND 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 3975 7610 3988 7600 3992 7602 4010 7595
      4014 7590 4019 7597 4113 7523 4113 7506
      4109 7502 4113 7494 4113 7444 4104 7449
      4105 7444 4101 7441 3953 7553 3958 7554
      3953 7556 3957 7611 3972 7624
TIME...MOT...LOC 1321Z 281DEG 42KT 4103 7505 3965 7614

$$

MPD

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 9, 3:36 AM EDT	Small Craft Advisory	PHI		36 hr
Sep 9, 9:09 AM EDT	Areal Flood Advisory	PHI	Sussex, Warren	3 hr
Sep 9, 9:41 AM EDT	Flash Flood Warning	PHI	Hunterdon, Morris, Somerset	3 hr
Sep 9, 9:59 AM EDT	Flash Flood Warning	PHI	Burlington, Camden, Gloucester, Salem	3 hr
Sep 9, 10:04 AM EDT	Flash Flood Warning	PHI	Hunterdon, Mercer, Middlesex, Morris, Somerset	3 hr
Sep 9, 10:57 AM EDT	Severe Thunderstorm Warning	PHI	Burlington, Mercer, Middlesex, Monmouth, Ocean	48 min
Sep 9, 11:07 AM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Gloucester, Salem	38 min
Sep 9, 11:50 AM EDT	Special Marine Warning	PHI		55 min
Sep 9, 12:11 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Ocean	49 min
Sep 9, 12:44 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Cape May, Cumberland	46 min
Sep 9, 1:05 PM EDT	Special Marine Warning	PHI		55 min
Sep 9, 1:07 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Cape May, Cumberland	53 min
Sep 9, 1:55 PM EDT	Special Marine Warning	PHI		65 min
Sep 9, 1:58 PM EDT	Severe Thunderstorm Warning	PHI	Cape May	92 min
Sep 9, 2:42 PM EDT	Areal Flood Advisory	PHI	Cape May	3 hr
Sep 9, 2:53 PM EDT	Special Marine Warning	PHI		86 min
Sep 9, 8:40 AM EDT	Severe Thunderstorm Warning	PHI	Carbon, Lehigh, Monroe, Northampton	50 min
Sep 9, 8:51 AM EDT	Areal Flood Advisory	PHI	Berks, Lehigh	3 hr
Sep 9, 8:51 AM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Carbon, Chester, Lehigh, Montgomery and 1 more	39 min
Sep 9, 9:30 AM EDT	Flash Flood Warning	PHI	Chester, Montgomery	3 hr
Sep 9, 1:09 PM EDT	Severe Thunderstorm Warning	PHI	Kent, Sussex	36 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2008 Severe Thunderstorm Warnings in New Jersey, 2008 Severe Thunderstorm Warnings in Delaware, 2008 Every severe thunderstorm warning in 2008

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.