Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 235, NWS Philadelphia/Mount Holly

August 9, 2011Gloucester County, New Jersey; New Castle County, Delaware; 4 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 9, 2011, 12:18 PM EDT for Gloucester County, New Jersey; New Castle County, Delaware; 4 counties in Pennsylvania. It was in force for 57 min. 9 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: Aug 9, 2011, 12:18 PM EDT (16:18 UTC)
Expired: Aug 9, 2011, 1:15 PM EDT
In force: 57 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties New Castle County, DE, Gloucester County, NJ, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 90 km from the middle of the area, began a volume at 16:22 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
Aug 9, 12:22 PM EDT	TSTM WND DMG	Coffee Run, DE	TREES DOWN WITH SOME HOUSE DAMAGE NEAR COFFEE RUNN AND BELLA VISTA
Aug 9, 12:30 PM EDT	TSTM WND DMG	Elsmere, DE	TREES DOWN WEST OF WILMINNTON
Aug 9, 12:37 PM EDT	FUNNEL CLOUD	2 Nw Wilmington, DE	FUNNEL CLOUD REPORTED NORTH OF WILMINTON
Aug 9, 12:40 PM EDT	TSTM WND DMG	North Minister, DE	TREES DOWN
Aug 9, 12:44 PM EDT	HAIL 1.25	Claymont, DE
Aug 9, 12:45 PM EDT	TSTM WND DMG	Claymont, DE	TREES DOWN NORTH OF WILMINGTON
Aug 9, 12:45 PM EDT	TSTM WND DMG	Hockessin, DE	TREES DOWN WITH CAR AND HOUSE DAMAGE
Aug 9, 12:45 PM EDT	HAIL 1	1 Nw Wilmington, DE
Aug 9, 1:13 PM EDT	TSTM WND DMG	Logan Twp, NJ	TREE DOWN IN LOGAN TWP

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, 4.3 hours before the alert went out and 68 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: 210 J/kg
Mixed-layer CIN: -77 J/kg
Mixed-layer LCL: 1178 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 96 m²/s²
0-3 km storm-relative helicity: 173 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

Open this sounding in Storm Lab

The text

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

856 
WUUS51 KPHI 091618
SVRPHI
DEC003-NJC015-PAC029-045-091-101-091715-
/O.NEW.KPHI.SV.W.0235.110809T1618Z-110809T1715Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1218 PM EDT TUE AUG 9 2011

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHERN NEW CASTLE COUNTY IN NORTHERN DELAWARE...
  THIS INCLUDES THE CITY OF WILMINGTON...
  SOUTHEASTERN CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
  THIS INCLUDES THE CITY OF WEST CHESTER...
  DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA...
  SOUTH CENTRAL MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...
  SOUTHWESTERN PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA...
  NORTHWESTERN GLOUCESTER COUNTY IN SOUTHERN NEW JERSEY...

* UNTIL 115 PM EDT

* AT 1213 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 LADENBERG...OR 7 MILES
  NORTH OF NEWARK...AND MOVING NORTHEAST AT 30 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  ASHLAND AROUND 1225 PM EDT...
  TALLEYVILLE AROUND 1235 PM EDT...
  ELAM...ARDEN AND WESTTOWN AROUND 1240 PM EDT...
  CHELSEA...CONCORDVILLE AND CHEYNEY AROUND 1245 PM EDT...
  GRADYVILLE AROUND 1250 PM EDT...
  LIMA AROUND 1255 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 4011 7534 3979 7509 3975 7539 3977 7540
      3978 7543 3976 7547 3974 7548 3969 7577
      3987 7587
TIME...MOT...LOC 1618Z 247DEG 24KT 3980 7571

$$

HEAVENER

2 follow-up statements

941 
WWUS51 KPHI 091643
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1243 PM EDT TUE AUG 9 2011

PAC091-091653-
/O.CAN.KPHI.SV.W.0235.000000T0000Z-110809T1715Z/
MONTGOMERY PA-
1243 PM EDT TUE AUG 9 2011

...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL MONTGOMERY
COUNTY 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 3981 7574 4005 7536 4001 7533 4001 7531
      3979 7509 3975 7539 3977 7540 3978 7543
      3976 7547 3974 7548 3969 7577
TIME...MOT...LOC 1643Z 247DEG 24KT 3986 7551

$$

DEC003-NJC015-PAC029-045-101-091715-
/O.CON.KPHI.SV.W.0235.000000T0000Z-110809T1715Z/
GLOUCESTER NJ-DELAWARE PA-PHILADELPHIA PA-CHESTER PA-NEW CASTLE DE-
1243 PM EDT TUE AUG 9 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 115 PM EDT
FOR NORTHERN NEW CASTLE...CENTRAL CHESTER...SOUTHWESTERN
PHILADELPHIA...DELAWARE AND NORTHWESTERN GLOUCESTER COUNTIES...

AT 1239 PM EDT...THE PUBLIC REPORTED A SEVERE THUNDERSTORM CAPABLE OF
PRODUCING DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED
NEAR ELAM...OR 8 MILES SOUTHEAST OF WEST CHESTER...MOVING NORTHEAST
AT 30 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  CHESTER HEIGHTS...VILLAGE GREEN-GREEN RIDGE...BOOTHWYN AND
  GRADYVILLE BY 1250 PM EDT...
  LIMA...BROOKHAVEN...PARKSIDE AND UPLAND BY 1255 PM EDT...
  ROSE VALLEY AND NETHER PROVIDENCE TOWNSHIP BY 100 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 3981 7574 4005 7536 4001 7533 4001 7531
      3979 7509 3975 7539 3977 7540 3978 7543
      3976 7547 3974 7548 3969 7577
TIME...MOT...LOC 1643Z 247DEG 24KT 3986 7551

$$

HEAVENER

524 
WWUS51 KPHI 091658
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1258 PM EDT TUE AUG 9 2011

PAC029-091708-
/O.CAN.KPHI.SV.W.0235.000000T0000Z-110809T1715Z/
CHESTER PA-
1258 PM EDT TUE AUG 9 2011

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL CHESTER COUNTY 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 3973 7555 3985 7556 3995 7525 3979 7509
      3975 7539 3977 7540 3978 7543 3976 7547
      3974 7548
TIME...MOT...LOC 1658Z 247DEG 24KT 3990 7539

$$

DEC003-NJC015-PAC045-101-091715-
/O.CON.KPHI.SV.W.0235.000000T0000Z-110809T1715Z/
GLOUCESTER NJ-DELAWARE PA-PHILADELPHIA PA-NEW CASTLE DE-
1258 PM EDT TUE AUG 9 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 115 PM EDT
FOR NORTHEASTERN NEW CASTLE...SOUTHWESTERN PHILADELPHIA...SOUTHERN
DELAWARE AND NORTHWESTERN GLOUCESTER COUNTIES...

AT 1256 PM EDT...THE PUBLIC REPORTED A SEVERE THUNDERSTORM CAPABLE OF
PRODUCING DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED
NEAR ROSE VALLEY...OR 12 MILES SOUTHEAST OF WEST CHESTER...MOVING
NORTHEAST AT 30 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  MORTON...SWARTHMORE...RUTLEDGE AND FOLSOM BY 105 PM EDT...
  CLIFTON HEIGHTS...ALDAN...DARBY AND COLLINGDALE BY 110 PM EDT...
  YEADON AND COLWYN BY 115 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 3973 7555 3985 7556 3995 7525 3979 7509
      3975 7539 3977 7540 3978 7543 3976 7547
      3974 7548
TIME...MOT...LOC 1658Z 247DEG 24KT 3990 7539

$$

HEAVENER

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 9, 12:32 PM EDT	Tornado Warning	PHI	Gloucester	28 min
Aug 9, 1:02 PM EDT	Special Weather Statement	PHI	Camden, Gloucester, Salem	58 min
Aug 9, 1:08 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Camden, Cumberland, Gloucester, Salem	67 min
Aug 9, 1:17 PM EDT	Special Weather Statement	PHI	Burlington, Camden, Gloucester	58 min
Aug 9, 2:16 PM EDT	Special Weather Statement	PHI	Atlantic	59 min
Aug 9, 2:22 PM EDT	Areal Flood Advisory	PHI	Camden, Cumberland, Gloucester, Salem	3 hr
Aug 9, 2:22 PM EDT	Severe Thunderstorm Warning	PHI	Mercer, Middlesex, Monmouth	53 min
Aug 9, 2:53 PM EDT	Areal Flood Advisory	PHI	Middlesex, Morris, Somerset	3 hr
Aug 9, 3:27 PM EDT	Special Weather Statement	PHI	Atlantic	63 min
Aug 9, 4:13 PM EDT	Special Marine Warning	PHI		92 min
Aug 9, 5:48 PM EDT	Special Weather Statement	PHI	Gloucester	87 min
Aug 9, 6:54 PM EDT	Special Weather Statement	PHI	Atlantic, Camden, Cape May, Cumberland, Gloucester, Salem	81 min
Aug 9, 12:40 PM EDT	Special Weather Statement	PHI	New Castle	65 min
Aug 9, 11:46 AM EDT	Special Weather Statement	PHI	Chester, Delaware, Montgomery	59 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2011 Severe Thunderstorm Warnings in New Jersey, 2011 Severe Thunderstorm Warnings in Delaware, 2011 Every severe thunderstorm warning in 2011

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.