Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 226, NWS Philadelphia/Mount Holly

September 18, 20127 counties in Pennsylvania; Hunterdon County, Warren County, New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Sep 18, 2012, 5:01 PM EDT for 7 counties in Pennsylvania; Hunterdon County, Warren County, New Jersey. It was in force for 59 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: Sep 18, 2012, 5:01 PM EDT (21:01 UTC)
Expired: Sep 18, 2012, 6:00 PM EDT
In force: 59 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties Hunterdon County, NJ, Warren County, NJ, Bucks County, PA, Chester County, PA, Delaware County, PA, Lehigh County, PA, Montgomery County, PA, Northampton County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 68 km from the middle of the area, began a volume at 21:03 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 18, 5:15 PM EDT	TSTM WND DMG	Easton, PA	TREE LIMBS DOWN.
Sep 18, 5:20 PM EDT	TSTM WND DMG	Glen Mills, PA	TREES DOWN.

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

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Sep 18, 12:10 PM EDT	Tornado Watch	SPC	9 hr

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 9.0 hours before the alert went out and 124 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: 330 J/kg
Mixed-layer CIN: -6 J/kg
Mixed-layer LCL: 519 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 265 m²/s²
0-3 km storm-relative helicity: 275 m²/s²
Significant tornado parameter: 0.4
Supercell composite: 2.3

Open this sounding in Storm Lab

The text

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

237 
WUUS51 KPHI 182101
SVRPHI
NJC019-041-PAC017-029-045-077-091-095-101-182200-
/O.NEW.KPHI.SV.W.0226.120918T2101Z-120918T2200Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
501 PM EDT TUE SEP 18 2012

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHEASTERN LEHIGH COUNTY IN EASTERN PENNSYLVANIA...
  SOUTH CENTRAL NORTHAMPTON COUNTY IN EASTERN PENNSYLVANIA...
  THIS INCLUDES THE CITY OF EASTON...
  WESTERN HUNTERDON COUNTY IN NORTHWEST NEW JERSEY...
  SOUTHERN WARREN COUNTY IN NORTHWEST NEW JERSEY...
  BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...
  NORTHEASTERN CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
  THIS INCLUDES THE CITY OF WEST CHESTER...
  DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA...
  MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...
  PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA...
  THIS INCLUDES THE CITY OF PHILADELPHIA...

* UNTIL 600 PM EDT

* AT 459 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 HELLERTOWN TO SPRING MOUNT TO 9 MILES WEST OF WEST CHESTER...
  OR ALONG A LINE EXTENDING FROM ALLENTOWN TO 21 MILES EAST OF
  READING TO 9 MILES WEST OF WEST CHESTER...AND MOVING NORTHEAST AT
  50 MPH.

THE STRONGEST WINDS MAY OCCUR NEAR THE LEADING EDGE OF THE LINE.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  GRADYVILLE...SWARTHMORE...PAOLI AND NETHER PROVIDENCE TOWNSHIP
  AROUND 510 PM EDT...
  TROUT LAKE...NEWTOWN SQUARE...YEADON AND RADNOR TOWNSHIP AROUND 515
  PM EDT...
  ROXBOROUGH AND MORRIS PARK AROUND 520 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS LINE OF STORMS MAY CONTAIN LITTLE OR NO LIGHTNING. 
DO NOT WAIT TO HEAR THUNDER BEFORE TAKING COVER. SEEK SHELTER 
IMMEDIATELY INSIDE A STURDY STRUCTURE AND STAY 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.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 700 PM EDT TUESDAY EVENING
FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW JERSEY AND EASTERN
PENNSYLVANIA.

&&

LAT...LON 4090 7491 4034 7486 4034 7494 4029 7486
      4010 7484 4007 7491 4007 7494 3999 7507
      3991 7525 3984 7560 4021 7563 4054 7548
TIME...MOT...LOC 2101Z 228DEG 49KT 4061 7539 4030 7551
          4001 7574

$$

GORSE

1 follow-up statement

977 
WWUS51 KPHI 182126
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
526 PM EDT TUE SEP 18 2012

PAC077-182133-
/O.CAN.KPHI.SV.W.0226.000000T0000Z-120918T2200Z/
LEHIGH PA-
526 PM EDT TUE SEP 18 2012

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN LEHIGH 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.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 700 PM EDT TUESDAY EVENING
FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW JERSEY AND EASTERN
PENNSYLVANIA.

LAT...LON 4090 7491 4034 7486 4034 7494 4029 7486
      4010 7484 4007 7494 3991 7525 3985 7555
      4021 7557 4048 7542 4054 7533 4057 7538
      4063 7534
TIME...MOT...LOC 2123Z 228DEG 49KT 4081 7509 4050 7522
          4022 7542 3991 7546

$$

NJC019-041-PAC017-029-045-091-095-101-182200-
/O.CON.KPHI.SV.W.0226.000000T0000Z-120918T2200Z/
WARREN NJ-HUNTERDON NJ-BUCKS PA-MONTGOMERY PA-PHILADELPHIA PA-
DELAWARE PA-NORTHAMPTON PA-CHESTER PA-
526 PM EDT TUE SEP 18 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 600 PM EDT
FOR NORTHEASTERN CHESTER...SOUTH CENTRAL NORTHAMPTON...DELAWARE...
PHILADELPHIA...MONTGOMERY...BUCKS...WESTERN HUNTERDON AND SOUTHERN
WARREN COUNTIES...

AT 520 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 ROXBURG TO RICHLANDTOWN TO COLLEGEVILLE TO 
CONCORDVILLE...MOVING NORTHEAST AT 50 MPH.

DOPPLER RADAR DATA INDICATES POCKETS OF STRONGER WINDS EMBEDDED 
WITHIN THE LINE, ESPECIALLY ALONG THE LEADING EDGE. AS OF 523 PM, 
THE STRONGER WIND SIGNATURE WAS MOVING THROUGH DELAWARE COUNTY.

SEVERE THUNDERSTORMS WILL BE NEAR...
  YEADON...EAST LANSDOWNE...DARBY AND COLWYN BY 530 PM EDT...
  ROXBOROUGH...OTTSVILLE...MORRIS PARK AND FRICKS BY 535 PM EDT...
  KENSINGTON AND CENTER CITY BY 540 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS LINE OF STORMS MAY CONTAIN LITTLE OR NO LIGHTNING. DO 
NOT WAIT FOR THUNDER BEFORE TAKING COVER. SEEK SHELTER IMMEDIATELY 
INSIDE A STURDY STRUCTURE AND STAY 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.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 700 PM EDT TUESDAY EVENING
FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW JERSEY AND EASTERN
PENNSYLVANIA.

&&

LAT...LON 4090 7491 4034 7486 4034 7494 4029 7486
      4010 7484 4007 7494 3991 7525 3985 7555
      4021 7557 4048 7542 4054 7533 4057 7538
      4063 7534
TIME...MOT...LOC 2123Z 228DEG 45KT 4081 7509 4050 7522
          4022 7542 3991 7546

$$

GORSE

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 18, 4:13 AM EDT	Coastal Flood Advisory	PHI	Delaware, Philadelphia	21 hr
Sep 18, 12:58 PM EDT	Areal Flood Advisory	PHI	Carbon, Monroe	93 min
Sep 18, 12:59 PM EDT	Special Weather Statement	PHI	Berks, Lehigh	46 min
Sep 18, 1:05 PM EDT	Areal Flood Advisory	PHI	Berks, Lehigh	115 min
Sep 18, 1:32 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh	43 min
Sep 18, 2:00 PM EDT	Special Weather Statement	PHI	Chester, Montgomery	60 min
Sep 18, 2:18 PM EDT	Special Weather Statement	PHI	Carbon, Monroe	57 min
Sep 18, 2:23 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Montgomery	30 min
Sep 18, 2:25 PM EDT	Flash Flood Warning	PHI	Carbon, Lehigh, Monroe, Northampton	4 hr
Sep 18, 2:52 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Lehigh, Northampton	17 min
Sep 18, 3:07 PM EDT	Areal Flood Warning	PHI	Berks, Lehigh	8 hr
Sep 18, 3:16 PM EDT	Special Weather Statement	PHI	Monroe	59 min
Sep 18, 3:24 PM EDT	Special Weather Statement	PHI	Berks, Carbon	51 min
Sep 18, 3:52 PM EDT	Special Weather Statement	PHI	Chester	53 min
Sep 18, 4:05 PM EDT	Areal Flood Advisory	PHI	Berks, Lehigh	55 min
Sep 18, 4:19 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester, Delaware, Montgomery	56 min
Sep 18, 4:23 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh, Monroe, Northampton	52 min
Sep 18, 4:26 PM EDT	Areal Flood Advisory	PHI	Bucks, Lehigh, Northampton	3 hr
Sep 18, 4:35 PM EDT	Areal Flood Advisory	PHI	Bucks, Chester, Lehigh, Montgomery	55 min
Sep 18, 5:12 PM EDT	Areal Flood Advisory	PHI	Bucks, Chester, Delaware, Montgomery	63 min
Sep 18, 5:12 PM EDT	Severe Thunderstorm Warning	PHI	Delaware, Philadelphia	78 min
Sep 18, 5:13 PM EDT	Severe Thunderstorm Warning	PHI	Monroe, Northampton	62 min
Sep 18, 6:00 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery, Philadelphia	60 min
Sep 18, 6:06 PM EDT	Areal Flood Advisory	PHI	Bucks, Montgomery, Philadelphia	54 min
Sep 18, 6:19 PM EDT	Areal Flood Warning	PHI	Carbon, Lehigh, Monroe, Northampton	16 hr
Sep 18, 6:54 PM EDT	Areal Flood Advisory	PHI	Bucks	111 min
Sep 17, 8:54 PM EDT	Rip Current Statement	PHI	Atlantic, Cape May, Monmouth, Ocean	23 hr
Sep 18, 4:21 PM EDT	Severe Thunderstorm Warning	PHI	Salem	69 min
Sep 18, 5:23 PM EDT	Severe Thunderstorm Warning	PHI	Salem	52 min
Sep 18, 6:02 PM EDT	Special Marine Warning	PHI		88 min
Sep 18, 6:46 PM EDT	Areal Flood Advisory	PHI	Atlantic, Burlington, Camden, Cumberland, Gloucester, Salem	119 min
Sep 18, 6:52 PM EDT	Severe Thunderstorm Warning	PHI	Middlesex, Monmouth, Morris, Somerset	53 min
Sep 18, 7:04 PM EDT	Special Weather Statement	PHI	Atlantic, Burlington, Cumberland	56 min
Sep 18, 7:16 PM EDT	Areal Flood Advisory	PHI	Cape May	59 min
Sep 18, 7:51 PM EDT	Special Weather Statement	PHI	Atlantic, Cape May, Ocean	54 min
Sep 18, 7:52 PM EDT	Special Marine Warning	PHI		77 min
Sep 18, 7:56 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Cape May, Ocean	64 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2012 Severe Thunderstorm Warnings in New Jersey, 2012 Every 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.