Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 21, NWS Philadelphia/Mount Holly

May 29, 2012Bucks County, Chester County, Montgomery County, Pennsylvania; Hunterdon County, Warren County, New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 29, 2012, 6:52 PM EDT for Bucks County, Chester County, Montgomery County, Pennsylvania; Hunterdon County, Warren County, New Jersey. It was in force for 53 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 29, 2012, 6:52 PM EDT (22:52 UTC)
Expired: May 29, 2012, 7:45 PM EDT
In force: 53 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties Hunterdon County, NJ, Warren County, NJ, Bucks County, PA, Chester County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 102 km from the middle of the area, began a volume at 22:55 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
May 29, 7:00 PM EDT	TSTM WND DMG	South Coventry Twp, PA	SOME WIRES ARE DOWN
May 29, 7:15 PM EDT	TSTM WND DMG	Upper Providence Twp, PA	SOME WIRES ARE 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
May 29, 5:54 PM EDT	Severe Thunderstorm Watch	SPC	3 hr

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 10.9 hours before the alert went out and 107 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: 667 J/kg
Mixed-layer CIN: -217 J/kg
Mixed-layer LCL: 1153 m above ground
0-6 km bulk shear: 6 kt
0-1 km storm-relative helicity: -39 m²/s²
0-3 km storm-relative helicity: -10 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.

351 
WUUS51 KPHI 292252
SVRPHI
NJC019-041-PAC017-029-091-292345-
/O.NEW.KPHI.SV.W.0021.120529T2252Z-120529T2345Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
652 PM EDT TUE MAY 29 2012

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  WESTERN HUNTERDON COUNTY IN NORTHWEST NEW JERSEY...
  SOUTHERN WARREN COUNTY IN NORTHWEST NEW JERSEY...
  NORTHWESTERN BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...
  CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
  THIS INCLUDES THE CITY OF WEST CHESTER...
  MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 745 PM EDT

* AT 650 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WINDS TO
  60 MPH.  THESE STORMS WERE LOCATED ALONG A LINE EXTENDING
  FROM SPRINGTOWN TO POTTSTOWN TO 8 MILES NORTHWEST OF MOUNT
  VERNON...OR ALONG A LINE EXTENDING FROM 7 MILES EAST OF ALLENTOWN
  TO 17 MILES EAST OF READING TO 13 MILES SOUTHEAST OF LANCASTER...
  AND MOVING EAST AT 35 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  MOUNT VERNON AROUND 655 PM EDT...
  PUGHTOWN...PLEASANT VALLEY...GLENMOORE AND QUAKERTOWN AROUND 700 PM
  EDT...
  RIEGELSVILLE...HOMEVILLE...SPRING MOUNT AND PARKESBURG AROUND 705
  PM EDT...
  ALPHA AROUND 710 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.

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...HEAVY RAIN WILL OCCUR
WITH THESE STORMS AND CAUSE LOW-LYING AND POOR DRAINAGE FLOODING.

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 SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 1000 PM EDT
TUESDAY EVENING FOR NEW JERSEY AND SOUTHEASTERN PENNSYLVANIA.

&&

LAT...LON 4009 7594 4025 7569 4044 7554 4042 7548
      4050 7540 4060 7520 4068 7519 4078 7488
      4036 7502 3980 7571 3981 7604
TIME...MOT...LOC 2251Z 257DEG 32KT 4056 7535 4026 7561
          3989 7614

$$

TFG

1 follow-up statement

443 
WWUS51 KPHI 292336
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
736 PM EDT TUE MAY 29 2012

NJC041-292346-
/O.CAN.KPHI.SV.W.0021.000000T0000Z-120529T2345Z/
WARREN NJ-
736 PM EDT TUE MAY 29 2012

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN WARREN COUNTY IS
CANCELLED...

THE LINE OF STORMS IS SOUTH OF THE AREA.

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 SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM EDT
TUESDAY EVENING FOR NORTHEASTERN PENNSYLVANIA. A SEVERE THUNDERSTORM
WATCH ALSO REMAINS IN EFFECT UNTIL 1000 PM EDT TUESDAY EVENING FOR
NEW JERSEY AND SOUTHEASTERN PENNSYLVANIA.

LAT...LON 4004 7574 4021 7548 4035 7540 4041 7530
      4052 7523 4057 7516 4063 7510 4070 7491
      4036 7502 3980 7571 3981 7604
TIME...MOT...LOC 2336Z 257DEG 32KT 4064 7483 4035 7510
          3998 7563

$$

NJC019-PAC017-029-091-292345-
/O.CON.KPHI.SV.W.0021.000000T0000Z-120529T2345Z/
HUNTERDON NJ-BUCKS PA-MONTGOMERY PA-CHESTER PA-
736 PM EDT TUE MAY 29 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 745 PM EDT
FOR CHESTER...CENTRAL MONTGOMERY...NORTHWESTERN BUCKS AND WESTERN
HUNTERDON COUNTIES...

AT 733 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING
WINDS TO 60 MPH.  THESE STORMS WERE LOCATED ALONG A LINE
EXTENDING FROM 13 MILES NORTHEAST OF FRENCHTOWN TO ROBESONIA TO
MARSHALLTON...OR ALONG A LINE EXTENDING FROM 14 MILES WEST OF
SOMERVILLE TO 21 MILES WEST OF TRENTON TO WEST CHESTER...MOVING EAST
AT 35 MPH.

SEVERE THUNDERSTORMS WILL BE NEAR...
  NORRISTOWN...DEVON-BERWYN...BRIDGEPORT AND KING OF PRUSSIA BY 745
  PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

PLEASE SEEK SHELTER AT THE FIRST SIGN OF THREATENING WEATHER.

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 SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 1000 PM EDT
TUESDAY EVENING FOR NEW JERSEY AND SOUTHEASTERN PENNSYLVANIA.

&&

LAT...LON 4004 7574 4021 7548 4035 7540 4041 7530
      4052 7523 4057 7516 4063 7510 4070 7491
      4036 7502 3980 7571 3981 7604
TIME...MOT...LOC 2336Z 257DEG 32KT 4064 7483 4035 7510
          3998 7563

$$

TFG

The office that day

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

Issued	Product	Office	Counties	Lasted
May 29, 12:29 PM EDT	Flash Flood Watch	PHI	Berks, Carbon, Delaware, Lehigh, Monroe, Northampton and 1 more	8 hr
May 29, 1:36 PM EDT	Special Weather Statement	PHI	Monroe	54 min
May 29, 1:50 PM EDT	Areal Flood Advisory	PHI	Carbon, Monroe	115 min
May 29, 5:06 PM EDT	Special Weather Statement	PHI	Berks, Carbon, Lehigh, Monroe, Northampton	114 min
May 29, 5:25 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Carbon, Lehigh	95 min
May 29, 5:45 PM EDT	Severe Thunderstorm Warning	PHI	Monroe, Northampton	75 min
May 29, 6:14 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh, Northampton	91 min
May 29, 6:23 PM EDT	Flash Flood Warning	PHI	Carbon, Monroe	112 min
May 29, 6:44 PM EDT	Areal Flood Advisory	PHI	Berks, Bucks, Lehigh, Montgomery	3 hr
May 29, 6:46 PM EDT	Special Weather Statement	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	89 min
May 29, 7:34 PM EDT	Special Weather Statement	PHI	Delaware, Philadelphia	56 min
May 29, 7:35 PM EDT	Areal Flood Advisory	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	115 min
May 29, 7:44 PM EDT	Special Weather Statement	PHI	Bucks	61 min
May 29, 3:27 AM EDT	Small Craft Advisory	PHI		21 hr
May 29, 6:22 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	53 min
May 29, 6:32 PM EDT	Severe Thunderstorm Warning	PHI	Morris, Sussex, Warren	66 min
May 29, 6:51 PM EDT	Areal Flood Advisory	PHI	Sussex, Warren	114 min
May 29, 7:21 PM EDT	Areal Flood Warning	PHI	Sussex	2 hr

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.