Alert archive / Pennsylvania / Tornado Warnings in 2011

Tornado Warning 28, NWS Philadelphia/Mount Holly

August 27, 2011Bucks County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this tornado warning at Aug 27, 2011, 11:22 PM EDT for Bucks County, Montgomery County, Pennsylvania. It was in force for 23 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
Aug 27, 2011, 11:22 PM EDT (03:22 UTC)
Expired
Aug 27, 2011, 11:45 PM EDT
In force
23 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Bucks County, PA, Montgomery County, PA

The watch it was issued in

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

IssuedProductOfficeLasted
Aug 27, 7:56 PM EDTTornado WatchSPC9 hr

The nearest sounding before it

Brookhaven, NY (KOKX), launched 00:00Z, 3.4 hours before the alert went out and 194 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 00:00Z on 2011-08-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 957 joules per kilogram.LCLEL10008507005003002001001 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 00:00Z on 2011-08-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 110 square meters per square second.19395878Sfc1 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
957 J/kg
Mixed-layer CIN
-1 J/kg
Mixed-layer LCL
466 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
110 m²/s²
0-3 km storm-relative helicity
269 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.

622 
WFUS51 KPHI 280322
TORPHI
PAC017-091-280345-
/O.NEW.KPHI.TO.W.0028.110828T0322Z-110828T0345Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1122 PM EDT SAT AUG 27 2011

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* TORNADO WARNING FOR...
  SOUTHERN BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...
  EAST CENTRAL MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 1145 PM EDT

* AT 1121 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO NEAR LANGHORN...
  OR 9 MILES WEST OF TRENTON...MOVING NORTHWEST AT 45 MPH.

* THE TORNADO WILL BE NEAR...
  RICHBORO AND IVYLAND BY 1130 PM EDT...
  HATBORO BY 1135 PM EDT...
  CHALFONT...DOYLESTOWN AND ROBESONIA BY 1140 PM EDT...
  FRICKS...HATFIELD...DUBLIN AND LANSDALE BY 1145 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THE SAFEST PLACE TO BE DURING A TORNADO IS IN A BASEMENT. GET UNDER A
WORKBENCH OR OTHER PIECE OF STURDY FURNITURE. IF NO BASEMENT IS
AVAILABLE...SEEK SHELTER ON THE LOWEST FLOOR OF THE BUILDING IN AN
INTERIOR HALLWAY OR ROOM SUCH AS A CLOSET. USE BLANKETS OR PILLOWS TO
COVER YOUR BODY AND ALWAYS STAY AWAY FROM WINDOWS.

IF IN MOBILE HOMES OR VEHICLES...EVACUATE THEM AND GET INSIDE A
SUBSTANTIAL SHELTER. IF NO SHELTER IS AVAILABLE...LIE FLAT IN THE
NEAREST DITCH OR OTHER LOW SPOT AND COVER YOUR HEAD WITH YOUR HANDS.

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 500 AM EDT SUNDAY MORNING FOR
DELAWARE AND NORTHEASTERN MARYLAND AND NEW JERSEY AND SOUTHEAST
PENNSYLVANIA.

&&

LAT...LON 4009 7485 4007 7488 4010 7497 4011 7497
      4013 7500 4012 7505 4022 7534 4041 7524
      4026 7485 4024 7484 4021 7478
TIME...MOT...LOC 0322Z 117DEG 39KT 4019 7492

$$

HAYES/GAINES
1 follow-up statement
535 
WWUS51 KPHI 280343
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1143 PM EDT SAT AUG 27 2011

PAC017-091-280354-
/O.EXP.KPHI.TO.W.0028.000000T0000Z-110828T0345Z/
MONTGOMERY PA-BUCKS PA-
1143 PM EDT SAT AUG 27 2011

...THE TORNADO WARNING FOR SOUTHERN BUCKS AND EAST CENTRAL MONTGOMERY
COUNTIES WILL EXPIRE AT 1145 PM EDT...

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 500 AM EDT SUNDAY MORNING FOR
DELAWARE AND NORTHEASTERN MARYLAND AND NEW JERSEY AND SOUTHEAST
PENNSYLVANIA.

LAT...LON 4009 7485 4007 7488 4010 7497 4011 7497
      4013 7500 4012 7505 4022 7534 4041 7524
      4026 7485 4024 7484 4021 7478
TIME...MOT...LOC 0344Z 117DEG 39KT 4030 7520

$$

HAYES

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 27, 8:28 PM EDTFlash Flood WarningPHIChester12 hr
Aug 27, 9:29 PM EDTTornado WarningPHIDelaware31 min
Aug 27, 9:43 PM EDTAreal Flood WarningPHIBerks, Bucks, Chester, Lehigh, Montgomery, Northampton6 hr
Aug 27, 9:58 PM EDTRiver Flood WarningPHIMonroe, Northampton48 hr
Aug 27, 9:58 PM EDTRiver Flood WarningPHIMonroe, Northampton17 hr
Aug 27, 10:14 PM EDTTornado WarningPHIChester, Delaware31 min
Aug 27, 10:23 PM EDTTornado WarningPHIChester, Delaware, Montgomery, Philadelphia37 min
Aug 27, 10:36 PM EDTTornado WarningPHIBucks, Montgomery, Philadelphia24 min
Aug 27, 11:21 PM EDTAreal Flood WarningPHICarbon, Monroe6 hr
Aug 27, 11:37 PM EDTFlash Flood WarningPHIBucks, Chester, Delaware, Montgomery, Philadelphia12 hr
Aug 28, 3:50 AM EDTFlash Flood WarningPHIBerks, Bucks, Chester, Lehigh, Montgomery, Northampton10 hr
Aug 28, 5:17 AM EDTFlash Flood WarningPHICarbon, Monroe10 hr
Aug 28, 11:07 AM EDTAreal Flood WarningPHIBucks, Chester, Delaware, Montgomery, Philadelphia18 hr
Aug 28, 1:27 PM EDTAreal Flood WarningPHIBerks, Bucks, Lehigh, Montgomery, Northampton8 hr
Aug 28, 3:23 PM EDTAreal Flood WarningPHICarbon, Monroe8 hr
Aug 28, 6:47 PM EDTRiver Flood WarningPHILehigh2 hr

Nearby

Tornado Warnings in Pennsylvania, 2011Every tornado warning in 2011Tornadoes 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; the sounding from the Mesonet's radiosonde archive.