Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 25, NWS Philadelphia/Mount Holly

April 28, 20115 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Apr 28, 2011, 4:36 AM EDT for 5 counties in Pennsylvania. It was in force for 54 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
Apr 28, 2011, 4:36 AM EDT (08:36 UTC)
Expired
Apr 28, 2011, 5:30 AM EDT
In force
54 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Berks County, PA, Carbon County, PA, Lehigh County, PA, Monroe County, PA, Northampton County, PA

The radar

The Binghamton radar (KBGM), 152 km from the middle of the area, began a volume at 08:36 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.

The watch it was issued in

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

IssuedProductOfficeLasted
Apr 28, 4:05 AM EDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Brookhaven, NY (KOKX), launched 00:00Z, 8.6 hours before the alert went out and 245 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 2011-04-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 172 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 00:00Z on 2011-04-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 207 square meters per square second.193958Sfc1 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
172 J/kg
Mixed-layer CIN
-34 J/kg
Mixed-layer LCL
447 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
207 m²/s²
0-3 km storm-relative helicity
246 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.

156 
WUUS51 KPHI 280836
SVRPHI
PAC011-025-077-089-095-280930-
/O.NEW.KPHI.SV.W.0025.110428T0836Z-110428T0930Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
436 AM EDT THU APR 28 2011

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHERN BERKS COUNTY IN EASTERN PENNSYLVANIA...
  LEHIGH COUNTY IN EASTERN PENNSYLVANIA...
  NORTHWESTERN NORTHAMPTON COUNTY IN EASTERN PENNSYLVANIA...
  CARBON COUNTY IN NORTHEAST PENNSYLVANIA...
  THIS INCLUDES THE CITY OF LEHIGHTON...
  MONROE COUNTY IN NORTHEAST PENNSYLVANIA...
  THIS INCLUDES THE CITY OF MOUNT POCONO...

* UNTIL 530 AM EDT

* AT 431 AM 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 44 MILES WEST OF LEHIGHTON TO 24 MILES WEST OF LANCASTER...   
  AND MOVING NORTHEAST AT 45 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  STRAUSSTOWN AROUND 450 AM EDT...
  WOMELSDORF AROUND 455 AM EDT...
  BERNVILLE AROUND 500 AM EDT...
  SHOEMAKERSVILLE AND HAMBURG AROUND 505 AM EDT...
  WANAMAKERS...NEW MAHONING...WHITE HAVEN AND WEATHERLY AROUND 510 AM
  EDT...
  NEW TRIPOLI AROUND 515 AM 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.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 1000 AM EDT
THURSDAY MORNING FOR DELAWARE AND NORTHEASTERN MARYLAND AND WESTERN
NEW JERSEY AND EASTERN PENNSYLVANIA.

&&

LAT...LON 4095 7521 4072 7535 4060 7553 4032 7616
      4049 7644 4051 7643 4054 7618 4060 7605
      4059 7603 4064 7600 4074 7578 4091 7600
      4101 7575 4105 7578 4111 7576 4114 7570
      4113 7564 4121 7557 4125 7550 4125 7519
TIME...MOT...LOC 0835Z 239DEG 57KT 4086 7650 4072 7641
          4060 7642 4041 7643 4034 7647 4018 7656
          4013 7667

$$

HAYES
2 follow-up statements
139 
WWUS51 KPHI 280854
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
454 AM EDT THU APR 28 2011

PAC011-025-077-089-095-280930-
/O.CON.KPHI.SV.W.0025.000000T0000Z-110428T0930Z/
BERKS PA-LEHIGH PA-NORTHAMPTON PA-CARBON PA-MONROE PA-
454 AM EDT THU APR 28 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 530 AM EDT
FOR MONROE...CARBON...NORTHWESTERN NORTHAMPTON...LEHIGH AND NORTHERN
BERKS COUNTIES...

AT 449 AM 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 26 MILES SOUTHWEST OF WILKES-BARRE TO 13 MILES 
NORTHWEST OF LANCASTER...MOVING NORTHEAST AT 45 MPH.

SEVERE THUNDERSTORMS WILL BE NEAR...
  WOMELSDORF BY 500 AM EDT...
  TRESCKOW...PORT CLINTON AND BERNVILLE BY 505 AM EDT...
  SHOEMAKERSVILLE...LANSFORD...HAMBURG AND CENTERPORT BY 510 AM
  EDT...
  WANAMAKERS AND NEW MAHONING BY 515 AM 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.

&&

LAT...LON 4095 7521 4072 7535 4060 7553 4032 7616
      4049 7644 4051 7643 4054 7618 4060 7605
      4059 7603 4064 7600 4074 7578 4091 7600
      4101 7575 4105 7578 4111 7576 4114 7570
      4113 7564 4121 7557 4125 7550 4125 7519
TIME...MOT...LOC 0853Z 240DEG 50KT 4104 7621 4079 7618
          4068 7618 4055 7618 4048 7621 4029 7631
          4021 7640

$$

HAYES
724 
WWUS51 KPHI 280929
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
529 AM EDT THU APR 28 2011

PAC011-025-077-089-095-280939-
/O.EXP.KPHI.SV.W.0025.000000T0000Z-110428T0930Z/
BERKS PA-LEHIGH PA-NORTHAMPTON PA-CARBON PA-MONROE PA-
529 AM EDT THU APR 28 2011

...THE SEVERE THUNDERSTORM WARNING FOR MONROE...CARBON...NORTHWESTERN
NORTHAMPTON...LEHIGH AND NORTHERN BERKS COUNTIES WILL EXPIRE AT 530
AM EDT...

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 1000 AM EDT
THURSDAY MORNING FOR DELAWARE AND NORTHEASTERN MARYLAND AND WESTERN
NEW JERSEY AND EASTERN PENNSYLVANIA.

LAT...LON 4095 7521 4072 7535 4060 7553 4032 7616
      4049 7644 4051 7643 4054 7618 4060 7605
      4059 7603 4064 7600 4074 7578 4091 7600
      4101 7575 4105 7578 4111 7576 4114 7570
      4113 7564 4121 7557 4125 7550 4125 7519
TIME...MOT...LOC 0929Z 240DEG 50KT 4127 7561 4102 7559
          4091 7559 4078 7559 4071 7563 4052 7573
          4044 7582

$$

HAYES

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 28, 4:24 AM EDTSpecial Weather StatementPHIBerks, Carbon, Lehigh, Northampton66 min
Apr 28, 5:31 AM EDTSpecial Weather StatementPHICarbon, Monroe59 min
Apr 28, 5:49 AM EDTSpecial Weather StatementPHICarbon56 min
Apr 28, 5:58 AM EDTAreal Flood AdvisoryPHIBerks, Carbon, Lehigh, Monroe, Northampton3 hr
Apr 28, 6:12 AM EDTSpecial Weather StatementPHIChester, Delaware, Philadelphia63 min
Apr 28, 6:18 AM EDTSevere Thunderstorm WarningPHICarbon, Monroe57 min
Apr 28, 6:23 AM EDTSpecial Weather StatementPHIBerks, Chester, Lehigh, Montgomery52 min
Apr 28, 6:56 AM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Chester, Delaware, Lehigh, Montgomery and 2 more34 min
Apr 28, 7:06 AM EDTFlash Flood WarningPHICarbon, Monroe6 hr
Apr 28, 7:35 AM EDTSpecial Weather StatementPHIBucks55 min
Apr 28, 8:17 AM EDTSpecial Weather StatementPHIBerks58 min
Apr 28, 8:55 AM EDTSevere Thunderstorm WarningPHIBerks, Lehigh65 min
Apr 28, 8:59 AM EDTAreal Flood AdvisoryPHIBerks, Lehigh4 hr
Apr 28, 9:11 AM EDTSpecial Weather StatementPHICarbon, Monroe49 min
Apr 28, 9:33 AM EDTSevere Thunderstorm WarningPHICarbon, Lehigh, Monroe, Northampton57 min
Apr 28, 10:00 AM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Chester, Lehigh, Montgomery60 min
Apr 28, 10:25 AM EDTSevere Thunderstorm WarningPHIBucks, Carbon, Lehigh, Monroe, Northampton50 min
Apr 28, 10:48 AM EDTAreal Flood AdvisoryPHIBucks, Chester, Montgomery, Northampton3 hr
Apr 28, 10:57 AM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Chester, Lehigh, Montgomery, Northampton63 min
Apr 28, 10:58 AM EDTTornado WarningPHIBucks, Northampton32 min
Apr 28, 11:11 AM EDTSevere Thunderstorm WarningPHINorthampton64 min
Apr 28, 12:03 PM EDTSpecial Weather StatementPHIMontgomery, Philadelphia57 min
Apr 28, 12:11 PM EDTSevere Thunderstorm WarningPHIBucks, Chester, Delaware, Montgomery31 min
Apr 28, 12:42 PM EDTSpecial Weather StatementPHIDelaware63 min
Apr 28, 12:45 PM EDTSpecial Weather StatementPHIBucks, Delaware, Montgomery, Philadelphia60 min
Apr 28, 1:23 PM EDTAreal Flood AdvisoryPHIPhiladelphia103 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2011Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.