Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 264, NWS Philadelphia/Mount Holly

August 27, 20204 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 27, 2020, 7:51 PM EDT for 4 counties in Pennsylvania. It was in force for 39 min. 14 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 27, 2020, 7:51 PM EDT (23:51 UTC)
Expired
Aug 27, 2020, 8:30 PM EDT
In force
39 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

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

The radar

The Philadelphia radar (KDIX), 137 km from the middle of the area, began a volume at 23:54 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

TimeReportWhereRemark
Aug 27, 8:05 PM EDTTSTM WND DMG4 Wnw Breinigsville, PADOWNED TREES AND WIRES NEAR KINES MILL ROAD. TIME ESTIMATED FROM RADAR.
Aug 27, 8:09 PM EDTTSTM WND DMG1 Nne Germansville, PADOWNED TREES AND WIRES NEAR BACHMAN ROAD NEAR GERMANSVILLE. TIME ESTIMATED FROM RADAR.
Aug 27, 8:18 PM EDTTSTM WND DMG1 Sse Bern Twp, PADOWNED TREES AND WIRES NEAR VICTORY CIRCLE. TIME ESTIMATED FROM RADAR.
Aug 27, 8:21 PM EDTTSTM WND DMG2 N Wyomissing, PATREE AND WIRES DOWN ON TULPEHOCKEN ROAD IN WYOMISSING. TIME BASED ON WIND GUST REPORT AT READING REGIONAL AIRPORT.
Aug 27, 8:21 PM EDTTSTM WND DMG2 N Wyomissing, PATREE INTO A HOUSE ON JEFFREY ROAD. TIME BASED ON REPORTED WIND GUST AT READING REGIONAL AIRPORT.
Aug 27, 8:21 PM EDTTSTM WND GST 58Reading Regional Airpor, PARDG ASOS MEASURED 50 KT WIND GUST.
Aug 27, 8:22 PM EDTTSTM WND DMG2 Nnw West Reading, PATOPS OF 2 LARGE OAK TREES SNAPPED OFF ABOUT 30 FEET UP THE TRUNK. TIME ESTIMATED FROM RADAR.
Aug 27, 8:25 PM EDTTSTM WND GST 811 Ne Reading, PACWOP MEASURED WIND GUST. THIS STATION IS VERY EXPOSED LOCATED ATOP THE WILLIAM PENN MEMORIAL FIRE TOWER AT AN ELEVATION OF 1115 FEET.
Aug 27, 8:27 PM EDTTSTM WND DMG1 E Reading, PADOWNED TREES AND WIRES NEAR MINERAL SPRING ROAD IN READING. TIME ESTIMATED FROM RADAR.
Aug 27, 8:29 PM EDTTSTM WND GST 56Lehigh Valley Internati, PAABE ASOS MEASURED 49 KT GUST.
Aug 27, 8:30 PM EDTTSTM WND DMG1 Ene Whitehall Twp, PADOWNED TREES AND WIRES NEAR NORTH IRVING STREET IN WHITEHALL TWP. TIME ESTIMATED FROM RADAR.
Aug 27, 8:30 PM EDTTSTM WND DMG4 Wsw Allentown, PASEVERAL REPORTS OF DOWNED TREES AND WIRES NEAR AND WEST OF ALLENTOWN. TIME ESTIMATED FROM RADAR.
Aug 27, 8:35 PM EDTTSTM WND GST 44Allentown Queen City Mu, PAXLL AWOS MEASURED 38 KT WIND GUST.
Aug 27, 8:40 PM EDTTSTM WND DMGBetlehem, PASEVERAL TREES DOWN IN THE BETHLEHEM AREA. TIME ESTIMATED FROM RADAR.

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

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 11.9 hours before the alert went out and 239 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, Washington/Dulle, VA at 12:00Z on 2020-08-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 636 joules per kilogram.LCLLFCEL10008507005003002001001 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, Washington/Dulle, VA at 12:00Z on 2020-08-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 140 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
636 J/kg
Mixed-layer CIN
-100 J/kg
Mixed-layer LCL
1293 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
140 m²/s²
0-3 km storm-relative helicity
195 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.0

Open this sounding in Storm Lab

The text

As transmitted.

277 
WUUS51 KPHI 272351
SVRPHI
PAC011-025-077-095-280030-
/O.NEW.KPHI.SV.W.0264.200827T2351Z-200828T0030Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
751 PM EDT Thu Aug 27 2020

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Berks County in eastern Pennsylvania...
  Lehigh County in eastern Pennsylvania...
  Southern Carbon County in northeastern Pennsylvania...
  Central Northampton County in eastern Pennsylvania...

* Until 830 PM EDT.

* At 751 PM EDT, severe thunderstorms were located along a line
  extending from Hometown to near Friedensburg, moving east at 50
  mph.

  HAZARD...60 mph wind gusts and penny size hail.

  SOURCE...Radar indicated.

  IMPACT...Damage to roofs, siding, trees, and power lines is 
           possible.

* Locations impacted include...
  Allentown, Reading, Lehighton, Bethlehem, Emmaus, Wyomissing,
  Northampton, Nazareth, Palmerton, Kutztown, Jim Thorpe, Hamburg,
  Slatington, Fleetwood, Laureldale, Nesquehoning, Bath, Walnutport,
  Topton and Leesport.

This includes the following highways...
 Northeast Extension between mile markers 52 and 76.
 Interstate 78 in Pennsylvania between mile markers 11 and 60.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4052 7625 4058 7605 4057 7602 4065 7598
      4074 7576 4088 7596 4083 7548 4081 7547
      4083 7543 4079 7512 4077 7515 4078 7517
      4074 7519 4030 7583 4049 7643
TIME...MOT...LOC 2351Z 282DEG 45KT 4082 7595 4059 7630 

HAIL...0.75IN
WIND...60MPH
 
$$

JEO
2 follow-up statements
580 
WWUS51 KPHI 280017
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
817 PM EDT Thu Aug 27 2020

PAC011-025-077-095-280030-
/O.CON.KPHI.SV.W.0264.000000T0000Z-200828T0030Z/
Berks PA-Lehigh PA-Carbon PA-Northampton PA-
817 PM EDT Thu Aug 27 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 830 PM EDT
FOR CENTRAL BERKS...LEHIGH...SOUTHEASTERN CARBON AND CENTRAL
NORTHAMPTON COUNTIES...

At 817 PM EDT, severe thunderstorms were located along a line
extending from near Berlinsville to near Lenhartsville, moving east
at 50 mph.

HAZARD...60 mph wind gusts and penny size hail.

SOURCE...Radar indicated.

IMPACT...Damage to roofs, siding, trees, and power lines is 
         possible.

Locations impacted include...
Allentown, Reading, Lehighton, Bethlehem, Emmaus, Wyomissing,
Northampton, Nazareth, Palmerton, Kutztown, Hamburg, Slatington,
Fleetwood, Laureldale, Bath, Walnutport, Topton, Leesport, Belfast
and Shoemakersville.

This includes the following highways...
 Northeast Extension between mile markers 52 and 76.
 Interstate 78 in Pennsylvania between mile markers 30 and 60.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4041 7618 4056 7600 4064 7599 4065 7598
      4074 7576 4078 7581 4079 7580 4081 7577
      4085 7572 4083 7548 4081 7547 4083 7543
      4079 7512 4077 7515 4078 7517 4074 7519
      4030 7583
TIME...MOT...LOC 0017Z 282DEG 45KT 4075 7553 4052 7588 

HAIL...0.75IN
WIND...60MPH
 
$$

JEO
734 
WWUS51 KPHI 280023
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
823 PM EDT Thu Aug 27 2020

PAC011-025-077-095-280032-
/O.EXP.KPHI.SV.W.0264.000000T0000Z-200828T0030Z/
Berks PA-Lehigh PA-Carbon PA-Northampton PA-
823 PM EDT Thu Aug 27 2020

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL BERKS...LEHIGH...
SOUTHEASTERN CARBON AND CENTRAL NORTHAMPTON COUNTIES WILL EXPIRE AT
830 PM EDT...
    
The storms which prompted the warning have moved out of the area.
Therefore, the warning will be allowed to expire.

LAT...LON 4041 7618 4056 7600 4064 7599 4065 7598
      4074 7576 4078 7581 4079 7580 4081 7577
      4085 7572 4083 7548 4081 7547 4083 7543
      4079 7512 4077 7515 4078 7517 4074 7519
      4030 7583
TIME...MOT...LOC 0022Z 282DEG 45KT 4075 7553 4052 7588 

$$

JEO

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2020Every severe thunderstorm warning in 2020

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.