Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 259, NWS Philadelphia/Mount Holly

August 12, 2021Berks County, Carbon County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 12, 2021, 10:27 PM EDT for Berks County, Carbon County, Pennsylvania. It was in force for 48 min. 1 report 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 12, 2021, 10:27 PM EDT (02:27 UTC)
Expired
Aug 12, 2021, 11:15 PM EDT
In force
48 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

The radar

The Philadelphia radar (KDIX), 160 km from the middle of the area, began a volume at 02:28 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 12, 10:50 PM EDTTSTM WND DMG1 Ssw Shartlesville, PATREE DOWN BLOCKING WOLF CREEK ROAD. 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 00:00Z, 2.5 hours before the alert went out and 214 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 00:00Z on 2021-08-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2808 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 00:00Z on 2021-08-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 38 square meters per square second.1939Sfc1 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
2808 J/kg
Mixed-layer CIN
-24 J/kg
Mixed-layer LCL
1565 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
38 m²/s²
0-3 km storm-relative helicity
153 m²/s²
Significant tornado parameter
0.0
Supercell composite
4.9

Open this sounding in Storm Lab

The text

As transmitted.

678 
WUUS51 KPHI 130227
SVRPHI
PAC011-025-130315-
/O.NEW.KPHI.SV.W.0259.210813T0227Z-210813T0315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
1027 PM EDT Thu Aug 12 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northwestern Berks County in eastern Pennsylvania...
  Southwestern Carbon County in northeastern Pennsylvania...

* Until 1115 PM EDT.

* At 1026 PM EDT, severe thunderstorms were located along a line
  extending from near Numidia to near Palmyra, moving northeast at 45
  mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Hamburg, Womelsdorf, Weatherly, Wernersville, Robesonia, Bernville,
  Strausstown, Lansford, Beaver Meadows, Centerport and Tresckow.

This includes Interstate 78 in Pennsylvania near mile marker 8, and
between mile markers 10 and 31.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4052 7634 4052 7625 4056 7609 4058 7606
      4058 7604 4057 7602 4063 7600 4066 7595
      4080 7590 4091 7599 4098 7582 4033 7607
      4032 7617 4049 7643
TIME...MOT...LOC 0226Z 240DEG 38KT 4089 7632 4034 7658 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Fitzsimmons
1 follow-up statement
065 
WWUS51 KPHI 130258
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
1058 PM EDT Thu Aug 12 2021

PAC011-025-130315-
/O.CON.KPHI.SV.W.0259.000000T0000Z-210813T0315Z/
Berks PA-Carbon PA-
1058 PM EDT Thu Aug 12 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1115 PM EDT
FOR NORTHWESTERN BERKS AND SOUTHWESTERN CARBON COUNTIES...

At 1058 PM EDT, severe thunderstorms were located along a line
extending from near Hazleton to near Strausstown, moving east at 40
mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Hamburg, Weatherly, Bernville, Strausstown, Lansford, Beaver Meadows
and Tresckow.

This includes Interstate 78 in Pennsylvania near mile marker 8, and
between mile markers 10 and 31.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4042 7604 4045 7636 4045 7637 4049 7643
      4052 7634 4052 7625 4056 7609 4058 7606
      4058 7604 4057 7602 4063 7600 4066 7595
      4080 7590 4091 7599 4098 7582
TIME...MOT...LOC 0258Z 250DEG 35KT 4098 7596 4043 7622 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Fitzsimmons

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 12, 11:20 PM EDTSpecial Weather StatementPHICarbon, Lehigh, Northampton40 min
Aug 12, 11:49 PM EDTSpecial Weather StatementPHINorthampton56 min
Aug 13, 5:31 PM EDTSpecial Weather StatementPHIChester44 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2021Every severe thunderstorm warning in 2021

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.