Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 305, NWS Philadelphia/Mount Holly

September 15, 2021Berks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Sep 15, 2021, 7:08 PM EDT for Berks County, Pennsylvania. It was in force for 37 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
Sep 15, 2021, 7:08 PM EDT (23:08 UTC)
Expired
Sep 15, 2021, 7:45 PM EDT
In force
37 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.88 in
Wind
60.0 mph

County Berks County, PA

The radar

The Philadelphia radar (KDIX), 151 km from the middle of the area, began a volume at 23:09 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
Sep 15, 11:55 AM EDTSevere Thunderstorm WatchSPC8 hr
Sep 15, 3:43 PM EDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 11.1 hours before the alert went out and 192 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 2021-09-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 13 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 2021-09-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 73 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
13 J/kg
Mixed-layer CIN
-270 J/kg
Mixed-layer LCL
1457 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
73 m²/s²
0-3 km storm-relative helicity
106 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

728 
WUUS51 KPHI 152308
SVRPHI
PAC011-152345-
/O.NEW.KPHI.SV.W.0305.210915T2308Z-210915T2345Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
708 PM EDT Wed Sep 15 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Central Berks County in eastern Pennsylvania...

* Until 745 PM EDT.

* At 708 PM EDT, a severe thunderstorm was located over Robesonia, or
  9 miles east of Myerstown, moving east at 20 mph.

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

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Reading, Wyomissing, Sinking Spring, Laureldale, Womelsdorf,
  Wernersville, Robesonia, Leesport, Bernville, Spring Ridge,
  Fairview Hgts, Shillington, West Reading, Mount Penn, Mohnton,
  Kenhorst, St. Lawrence, Centerport, West Lawn and Wyomissing Hills.

This includes Interstate 176 in Pennsylvania between mile markers 7
and 11.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

To report severe weather, contact your nearest law enforcement
agency. They will send your report to the National Weather Service
office in Mount Holly NJ.

&&

LAT...LON 4042 7624 4051 7590 4024 7584 4024 7604
      4031 7614 4036 7621 4037 7623
TIME...MOT...LOC 2308Z 261DEG 19KT 4035 7613 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.88 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

MPS
2 follow-up statements
901 
WWUS51 KPHI 152319
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
719 PM EDT Wed Sep 15 2021

PAC011-152345-
/O.CON.KPHI.SV.W.0305.000000T0000Z-210915T2345Z/
Berks PA-
719 PM EDT Wed Sep 15 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 745 PM EDT
FOR CENTRAL BERKS COUNTY...

At 719 PM EDT, a severe thunderstorm was located near Wernersville,
or 7 miles west of Reading, moving east at 20 mph.

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

SOURCE...Radar indicated.

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

Locations impacted include...
Reading, Wyomissing, Sinking Spring, Laureldale, Wernersville,
Robesonia, Leesport, Bernville, Fairview Hgts, Spring Ridge,
Shillington, West Reading, Mount Penn, Mohnton, Kenhorst, St.
Lawrence, Centerport, Wyomissing Hills, West Lawn and Reiffton.

This includes Interstate 176 in Pennsylvania between mile markers 10
and 11.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

To report severe weather contact your nearest law enforcement agency.
They will send your report to the National Weather Service office in
Mount Holly NJ.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4030 7613 4043 7618 4045 7613 4051 7590
      4029 7585 4026 7607
TIME...MOT...LOC 2319Z 252DEG 19KT 4038 7606 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.88 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

MPS
061 
WWUS51 KPHI 152337
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
737 PM EDT Wed Sep 15 2021

PAC011-152346-
/O.EXP.KPHI.SV.W.0305.000000T0000Z-210915T2345Z/
Berks PA-
737 PM EDT Wed Sep 15 2021

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL BERKS COUNTY WILL
EXPIRE AT 745 PM EDT...
                
The storm which prompted the warning has weakened below severe 
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire.  However, gusty 
winds and heavy rain are still possible with this thunderstorm.

A Severe Thunderstorm Watch remains in effect until 1000 PM EDT for
eastern Pennsylvania.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Mount Holly NJ.

LAT...LON 4030 7613 4043 7618 4045 7613 4051 7590
      4029 7585 4026 7607
TIME...MOT...LOC 2336Z 261DEG 19KT 4039 7595 

$$

MPS

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 15, 5:31 PM EDTSpecial Weather StatementPHIMonroe29 min
Sep 15, 6:29 PM EDTSpecial Weather StatementPHILebanon31 min
Sep 15, 6:48 PM EDTSpecial Weather StatementPHIBerks27 min
Sep 15, 7:17 PM EDTSpecial Weather StatementPHILehigh28 min
Sep 15, 7:36 PM EDTSpecial Weather StatementPHIMontgomery24 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.