Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 160, NWS Philadelphia/Mount Holly

August 12, 2017Berks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 12, 2017, 5:24 PM EDT for Berks County, Pennsylvania. It was in force for 51 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 12, 2017, 5:24 PM EDT (21:24 UTC)
Expired
Aug 12, 2017, 6:15 PM EDT
In force
51 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

County Berks County, PA

The radar

The Philadelphia radar (KDIX), 145 km from the middle of the area, began a volume at 21:26 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
Aug 12, 2:44 PM EDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 9.4 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 2017-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 248 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 2017-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 12 square meters per square second.1939587897Sfc1 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
248 J/kg
Mixed-layer CIN
-78 J/kg
Mixed-layer LCL
772 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
12 m²/s²
0-3 km storm-relative helicity
78 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

954 
WUUS51 KPHI 122124
SVRPHI
PAC011-122215-
/O.NEW.KPHI.SV.W.0160.170812T2124Z-170812T2215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
524 PM EDT SAT AUG 12 2017

The National Weather Service in Mount Holly NJ has issued a

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

* Until 615 PM EDT

* At 522 PM EDT, a severe thunderstorm was located over
  Kleinfeltersville, or near Myerstown, moving east at 25 mph.

  HAZARD...60 mph wind gusts. 

  SOURCE...Radar indicated. 

  IMPACT...Expect damage to trees and power lines. 

* Locations impacted include...
  Reading, Wyomissing, Birdsboro, Sinking Spring, Womelsdorf,
  Wernersville, New Morgan, Spring Ridge, Shillington, West Reading,
  Mount Penn, Mohnton, Kenhorst, St. Lawrence, Wyomissing Hills, West
  Lawn, Lorane, Reiffton, Whitfield and West Wyomissing.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In addition to damaging winds...frequent cloud to ground lightning 
is occurring with this storm. Move indoors immediately. 
Remember...if you can hear thunder...you are close enough to be 
struck by lightning.

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

&&

LAT...LON 4043 7630 4035 7573 4019 7579 4014 7587
      4042 7630
TIME...MOT...LOC 2122Z 284DEG 23KT 4031 7625 

HAIL...<.75IN
WIND...60MPH
 
$$

Meola
2 follow-up statements
784 
WWUS51 KPHI 122152
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
552 PM EDT SAT AUG 12 2017

PAC011-122215-
/O.CON.KPHI.SV.W.0160.000000T0000Z-170812T2215Z/
Berks PA-
552 PM EDT SAT AUG 12 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 615 PM EDT
FOR SOUTH CENTRAL BERKS COUNTY...

At 552 PM EDT, a severe thunderstorm was located over Adamstown, or 7
miles northeast of Ephrata, moving east at 20 mph.

HAZARD...60 mph wind gusts. 

SOURCE...Radar indicated. 

IMPACT...Expect damage to trees and power lines. 

Locations impacted include...
Reading, Wyomissing, Birdsboro, Sinking Spring, Wernersville, New
Morgan, Shillington, Mohnton, Kenhorst, West Lawn, Lorane, West
Wyomissing, Flying Hills, Reiffton, Whitfield and Wyomissing Hills.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In addition to damaging winds...frequent cloud to ground lightning 
is occurring with this storm. Move indoors immediately. Remember... 
if you can hear thunder...you are close enough to be struck by 
lightning.

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

&&

LAT...LON 4030 7575 4019 7579 4014 7587 4036 7620
TIME...MOT...LOC 2152Z 287DEG 18KT 4026 7607 

HAIL...<.75IN
WIND...60MPH
 
$$

Meola
132 
WWUS51 KPHI 122215
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
615 PM EDT SAT AUG 12 2017

PAC011-122225-
/O.EXP.KPHI.SV.W.0160.000000T0000Z-170812T2215Z/
Berks PA-
615 PM EDT SAT AUG 12 2017

...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL BERKS COUNTY HAS
EXPIRED...
                
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 has been allowed to expire.

A severe thunderstorm watch remains in effect until 900 PM EDT for
eastern Pennsylvania.

LAT...LON 4030 7575 4019 7579 4014 7587 4036 7620
TIME...MOT...LOC 2215Z 284DEG 23KT 4023 7591 

$$

Meola

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 11, 10:49 PM EDTSpecial Weather StatementPHIBerks, Lehigh, Northampton41 min
Aug 11, 11:05 PM EDTAreal Flood AdvisoryPHIBerks, Carbon, Lehigh, Monroe, Northampton5 hr
Aug 12, 5:00 PM EDTSpecial Weather StatementPHIBerks60 min
Aug 12, 5:39 PM EDTAreal Flood AdvisoryPHIBerks4 hr
Aug 12, 6:18 PM EDTSpecial Weather StatementPHIChester27 min
Aug 12, 7:10 PM EDTSpecial Weather StatementPHIChester50 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2017Every severe thunderstorm warning in 2017

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.