Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 105, NWS Philadelphia/Mount Holly

July 17, 2017Berks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 17, 2017, 1:20 PM EDT for Berks County, Pennsylvania. It was in force for 40 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
Jul 17, 2017, 1:20 PM EDT (17:20 UTC)
Expired
Jul 17, 2017, 2:00 PM EDT
In force
40 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

County Berks County, PA

The radar

The State College radar (KCCX), 156 km from the middle of the area, began a volume at 17:19 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 nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 5.3 hours before the alert went out and 199 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 2017-07-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1198 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 2017-07-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 40 square meters per square second.19395878Sfc1 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
1198 J/kg
Mixed-layer CIN
-50 J/kg
Mixed-layer LCL
1021 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
40 m²/s²
0-3 km storm-relative helicity
28 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.6

Open this sounding in Storm Lab

The text

As transmitted.

824 
WUUS51 KPHI 171720
SVRPHI
PAC011-171800-
/O.NEW.KPHI.SV.W.0105.170717T1720Z-170717T1800Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
120 PM EDT MON JUL 17 2017

The National Weather Service in Mount Holly NJ has issued a

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

* Until 200 PM EDT

* At 120 PM EDT, a severe thunderstorm was located near Pine Grove,
  or 9 miles north of Myerstown, moving northeast at 5 mph.

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

  SOURCE...Radar indicated. 

  IMPACT...Minor damage to vehicles is possible. Expect damage to 
           trees and power lines. 

* Locations impacted include...
  Strausstown.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4052 7634 4052 7625 4058 7606 4054 7601
      4038 7626 4049 7643
TIME...MOT...LOC 1720Z 222DEG 6KT 4051 7630 

HAIL...1.00IN
WIND...60MPH
 
$$

SFJ
2 follow-up statements
275 
WWUS51 KPHI 171737
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
137 PM EDT MON JUL 17 2017

PAC011-171800-
/O.CON.KPHI.SV.W.0105.000000T0000Z-170717T1800Z/
Berks PA-
137 PM EDT MON JUL 17 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 200 PM EDT
FOR NORTHWESTERN BERKS COUNTY...

At 136 PM EDT, a severe thunderstorm was located near Strausstown, or
7 miles north of Myerstown, and is nearly stationary.

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

SOURCE...Radar indicated. 

IMPACT...Minor damage to vehicles is possible. Expect damage to 
         trees and power lines. 

Locations impacted include...
Strausstown.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

In addition to large hail and 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 4052 7634 4052 7625 4058 7606 4052 7605
      4040 7629 4049 7643
TIME...MOT...LOC 1736Z 272DEG 1KT 4048 7630 

HAIL...1.00IN
WIND...60MPH
 
$$

SFJ
225 
WWUS51 KPHI 171755
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
155 PM EDT MON JUL 17 2017

PAC011-171804-
/O.EXP.KPHI.SV.W.0105.000000T0000Z-170717T1800Z/
Berks PA-
155 PM EDT MON JUL 17 2017

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN BERKS COUNTY WILL
EXPIRE AT 200 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 small 
hail, frequent lightning, and heavy rain are still possible with 
this thunderstorm. A flash flood warning remains in effect.

LAT...LON 4052 7634 4052 7625 4058 7606 4052 7605
      4040 7629 4049 7643
TIME...MOT...LOC 1754Z 222DEG 6KT 4050 7627 

$$

SFJ

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 17, 1:09 PM EDTSpecial Weather StatementPHILehigh36 min
Jul 17, 1:24 PM EDTAreal Flood AdvisoryPHIBerks5 hr
Jul 17, 1:41 PM EDTFlash Flood WarningPHIBerks7 hr
Jul 17, 1:57 PM EDTSpecial Weather StatementPHILebanon33 min
Jul 17, 3:16 PM EDTAreal Flood AdvisoryPHIBerks119 min
Jul 17, 3:56 PM EDTAreal Flood AdvisoryPHIBucks, Lehigh, Monroe, Northampton4 hr
Jul 17, 4:24 PM EDTSpecial Weather StatementPHINorthampton51 min
Jul 17, 4:35 PM EDTAreal Flood AdvisoryPHIMonroe, Northampton115 min
Jul 17, 4:44 PM EDTAreal Flood AdvisoryPHIBucks, Delaware, Montgomery, Philadelphia3 hr
Jul 17, 4:56 PM EDTSpecial Weather StatementPHIPhiladelphia49 min
Jul 17, 4:57 PM EDTSpecial Weather StatementPHIChester33 min
Jul 17, 5:51 PM EDTSpecial Weather StatementPHIBucks39 min
Jul 17, 5:55 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.