Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 178, NWS Philadelphia/Mount Holly

August 21, 2017Berks County, Lehigh County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 21, 2017, 6:24 PM EDT for Berks County, Lehigh County, Pennsylvania. It was in force for 33 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 21, 2017, 6:24 PM EDT (22:24 UTC)
Expired
Aug 21, 2017, 6:57 PM EDT
In force
33 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Berks County, PA, Lehigh County, PA

The radar

The Philadelphia radar (KDIX), 143 km from the middle of the area, began a volume at 22:27 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 21, 6:28 PM EDTTSTM WND DMG1 N Lenhartsville, PATREES REPORTED DOWN IN WESTERN GREENWICH TOWNSHIP.

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, 10.4 hours before the alert went out and 230 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 2017-08-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 832 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 2017-08-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 100 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
832 J/kg
Mixed-layer CIN
-46 J/kg
Mixed-layer LCL
855 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
100 m²/s²
0-3 km storm-relative helicity
119 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

129 
WUUS51 KPHI 212224
SVRPHI
PAC011-077-212315-
/O.NEW.KPHI.SV.W.0178.170821T2224Z-170821T2315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
624 PM EDT MON AUG 21 2017

The National Weather Service in Mount Holly NJ has issued a

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

* Until 715 PM EDT

* At 624 PM EDT, a severe thunderstorm was located over 
  Lenhartsville, moving northeast at 15 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...
  Allentown, Kutztown, Hamburg, Slatington, Shoemakersville,
  Lenhartsville, Neffs, Wanamakers, Coffeetown, New Tripoli, Jordan
  Valley, Emerald, Schnecksville, Claussville and Ancient Oaks.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4057 7602 4064 7600 4069 7587 4070 7583
      4077 7570 4078 7564 4057 7549 4045 7594
TIME...MOT...LOC 2224Z 243DEG 15KT 4057 7591 

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

Iovino
2 follow-up statements
315 
WWUS51 KPHI 212248
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
648 PM EDT MON AUG 21 2017

PAC011-212256-
/O.CAN.KPHI.SV.W.0178.000000T0000Z-170821T2315Z/
Berks PA-
648 PM EDT MON AUG 21 2017

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN BERKS COUNTY IS
CANCELLED...
    
The severe thunderstorm which prompted the warning was moving out of 
Berks County. Therefore, the warning has been cancelled.

LAT...LON 4069 7587 4070 7583 4077 7570 4078 7564
      4057 7549 4053 7566 4068 7589
TIME...MOT...LOC 2246Z 243DEG 17KT 4062 7578 

$$

PAC077-212315-
/O.CON.KPHI.SV.W.0178.000000T0000Z-170821T2315Z/
Lehigh PA-
648 PM EDT MON AUG 21 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 715 PM EDT
FOR CENTRAL LEHIGH COUNTY...

At 646 PM EDT, a severe thunderstorm was located near Wanamakers, 
moving northeast at 20 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...
Slatington, Jordan Valley, Neffs, Wanamakers, Emerald, 
Schnecksville, Coffeetown, New Tripoli and Claussville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4069 7587 4070 7583 4077 7570 4078 7564
      4057 7549 4053 7566 4068 7589
TIME...MOT...LOC 2246Z 243DEG 17KT 4062 7578 

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

Iovino
585 
WWUS51 KPHI 212257
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
657 PM EDT MON AUG 21 2017

PAC077-212307-
/O.CAN.KPHI.SV.W.0178.000000T0000Z-170821T2315Z/
Lehigh PA-
657 PM EDT MON AUG 21 2017

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL LEHIGH COUNTY IS
CANCELLED...
    
The severe thunderstorm which prompted the warning has weakened.
Therefore, the warning has been cancelled.

LAT...LON 4069 7587 4070 7583 4077 7570 4078 7564
      4057 7549 4053 7566 4068 7589
TIME...MOT...LOC 2256Z 243DEG 15KT 4064 7573 

$$

Iovino

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 21, 3:14 PM EDTHeat AdvisoryPHIBucks, Chester, Delaware, Montgomery, Philadelphia29 hr
Aug 21, 5:44 PM EDTAreal Flood AdvisoryPHIBerks4 hr
Aug 21, 6:20 PM EDTSpecial Weather StatementPHILehigh55 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.