Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 177, NWS Philadelphia/Mount Holly

August 19, 20177 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 19, 2017, 9:00 PM EDT for 7 counties in Pennsylvania. It was in force for 60 min. 3 reports 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 19, 2017, 9:00 PM EDT (01:00 UTC)
Expired
Aug 19, 2017, 10:00 PM EDT
In force
60 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Berks County, PA, Bucks County, PA, Carbon County, PA, Lehigh County, PA, Monroe County, PA, Montgomery County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 116 km from the middle of the area, began a volume at 01:02 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 19, 9:03 PM EDTTSTM WND DMGAmity Twp, PATREES AND WIRES BLOWN DOWN. TIME ESITMATED FROM RADAR.
Aug 19, 9:17 PM EDTTSTM WND GST 46S Allentown, PA
Aug 19, 9:23 PM EDTTSTM WND GST 44Lehigh Valley Intl Airp, PA

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Brookhaven, NY (KOKX), launched 00:00Z, 1.0 hours before the alert went out and 207 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, Brookhaven, NY at 00:00Z on 2017-08-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 149 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, Brookhaven, NY at 00:00Z on 2017-08-20The 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
149 J/kg
Mixed-layer CIN
-60 J/kg
Mixed-layer LCL
1304 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
40 m²/s²
0-3 km storm-relative helicity
48 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

As transmitted.

636 
WUUS51 KPHI 200100
SVRPHI
PAC011-017-025-077-089-091-095-200200-
/O.NEW.KPHI.SV.W.0177.170820T0100Z-170820T0200Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
900 PM EDT SAT AUG 19 2017

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Eastern Berks County in eastern Pennsylvania...
  Northwestern Montgomery County in southeastern Pennsylvania...
  Lehigh County in eastern Pennsylvania...
  Southeastern Carbon County in northeastern Pennsylvania...
  Northwestern Bucks County in southeastern Pennsylvania...
  Southern Monroe County in northeastern Pennsylvania...
  Northampton County in eastern Pennsylvania...

* Until 1000 PM EDT

* At 859 PM EDT, severe thunderstorms were located along a line
  extending from near Jordan Valley to near Claussville to near
  Fleetwood to near New Morgan, moving northeast at 40 mph.

  HAZARD...60 mph wind gusts. 

  SOURCE...Radar indicated. 

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

* Locations impacted include...
  Allentown, Easton, Lehighton, Bethlehem, Pottstown, Forks, Emmaus,
  Northampton, East Stroudsburg, Quakertown, Perkasie, Wilson,
  Bedminster, Hellertown, Nazareth, Palmerton, Bangor, Birdsboro,
  Kutztown and Jim Thorpe.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4108 7503 4109 7497 4098 7514 4086 7505
      4085 7510 4080 7510 4075 7519 4068 7517
      4057 7519 4058 7512 4054 7507 4044 7507
      4017 7593 4020 7596 4054 7578 4069 7584
      4074 7576 4081 7587 4114 7508
TIME...MOT...LOC 0059Z 236DEG 42KT 4074 7574 4058 7571 4042 7579 4021
7590

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

Iovino
2 follow-up statements
025 
WWUS51 KPHI 200116
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
916 PM EDT SAT AUG 19 2017

PAC011-017-025-077-089-091-095-200200-
/O.CON.KPHI.SV.W.0177.000000T0000Z-170820T0200Z/
Berks PA-Montgomery PA-Lehigh PA-Carbon PA-Bucks PA-Monroe PA-
Northampton PA-
916 PM EDT SAT AUG 19 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1000 PM EDT
FOR EASTERN BERKS...NORTHWESTERN MONTGOMERY...LEHIGH...SOUTHEASTERN
CARBON...NORTHWESTERN BUCKS...SOUTHERN MONROE AND NORTHAMPTON
COUNTIES...

At 915 PM EDT, severe thunderstorms were located along a line
extending from Beltzville State Park to Coffeetown to Ancient Oaks to
near Birdsboro, moving northeast at 40 mph.

HAZARD...60 mph wind gusts. 

SOURCE...Radar indicated. 

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

Locations impacted include...
Allentown, Easton, Lehighton, Bethlehem, Pottstown, Forks, Emmaus,
Northampton, East Stroudsburg, Quakertown, Perkasie, Wilson,
Bedminster, Hellertown, Nazareth, Palmerton, Bangor, Birdsboro,
Kutztown and Jim Thorpe.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4108 7503 4109 7497 4098 7514 4086 7505
      4085 7510 4080 7510 4075 7519 4068 7517
      4057 7519 4058 7512 4054 7507 4044 7507
      4021 7582 4038 7587 4054 7578 4069 7584
      4074 7576 4081 7587 4114 7508
TIME...MOT...LOC 0115Z 236DEG 41KT 4087 7564 4065 7555 4051 7561 4030
7572

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

Iovino
388 
WWUS51 KPHI 200134
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
934 PM EDT SAT AUG 19 2017

PAC011-025-200143-
/O.CAN.KPHI.SV.W.0177.000000T0000Z-170820T0200Z/
Berks PA-Carbon PA-
934 PM EDT SAT AUG 19 2017

...THE SEVERE THUNDERSTORM WARNING FOR EASTERN BERKS AND SOUTHEASTERN
CARBON COUNTIES IS CANCELLED...

The storms which prompted the warning have moved out of Berks County 
and Carbon County. Therefore, the warning has been cancelled for 
those counties.

LAT...LON 4108 7503 4109 7497 4098 7514 4086 7505
      4085 7510 4080 7510 4075 7519 4068 7520
      4068 7517 4061 7520 4057 7518 4058 7512
      4054 7507 4044 7507 4028 7560 4044 7553
      4065 7549 4083 7548 4095 7550 4114 7508
TIME...MOT...LOC 0133Z 236DEG 42KT 4097 7544 4075 7535 4061 7541 4040
7553

$$

PAC017-077-089-091-095-200200-
/O.CON.KPHI.SV.W.0177.000000T0000Z-170820T0200Z/
Montgomery PA-Lehigh PA-Bucks PA-Monroe PA-Northampton PA-
934 PM EDT SAT AUG 19 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1000 PM EDT
FOR NORTHWESTERN MONTGOMERY...SOUTHEASTERN LEHIGH...NORTHWESTERN
BUCKS...SOUTHERN MONROE AND NORTHAMPTON COUNTIES...

At 933 PM EDT, severe thunderstorms were located along a line
extending from Sun Valley to near Nazareth to Lehigh University to
East Greenville, moving northeast at 40 mph.

HAZARD...60 mph wind gusts. 

SOURCE...Radar indicated. 

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

Locations impacted include...
Allentown, Easton, Bethlehem, Forks, Emmaus, Northampton, East
Stroudsburg, Quakertown, Perkasie, Wilson, Bedminster, Hellertown,
Nazareth, Bangor, Tinicum, Pen Argyl, East Greenville, Wind Gap, Bath
and Ferndale.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4108 7503 4109 7497 4098 7514 4086 7505
      4085 7510 4080 7510 4075 7519 4068 7520
      4068 7517 4061 7520 4057 7518 4058 7512
      4054 7507 4044 7507 4028 7560 4044 7553
      4065 7549 4083 7548 4095 7550 4114 7508
TIME...MOT...LOC 0133Z 236DEG 42KT 4097 7544 4075 7535 4061 7541 4040
7553

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

Iovino

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 19, 8:01 PM EDTSevere Thunderstorm WarningPHIBerks59 min
Aug 19, 8:34 PM EDTSpecial Weather StatementPHICarbon, Lehigh, Montgomery56 min
Aug 19, 9:29 PM EDTSpecial Weather StatementPHIMonroe31 min
Aug 19, 9:35 PM EDTSpecial Weather StatementPHIBucks, Delaware, Montgomery, Philadelphia25 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.