Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 42, NWS Philadelphia/Mount Holly

June 19, 2017Berks County, Chester County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 19, 2017, 3:08 PM EDT for Berks County, Chester County, Montgomery County, Pennsylvania. It was in force for 52 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
Jun 19, 2017, 3:08 PM EDT (19:08 UTC)
Expired
Jun 19, 2017, 4:00 PM EDT
In force
52 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Berks County, PA, Chester County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 112 km from the middle of the area, began a volume at 19:10 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
Jun 19, 3:39 PM EDTTSTM WND DMG1 Wnw Perkiomenville, PATWO FT DIAMETER TREES AND WIRES DOWN ON SNYDER AND HAUCK ROAD

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

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jun 19, 11:13 AM EDTSevere Thunderstorm WatchSPC9 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 7.1 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, Washington/Dulle, VA at 12:00Z on 2017-06-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 448 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 2017-06-19The 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
448 J/kg
Mixed-layer CIN
-97 J/kg
Mixed-layer LCL
1049 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
73 m²/s²
0-3 km storm-relative helicity
82 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

As transmitted.

176 
WUUS51 KPHI 191908
SVRPHI
PAC011-029-091-192000-
/O.NEW.KPHI.SV.W.0042.170619T1908Z-170619T2000Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
308 PM EDT MON JUN 19 2017

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Southeastern Berks County in eastern Pennsylvania...
  Northwestern Montgomery County in southeastern Pennsylvania...
  North central Chester County in southeastern Pennsylvania...

* Until 400 PM EDT

* At 307 PM EDT, severe thunderstorms were located along a line
  extending from near Reading to near New Morgan, moving east at 40
  mph.

  HAZARD...60 mph wind gusts. 

  SOURCE...Radar indicated. 

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

* Severe thunderstorms will be near,
  Birdsboro around 315 PM EDT. 
  Pottstown and Pughtown around 325 PM EDT. 
  Gilbertsville and Cedarville around 330 PM EDT. 
  Phoenixville and Royersford around 335 PM EDT. 
  Collegeville, Trappe, Schwenksville, Green Lane and Spring Mount 
  around 345 PM EDT. 
  East Norriton around 355 PM EDT. 

Other locations impacted by these severe thunderstorms include
Harleysville, Boyertown, Pottsgrove, Lorane, South Pottstown,
Evansburg, Amity Gardens, Spring City, Stowe and Sanatoga.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4038 7542 4036 7538 4017 7535 4011 7593
      4014 7588 4018 7594 4027 7598
TIME...MOT...LOC 1907Z 253DEG 34KT 4028 7589 4014 7589 

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

Drag
2 follow-up statements
260 
WWUS51 KPHI 191925
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
325 PM EDT MON JUN 19 2017

PAC011-029-091-192000-
/O.CON.KPHI.SV.W.0042.000000T0000Z-170619T2000Z/
Berks PA-Montgomery PA-Chester PA-
325 PM EDT MON JUN 19 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 400 PM EDT
FOR SOUTHEASTERN BERKS...NORTHWESTERN MONTGOMERY AND NORTHEASTERN
CHESTER COUNTIES...

At 324 PM EDT, severe thunderstorms were located along a line
extending from near Gilbertsville to near Pughtown, moving east at 40
mph.

HAZARD...60 mph wind gusts. 

SOURCE...Radar indicated. 

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

These severe storms will be near...
  Gilbertsville around 330 PM EDT. 
  Royersford and Green Lane around 340 PM EDT. 
  Collegeville, Trappe and Schwenksville around 345 PM EDT. 
  Spring Mount around 350 PM EDT. 
  East Norriton around 355 PM EDT. 

Other locations impacted by these severe thunderstorms include
Harleysville, Boyertown, Pottsgrove, South Pottstown, Evansburg,
Spring City, Stowe, Sanatoga, Kenilworth and Halfway House.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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.

&&

LAT...LON 4038 7542 4036 7538 4017 7535 4017 7572
      4019 7576 4021 7578 4033 7569
TIME...MOT...LOC 1924Z 255DEG 34KT 4033 7565 4018 7572 

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

Drag
724 
WWUS51 KPHI 191938 RRA
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
338 PM EDT MON JUN 19 2017

PAC011-029-191948-
/O.CAN.KPHI.SV.W.0042.000000T0000Z-170619T2000Z/
Berks PA-Chester PA-
338 PM EDT MON JUN 19 2017

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN BERKS AND
NORTHEASTERN CHESTER COUNTIES IS CANCELLED...

The storms which prompted the warning have moved out of the warned 
area. Therefore, the warning has been cancelled.

A severe thunderstorm watch remains in effect until 800 PM EDT for
southeastern Pennsylvania.

LAT...LON 4029 7556 4036 7555 4038 7542 4035 7538
      4017 7535 4018 7555 4021 7556 4020 7556
      4020 7558 4023 7559
TIME...MOT...LOC 1938Z 253DEG 34KT 4037 7549 4022 7556 

$$

PAC091-192000-
/O.CON.KPHI.SV.W.0042.000000T0000Z-170619T2000Z/
Montgomery PA-
338 PM EDT MON JUN 19 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 400 PM EDT
FOR NORTHWESTERN MONTGOMERY COUNTY...

At 338 PM EDT, severe thunderstorms were located along a line
extending from near Green Lane to near Royersford, moving east at 40
mph.

HAZARD...60 mph wind gusts. 

SOURCE...Radar indicated. 

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

These severe storms will be near...
  East Norriton around 355 PM EDT. 

Other locations impacted by these severe thunderstorms include
Harleysville, Evansburg, Skippack, Spring City, Red Hill and
Sanatoga.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4029 7556 4036 7555 4038 7542 4035 7538
      4017 7535 4018 7555 4021 7556 4020 7556
      4020 7558 4023 7559
TIME...MOT...LOC 1938Z 253DEG 34KT 4037 7549 4022 7556 

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

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 19, 12:24 PM EDTSpecial Weather StatementPHIMonroe21 min
Jun 19, 12:44 PM EDTSpecial Weather StatementPHICarbon31 min
Jun 19, 12:46 PM EDTSpecial Weather StatementPHIBerks29 min
Jun 19, 12:55 PM EDTSevere Thunderstorm WarningPHICarbon, Monroe50 min
Jun 19, 1:25 PM EDTSpecial Weather StatementPHILehigh35 min
Jun 19, 1:29 PM EDTAreal Flood AdvisoryPHIBerks, Carbon, Lehigh, Monroe, Northampton4 hr
Jun 19, 1:42 PM EDTSpecial Weather StatementPHIBerks63 min
Jun 19, 2:08 PM EDTSevere Thunderstorm WarningPHIBerks52 min
Jun 19, 2:20 PM EDTSpecial Weather StatementPHINorthampton40 min
Jun 19, 2:25 PM EDTSpecial Weather StatementPHIBerks50 min
Jun 19, 2:38 PM EDTSpecial Weather StatementPHIPhiladelphia22 min
Jun 19, 2:43 PM EDTSpecial Weather StatementPHIBerks, Lehigh, Northampton47 min
Jun 19, 2:49 PM EDTSevere Thunderstorm WarningPHIBerks, Lehigh, Montgomery, Northampton41 min
Jun 19, 2:53 PM EDTSevere Thunderstorm WarningPHICarbon, Monroe52 min
Jun 19, 2:57 PM EDTSevere Thunderstorm WarningPHIMonroe, Northampton48 min
Jun 19, 3:17 PM EDTFlash Flood WarningPHIMonroe3 hr
Jun 19, 3:24 PM EDTFlash Flood WarningPHICarbon, Lehigh, Monroe, Northampton3 hr
Jun 19, 3:25 PM EDTSpecial Weather StatementPHIChester50 min
Jun 19, 3:35 PM EDTAreal Flood AdvisoryPHIBerks, Bucks, Chester, Delaware, Montgomery, Philadelphia3 hr
Jun 19, 3:35 PM EDTSevere Thunderstorm WarningPHILehigh, Monroe, Northampton25 min
Jun 19, 3:53 PM EDTSevere Thunderstorm WarningPHIMonroe, Northampton37 min
Jun 19, 3:56 PM EDTSevere Thunderstorm WarningPHIBucks, Northampton49 min
Jun 19, 4:07 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Montgomery38 min
Jun 19, 4:07 PM EDTSevere Thunderstorm WarningPHIDelaware38 min
Jun 19, 4:34 PM EDTSevere Thunderstorm WarningPHIBucks, Chester, Delaware, Montgomery, Philadelphia41 min
Jun 19, 5:09 PM EDTSevere Thunderstorm WarningPHIBucks, Philadelphia51 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.