Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 194, NWS Philadelphia/Mount Holly

September 5, 2017Berks County, Chester County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Sep 5, 2017, 5:19 PM EDT for Berks County, Chester County, Montgomery County, Pennsylvania. It was in force for 56 min. 13 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: Sep 5, 2017, 5:19 PM EDT (21:19 UTC)
Expired: Sep 5, 2017, 6:15 PM EDT
In force: 56 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

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

The radar

The Philadelphia radar (KDIX), 127 km from the middle of the area, began a volume at 21:19 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.

What was reported inside it

Time	Report	Where	Remark
Sep 5, 5:28 PM EDT	TSTM WND DMG	West Lawn, PA	TREE DOWN ON HOUSE AT WOODSIDE AND NOBLE STREETS. ALSO... PEA-SIZE HAIL. TIME BASED ON RADAR.
Sep 5, 5:30 PM EDT	TSTM WND DMG	Sinking Spring, PA	TREE DOWN ON HOUSE AND PEA TO MARBLE SIZE HAIL REPORTED IN SINKING SPRING PA.
Sep 5, 5:30 PM EDT	HAIL 0.5	Sinking Spring, PA	PEA TO MARBLE SIZE HAIL REPORTED IN SINKING SPRING... PA... ALONG WITH A 50 MPH WIND GUST.
Sep 5, 5:38 PM EDT	TSTM WND DMG	Angelica, PA	TREES... POLES AND WIRES DOWN... CLOSING ROUTE 625 BETWEEN HICKORY ROAD AND CHURCH ROAD IN CUMRU TOWNSHIP. TIME ESTIMATED FROM RADAR.
Sep 5, 5:40 PM EDT	TSTM WND GST 60	1 Ne Reading, PA
Sep 5, 5:50 PM EDT	TSTM WND DMG	Amityville, PA	DOWNED TREES AND POWER LINES CLOSED A STRETCH OF ROUTE 662 IN AMITY TOWNSHIP. TIME ESTIMATED FROM RADAR.
Sep 5, 5:50 PM EDT	HAIL 0.75	West Wyomissing, PA	PENNY SIZE HAIL ALONG WITH HEAVY RAIN AND GUSTY WINDS.
Sep 5, 5:54 PM EDT	TSTM WND DMG	3 Ne Cedarville, PA	LARGE TREE LIMBS DOWN AND SHINGLES BLOWN OFF SOME HOUSES IN THE POTTSTOWN AREA.
Sep 5, 5:54 PM EDT	TSTM WND DMG	Pottstown, PA	TWO POLES AND ALSO TREES DOWN BLOCKING SOME ROADWAYS.
Sep 5, 5:54 PM EDT	HAIL 0.75	Pottstown, PA	PENNY SIZE HAIL REPORTED.
Sep 5, 5:54 PM EDT	HAIL 1	Pottstown, PA	QUARTER SIZED HAIL ALONG WITH LARGE BRANCHES AND SHINGLES BLOWN OFF ROOF.
Sep 5, 5:56 PM EDT	TSTM WND DMG	Hereford, PA	DOWNED TREES BLOCKING ROUTE 100 NEAR CHESTNUT STREET IN HEREFORD TOWNSHIP.
Sep 5, 6:04 PM EDT	TSTM WND DMG	2 W Green Lane, PA	TREES AND POWER LINES DOWN NEAR BECKER AND WOODLAND ROADS IN UPPER FREDERICK TOWNSHIP.

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.

Issued	Product	Office	Lasted
Sep 5, 3:26 PM EDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 9.3 hours before the alert went out and 177 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 4 J/kg
Mixed-layer CIN: -324 J/kg
Mixed-layer LCL: 1529 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 8 m²/s²
0-3 km storm-relative helicity: 79 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

748 
WUUS51 KPHI 052119
SVRPHI
PAC011-029-091-052215-
/O.NEW.KPHI.SV.W.0194.170905T2119Z-170905T2215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
519 PM EDT TUE SEP 5 2017

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Berks County in eastern Pennsylvania...
  Western Montgomery County in southeastern Pennsylvania...
  Chester County in southeastern Pennsylvania...

* Until 615 PM EDT

* At 518 PM EDT, severe thunderstorms were located along a line
  extending from near Womelsdorf to Leola to Sunnyburn, moving east
  at 40 mph.

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

  SOURCE...Radar and spotter indicated. This storm has a history of 
           producing large hail and damaging winds over York and 
           Lancaster Counties in southern Pennsylvania.

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

* Severe thunderstorms will be near,
  Sinking Spring, Wernersville and Robesonia around 525 PM EDT. 
  Reading, Wyomissing, Leesport, Spring Ridge and Fairview Hgts 
  around 530 PM EDT. 
  Laureldale and Honey Brook around 535 PM EDT. 
  Birdsboro, Fleetwood, Elverson, New Morgan, Mount Vernon and Glen 
  Roy around 540 PM EDT. 
  Oxford, Lyons, Homeville and Glenmoore around 545 PM EDT. 
  Cochranville around 550 PM EDT. 
  Pottstown, West Grove, Bally, Bechtelsville, Pughtown, 
  Gilbertsville, Chester Springs, Cedarville, Lionville-Marchwood 
  and Lionville around 555 PM EDT. 
  Royersford and East Greenville around 600 PM EDT. 

Other locations impacted by these severe thunderstorms include
Harleysville, West Lawn, Boyertown, West Reading, Modena, Pottsgrove,
Lorane, Kenhorst, South Pottstown and Thorndale.

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 4039 7625 4053 7565 4032 7532 4016 7530
      3985 7562 3976 7584 3974 7610 3976 7606
      3983 7604 3983 7602 3987 7599 3994 7598
      3995 7600 4004 7593 4011 7594 4014 7588
TIME...MOT...LOC 2118Z 262DEG 41KT 4034 7615 4009 7619 3980 7637 

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

JRK

2 follow-up statements

280 
WWUS51 KPHI 052135
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
535 PM EDT TUE SEP 5 2017

PAC011-029-091-052215-
/O.CON.KPHI.SV.W.0194.000000T0000Z-170905T2215Z/
Berks PA-Montgomery PA-Chester PA-
535 PM EDT TUE SEP 5 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 615 PM EDT
FOR SOUTHEASTERN BERKS...WESTERN MONTGOMERY AND CHESTER COUNTIES...

At 534 PM EDT, severe thunderstorms were located along a line
extending from near Laureldale to Churchtown to near Quarryville,
moving east at 40 mph.

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

SOURCE...Radar indicated. This storm has a history of producing 
         large hail and damaging winds over York and Lancaster 
         Counties in southern Pennsylvania.

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

These severe storms will be near...
  Reading, Wyomissing, Laureldale, Leesport, Honey Brook, New 
  Morgan, Spring Ridge and Fairview Hgts around 540 PM EDT. 
  Fleetwood and Elverson around 545 PM EDT. 
  Birdsboro, Lyons and Glenmoore around 550 PM EDT. 
  Parkesburg, Topton, Bechtelsville, Cochranville and Gilbertsville 
  around 555 PM EDT. 
  Pottstown, Coatesville, West Grove, Bally, Pughtown, Cedarville 
  and Chester Springs around 600 PM EDT. 
  Phoenixville, Kennett Square, Royersford and East Greenville 
  around 605 PM EDT. 
  Downingtown, Trappe, Marshallton, Geryville and Valley Forge 
  around 610 PM EDT. 
  West Chester, Norristown, West Norriton, East Norriton, Westtown, 
  Collegeville, Schwenksville and Spring Mount around 615 PM EDT. 

Other locations impacted by these severe thunderstorms include
Harleysville, West Lawn, Boyertown, West Reading, Modena, Pottsgrove,
Lorane, Kenhorst, South Pottstown and Thorndale.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain alert for a possible tornado! Tornadoes can develop quickly
from severe thunderstorms. If you spot a tornado go at once into the
basement or small central room in a sturdy structure.

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 3979 7577 3976 7607 3977 7606 3983 7604
      3983 7602 3987 7599 3994 7598 3995 7600
      4004 7593 4011 7594 4014 7588 4033 7615
      4041 7615 4053 7565 4032 7532 4016 7530
      3985 7562
TIME...MOT...LOC 2134Z 258DEG 39KT 4038 7595 4013 7599 3984 7617 

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

JRK

299 
WWUS51 KPHI 052213
SVSPHI

Severe Weather Statement
National Weather Service MOUNT HOLLY NJ
613 PM EDT TUE SEP 5 2017

PAC011-029-091-052220-
/O.EXP.KPHI.SV.W.0194.000000T0000Z-170905T2215Z/
Berks PA-Montgomery PA-Chester PA-
613 PM EDT TUE SEP 5 2017

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN BERKS...CENTRAL 
MONTGOMERY AND CHESTER COUNTIES WILL EXPIRE AT 615 PM EDT...
            
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore the warning will be allowed to expire.

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

Remember, a Severe Thunderstorm Warning still remains in effect for 
parts of eastern Berks County and northern Montgomery County until 
630 PM EDT.

LAT...LON 3979 7577 3976 7607 3977 7606 3983 7604
      3983 7602 3987 7599 3994 7598 3995 7600
      4004 7593 4011 7594 4014 7588 4033 7615
      4041 7615 4053 7565 4032 7532 4016 7530
      3985 7562
TIME...MOT...LOC 2210Z 262DEG 41KT 4043 7543 4018 7547 3990 7565 

$$

amc

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 5, 3:59 PM EDT	Special Weather Statement	PHI	Berks, Lehigh	31 min
Sep 5, 4:08 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Carbon, Lehigh, Northampton	52 min
Sep 5, 4:34 PM EDT	Areal Flood Advisory	PHI	Berks	6 hr
Sep 5, 4:54 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Carbon, Lehigh, Monroe, Northampton	51 min
Sep 5, 5:14 PM EDT	Flash Flood Warning	PHI	Berks	4 hr
Sep 5, 5:22 PM EDT	Areal Flood Advisory	PHI	Northampton	4 hr
Sep 5, 5:30 PM EDT	Flash Flood Warning	PHI	Berks	4 hr
Sep 5, 5:49 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Lehigh, Montgomery, Northampton	41 min
Sep 5, 6:03 PM EDT	Areal Flood Advisory	PHI	Lehigh, Northampton	3 hr
Sep 5, 6:19 PM EDT	Special Weather Statement	PHI	Chester, Delaware	41 min
Sep 5, 6:26 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Lehigh, Northampton	49 min
Sep 5, 6:44 PM EDT	Special Weather Statement	PHI	Bucks	31 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2017 Every 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.