Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 185, NWS Philadelphia/Mount Holly

August 22, 2017Berks County, Chester County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 22, 2017, 9:23 PM EDT for Berks County, Chester County, Montgomery County, Pennsylvania. It was in force for 52 min. 6 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 22, 2017, 9:23 PM EDT (01:23 UTC)
Expired: Aug 22, 2017, 10:15 PM EDT
In force: 52 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Tornado: Possible
Hail: 1.0 in
Wind: 60.0 mph

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

The radar

The Philadelphia radar (KDIX), 121 km from the middle of the area, began a volume at 01:24 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
Aug 22, 9:32 PM EDT	TSTM WND DMG	1 S Reading, PA	A TREE FELL ONTO A PROPANE TANK.
Aug 22, 9:32 PM EDT	TSTM WND GST 60	Exeter Twp, PA
Aug 22, 9:45 PM EDT	TSTM WND DMG	2 Ene Brecknock Twp, PA	ROOF BLOWN OFF A BUILDING AT THE GREEN HILLS AUCTION CENTER ON ROUTE 568 IN BRECKNOCK TOWNSHIP. SOME OTHER BUILDINGS IN THE AREA HAD SOME DAMAGE AND TREES WERE BLOWN OVER. TIME ESTIMATED FROM RADAR.
Aug 22, 9:47 PM EDT	TSTM WND DMG	1 Nnw Beckersville, PA	TREE AND WIRES DOWN ON KURTZ MILL ROAD IN ROBESON TWP. TIME ESTIMATED BY RADAR.
Aug 22, 9:58 PM EDT	TSTM WND DMG	1 W Halfway House, PA	TREE BLOWN DOWN ON LEVENGOOD ROAD NEAR THE BERKS/MONTGOMERY COUNTY LINE. TIME ESTIMATED BY RADAR.
Aug 22, 10:15 PM EDT	HAIL 0.88	Cedarville, PA

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
Aug 22, 4:19 PM EDT	Severe Thunderstorm Watch	SPC	8 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 1.4 hours before the alert went out and 205 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: 550 J/kg
Mixed-layer CIN: -36 J/kg
Mixed-layer LCL: 1559 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 134 m²/s²
0-3 km storm-relative helicity: 248 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 2.1

Open this sounding in Storm Lab

The text

As transmitted.

863 
WUUS51 KPHI 230123
SVRPHI
PAC011-029-091-230215-
/O.NEW.KPHI.SV.W.0185.170823T0123Z-170823T0215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
923 PM EDT TUE AUG 22 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...
  Northeastern Chester County in southeastern Pennsylvania...

* Until 1015 PM EDT

* At 922 PM EDT, a severe thunderstorm was located over Adamstown, or
  7 miles southwest of Reading, moving east at 40 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...
  Reading, Pottstown, Phoenixville, West Norriton, Wyomissing,
  Birdsboro, Collegeville, Royersford, Sinking Spring, Laureldale,
  Trappe, East Greenville, Wernersville, Leesport, Honey Brook,
  Schwenksville, Elverson, Bally, Bernville and Bechtelsville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4046 7610 4041 7546 4038 7541 4036 7539
      4002 7542 4010 7594 4014 7588 4031 7614
TIME...MOT...LOC 0122Z 270DEG 34KT 4028 7606 

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

MWG

1 follow-up statement

323 
WWUS51 KPHI 230158
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
958 PM EDT TUE AUG 22 2017

PAC011-029-091-230215-
/O.CON.KPHI.SV.W.0185.000000T0000Z-170823T0215Z/
Berks PA-Montgomery PA-Chester PA-
958 PM EDT TUE AUG 22 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1015 PM EDT
FOR SOUTHEASTERN BERKS...NORTHWESTERN MONTGOMERY AND NORTHEASTERN
CHESTER COUNTIES...

At 958 PM EDT, a severe thunderstorm was located over Pottstown, or
16 miles east of Reading, moving east at 40 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...
Pottstown, Phoenixville, West Norriton, Birdsboro, Collegeville,
Royersford, Trappe, East Greenville, Honey Brook, Schwenksville,
Elverson, Bally, Bechtelsville, Green Lane, New Morgan, Pughtown,
Spring Mount, Gilbertsville, Valley Forge and Glenmoore.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4041 7546 4038 7541 4036 7539 4002 7542
      4010 7594 4014 7588 4022 7601 4043 7571
TIME...MOT...LOC 0158Z 270DEG 34KT 4028 7561 

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

MWG

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 22, 8:12 PM EDT	Severe Thunderstorm Warning	PHI	Monroe, Northampton	48 min
Aug 22, 8:15 PM EDT	Tornado Warning	PHI	Monroe, Northampton	30 min
Aug 22, 8:45 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Carbon, Chester, Lehigh, Monroe and 2 more	60 min
Aug 22, 8:58 PM EDT	Severe Thunderstorm Warning	PHI	Monroe, Northampton	24 min
Aug 22, 9:18 PM EDT	Areal Flood Advisory	PHI	Berks, Montgomery	4 hr
Aug 22, 9:40 PM EDT	Tornado Warning	PHI	Berks, Chester, Montgomery	20 min
Aug 22, 9:42 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery	48 min
Aug 22, 10:07 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Chester, Delaware, Montgomery, Philadelphia	53 min
Aug 22, 10:27 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery	48 min
Aug 22, 10:37 PM EDT	Areal Flood Advisory	PHI	Berks, Bucks, Lehigh, Montgomery, Northampton	4 hr
Aug 22, 10:40 PM EDT	Areal Flood Advisory	PHI	Berks, Bucks, Chester, Delaware, Montgomery, Philadelphia	4 hr
Aug 22, 10:58 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	62 min
Aug 22, 11:46 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	44 min
Aug 23, 12:06 AM EDT	Flash Flood Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	4 hr
Aug 23, 12:29 AM EDT	Severe Thunderstorm Warning	PHI	Philadelphia	46 min
Aug 23, 4:02 AM EDT	Areal Flood Warning	PHI	Chester, Delaware, Philadelphia	4 hr

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.