Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 70, NWS Philadelphia/Mount Holly

June 23, 20174 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 23, 2017, 5:33 PM EDT for 4 counties in Pennsylvania. It was in force for 57 min. 2 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: Jun 23, 2017, 5:33 PM EDT (21:33 UTC)
Expired: Jun 23, 2017, 6:30 PM EDT
In force: 57 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, Chester County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 130 km from the middle of the area, began a volume at 21:33 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
Jun 23, 5:34 PM EDT	TSTM WND DMG	Wyomissing, PA	TREE DOWN ON WELLINGTON ROAD.
Jun 23, 5:58 PM EDT	TSTM WND DMG	Union Twp, PA	A TREE BLOCKED TRAFFIC ON A LOCAL 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.

Issued	Product	Office	Lasted
Jun 23, 5:09 PM EDT	Severe Thunderstorm Watch	SPC	4 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 9.6 hours before the alert went out and 196 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: 83 J/kg
Mixed-layer CIN: -143 J/kg
Mixed-layer LCL: 649 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: 271 m²/s²
0-3 km storm-relative helicity: 349 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

563 
WUUS51 KPHI 232133
SVRPHI
PAC011-017-029-091-232230-
/O.NEW.KPHI.SV.W.0070.170623T2133Z-170623T2230Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
533 PM EDT FRI JUN 23 2017

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Southeastern Berks County in eastern Pennsylvania...
  Montgomery County in southeastern Pennsylvania...
  West central Bucks County in southeastern Pennsylvania...
  Northeastern Chester County in southeastern Pennsylvania...

* Until 630 PM EDT

* At 533 PM EDT, a severe thunderstorm was located over Adamstown, 
  or near Ephrata, moving east at 40 mph. 

  HAZARD...60 mph wind gusts. 

  SOURCE...Radar indicated. 

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

* Locations impacted include...
  Reading, Norristown, Pottstown, Phoenixville, Lansdale, West
  Norriton, East Norriton, Wyomissing, Perkasie, Souderton,
  Birdsboro, Collegeville, Royersford, Sinking Spring, Trappe,
  Hatfield, East Greenville, Wernersville, Robesonia and
  Schwenksville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In addition to 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 4035 7617 4043 7531 4011 7528 4012 7592
      4014 7588 4031 7614 4034 7617
TIME...MOT...LOC 2133Z 267DEG 36KT 4022 7606 

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

Meola

1 follow-up statement

523 
WWUS51 KPHI 232214
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
614 PM EDT FRI JUN 23 2017

PAC029-232223-
/O.CAN.KPHI.SV.W.0070.000000T0000Z-170623T2230Z/
Chester PA-
614 PM EDT FRI JUN 23 2017

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN CHESTER COUNTY IS
CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

A severe thunderstorm watch remains in effect until 1000 PM EDT for
eastern and southeastern Pennsylvania.

LAT...LON 4030 7590 4038 7585 4043 7531 4023 7529
      4020 7555 4021 7556 4020 7558 4024 7560
      4022 7561 4024 7568 4023 7571 4017 7582
      4016 7590
TIME...MOT...LOC 2213Z 267DEG 36KT 4024 7553 

$$

PAC011-017-091-232230-
/O.CON.KPHI.SV.W.0070.000000T0000Z-170623T2230Z/
Berks PA-Montgomery PA-Bucks PA-
614 PM EDT FRI JUN 23 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 630 PM EDT
FOR SOUTHEASTERN BERKS...NORTHWESTERN MONTGOMERY AND WEST CENTRAL
BUCKS COUNTIES...

At 613 PM EDT, a severe thunderstorm was located near Schwenksville,
or 19 miles north of West Chester, moving east at 40 mph.

HAZARD...60 mph wind gusts. 

SOURCE...Radar indicated. 

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

Locations impacted include...
Pottstown, Lansdale, Perkasie, Souderton, Birdsboro, Trappe,
Hatfield, East Greenville, Schwenksville, Bally, Bechtelsville, Green
Lane, New Morgan, Spring Mount, Gilbertsville, Geryville, Skippack,
Stowe, Telford and Sellersville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4030 7590 4038 7585 4043 7531 4023 7529
      4020 7555 4021 7556 4020 7558 4024 7560
      4022 7561 4024 7568 4023 7571 4017 7582
      4016 7590
TIME...MOT...LOC 2213Z 267DEG 36KT 4024 7553 

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

Meola

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 23, 4:53 PM EDT	Special Weather Statement	PHI	Berks	52 min
Jun 23, 5:15 PM EDT	Areal Flood Advisory	PHI	Berks, Carbon, Lehigh, Northampton	4 hr
Jun 23, 5:21 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Lehigh, Montgomery	54 min
Jun 23, 6:10 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Lehigh, Montgomery	50 min
Jun 23, 6:57 PM EDT	Special Weather Statement	PHI	Bucks	33 min
Jun 23, 6:58 PM EDT	Areal Flood Advisory	PHI	Bucks, Lehigh, Northampton	4 hr
Jun 23, 7:30 PM EDT	Areal Flood Advisory	PHI	Bucks, Montgomery	4 hr
Jun 23, 7:46 PM EDT	Special Weather Statement	PHI	Berks, Carbon, Lehigh, Northampton	59 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.