Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 71, NWS Philadelphia/Mount Holly

June 23, 20174 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 23, 2017, 6:10 PM EDT for 4 counties in Pennsylvania. It was in force for 50 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, 6:10 PM EDT (22:10 UTC)
Expired: Jun 23, 2017, 7:00 PM EDT
In force: 50 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, Lehigh County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 97 km from the middle of the area, began a volume at 22:11 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, 6:16 PM EDT	TSTM WND DMG	Springfield Twp, PA	TREES AND WIRES REPORTED DOWN
Jun 23, 6:41 PM EDT	TSTM WND DMG	Hilltown Twp, PA	TREES AND WIRES REPORTED DOWN.

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

Brookhaven, NY (KOKX), launched 12:00Z, 10.2 hours before the alert went out and 219 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: 688 J/kg
Mixed-layer CIN: -89 J/kg
Mixed-layer LCL: 1159 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 83 m²/s²
0-3 km storm-relative helicity: 100 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.6

Open this sounding in Storm Lab

The text

As transmitted.

671 
WUUS51 KPHI 232210
SVRPHI
PAC011-017-077-091-232300-
/O.NEW.KPHI.SV.W.0071.170623T2210Z-170623T2300Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
610 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...
  Northwestern Montgomery County in southeastern Pennsylvania...
  Southeastern Lehigh County in eastern Pennsylvania...
  Bucks County in southeastern Pennsylvania...

* Until 700 PM EDT

* At 609 PM EDT, a severe thunderstorm was located over Bally, or 15 
  miles south of Allentown, moving east at 40 mph. Some rotation has 
  been indicated by radar inside this storm. While not likely, a 
  tornado is possible.

  HAZARD...60 mph wind gusts. 

  SOURCE...Radar indicated. 

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

* Locations impacted include...
  Pottstown, Lansdale, Emmaus, Quakertown, Perkasie, Doylestown,
  Souderton, Bedminster, Chalfont, Tinicum, Hatfield, East
  Greenville, Dublin, Ferndale, Schwenksville, Bally, Bechtelsville,
  Green Lane, Pleasant Valley and Fricks.

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 4053 7566 4056 7536 4054 7533 4056 7530
      4058 7512 4055 7508 4041 7506 4040 7501
      4025 7495 4023 7559 4024 7561 4023 7562
      4024 7568 4022 7576
TIME...MOT...LOC 2209Z 262DEG 35KT 4037 7556 

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

Meola

1 follow-up statement

744 
WWUS51 KPHI 232231
SVSPHI

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

PAC011-077-232240-
/O.CAN.KPHI.SV.W.0071.000000T0000Z-170623T2300Z/
Berks PA-Lehigh PA-
631 PM EDT FRI JUN 23 2017

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN BERKS AND
SOUTHEASTERN LEHIGH COUNTIES 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
northwestern New Jersey...and southeastern Pennsylvania.

LAT...LON 4028 7558 4046 7543 4048 7507 4041 7506
      4040 7501 4025 7495 4023 7556
TIME...MOT...LOC 2230Z 266DEG 39KT 4035 7531 

$$

PAC017-091-232300-
/O.CON.KPHI.SV.W.0071.000000T0000Z-170623T2300Z/
Montgomery PA-Bucks PA-
631 PM EDT FRI JUN 23 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 700 PM EDT
FOR NORTHWESTERN MONTGOMERY AND CENTRAL BUCKS COUNTIES...

At 630 PM EDT, a severe thunderstorm was located over Perkasie, or 19
miles southeast of Allentown, moving east at 45 mph.

HAZARD...60 mph wind gusts. 

SOURCE...Radar indicated. 

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

Locations impacted include...
Lansdale, Quakertown, Perkasie, Doylestown, Souderton, Bedminster,
Chalfont, Tinicum, Hatfield, Dublin, Schwenksville, Green Lane,
Fricks, Spring Mount, Ottsville, Pipersville, Gardenville,
Lumberville, Richboro and Skippack.

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 4028 7558 4046 7543 4048 7507 4041 7506
      4040 7501 4025 7495 4023 7556
TIME...MOT...LOC 2230Z 266DEG 39KT 4035 7531 

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, 5:33 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Chester, Montgomery	57 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.