Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2019

Severe Thunderstorm Warning 309, NWS Philadelphia/Mount Holly

August 6, 2019Montgomery County, Philadelphia County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 6, 2019, 12:36 PM EDT for Montgomery County, Philadelphia County, Pennsylvania. It was in force for 39 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: Aug 6, 2019, 12:36 PM EDT (16:36 UTC)
Expired: Aug 6, 2019, 1:15 PM EDT
In force: 39 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 71 km from the middle of the area, began a volume at 16:38 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 6, 12:36 PM EDT	TSTM WND DMG	1 Ssw Flourtown, PA	DOWNED WIRES NEAR MONTGOMERY AVENUE AND BETHLEHEM PIKE. TIME ESTIMATED FROM RADAR.
Aug 6, 12:49 PM EDT	TSTM WND DMG	2 Ne Plymouth Meeting, PA	DOWNED TREE INTO WIRES NEAR WHERE STENTON AVE PASSES UNDER THE PENNSYLVANIA TURNPIKE. TIME ESTIMATED FROM RADAR.

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

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 4.6 hours before the alert went out and 217 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: 57 J/kg
Mixed-layer CIN: -73 J/kg
Mixed-layer LCL: 1078 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: -3 m²/s²
0-3 km storm-relative helicity: 18 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

Open this sounding in Storm Lab

The text

As transmitted.

896 
WUUS51 KPHI 061636
SVRPHI
PAC091-101-061715-
/O.NEW.KPHI.SV.W.0309.190806T1636Z-190806T1715Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
1236 PM EDT Tue Aug 6 2019

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Southeastern Montgomery County in southeastern Pennsylvania...
  Northwestern Philadelphia County in southeastern Pennsylvania...

* Until 115 PM EDT.

* At 1235 PM EDT, a severe thunderstorm was located over Chestnut
  Hill, or near Philadelphia, moving northeast at 5 mph.

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

  SOURCE...Radar indicated.

  IMPACT...Minor damage to vehicles is possible. Wind damage to 
           roofs, siding, trees, and power lines is possible.

* Locations impacted include...
  Philadelphia, Conshohocken, Ambler, Jenkintown, Rockledge,
  Abington, Willow Grove, Plymouth Meeting, Germantown, Chestnut
  Hill, Horsham, West Conshohocken, Fort Washington, Blue Bell, Maple
  Glen, Glenside, Flourtown, Spring House, Oreland and Wyndmoor.

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 4000 7523 4006 7532 4020 7528 4025 7520
      4010 7506
TIME...MOT...LOC 1635Z 240DEG 5KT 4008 7523 

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

Staarmann

2 follow-up statements

882 
WWUS51 KPHI 061657
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
1257 PM EDT Tue Aug 6 2019

PAC101-061706-
/O.CAN.KPHI.SV.W.0309.000000T0000Z-190806T1715Z/
Philadelphia PA-
1257 PM EDT Tue Aug 6 2019

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

LAT...LON 4009 7508 4006 7513 4007 7514 4011 7522
      4020 7528 4025 7520 4010 7506
TIME...MOT...LOC 1656Z 239DEG 4KT 4017 7519 

$$

PAC091-061715-
/O.CON.KPHI.SV.W.0309.000000T0000Z-190806T1715Z/
Montgomery PA-
1257 PM EDT Tue Aug 6 2019

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 115 PM EDT
FOR EAST CENTRAL MONTGOMERY COUNTY...

At 1256 PM EDT, a severe thunderstorm was located over Ambler, or 11
miles north of Philadelphia, and is nearly stationary.

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

SOURCE...Radar indicated.

IMPACT...Minor damage to vehicles is possible. Wind damage to roofs, 
         siding, trees, and power lines is possible.

Locations impacted include...
Ambler, Jenkintown, Rockledge, Abington, Willow Grove, Horsham, Fort
Washington, Maple Glen, Glenside, Spring House, Oreland, Wyncote,
Flourtown, Blue Bell and Montgomeryville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

&&

LAT...LON 4009 7508 4006 7513 4007 7514 4011 7522
      4020 7528 4025 7520 4010 7506
TIME...MOT...LOC 1656Z 239DEG 4KT 4017 7519 

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

Staarmann

585 
WWUS51 KPHI 061706
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
106 PM EDT Tue Aug 6 2019

PAC091-061716-
/O.EXP.KPHI.SV.W.0309.000000T0000Z-190806T1715Z/
Montgomery PA-
106 PM EDT Tue Aug 6 2019

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL MONTGOMERY COUNTY
WILL EXPIRE AT 115 PM EDT...
        
The storm which prompted the warning has weakened below severe 
limits, and is moving out of the warned area. Therefore, the warning 
will be allowed to expire.  However small hail, gusty winds, and 
heavy rain are still possible with this thunderstorm.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Mount Holly NJ.

LAT...LON 4009 7508 4006 7513 4007 7514 4011 7522
      4020 7528 4025 7520 4010 7506
TIME...MOT...LOC 1706Z 240DEG 5KT 4018 7518 

$$

Staarmann

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 6, 11:46 AM EDT	Special Weather Statement	PHI	Philadelphia	29 min
Aug 6, 12:13 PM EDT	Special Weather Statement	PHI	Philadelphia	47 min
Aug 6, 12:21 PM EDT	Areal Flood Advisory	PHI	Montgomery, Philadelphia	102 min
Aug 6, 1:18 PM EDT	Special Weather Statement	PHI	Bucks	27 min
Aug 6, 2:35 PM EDT	Special Weather Statement	PHI	Monroe	25 min
Aug 6, 3:05 PM EDT	Special Weather Statement	PHI	Monroe	25 min
Aug 6, 4:40 PM EDT	Special Weather Statement	PHI	Carbon	35 min
Aug 6, 5:51 PM EDT	Special Weather Statement	PHI	Monroe	39 min
Aug 6, 6:32 PM EDT	Special Weather Statement	PHI	Monroe	28 min
Aug 6, 6:38 PM EDT	Special Weather Statement	PHI	Carbon	37 min
Aug 6, 6:57 PM EDT	Flash Flood Warning	PHI	Monroe	104 min
Aug 6, 7:10 PM EDT	Special Weather Statement	PHI	Northampton	35 min
Aug 6, 7:32 PM EDT	Severe Thunderstorm Warning	PHI	Northampton	43 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2019 Every severe thunderstorm warning in 2019

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.