Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2024

Severe Thunderstorm Warning 134, NWS Philadelphia/Mount Holly

July 16, 20244 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 16, 2024, 7:54 PM EDT for 4 counties in Pennsylvania. It was in force for 66 min. 9 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: Jul 16, 2024, 7:54 PM EDT (23:54 UTC)
Expired: Jul 16, 2024, 9:00 PM EDT
In force: 66 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Damage threat: Considerable
Hail: 1.0 in
Wind: 70.0 mph

Counties Bucks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 107 km from the middle of the area, began a volume at 23:53 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
Jul 16, 7:55 PM EDT	TSTM WND DMG	1 Nw Graterford, PA	Large tree snapped and fell onto a house on French Road in Perkiomen Township. Time estimated from radar.
Jul 16, 7:58 PM EDT	TSTM WND DMG	Graterford, PA	Delayed storm damage report. Large pine tree snapped at the trunk, fell onto house collapsing a portion of the roof on Bridge Street in Perkiomen Township. About a half dozen trees on the north side of Bridge Street also had split trunks. Time estimated.
Jul 16, 7:58 PM EDT	NON-TSTM WND GST 60	2 S Glenmoore, PA	Video relayed via social media showing wind gusts near 50 to 60 mph, as well as some tree limbs being blown down. Time estimated.
Jul 16, 8:00 PM EDT	TSTM WND GST 55	Glenmoore, PA	55 mph wind gust at Glenmoore DEOS site.
Jul 16, 8:08 PM EDT	TSTM WND DMG	1 E East Brandywine Twp, PA	Large tree limb in excess of 6 inches in diameter down. Also video of what looks to be estimated 60 mph winds. Time estimated.
Jul 16, 8:20 PM EDT	TSTM WND DMG	Coatesville, PA	NWS Employee relays report of a large tree down on a vehicle in Coatesville.
Jul 16, 8:20 PM EDT	TSTM WND DMG	Coatesville, PA	Trees down with estimated 60 mph wind gusts.
Jul 16, 8:22 PM EDT	TSTM WND DMG	King Of Prussia, PA	Trees down in King of Prussia.
Jul 16, 8:49 PM EDT	TSTM WND GST 43	1 Nnw West Goshen, PA	AWOS station KOQN West Chester.

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
Jul 16, 3:36 PM EDT	Severe Thunderstorm Watch	SPC	9 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 11.9 hours before the alert went out and 195 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: 508 J/kg
Mixed-layer CIN: -148 J/kg
Mixed-layer LCL: 1812 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 50 m²/s²
0-3 km storm-relative helicity: 93 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.3

Open this sounding in Storm Lab

The text

As transmitted.

434 
WUUS51 KPHI 162354
SVRPHI
PAC017-029-045-091-170100-
/O.NEW.KPHI.SV.W.0134.240716T2354Z-240717T0100Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
754 PM EDT Tue Jul 16 2024

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Central Montgomery County in southeastern Pennsylvania...
  Central Bucks County in southeastern Pennsylvania...
  Northern Chester County in southeastern Pennsylvania...
  Northwestern Delaware County in southeastern Pennsylvania...

* Until 900 PM EDT.

* At 754 PM EDT, severe thunderstorms were located along a line
  extending from near Royersford to near Glenmoore to near Honey
  Brook, moving east at 30 mph.

  HAZARD...70 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Minor damage to vehicles is possible. Expect considerable 
           tree damage. Wind damage is also likely to mobile homes, 
           roofs, and outbuildings.

* Locations impacted include...
  West Chester, Norristown, Pottstown, Phoenixville, Lansdale, West
  Norriton, East Norriton, Coatesville, Westtown, Downingtown,
  Conshohocken, Ambler, Collegeville, Royersford, Parkesburg, Trappe,
  Hatfield, Honey Brook, Schwenksville, and Elverson.

This includes the following highways...
 Pennsylvania Turnpike between mile markers 301 and 339.
 Northeast Extension between mile markers 21 and 31.
 Interstate 76 in Pennsylvania between mile markers 327 and 335.
 Interstate 476 in Pennsylvania between mile markers 11 and 19.

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 these storms. 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 4004 7593 4009 7594 4028 7563 4026 7504
      4004 7528 3989 7556 3998 7598
TIME...MOT...LOC 2354Z 273DEG 26KT 4023 7554 4011 7571 4003 7593 

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH

$$

Staarmann

3 follow-up statements

388 
WWUS51 KPHI 170019
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
819 PM EDT Tue Jul 16 2024

PAC017-029-045-091-170100-
/O.CON.KPHI.SV.W.0134.000000T0000Z-240717T0100Z/
Montgomery PA-Bucks PA-Chester PA-Delaware PA-
819 PM EDT Tue Jul 16 2024

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 900 PM EDT
FOR CENTRAL MONTGOMERY...CENTRAL BUCKS...CENTRAL CHESTER AND
NORTHWESTERN DELAWARE COUNTIES...

At 818 PM EDT, severe thunderstorms were located along a line
extending from near Lansdale to near King Of Prussia to near
Coatesville, moving east at 30 mph.

HAZARD...70 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Minor damage to vehicles is possible. Expect considerable 
         tree damage. Wind damage is also likely to mobile homes, 
         roofs, and outbuildings.

Locations impacted include...
West Chester, Norristown, Phoenixville, Lansdale, West Norriton, East
Norriton, Coatesville, Westtown, Downingtown, Conshohocken, Ambler,
Collegeville, Royersford, Parkesburg, Trappe, Schwenksville, Cheyney,
Pughtown, Bryn Mawr, and Marshallton.

This includes the following highways...
 Pennsylvania Turnpike between mile markers 305 and 339.
 Northeast Extension between mile markers 21 and 31.
 Interstate 76 in Pennsylvania between mile markers 327 and 335.
 Interstate 476 in Pennsylvania between mile markers 11 and 19.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Frequent cloud to ground lightning is occurring with these storms.
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.

Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4004 7593 4007 7593 4027 7543 4026 7504
      4004 7528 3989 7556 3998 7598
TIME...MOT...LOC 0018Z 273DEG 28KT 4022 7534 4007 7541 3997 7576 

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH

$$

Staarmann

277 
WWUS51 KPHI 170027
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
827 PM EDT Tue Jul 16 2024

PAC017-029-045-091-170100-
/O.CON.KPHI.SV.W.0134.000000T0000Z-240717T0100Z/
Montgomery PA-Bucks PA-Chester PA-Delaware PA-
827 PM EDT Tue Jul 16 2024

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 900 PM EDT
FOR CENTRAL MONTGOMERY...CENTRAL BUCKS...CENTRAL CHESTER AND
NORTHWESTERN DELAWARE COUNTIES...

At 826 PM EDT, severe thunderstorms were located along a line
extending from Lansdale to near Conshohocken to near Marshallton,
moving east at 30 mph.

HAZARD...70 mph wind gusts and quarter size hail.

SOURCE...Radar indicated. At 8:16 PM EDT, emergency management 
         reported numerous trees and wires down across western 
         Chester County.

IMPACT...Minor damage to vehicles is possible. Expect considerable 
         tree damage. Wind damage is also likely to mobile homes, 
         roofs, and outbuildings.

Locations impacted include...
West Chester, Norristown, Phoenixville, Lansdale, West Norriton, East
Norriton, Coatesville, Westtown, Downingtown, Conshohocken, Ambler,
Collegeville, Royersford, Parkesburg, Trappe, Schwenksville, Cheyney,
Pughtown, Bryn Mawr, and Marshallton.

This includes the following highways...
 Pennsylvania Turnpike between mile markers 305 and 339.
 Northeast Extension between mile markers 21 and 31.
 Interstate 76 in Pennsylvania between mile markers 327 and 335.
 Interstate 476 in Pennsylvania between mile markers 11 and 19.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Frequent cloud to ground lightning is occurring with these storms.
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.

Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4004 7593 4007 7593 4027 7543 4026 7504
      4004 7528 3989 7556 3998 7598
TIME...MOT...LOC 0026Z 272DEG 26KT 4023 7529 4007 7535 3996 7575 

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...OBSERVED
MAX WIND GUST...70 MPH

$$

Staarmann

022 
WWUS51 KPHI 170054
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
854 PM EDT Tue Jul 16 2024

PAC017-029-045-091-170100-
/O.CON.KPHI.SV.W.0134.000000T0000Z-240717T0100Z/
Montgomery PA-Bucks PA-Chester PA-Delaware PA-
854 PM EDT Tue Jul 16 2024

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 900 PM EDT
FOR SOUTHEASTERN MONTGOMERY...CENTRAL BUCKS...EAST CENTRAL CHESTER
AND NORTHWESTERN DELAWARE COUNTIES...

At 853 PM EDT, severe thunderstorms were located along a line
extending from Ivyland to Wissinoming to Westtown, moving east at 30 
mph. This storm has a history of producing extensive wind damage 
across southeastern Pennsylvania.

HAZARD...70 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Minor damage to vehicles is possible. Expect considerable 
         tree damage. Wind damage is also likely to mobile homes, 
         roofs, and outbuildings.

Locations impacted include...
West Chester, Norristown, Lansdale, West Norriton, East Norriton,
Westtown, Downingtown, Conshohocken, Ambler, Cheyney, Bryn Mawr,
Marshallton, Radnor Township, Gradyville, Valley Forge, Plymouth
Meeting, Paoli, Newtown Square, King Of Prussia, and
Lionville-Marchwood.

This includes the following highways...
 Pennsylvania Turnpike between mile markers 316 and 339.
 Northeast Extension between mile markers 21 and 25.
 Interstate 76 in Pennsylvania between mile markers 327 and 335.
 Interstate 476 in Pennsylvania between mile markers 11 and 19.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Frequent cloud to ground lightning is occurring with these storms.
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.

Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4009 7556 4011 7539 4026 7525 4026 7504
      4004 7528 3989 7556 3995 7585
TIME...MOT...LOC 0053Z 274DEG 27KT 4022 7505 4003 7507 3992 7556 

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...OBSERVED
MAX WIND GUST...70 MPH

$$

Staarmann

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 16, 4:03 PM EDT	Severe Thunderstorm Warning	PHI	Berks	42 min
Jul 16, 4:41 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester, Lehigh, Montgomery	49 min
Jul 16, 4:59 PM EDT	Severe Thunderstorm Warning	PHI	Monroe	46 min
Jul 16, 5:01 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Lehigh, Northampton	44 min
Jul 16, 5:15 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Chester, Lehigh, Montgomery	60 min
Jul 16, 5:43 PM EDT	Severe Thunderstorm Warning Considerable damage threat	PHI	Bucks	47 min
Jul 16, 7:06 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester, Montgomery	54 min
Jul 16, 7:11 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Lehigh, Northampton	49 min
Jul 16, 7:23 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Lehigh, Montgomery	52 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2024 Every severe thunderstorm warning in 2024

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.