Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 233, NWS Philadelphia/Mount Holly

July 29, 2021Burlington County, Mercer County, New Jersey; Bucks County, Montgomery County, Philadelphia County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 29, 2021, 6:45 PM EDT for Burlington County, Mercer County, New Jersey; Bucks County, Montgomery County, Philadelphia County, Pennsylvania. It was in force for 45 min. 10 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 29, 2021, 6:45 PM EDT (22:45 UTC)
Expired: Jul 29, 2021, 7:30 PM EDT
In force: 45 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Tornado: Possible
Hail: 1.0 in
Wind: 60.0 mph

Counties Burlington County, NJ, Mercer County, NJ, Bucks County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 58 km from the middle of the area, began a volume at 22:48 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 29, 6:49 PM EDT	FUNNEL CLOUD	Willow Grove, PA	ROTATING WALL CLOUD OBSERVED NEAR WILLOW GROVE, PA. TIME ESTIMATED FROM RADAR.
Jul 29, 7:04 PM EDT	TORNADO	Somerton, PA	* 5 INJ * THE SOMERTON-TREVOSE-BENSALEM TORNADO BEGAN IN SOMERTON IN PHILADELPHIA COUNTY NEAR SOUTHAMPTON ROAD, KELVIN AVENUE, AND TREVOSE ROAD WHERE IT UPROOTED AND BLEW DOWN LARGE LIMBS FROM A FEW SOFTWOOD AND HARDWOOD TREES. THE TORNADO CROSSED COUNTY L
Jul 29, 7:07 PM EDT	TSTM WND DMG	1 Wnw Feasterville-Trev, PA	FAULKNER AUTO BUILDING ROOF WAS BLOWN OFF AND COLLAPSED. MULTIPLE SECTIONS OF THE EXTERIOR WALLS ALSO APPEAR TO BE COLLAPSED. PROBABLE TORNADO. TIME ESTIMATED RADAR.
Jul 29, 7:07 PM EDT	TSTM WND DMG	Feasterville-Trevose, PA	REPORTS OF DAMAGE TO THE LOWES OUTDOOR GARDEN CENTER JUST WEST OF NESHAMINY MALL. MULTIPLE TREES DOWN AS WELL AS WINDOWS BLOWN OUT OF VEHICLES. POSSIBLE TORNADO. TIME ESTIMATED FROM RADAR.
Jul 29, 7:10 PM EDT	TSTM WND DMG	1 N Burlington Twp, NJ	TREES AND WIRES DOWN ALONG NECK ROAD.
Jul 29, 7:10 PM EDT	TSTM WND DMG	1 Wnw Feasterville-Trev, PA	BUILDING DAMAGE AND TREES DOWN IN BENSALEM TOWNSHIP NEAR STREET ROAD AND THE TURNPIKE.
Jul 29, 7:10 PM EDT	TORNADO	1 Ne Feasterville-Trevo, PA	DEBRIS IN THE AIR AT THE NESHAMINY MALL IN BENSALEM TOWNSHIP.
Jul 29, 7:19 PM EDT	HAIL 1	Edgewater Park, NJ
Jul 29, 7:24 PM EDT	TSTM WND DMG	Bensalem, PA	TWITTER VIDEO OF DEBRIS RAINING DOWN NEAR BENSALEM, PA. TIME ESTIMATED FROM RADAR.
Jul 29, 7:29 PM EDT	HAIL 1.25	Mount Holly Wfo, NJ

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 29, 2:23 PM EDT	Tornado Watch	SPC	8 hr

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 10.8 hours before the alert went out and 198 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: 54 J/kg
Mixed-layer CIN: -32 J/kg
Mixed-layer LCL: 823 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 65 m²/s²
0-3 km storm-relative helicity: 127 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

As transmitted.

089 
WUUS51 KPHI 292245
SVRPHI
NJC005-021-PAC017-091-101-292330-
/O.NEW.KPHI.SV.W.0233.210729T2245Z-210729T2330Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
645 PM EDT Thu Jul 29 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Southwestern Mercer County in central New Jersey...
  Northwestern Burlington County in southern New Jersey...
  East central Montgomery County in southeastern Pennsylvania...
  Southeastern Bucks County in southeastern Pennsylvania...
  Northeastern Philadelphia County in southeastern Pennsylvania...

* Until 730 PM EDT.

* At 645 PM EDT, a severe thunderstorm was located over Ivyland, or
  14 miles north of Philadelphia, moving east at 25 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, Trenton, Bensalem, Ewing, Florence, Burlington,
  Bristol, Hatboro, Ambler, Beverly, Yardley, Newtown, Tullytown,
  Abington, Langhorne, Bryn Athyn, Ivyland, Feasterville-Trevose,
  Willow Grove and Florence-Roebling.

This includes the following highways...
 New Jersey Turnpike between exits 5 and 6A.
 Pennsylvania Turnpike between mile markers 339 and 359.
 Interstate 95 in Pennsylvania between mile markers 34 and 40.
 Interstate 295 in New Jersey between mile markers 47 and 50, and
between mile markers 75 and 76.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 900 PM EDT for southern and
central New Jersey...and southeastern Pennsylvania.

Remain alert for a possible tornado! Tornadoes can develop quickly
from severe thunderstorms. If you spot a tornado go at once into the
basement or small central room in a sturdy structure.

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

&&

LAT...LON 4014 7522 4027 7516 4028 7472 4001 7480
TIME...MOT...LOC 2245Z 274DEG 22KT 4021 7512 

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

Staarmann

3 follow-up statements

830 
WWUS51 KPHI 292259
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
659 PM EDT Thu Jul 29 2021

NJC005-021-PAC017-091-101-292330-
/O.CON.KPHI.SV.W.0233.000000T0000Z-210729T2330Z/
Mercer NJ-Burlington NJ-Montgomery PA-Bucks PA-Philadelphia PA-
659 PM EDT Thu Jul 29 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 730 PM EDT
FOR SOUTH CENTRAL MERCER...NORTHWESTERN BURLINGTON...EAST CENTRAL
MONTGOMERY...SOUTHEASTERN BUCKS AND NORTHEASTERN PHILADELPHIA
COUNTIES...

At 659 PM EDT, a severe thunderstorm was located over
Feasterville-Trevose, or 11 miles northeast of Philadelphia, moving
east at 25 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, Trenton, Bensalem, Florence, Burlington, Bristol,
Beverly, Newtown, Tullytown, Langhorne, Bryn Athyn,
Feasterville-Trevose, Florence-Roebling, Northeast Philadelphia,
Feasterville, Richboro, Andalusia, Langhorn, Levittown and Woodside.

This includes the following highways...
 New Jersey Turnpike between exits 5 and 6A.
 Pennsylvania Turnpike between mile markers 345 and 359.
 Interstate 95 in Pennsylvania between mile markers 34 and 40.
 Interstate 295 in New Jersey between mile markers 47 and 50.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 900 PM EDT for southern and
central New Jersey...and southeastern Pennsylvania.

Remain alert for a possible tornado! Tornadoes can develop quickly
from severe thunderstorms. If you spot a tornado go at once into the
basement or small central room in a sturdy structure.

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

Frequent cloud to ground lightning is occurring with this storm, and
the storm will affect the beaches. For your safety, immediately move
off the beach and seek shelter indoors.

&&

LAT...LON 4011 7512 4024 7505 4022 7474 4001 7480
TIME...MOT...LOC 2259Z 284DEG 23KT 4014 7500 

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

Staarmann

262 
WWUS51 KPHI 292311
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
711 PM EDT Thu Jul 29 2021

NJC021-PAC091-292321-
/O.CAN.KPHI.SV.W.0233.000000T0000Z-210729T2330Z/
Mercer NJ-Montgomery PA-
711 PM EDT Thu Jul 29 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL MERCER AND EAST
CENTRAL MONTGOMERY COUNTIES IS CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

A Tornado Watch remains in effect until 900 PM EDT for southern New
Jersey...and southeastern Pennsylvania.

LAT...LON 4001 7480 4008 7505 4010 7506 4020 7496
      4018 7475
TIME...MOT...LOC 2311Z 282DEG 21KT 4009 7492 

$$

NJC005-PAC017-101-292330-
/O.CON.KPHI.SV.W.0233.000000T0000Z-210729T2330Z/
Burlington NJ-Bucks PA-Philadelphia PA-
711 PM EDT Thu Jul 29 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 730 PM EDT
FOR NORTHWESTERN BURLINGTON...SOUTHEASTERN BUCKS AND NORTHEASTERN
PHILADELPHIA COUNTIES...

At 711 PM EDT, a severe thunderstorm was located over Bensalem, or 
12 miles southwest of Trenton, moving east at 25 mph. A Tornado 
Warning remains in effect for these areas as well.

HAZARD...Ping pong ball size hail and 60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...People and animals outdoors will be injured. Expect hail 
         damage to roofs, siding, windows, and vehicles. Wind damage 
         to roofs, siding, trees, and power lines is possible.

Locations impacted include...
Philadelphia, Bensalem, Florence, Burlington, Bristol, Beverly,
Tullytown, Langhorne, Feasterville-Trevose, Andalusia,
Florence-Roebling, Northeast Philadelphia, Langhorn, Levittown,
Feasterville, Edgewater Park, Penndel, Langhorne Manor, Hulmeville
and Cornwells Heights-Eddington.

This includes the following highways...
 New Jersey Turnpike between exits 5 and 6A.
 Pennsylvania Turnpike between mile markers 349 and 359.
 Interstate 95 in Pennsylvania between mile markers 34 and 40.
 Interstate 295 in New Jersey between mile markers 46 and 50.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 900 PM EDT for southern New
Jersey...and southeastern Pennsylvania.

Remain alert for a possible tornado! Tornadoes can develop quickly
from severe thunderstorms. If you spot a tornado go at once into the
basement or small central room in a sturdy structure.

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

&&

LAT...LON 4001 7480 4008 7505 4010 7506 4020 7496
      4018 7475
TIME...MOT...LOC 2311Z 282DEG 21KT 4009 7492 

TORNADO...POSSIBLE
HAIL...1.50IN
WIND...60MPH
 
$$

Staarmann

750 
WWUS51 KPHI 292321
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
721 PM EDT Thu Jul 29 2021

NJC005-PAC017-101-292330-
/O.CON.KPHI.SV.W.0233.000000T0000Z-210729T2330Z/
Burlington NJ-Bucks PA-Philadelphia PA-
721 PM EDT Thu Jul 29 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 730 PM EDT
FOR NORTHWESTERN BURLINGTON...SOUTHEASTERN BUCKS AND NORTHEASTERN
PHILADELPHIA COUNTIES...

At 721 PM EDT, a severe thunderstorm was located over Burlington, or
13 miles southwest of Trenton, moving east at 25 mph.

HAZARD...Ping pong ball size hail and 60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...People and animals outdoors will be injured. Expect hail 
         damage to roofs, siding, windows, and vehicles. Wind damage 
         to roofs, siding, trees, and power lines is possible.

Locations impacted include...
Philadelphia, Bensalem, Florence, Burlington, Bristol, Beverly,
Tullytown, Langhorne, Feasterville-Trevose, Andalusia,
Florence-Roebling, Northeast Philadelphia, Langhorn, Levittown,
Feasterville, Edgewater Park, Penndel, Langhorne Manor, Hulmeville
and Cornwells Heights-Eddington.

This includes the following highways...
 New Jersey Turnpike between exits 5 and 6A.
 Pennsylvania Turnpike between mile markers 349 and 359.
 Interstate 95 in Pennsylvania between mile markers 34 and 40.
 Interstate 295 in New Jersey between mile markers 46 and 50.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 900 PM EDT for southern New
Jersey...and southeastern Pennsylvania.

Remain alert for a possible tornado! Tornadoes can develop quickly
from severe thunderstorms. If you spot a tornado go at once into the
basement or small central room in a sturdy structure.

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

&&

LAT...LON 4001 7480 4008 7505 4010 7506 4020 7496
      4018 7475
TIME...MOT...LOC 2321Z 280DEG 21KT 4005 7487 

TORNADO...POSSIBLE
HAIL...1.50IN
WIND...60MPH
 
$$

Staarmann

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 29, 3:33 AM EDT	Small Craft Advisory	PHI		20 hr
Jul 29, 1:33 PM EDT	Special Marine Warning	PHI		42 min
Jul 29, 2:53 PM EDT	Special Marine Warning	PHI		100 min
Jul 29, 4:26 PM EDT	Special Weather Statement	PHI	Morris	34 min
Jul 29, 4:30 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Warren	45 min
Jul 29, 4:57 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Morris, Sussex, Warren	3 hr
Jul 29, 5:01 PM EDT	Special Weather Statement	PHI	Morris	29 min
Jul 29, 5:03 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Morris, Somerset, Sussex, Warren	42 min
Jul 29, 5:08 PM EDT	Tornado Warning	PHI	Hunterdon	37 min
Jul 29, 5:27 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Mercer, Morris, Somerset	3 hr
Jul 29, 5:32 PM EDT	Flash Flood Warning	PHI	Warren	2 hr
Jul 29, 5:32 PM EDT	Tornado Warning	PHI	Hunterdon	28 min
Jul 29, 5:51 PM EDT	Tornado Warning Tornado observedConsiderable damage threat	PHI	Hunterdon, Mercer	24 min
Jul 29, 5:58 PM EDT	Flash Flood Warning	PHI	Hunterdon, Mercer, Somerset	3 hr
Jul 29, 6:06 PM EDT	Tornado Warning Considerable damage threat	PHI	Burlington, Hunterdon, Mercer, Middlesex, Monmouth	39 min
Jul 29, 6:44 PM EDT	Tornado Warning	PHI	Mercer, Monmouth, Ocean	46 min
Jul 29, 6:56 PM EDT	Flash Flood Warning	PHI	Mercer, Middlesex, Monmouth, Ocean, Somerset	4 hr
Jul 29, 7:07 PM EDT	Tornado Warning	PHI	Burlington	23 min
Jul 29, 7:12 PM EDT	Flash Flood Warning	PHI	Burlington	4 hr
Jul 29, 7:18 PM EDT	Tornado Warning	PHI	Mercer, Middlesex, Monmouth, Ocean	27 min
Jul 29, 7:25 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Monmouth, Ocean	50 min
Jul 29, 7:28 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Mercer, Middlesex, Monmouth, Ocean	47 min
Jul 29, 7:52 PM EDT	Special Marine Warning	PHI		113 min
Jul 29, 3:48 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh, Northampton	42 min
Jul 29, 4:03 PM EDT	Tornado Warning	PHI	Berks, Lehigh, Northampton	27 min
Jul 29, 4:27 PM EDT	Tornado Warning	PHI	Lehigh, Northampton	16 min
Jul 29, 4:46 PM EDT	Areal Flood Advisory	PHI	Berks, Lehigh, Northampton	3 hr
Jul 29, 4:56 PM EDT	Tornado Warning	PHI	Bucks, Lehigh, Northampton	34 min
Jul 29, 6:21 PM EDT	Special Weather Statement	PHI	Bucks	24 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2021 Severe Thunderstorm Warnings in New Jersey, 2021 Every severe thunderstorm warning in 2021

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.