Alert archive / New Jersey / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 228, NWS Philadelphia/Mount Holly

August 12, 20204 counties in Pennsylvania; 5 counties in New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 12, 2020, 1:12 PM EDT for 4 counties in Pennsylvania; 5 counties in New Jersey. It was in force for 48 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: Aug 12, 2020, 1:12 PM EDT (17:12 UTC)
Expired: Aug 12, 2020, 2:00 PM EDT
In force: 48 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Burlington County, NJ, Camden County, NJ, Gloucester County, NJ, Monmouth County, NJ, Ocean County, NJ, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 39 km from the middle of the area, began a volume at 17:14 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 12, 1:14 PM EDT	TSTM WND DMG	Moorestown Twp, NJ	DOWNED POWER LINES NEAR MARKET STREET IN MOORESTOWN. TIME ESTIMATED FROM RADAR.
Aug 12, 1:14 PM EDT	TSTM WND DMG	Pennsauken, NJ	NUMEROUS REPORTS OF DOWNED POWER LINES IN THE PENNSAUKEN AREA. TIME ESTIMATED FROM RADAR.
Aug 12, 1:19 PM EDT	TSTM WND DMG	Maple Shade, NJ	SEVERAL REPORTS OF WIRES DOWN IN THE MAPLE SHADE AREA. TIME ESTIMATED FROM RADAR.
Aug 12, 1:19 PM EDT	TSTM WND DMG	Moorestown Twp, NJ	CORRECTS PREVIOUS TSTM WND DMG REPORT FROM MOORESTOWN TWP. SEVERAL REPORTS OF TREE LIMBS AND WIRES DOWN IN MOORESTOWN. TIME ESTIMATED FROM RADAR.
Aug 12, 1:28 PM EDT	TSTM WND DMG	1 Nne Ellisburg, NJ	DOWNED TREE LIMBS AND WIRES NEAR GREENSWARD LANE. TIME ESTIMATED FROM RADAR.
Aug 12, 1:37 PM EDT	TSTM WND DMG	1 Se Ellisburg, NJ	DOWNED TREE LIMBS AND POWER LINES NEAR THE INTERSECTION OF GREENBRIAR ROAD AND RANDLE DRIVE. TIME ESTIMATED FROM RADAR.
Aug 12, 1:37 PM EDT	TSTM WND DMG	Ellisburg, NJ	SEVERAL REPORTS OF POWER LINES DOWN IN ELLISBURG. TIME ESTIMATED FROM RADAR.
Aug 12, 1:44 PM EDT	TSTM WND DMG	Cherry Hill Twp, NJ	SEVERAL REPORTS OF TREE LIMBS AND WIRES DOWN IN IN THE CHERRY HILL AREA. TIME ESTIMATED FROM RADAR.
Aug 12, 1:46 PM EDT	TSTM WND DMG	1 Se Greentree, NJ	DOWNED TREE AND WIRES NEAR LAMP POST LANE IN GREENTREE. 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, 5.2 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: 1221 J/kg
Mixed-layer CIN: -60 J/kg
Mixed-layer LCL: 921 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 70 m²/s²
0-3 km storm-relative helicity: 58 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.4

Open this sounding in Storm Lab

The text

As transmitted.

490 
WUUS51 KPHI 121712
SVRPHI
NJC005-007-015-025-029-PAC029-045-091-101-121800-
/O.NEW.KPHI.SV.W.0228.200812T1712Z-200812T1800Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
112 PM EDT Wed Aug 12 2020

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northwestern Ocean County in southern New Jersey...
  Northwestern Camden County in southern New Jersey...
  Northwestern Gloucester County in southern New Jersey...
  Central Burlington County in southern New Jersey...
  Southwestern Monmouth County in central New Jersey...
  Southeastern Montgomery County in southeastern Pennsylvania...
  East central Chester County in southeastern Pennsylvania...
  Southwestern Philadelphia County in southeastern Pennsylvania...
  Delaware County in southeastern Pennsylvania...

* Until 200 PM EDT.

* At 112 PM EDT, severe thunderstorms were located along a line
  extending from near Pemberton to near Mount Laurel to Gradyville,
  moving south at 5 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Law enforcement.

  IMPACT...Damage to roofs, siding, trees, and power lines is 
           possible.

* Locations impacted include...
  Philadelphia, Camden, Gloucester City, Cherry Hill, Evesham, Mount
  Laurel, Chester, Deptford, Voorhees, Medford, West Deptford,
  Lindenwold, Lumberton, Bellmawr, Yeadon, Woodbury, Mount Holly,
  Berlin, Palmyra and Tabernacle.

This includes the following highways...
 New Jersey Turnpike between exits 3 and 4.
 Interstate 95 in Pennsylvania between mile markers 2 and 28.
 Interstate 76 in Pennsylvania between mile markers 337 and 351.
 Interstate 76 in New Jersey between mile markers 0 and 3.
 Interstate 295 in New Jersey between mile markers 18 and 43.
 Interstate 676 in Pennsylvania between mile markers 0 and 1.
 Interstate 676 in New Jersey between mile markers 0 and 4.
 Interstate 476 in Pennsylvania between mile markers 0 and 14.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

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 3990 7441 3980 7494 3984 7562 4006 7542
      3999 7486 4014 7445
TIME...MOT...LOC 1712Z 017DEG 6KT 3999 7464 3993 7489 3997 7546 

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

CMS

2 follow-up statements

454 
WWUS51 KPHI 121732
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
132 PM EDT Wed Aug 12 2020

NJC005-007-015-025-029-PAC029-045-091-101-121800-
/O.CON.KPHI.SV.W.0228.000000T0000Z-200812T1800Z/
Ocean NJ-Camden NJ-Gloucester NJ-Burlington NJ-Monmouth NJ-
Montgomery PA-Chester PA-Philadelphia PA-Delaware PA-
132 PM EDT Wed Aug 12 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 200 PM EDT
FOR NORTHWESTERN OCEAN...NORTHWESTERN CAMDEN...NORTHWESTERN
GLOUCESTER...CENTRAL BURLINGTON...SOUTHWESTERN MONMOUTH...
SOUTHEASTERN MONTGOMERY...EAST CENTRAL CHESTER...SOUTHWESTERN
PHILADELPHIA AND DELAWARE COUNTIES...

At 131 PM EDT, severe thunderstorms were located along a line
extending from Pemberton to Marlton to Gradyville, moving south at 5
mph.

HAZARD...60 mph wind gusts.

SOURCE...Law enforcement. Several reports of wires down have been 
         received from the Willingboro and Moorestown area from 
         these storms.

IMPACT...Damage to roofs, siding, trees, and power lines is 
         possible.

Locations impacted include...
Philadelphia, Camden, Gloucester City, Cherry Hill, Evesham, Mount
Laurel, Chester, Deptford, Voorhees, Medford, West Deptford,
Lindenwold, Lumberton, Bellmawr, Yeadon, Woodbury, Mount Holly,
Berlin, Palmyra and Tabernacle.

This includes the following highways...
 New Jersey Turnpike between exits 3 and 4.
 Interstate 95 in Pennsylvania between mile markers 2 and 28.
 Interstate 76 in Pennsylvania between mile markers 337 and 351.
 Interstate 76 in New Jersey between mile markers 0 and 3.
 Interstate 295 in New Jersey between mile markers 18 and 43.
 Interstate 676 in Pennsylvania between mile markers 0 and 1.
 Interstate 676 in New Jersey between mile markers 0 and 4.
 Interstate 476 in Pennsylvania between mile markers 0 and 14.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

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 3990 7441 3980 7494 3984 7562 4006 7542
      3999 7486 4014 7445
TIME...MOT...LOC 1731Z 017DEG 6KT 3996 7465 3990 7490 3994 7547 

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

CMS

163 
WWUS51 KPHI 121749
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
149 PM EDT Wed Aug 12 2020

NJC025-029-121758-
/O.CAN.KPHI.SV.W.0228.000000T0000Z-200812T1800Z/
Ocean NJ-Monmouth NJ-
149 PM EDT Wed Aug 12 2020

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN OCEAN AND
SOUTHWESTERN MONMOUTH COUNTIES IS CANCELLED...

The storms which prompted the warning have moved out of the warned 
area. Therefore, the warning has been cancelled.

LAT...LON 3984 7473 3980 7494 3984 7562 4006 7542
      3999 7486
TIME...MOT...LOC 1748Z 062DEG 9KT 3990 7483 3989 7501 3994 7549 

$$

NJC005-007-015-PAC029-045-091-101-121800-
/O.CON.KPHI.SV.W.0228.000000T0000Z-200812T1800Z/
Camden NJ-Gloucester NJ-Burlington NJ-Montgomery PA-Chester PA-
Philadelphia PA-Delaware PA-
149 PM EDT Wed Aug 12 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 200 PM EDT
FOR NORTHWESTERN CAMDEN...NORTHWESTERN GLOUCESTER...WEST CENTRAL
BURLINGTON...SOUTHEASTERN MONTGOMERY...EAST CENTRAL CHESTER...
SOUTHWESTERN PHILADELPHIA AND DELAWARE COUNTIES...

At 148 PM EDT, severe thunderstorms were located along a line
extending from Medford to Cherry Hill to Gradyville, moving southwest
at 10 mph.

HAZARD...60 mph wind gusts.

SOURCE...Law enforcement. Several reports of wires down have been 
         received from Moorestown and Maple Shade.

IMPACT...Damage to roofs, siding, trees, and power lines is 
         possible.

Locations impacted include...
Philadelphia, Camden, Gloucester City, Cherry Hill, Evesham, Mount
Laurel, Chester, Deptford, Voorhees, Medford, West Deptford,
Lindenwold, Bellmawr, Yeadon, Woodbury, Berlin, Palmyra, Folcroft,
Swarthmore and Paulsboro.

This includes the following highways...
 New Jersey Turnpike between exits 3 and 4.
 Interstate 95 in Pennsylvania between mile markers 2 and 28.
 Interstate 76 in Pennsylvania between mile markers 337 and 351.
 Interstate 76 in New Jersey between mile markers 0 and 3.
 Interstate 295 in New Jersey between mile markers 18 and 43.
 Interstate 676 in Pennsylvania between mile markers 0 and 1.
 Interstate 676 in New Jersey between mile markers 0 and 4.
 Interstate 476 in Pennsylvania between mile markers 0 and 14.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

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 3984 7473 3980 7494 3984 7562 4006 7542
      3999 7486
TIME...MOT...LOC 1748Z 062DEG 9KT 3990 7483 3989 7501 3994 7549 

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

CMS

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 12, 11:48 AM EDT	Special Weather Statement	PHI	Philadelphia	27 min
Aug 12, 12:43 PM EDT	Areal Flood Advisory	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	3 hr
Aug 12, 1:47 PM EDT	Flash Flood Warning	PHI	Chester, Delaware	2 hr
Aug 12, 1:54 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	51 min
Aug 12, 2:04 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery, Philadelphia	21 min
Aug 12, 2:40 PM EDT	Flash Flood Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	3 hr
Aug 12, 2:44 PM EDT	Severe Thunderstorm Warning	PHI	Delaware, Philadelphia	46 min
Aug 12, 3:20 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware	29 min
Aug 12, 3:36 PM EDT	Flash Flood Warning	PHI	Chester	108 min
Aug 12, 5:04 PM EDT	Areal Flood Advisory	PHI	Lehigh, Northampton	56 min
Aug 12, 5:09 PM EDT	Areal Flood Warning	PHI	Berks	51 min
Aug 12, 12:06 PM EDT	Special Weather Statement	PHI	Monmouth	24 min
Aug 12, 12:16 PM EDT	Special Weather Statement	PHI	Burlington	29 min
Aug 12, 12:33 PM EDT	Severe Thunderstorm Warning	PHI	Burlington	42 min
Aug 12, 12:45 PM EDT	Severe Thunderstorm Warning	PHI	Monmouth, Ocean	45 min
Aug 12, 1:12 PM EDT	Flash Flood Warning	PHI	Burlington	3 hr
Aug 12, 1:25 PM EDT	Severe Thunderstorm Warning	PHI	Monmouth, Ocean	50 min
Aug 12, 1:57 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Ocean	48 min
Aug 12, 2:42 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Ocean	25 min
Aug 12, 3:12 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Camden, Gloucester, Salem	29 min
Aug 12, 3:54 PM EDT	Special Marine Warning	PHI		53 min

Nearby

Severe Thunderstorm Warnings in New Jersey, 2020 Severe Thunderstorm Warnings in Pennsylvania, 2020 Every severe thunderstorm warning in 2020

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.