Alert archive / New Jersey / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 235, NWS Philadelphia/Mount Holly

August 12, 2020Camden County, Gloucester County, New Jersey; Delaware County, Philadelphia County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 12, 2020, 2:44 PM EDT for Camden County, Gloucester County, New Jersey; Delaware County, Philadelphia County, Pennsylvania. It was in force for 46 min. 3 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, 2:44 PM EDT (18:44 UTC)
Expired
Aug 12, 2020, 3:30 PM EDT
In force
46 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Camden County, NJ, Gloucester County, NJ, Delaware County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 62 km from the middle of the area, began a volume at 18:43 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

TimeReportWhereRemark
Aug 12, 2:54 PM EDTTSTM WND DMG1 N Blackwood, NJDOWNED TREE LIMBS AND POWER LINES NEAR KEYSTONE AVENUE IN BLACKWOOD. TIME ESTIMATED FROM RADAR.
Aug 12, 2:57 PM EDTTSTM WND DMGBlackwood, NJSEVERAL REPORTS OF WIRES DOWN IN THE BLACKWOOD AREA. TIME ESTIMATED FROM RADAR.
Aug 12, 3:25 PM EDTTSTM WND DMG1 S Sewell, NJLARGE TREE DOWN ON NEW ST. 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

Wallops Is Stn, VA (KWAL), launched 12:00Z, 6.7 hours before the alert went out and 218 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-pSkew-T log-p diagram, Wallops Is Stn, VA at 12:00Z on 2020-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1590 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Wallops Is Stn, VA at 12:00Z on 2020-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 3 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
1590 J/kg
Mixed-layer CIN
-21 J/kg
Mixed-layer LCL
729 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
3 m²/s²
0-3 km storm-relative helicity
17 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

164 
WUUS51 KPHI 121844
SVRPHI
NJC007-015-PAC045-101-121930-
/O.NEW.KPHI.SV.W.0235.200812T1844Z-200812T1930Z/

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

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northwestern Camden County in southern New Jersey...
  Northern Gloucester County in southern New Jersey...
  Southwestern Philadelphia County in southeastern Pennsylvania...
  Southeastern Delaware County in southeastern Pennsylvania...

* Until 330 PM EDT.

* At 244 PM EDT, a severe thunderstorm was located over Woodbury
  Heights, or near Gloucester City, and is nearly stationary.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Philadelphia, Camden, Gloucester City, Cherry Hill, Chester,
  Deptford, West Deptford, Lindenwold, Bellmawr, Yeadon, Woodbury,
  Pitman, Folcroft, Swarthmore, Paulsboro, Magnolia, Westville,
  Woodbury Heights, National Park and East Lansdowne.

This includes the following highways...
 New Jersey Turnpike near exit 3.
 Interstate 95 in Pennsylvania between mile markers 7 and 24.
 Interstate 76 in Pennsylvania between mile markers 344 and 351.
 Interstate 76 in New Jersey between mile markers 0 and 3.
 Interstate 295 in New Jersey between mile markers 12 and 35.
 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 1, and
near mile marker 6.
 Atlantic City Expressway between mile markers 39 and 44.

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 this storm. Move indoors
immediately. Remember, if you can hear thunder, you are close enough
to be struck by lightning.

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

&&

LAT...LON 3977 7534 3995 7536 3999 7502 3998 7501
      3995 7502 3994 7498 3971 7498
TIME...MOT...LOC 1844Z 271DEG 1KT 3981 7514 

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

CMS
2 follow-up statements
885 
WWUS51 KPHI 121903
SVSPHI

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

NJC007-015-PAC045-101-121930-
/O.CON.KPHI.SV.W.0235.000000T0000Z-200812T1930Z/
Camden NJ-Gloucester NJ-Philadelphia PA-Delaware PA-
303 PM EDT Wed Aug 12 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 330 PM EDT
FOR NORTHWESTERN CAMDEN...NORTHERN GLOUCESTER...SOUTHWESTERN
PHILADELPHIA AND SOUTHEASTERN DELAWARE COUNTIES...

At 302 PM EDT, a severe thunderstorm was located over Woodbury
Heights, or near Gloucester City, and is nearly stationary.

HAZARD...60 mph wind gusts.

SOURCE...Law enforcement. Reports of trees and wires down have been 
         received from the West Deptford area.

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

Locations impacted include...
Philadelphia, Camden, Gloucester City, Cherry Hill, Deptford, West
Deptford, Lindenwold, Bellmawr, Yeadon, Woodbury, Pitman, Folcroft,
Paulsboro, Magnolia, Westville, Woodbury Heights, National Park, East
Lansdowne, Brooklawn and Audubon Park.

This includes the following highways...
 New Jersey Turnpike near exit 3.
 Interstate 95 in Pennsylvania between mile markers 9 and 21.
 Interstate 76 in Pennsylvania between mile markers 345 and 351.
 Interstate 76 in New Jersey between mile markers 0 and 3.
 Interstate 295 in New Jersey between mile markers 13 and 35.
 Interstate 676 in New Jersey between mile markers 0 and 4.
 Atlantic City Expressway between mile markers 39 and 44.

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 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.

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

&&

LAT...LON 3977 7534 3996 7528 3996 7520 3994 7498
      3971 7498
TIME...MOT...LOC 1902Z 271DEG 1KT 3981 7513 

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

CMS
741 
WWUS51 KPHI 121925
SVSPHI

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

NJC007-015-PAC045-101-121935-
/O.EXP.KPHI.SV.W.0235.000000T0000Z-200812T1930Z/
Camden NJ-Gloucester NJ-Philadelphia PA-Delaware PA-
325 PM EDT Wed Aug 12 2020

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN CAMDEN...NORTHERN
GLOUCESTER...SOUTHWESTERN PHILADELPHIA AND SOUTHEASTERN DELAWARE
COUNTIES WILL EXPIRE AT 330 PM EDT...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.  However, heavy 
rain is still possible with this thunderstorm.

LAT...LON 3977 7534 3996 7528 3996 7520 3994 7498
      3971 7498
TIME...MOT...LOC 1925Z 271DEG 1KT 3981 7512 

$$

CMS

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 12, 12:06 PM EDTSpecial Weather StatementPHIMonmouth24 min
Aug 12, 12:16 PM EDTSpecial Weather StatementPHIBurlington29 min
Aug 12, 12:33 PM EDTSevere Thunderstorm WarningPHIBurlington42 min
Aug 12, 12:43 PM EDTAreal Flood AdvisoryPHIBurlington, Camden, Gloucester, Mercer, Monmouth, Ocean and 1 more3 hr
Aug 12, 12:45 PM EDTSevere Thunderstorm WarningPHIMonmouth, Ocean45 min
Aug 12, 1:12 PM EDTFlash Flood WarningPHIBurlington3 hr
Aug 12, 1:12 PM EDTSevere Thunderstorm WarningPHIBurlington, Camden, Gloucester, Monmouth, Ocean48 min
Aug 12, 1:25 PM EDTSevere Thunderstorm WarningPHIMonmouth, Ocean50 min
Aug 12, 1:54 PM EDTSevere Thunderstorm WarningPHIBurlington, Camden, Gloucester51 min
Aug 12, 1:57 PM EDTSevere Thunderstorm WarningPHIAtlantic, Burlington, Ocean48 min
Aug 12, 2:40 PM EDTFlash Flood WarningPHIBurlington, Camden, Gloucester3 hr
Aug 12, 2:42 PM EDTSevere Thunderstorm WarningPHIBurlington, Ocean25 min
Aug 12, 3:12 PM EDTSevere Thunderstorm WarningPHIAtlantic, Burlington, Camden, Gloucester, Salem29 min
Aug 12, 3:54 PM EDTSpecial Marine WarningPHI53 min
Aug 12, 11:48 AM EDTSpecial Weather StatementPHIPhiladelphia27 min
Aug 12, 1:47 PM EDTFlash Flood WarningPHIChester, Delaware2 hr
Aug 12, 2:04 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery, Philadelphia21 min
Aug 12, 3:20 PM EDTSevere Thunderstorm WarningPHIChester, Delaware29 min
Aug 12, 3:36 PM EDTFlash Flood WarningPHIChester108 min
Aug 12, 5:04 PM EDTAreal Flood AdvisoryPHILehigh, Northampton56 min
Aug 12, 5:09 PM EDTAreal Flood WarningPHIBerks51 min

Nearby

Severe Thunderstorm Warnings in New Jersey, 2020Severe Thunderstorm Warnings in Pennsylvania, 2020Every 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.