Alert archive / New Jersey / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 23, NWS Philadelphia/Mount Holly

April 29, 2021Delaware County, Philadelphia County, Pennsylvania; Camden County, Gloucester County, Salem County, New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Apr 29, 2021, 7:45 PM EDT for Delaware County, Philadelphia County, Pennsylvania; Camden County, Gloucester County, Salem County, New Jersey. It was in force for 45 min. 5 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
Apr 29, 2021, 7:45 PM EDT (23:45 UTC)
Expired
Apr 29, 2021, 8:30 PM EDT
In force
45 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, Salem County, NJ, Delaware County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 65 km from the middle of the area, began a volume at 23:44 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
Apr 29, 7:49 PM EDTTSTM WND DMGWoodlyn, PADOWNED TREES AND WIRES NEAR VALLEY ROAD IN WOODLYN. TIME ESTIMATED FROM RADAR.
Apr 29, 7:51 PM EDTTSTM WND DMGFolcroft, PADOWNED WIRES NEAR HOOK ROAD IN DARBY TWP. TIME ESTIMATED FROM RADAR.
Apr 29, 8:00 PM EDTTSTM WND GST 51Philadelphia Internatio, PA
Apr 29, 8:06 PM EDTTSTM WND DMGTacony, PAMPING REPORT OF SNAPPED OR UPROOTED TREES AT THIS LOCATION. TIME ESTIMATED FROM RADAR.
Apr 29, 8:10 PM EDTTSTM WND DMGCherry Hill, NJSEVERAL DOWNED TREES AND WIRES IN THE CHERRY HILL AREA. 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

Washington/Dulle, VA (KIAD), launched 12:00Z, 11.8 hours before the alert went out and 219 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, Washington/Dulle, VA at 12:00Z on 2021-04-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 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, Washington/Dulle, VA at 12:00Z on 2021-04-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -8 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1285 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
-8 m²/s²
0-3 km storm-relative helicity
132 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

100 
WUUS51 KPHI 292345
SVRPHI
NJC007-015-033-PAC045-101-300030-
/O.NEW.KPHI.SV.W.0023.210429T2345Z-210430T0030Z/

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

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northwestern Salem County in southern New Jersey...
  Northwestern Camden County in southern New Jersey...
  Northwestern Gloucester County in southern New Jersey...
  Central Philadelphia County in southeastern Pennsylvania...
  Delaware County in southeastern Pennsylvania...

* Until 830 PM EDT.

* At 744 PM EDT, a severe thunderstorm was located over Nether
  Providence Township, or 12 miles west of Gloucester City, moving
  east at 45 mph.

  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, Voorhees, West Deptford, Lindenwold, Bellmawr, Yeadon,
  Woodbury, Berlin, Palmyra, Folcroft, Swarthmore, Paulsboro,
  Magnolia, Westville and Woodbury Heights.

People at the Pennsylvania Convention Center Vaccination Site, and
Gloucester County Mega Site should seek safe shelter immediately!

This includes the following highways...
 New Jersey Turnpike near exit 3.
 Interstate 95 in Pennsylvania between mile markers 0 and 29.
 Interstate 76 in Pennsylvania between mile markers 341 and 351.
 Interstate 76 in New Jersey between mile markers 0 and 3.
 Interstate 295 in New Jersey between mile markers 9 and 36.
 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 8.
 Atlantic City Expressway near mile marker 44.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3979 7491 3974 7544 3978 7545 3980 7541
      3982 7546 3996 7549 3999 7528 3998 7527
      4004 7504 4002 7502 3999 7506 3998 7501
      3995 7502 3994 7498 3988 7493
TIME...MOT...LOC 2344Z 257DEG 40KT 3990 7536 

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

Gorse
3 follow-up statements
169 
WWUS51 KPHI 292355
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
755 PM EDT Thu Apr 29 2021

NJC007-015-033-PAC045-101-300030-
/O.CON.KPHI.SV.W.0023.000000T0000Z-210430T0030Z/
Salem NJ-Camden NJ-Gloucester NJ-Philadelphia PA-Delaware PA-
755 PM EDT Thu Apr 29 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 830 PM EDT
FOR NORTHWESTERN SALEM...NORTHWESTERN CAMDEN...NORTHWESTERN
GLOUCESTER...CENTRAL PHILADELPHIA AND SOUTHEASTERN DELAWARE
COUNTIES...

At 754 PM EDT, a severe thunderstorm was located over South
Philadelphia, or near Gloucester City, moving east at 45 mph.

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, Voorhees, West Deptford, Lindenwold, Bellmawr, Yeadon,
Woodbury, Berlin, Palmyra, Folcroft, Swarthmore, Paulsboro, Magnolia,
Westville and Woodbury Heights.

People at the Pennsylvania Convention Center Vaccination Site, and
Gloucester County Mega Site should seek safe shelter immediately!

This includes the following highways...
 New Jersey Turnpike near exit 3.
 Interstate 95 in Pennsylvania between mile markers 5 and 29.
 Interstate 76 in Pennsylvania between mile markers 341 and 351.
 Interstate 76 in New Jersey between mile markers 0 and 3.
 Interstate 295 in New Jersey between mile markers 9 and 36.
 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.
 Atlantic City Expressway near mile marker 44.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3979 7491 3974 7544 3980 7541 3999 7528
      3998 7527 4004 7504 4002 7502 3999 7506
      3998 7501 3995 7502 3994 7498 3988 7493
TIME...MOT...LOC 2354Z 263DEG 39KT 3989 7521 

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

Gorse
774 
WWUS51 KPHI 300007
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
807 PM EDT Thu Apr 29 2021

NJC033-PAC045-300017-
/O.CAN.KPHI.SV.W.0023.000000T0000Z-210430T0030Z/
Salem NJ-Delaware PA-
807 PM EDT Thu Apr 29 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN SALEM AND
SOUTHEASTERN DELAWARE COUNTIES IS CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 3979 7491 3975 7529 3986 7524 3987 7521
      3988 7523 4001 7517 4004 7504 4002 7502
      3999 7506 3998 7501 3995 7502 3994 7498
      3993 7498 3988 7493
TIME...MOT...LOC 0007Z 257DEG 40KT 3992 7503 

$$

NJC007-015-PAC101-300030-
/O.CON.KPHI.SV.W.0023.000000T0000Z-210430T0030Z/
Camden NJ-Gloucester NJ-Philadelphia PA-
807 PM EDT Thu Apr 29 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 830 PM EDT
FOR NORTHWESTERN CAMDEN...NORTH CENTRAL GLOUCESTER AND CENTRAL
PHILADELPHIA COUNTIES...

At 807 PM EDT, a severe thunderstorm was located over
Erlton-Ellisburg, or near Camden, moving east at 45 mph.

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, Deptford,
Voorhees, West Deptford, Lindenwold, Bellmawr, Woodbury, Berlin,
Palmyra, Paulsboro, Magnolia, Westville, Woodbury Heights, National
Park, Brooklawn, Audubon Park and Wissinoming.

People at the Esperanza Community Vaccination Site, Pennsylvania
Convention Center Vaccination Site, and Gloucester County Mega Site
should seek safe shelter immediately!

This includes the following highways...
 New Jersey Turnpike between exits 2 and 3.
 Interstate 95 in Pennsylvania between mile markers 14 and 29.
 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 18 and 36.
 Interstate 676 in Pennsylvania between mile markers 0 and 1.
 Interstate 676 in New Jersey between mile markers 0 and 4.
 Atlantic City Expressway near mile marker 44.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3979 7491 3975 7529 3986 7524 3987 7521
      3988 7523 4001 7517 4004 7504 4002 7502
      3999 7506 3998 7501 3995 7502 3994 7498
      3993 7498 3988 7493
TIME...MOT...LOC 0007Z 257DEG 40KT 3992 7503 

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

Gorse
025 
WWUS51 KPHI 300021
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
821 PM EDT Thu Apr 29 2021

NJC007-015-PAC101-300031-
/O.EXP.KPHI.SV.W.0023.000000T0000Z-210430T0030Z/
Camden NJ-Gloucester NJ-Philadelphia PA-
821 PM EDT Thu Apr 29 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN CAMDEN...NORTH
CENTRAL GLOUCESTER AND CENTRAL PHILADELPHIA COUNTIES WILL EXPIRE AT
830 PM EDT...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.

LAT...LON 3979 7491 3975 7529 3986 7524 3987 7521
      3988 7523 4001 7517 4004 7504 4002 7502
      3999 7506 3998 7501 3995 7502 3994 7498
      3993 7498 3988 7493
TIME...MOT...LOC 0021Z 257DEG 40KT 3995 7484 

$$

Gorse

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 29, 3:32 AM EDTHigh Wind WatchPHIBerks, Bucks, Carbon, Chester, Delaware, Lehigh and 4 more16 hr
Apr 29, 7:23 PM EDTHigh Wind WarningPHIBerks, Bucks, Carbon, Chester, Delaware, Lehigh and 4 more26 hr
Apr 28, 8:05 PM EDTSpecial Weather StatementPHISussex40 min
Apr 28, 8:17 PM EDTSevere Thunderstorm WarningPHISussex43 min
Apr 28, 9:01 PM EDTSpecial Weather StatementPHIPassaic29 min
Apr 29, 3:29 AM EDTSmall Craft AdvisoryPHI27 hr
Apr 29, 3:29 AM EDTStorm WatchPHI21 hr
Apr 29, 3:47 PM EDTGale WarningPHI23 hr

Nearby

Severe Thunderstorm Warnings in New Jersey, 2021Severe Thunderstorm Warnings in Pennsylvania, 2021Every 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.