Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 15, NWS Philadelphia/Mount Holly

April 8, 20204 counties in Pennsylvania; Camden County, Gloucester County, New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Apr 8, 2020, 2:30 AM EDT for 4 counties in Pennsylvania; Camden County, Gloucester County, New Jersey. It was in force for 30 min. 4 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 8, 2020, 2:30 AM EDT (06:30 UTC)
Expired
Apr 8, 2020, 3:00 AM EDT
In force
30 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
1.0 in
Wind
50.0 mph

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

The radar

The Philadelphia radar (KDIX), 67 km from the middle of the area, began a volume at 06:30 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 8, 2:33 AM EDTHAIL 0.5Newtown Twp, PAPHOTO SHARED ON SOCIAL MEDIA OF A DECK PARTIALLY COVERED IN HAIL. LARGEST STONES APPEARED TO BE ABOUT A HALF INCH IN DIAMETER.
Apr 8, 2:36 AM EDTHAIL 0.251 Nw Broomall, PAMPING REPORT.
Apr 8, 2:46 AM EDTHAIL 0.251 E Roxborough, PAMPING REPORT.
Apr 8, 2:46 AM EDTHAIL 0.251 Sse Mount Royal, NJMPING REPORT.

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 00:00Z, 6.5 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, Brookhaven, NY at 00:00Z on 2020-04-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Brookhaven, NY at 00:00Z on 2020-04-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 237 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
2262 m above ground
0-6 km bulk shear
64 kt
0-1 km storm-relative helicity
237 m²/s²
0-3 km storm-relative helicity
151 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

818 
WUUS51 KPHI 080630
SVRPHI
NJC007-015-PAC029-045-091-101-080700-
/O.NEW.KPHI.SV.W.0015.200408T0630Z-200408T0700Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
230 AM EDT Wed Apr 8 2020

The National Weather Service in Mount Holly NJ has issued a

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

* Until 300 AM EDT.

* At 230 AM EDT, a severe thunderstorm was located over Paoli, or 8
  miles northeast of West Chester, moving east at 40 mph.

  HAZARD...Quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Minor damage to vehicles is possible.

* Locations impacted include...
  Philadelphia, Camden, West Chester, Gloucester City, Norristown,
  Chester, Deptford, West Deptford, Phoenixville, West Norriton,
  Bellmawr, Yeadon, Westtown, Woodbury, Conshohocken, Palmyra,
  Folcroft, Swarthmore, Paulsboro and Jenkintown.

People attending Covid-19 Drive through testing should seek safe
shelter immediately!

This includes the following highways...
 Interstate 295 in New Jersey between mile markers 16 and 29.
 Interstate 95 in Pennsylvania between mile markers 3 and 32.
 New Jersey Turnpike near exit 3.
 Interstate 476 in Pennsylvania between mile markers 0 and 19.
 Pennsylvania Turnpike between exits 320 and 333.
 Northeast Extension near exit A20.
 Interstate 676 in New Jersey between mile markers 0 and 4.
 Interstate 676 in Pennsylvania between mile markers 0 and 1.
 Interstate 76 in New Jersey between mile markers 0 and 3.
 Interstate 76 in Pennsylvania between mile markers 327 and 351.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4012 7560 4013 7499 4012 7497 4002 7500
      4002 7504 3999 7506 4000 7504 3998 7502
      3976 7509 3990 7565
TIME...MOT...LOC 0630Z 257DEG 37KT 4001 7546 

HAIL...1.00IN
WIND...<50MPH
 
$$

NC
2 follow-up statements
831 
WWUS51 KPHI 080644
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
244 AM EDT Wed Apr 8 2020

PAC029-080653-
/O.CAN.KPHI.SV.W.0015.000000T0000Z-200408T0700Z/
Chester PA-
244 AM EDT Wed Apr 8 2020

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL CHESTER COUNTY IS
CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area.  Therefore, the warning has been cancelled.

LAT...LON 4003 7500 4002 7504 3999 7506 4000 7504
      3998 7502 3976 7509 3982 7530 4005 7540
      4007 7536 4006 7539 4012 7544 4013 7499
      4012 7497
TIME...MOT...LOC 0643Z 257DEG 37KT 4004 7528 

$$

NJC007-015-PAC045-091-101-080700-
/O.CON.KPHI.SV.W.0015.000000T0000Z-200408T0700Z/
Camden NJ-Gloucester NJ-Montgomery PA-Philadelphia PA-Delaware PA-
244 AM EDT Wed Apr 8 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 300 AM EDT
FOR NORTHWESTERN CAMDEN...NORTH CENTRAL GLOUCESTER...SOUTHEASTERN
MONTGOMERY...PHILADELPHIA AND EASTERN DELAWARE COUNTIES...

At 243 AM EDT, a severe thunderstorm was located over Bryn Mawr, or 8
miles west of Philadelphia, moving east at 45 mph.

HAZARD...Quarter size hail.

SOURCE...Radar indicated.

IMPACT...Minor damage to vehicles is possible.

Locations impacted include...
Philadelphia, Camden, Gloucester City, Norristown, Deptford, West
Deptford, West Norriton, Bellmawr, Yeadon, Woodbury, Conshohocken,
Palmyra, Folcroft, Paulsboro, Jenkintown, Westville, Narberth,
Woodbury Heights, National Park and East Lansdowne.

This includes the following highways...
 Interstate 295 in New Jersey between mile markers 17 and 29.
 Interstate 95 in Pennsylvania between mile markers 8 and 32.
 New Jersey Turnpike near exit 3.
 Interstate 476 in Pennsylvania between mile markers 6 and 19.
 Pennsylvania Turnpike between exits 326 and 333.
 Northeast Extension near exit A20.
 Interstate 676 in New Jersey between mile markers 0 and 4.
 Interstate 676 in Pennsylvania between mile markers 0 and 1.
 Interstate 76 in New Jersey between mile markers 0 and 3.
 Interstate 76 in Pennsylvania between mile markers 327 and 351.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4003 7500 4002 7504 3999 7506 4000 7504
      3998 7502 3976 7509 3982 7530 4005 7540
      4007 7536 4006 7539 4012 7544 4013 7499
      4012 7497
TIME...MOT...LOC 0643Z 257DEG 37KT 4004 7528 

HAIL...1.00IN
WIND...<50MPH
 
$$

NC
400 
WWUS51 KPHI 080654
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
254 AM EDT Wed Apr 8 2020

NJC007-015-PAC045-091-101-080704-
/O.EXP.KPHI.SV.W.0015.000000T0000Z-200408T0700Z/
Camden NJ-Gloucester NJ-Montgomery PA-Philadelphia PA-Delaware PA-
254 AM EDT Wed Apr 8 2020

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN CAMDEN...NORTH
CENTRAL GLOUCESTER...SOUTHEASTERN MONTGOMERY...PHILADELPHIA AND
EASTERN DELAWARE COUNTIES WILL EXPIRE AT 300 AM EDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire.  However small hail
is still possible with this thunderstorm.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Mount Holly NJ.

LAT...LON 4003 7500 4002 7504 3999 7506 4000 7504
      3998 7502 3976 7509 3982 7530 4005 7540
      4007 7536 4006 7539 4012 7544 4013 7499
      4012 7497
TIME...MOT...LOC 0654Z 257DEG 37KT 4006 7514 

$$

NC

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 7, 9:30 PM EDTCoastal Flood AdvisoryPHIBucks, Delaware, Philadelphia33 hr
Apr 8, 1:53 AM EDTSpecial Weather StatementPHICarbon, Lehigh, Northampton37 min
Apr 8, 1:55 AM EDTSpecial Weather StatementPHIChester, Delaware50 min
Apr 8, 1:59 AM EDTSpecial Weather StatementPHIBerks46 min
Apr 8, 2:40 AM EDTSpecial Weather StatementPHILehigh, Northampton35 min
Apr 8, 7:19 PM EDTWind AdvisoryPHIBerks, Bucks, Carbon, Chester, Delaware, Lehigh and 4 more24 hr
Apr 8, 2:35 AM EDTSpecial Weather StatementPHICamden25 min
Apr 8, 2:51 AM EDTSpecial Weather StatementPHICumberland24 min
Apr 8, 2:58 AM EDTSpecial Weather StatementPHIBurlington32 min
Apr 8, 3:13 AM EDTSpecial Weather StatementPHIHunterdon, Mercer, Middlesex32 min
Apr 8, 3:25 AM EDTSpecial Weather StatementPHIBurlington, Ocean35 min
Apr 8, 3:50 AM EDTGale WatchPHI24 hr
Apr 8, 4:21 AM EDTSpecial Weather StatementPHICumberland39 min
Apr 8, 4:52 AM EDTSpecial Marine WarningPHI83 min
Apr 8, 4:56 AM EDTSpecial Weather StatementPHIAtlantic, Cape May, Cumberland64 min
Apr 8, 3:24 PM EDTGale WarningPHI58 hr

Nearby

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