Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 20, NWS Philadelphia/Mount Holly

April 9, 20204 states

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Apr 9, 2020, 1:12 PM EDT for 4 states. It was in force for 48 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
Apr 9, 2020, 1:12 PM EDT (17:12 UTC)
Expired
Apr 9, 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 New Castle County, DE, Cecil County, MD, Camden County, NJ, Gloucester County, NJ, Salem County, NJ, Chester County, PA, Delaware County, PA, Philadelphia County, PA

The radar

The Dover AFB radar (KDOX), 94 km from the middle of the area, began a volume at 17:13 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 9, 1:18 PM EDTTSTM WND DMG2 Nne Elkton, MDSEVERAL TREE LIMBS DOWN. TIME ESTIMATED FROM RADAR.
Apr 9, 1:20 PM EDTTSTM WND DMGWoodlyn, PATREE INTO A HOUSE IN WOODLYN. TIME ESTIMATED FROM RADAR.
Apr 9, 1:26 PM EDTTSTM WND GST 54New Castle Airport (Kil, DE
Apr 9, 1:28 PM EDTTSTM WND GST 50Aston Twp., PA
Apr 9, 1:29 PM EDTTSTM WND GST 59Philadelphia Internatio, PAKPHL MEASURED 51 KT WIND GUST.
Apr 9, 1:30 PM EDTTSTM WND GST 501 W Logan Twp., NJNJWXNET MEASURED GUST.
Apr 9, 1:35 PM EDTTSTM WND GST 634 Ssw Elsinboro Twp, NJNJWXNET MEASURED GUST.
Apr 9, 1:45 PM EDTHAIL 0.75Mullica Hill, NJREPORT FROM MPING: DIME (0.75 IN.).
Apr 9, 1:50 PM EDTTSTM WND GST 60Sewell, NJ
Apr 9, 2:03 PM EDTTSTM WND GST 591 S Eastwick, PAITWS MEASURED GUST.

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.

IssuedProductOfficeLasted
Apr 9, 12:01 PM EDTSevere Thunderstorm WatchSPC4 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 5.2 hours before the alert went out and 171 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 2020-04-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 20 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 2020-04-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 394 square meters per square second.1939587897117Sfc1 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
20 J/kg
Mixed-layer CIN
-589 J/kg
Mixed-layer LCL
1002 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
394 m²/s²
0-3 km storm-relative helicity
416 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

729 
WUUS51 KPHI 091712
SVRPHI
DEC003-MDC015-NJC007-015-033-PAC029-045-101-091800-
/O.NEW.KPHI.SV.W.0020.200409T1712Z-200409T1800Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
112 PM EDT Thu Apr 9 2020

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  New Castle County in northern Delaware...
  Northeastern Cecil County in northeastern Maryland...
  Salem County in southern New Jersey...
  West central Camden County in southern New Jersey...
  Northwestern Gloucester County in southern New Jersey...
  South central Chester County in southeastern Pennsylvania...
  Southwestern Philadelphia County in southeastern Pennsylvania...
  Southern Delaware County in southeastern Pennsylvania...

* Until 200 PM EDT.

* At 111 PM EDT, severe thunderstorms were located along a line
  extending from Westtown to Pike Creek to near Charlestown, moving
  east at 45 mph.

  HAZARD...60 mph wind gusts and penny size hail.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Philadelphia, Wilmington, Newark, Middletown, Elkton, Gloucester
  City, Chester, Deptford, West Deptford, Glassboro, Lindenwold,
  Pennsville, Bellmawr, Woodbury, Pitman, Carneys Point, Folcroft,
  Swarthmore, Elsmere and Paulsboro.

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 0 and 32.
 Interstate 95 in Pennsylvania between mile markers 0 and 14.
 Interstate 95 in Maryland between mile markers 103 and 109.
 New Jersey Turnpike between exits 1 and 3.
 Interstate 95 in Delaware between mile markers 0 and 23.
 Interstate 476 in Pennsylvania between mile markers 0 and 2.
 Interstate 76 in New Jersey between mile markers 0 and 1.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 3975 7577 3992 7559 3988 7496 3967 7515
      3941 7553 3950 7599 3952 7598 3955 7602
TIME...MOT...LOC 1711Z 276DEG 38KT 3992 7556 3974 7570 3953 7600 

HAIL...0.75IN
WIND...60MPH
 
$$

MPS
2 follow-up statements
426 
WWUS51 KPHI 091739
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
139 PM EDT Thu Apr 9 2020

MDC015-PAC029-091748-
/O.CAN.KPHI.SV.W.0020.000000T0000Z-200409T1800Z/
Cecil MD-Chester PA-
139 PM EDT Thu Apr 9 2020

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN CECIL AND SOUTH
CENTRAL CHESTER COUNTIES IS CANCELLED...

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

A Severe Thunderstorm Watch remains in effect until 400 PM EDT for
northern Delaware...southern New Jersey...and southeastern
Pennsylvania.

LAT...LON 3971 7541 3990 7526 3988 7496 3967 7515
      3941 7553 3946 7577
TIME...MOT...LOC 1738Z 275DEG 38KT 3989 7520 3971 7534 3950 7564 

$$

DEC003-NJC007-015-033-PAC045-101-091800-
/O.CON.KPHI.SV.W.0020.000000T0000Z-200409T1800Z/
New Castle DE-Salem NJ-Camden NJ-Gloucester NJ-Philadelphia PA-
Delaware PA-
139 PM EDT Thu Apr 9 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 200 PM EDT
FOR SOUTHWESTERN NEW CASTLE...WESTERN SALEM...WEST CENTRAL CAMDEN...
NORTHWESTERN GLOUCESTER...SOUTHWESTERN PHILADELPHIA AND SOUTHEASTERN
DELAWARE COUNTIES...

At 138 PM EDT, severe thunderstorms were located along a line
extending from South Philadelphia to near Swedesboro to near Port
Penn, moving east at 45 mph.

HAZARD...60 mph wind gusts and penny size hail.

SOURCE...Radar indicated.

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

Locations impacted include...
Philadelphia, Middletown, Gloucester City, Deptford, West Deptford,
Glassboro, Lindenwold, Pennsville, Bellmawr, Woodbury, Pitman,
Folcroft, Paulsboro, Salem, Magnolia, Westville, Woodstown, Alloway,
Woodbury Heights and National Park.

This includes the following highways...
 Interstate 295 in New Jersey between mile markers 9 and 32.
 Interstate 95 in Pennsylvania between mile markers 11 and 14.
 New Jersey Turnpike between exits 1 and 3.
 Interstate 76 in New Jersey between mile markers 0 and 1.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 3971 7541 3990 7526 3988 7496 3967 7515
      3941 7553 3946 7577
TIME...MOT...LOC 1738Z 275DEG 38KT 3989 7520 3971 7534 3950 7564 

HAIL...0.75IN
WIND...60MPH
 
$$

MPS
043 
WWUS51 KPHI 091750 RRA
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
150 PM EDT Thu Apr 9 2020

DEC003-NJC007-015-033-PAC045-101-091800-
/O.EXP.KPHI.SV.W.0020.000000T0000Z-200409T1800Z/
New Castle DE-Salem NJ-Camden NJ-Gloucester NJ-Philadelphia PA-
Delaware PA-
150 PM EDT Thu Apr 9 2020

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN NEW CASTLE...
WESTERN SALEM...WEST CENTRAL CAMDEN...NORTHWESTERN GLOUCESTER...
SOUTHWESTERN PHILADELPHIA AND SOUTHEASTERN DELAWARE COUNTIES WILL
EXPIRE AT 200 PM EDT...
    
The storms which prompted the warning have weakened below severe
limits, and have exited the warned area. Therefore, the warning will
be allowed to expire.

A Severe Thunderstorm Watch remains in effect until 400 PM EDT for
northern Delaware...southern New Jersey...and southeastern
Pennsylvania.

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 3971 7541 3990 7526 3988 7496 3967 7515
      3941 7553 3946 7577
TIME...MOT...LOC 1750Z 276DEG 38KT 3988 7504 3970 7518 3949 7549 

$$

MPS

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 9, 12:05 PM EDTSpecial Weather StatementPHIBerks, Carbon, Lehigh, Monroe, Northampton40 min
Apr 9, 12:23 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Chester, Lehigh, Montgomery52 min
Apr 9, 1:00 PM EDTSevere Thunderstorm WarningPHIBucks, Chester, Delaware, Montgomery, Philadelphia45 min
Apr 9, 1:23 PM EDTSevere Thunderstorm WarningPHIBucks52 min
Apr 9, 1:26 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Chester, Delaware, Montgomery, Philadelphia49 min
Apr 9, 1:33 PM EDTSevere Thunderstorm WarningPHIBucks, Delaware, Philadelphia42 min
Apr 9, 3:32 PM EDTWind AdvisoryPHIBerks, Bucks, Carbon, Chester, Delaware, Lehigh and 4 more27 hr
Apr 9, 9:57 AM EDTSpecial Marine WarningPHI63 min
Apr 9, 10:56 AM EDTSpecial Marine WarningPHI29 min
Apr 9, 12:52 PM EDTSpecial Weather StatementPHIHunterdon, Morris, Somerset, Sussex, Warren23 min
Apr 9, 1:14 PM EDTSpecial Weather StatementPHIMorris31 min
Apr 9, 1:18 PM EDTSpecial Weather StatementPHICumberland27 min
Apr 9, 1:30 PM EDTSpecial Marine WarningPHI60 min
Apr 9, 1:44 PM EDTSpecial Marine WarningPHI61 min
Apr 9, 2:08 PM EDTSevere Thunderstorm WarningPHIAtlantic, Burlington, Monmouth, Ocean30 min
Apr 9, 2:13 PM EDTSpecial Marine WarningPHI33 min
Apr 9, 3:13 PM EDTCoastal Flood StatementPHIOcean4 hr
Apr 9, 7:35 AM EDTSpecial Weather StatementPHIKent, Sussex40 min
Apr 9, 1:41 PM EDTSpecial Weather StatementPHIKent, Sussex34 min
Apr 9, 2:11 PM EDTSpecial Weather StatementPHISussex49 min
Apr 9, 6:53 AM EDTSpecial Weather StatementPHIQueen Anne's, Talbot37 min
Apr 9, 12:29 PM EDTSevere Thunderstorm WarningPHIKent, Queen Anne's31 min
Apr 9, 12:57 PM EDTSevere Thunderstorm WarningPHICaroline, Queen Anne's, Talbot33 min

Nearby

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