Alert archive / New Jersey / Severe Thunderstorm Warnings in 2026

Severe Thunderstorm Warning 42, NWS Philadelphia/Mount Holly

May 20, 2026New Castle County, Delaware; Camden County, Gloucester County, Salem County, New Jersey; Chester County, Delaware County, Philadelphia County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 20, 2026, 5:29 PM EDT for New Castle County, Delaware; Camden County, Gloucester County, Salem County, New Jersey; Chester County, 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: May 20, 2026, 5:29 PM EDT (21:29 UTC)
Expired: May 20, 2026, 6:15 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 New Castle County, DE, Camden County, NJ, Gloucester County, NJ, Salem County, NJ, Chester County, PA, Delaware County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 102 km from the middle of the area, began a volume at 21:30 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

Time	Report	Where	Remark
May 20, 5:37 PM EDT	TSTM WND GST 53	Philadelphia Internatio, PA	ASOS station KPHL Philadelphia International Airport.
May 20, 5:39 PM EDT	TSTM WND DMG	1 N Chester Heights, PA	Trees down on Route 1 across the roadway in Media resulting in lane closures. Time estimated from radar.
May 20, 5:39 PM EDT	TSTM WND DMG	1 N Chester Heights, PA	Trees down on Route 1 across the roadway in Media resulting in lane closures. Time estimated from radar.

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.

Issued	Product	Office	Lasted
May 20, 2:10 PM EDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 9.5 hours before the alert went out and 182 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: 47 J/kg
Mixed-layer CIN: -204 J/kg
Mixed-layer LCL: 1752 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: -79 m²/s²
0-3 km storm-relative helicity: -47 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

237 
WUUS51 KPHI 202129
SVRPHI
DEC003-NJC007-015-033-PAC029-045-101-202215-
/O.NEW.KPHI.SV.W.0042.260520T2129Z-260520T2215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
529 PM EDT Wed May 20 2026

The National Weather Service in Mount Holly NJ has issued a

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

* Until 615 PM EDT.

* At 528 PM EDT, a severe thunderstorm was located over Ashland, or 8
  miles northwest of Wilmington, moving east at 30 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, Wilmington, Newark, West Chester, Gloucester
  City, Chester, Deptford, West Deptford, Glassboro, Pennsville,
  Bellmawr, Yeadon, Westtown, Woodbury, Pitman, Clayton, Carneys
  Point, Folcroft, and Swarthmore.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3996 7580 3995 7504 3966 7505 3971 7579
      3972 7579 3972 7589
TIME...MOT...LOC 2128Z 273DEG 24KT 3983 7564 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Fitzsimmons

1 follow-up statement

414 
WWUS51 KPHI 202202
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
602 PM EDT Wed May 20 2026

PAC029-202212-
/O.CAN.KPHI.SV.W.0042.000000T0000Z-260520T2215Z/
Chester PA-
602 PM EDT Wed May 20 2026

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN CHESTER COUNTY IS
CANCELLED...

The severe thunderstorm which prompted the warning has moved out of 
the warned area. herefore, the warning has been
cancelled.

A Severe Thunderstorm Watch remains in effect until 900 PM EDT for
northern Delaware...southern New Jersey...and southeastern
Pennsylvania.

LAT...LON 3973 7549 3996 7547 3995 7504 3967 7505
TIME...MOT...LOC 2202Z 272DEG 25KT 3982 7531 

$$

DEC003-NJC007-015-033-PAC045-101-202215-
/O.CON.KPHI.SV.W.0042.000000T0000Z-260520T2215Z/
New Castle DE-Salem NJ-Camden NJ-Gloucester NJ-Philadelphia PA-
Delaware PA-
602 PM EDT Wed May 20 2026

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 615 PM EDT
FOR NORTHEASTERN NEW CASTLE...NORTH CENTRAL SALEM...NORTHWESTERN
CAMDEN...NORTHWESTERN GLOUCESTER...SOUTHWESTERN PHILADELPHIA AND
SOUTHEASTERN DELAWARE COUNTIES...

At 602 PM EDT, a severe thunderstorm was located over Gibbstown, or
11 miles southwest of Gloucester City, moving east at 30 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, Wilmington, Gloucester City, Chester, Deptford,
West Deptford, Glassboro, Bellmawr, Yeadon, Woodbury, Pitman,
Clayton, Carneys Point, Folcroft, Swarthmore, Paulsboro, Penns Grove,
Magnolia, and Westville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3973 7549 3996 7547 3995 7504 3967 7505
TIME...MOT...LOC 2202Z 272DEG 25KT 3982 7531 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Fitzsimmons

The office that day

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

Issued	Product	Office	Counties	Lasted
May 20, 4:50 PM EDT	Severe Thunderstorm Warning	PHI	New Castle	40 min
May 20, 5:18 PM EDT	Severe Thunderstorm Warning	PHI	Kent, New Castle	42 min
May 20, 5:35 PM EDT	Severe Thunderstorm Warning	PHI	New Castle	40 min
May 20, 2:25 PM EDT	Small Craft Advisory	PHI		3 days
May 20, 4:43 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Warren	47 min
May 20, 5:01 PM EDT	Special Marine Warning	PHI		86 min
May 20, 5:10 PM EDT	Severe Thunderstorm Warning	PHI	Camden, Gloucester	50 min
May 20, 5:15 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Hunterdon, Mercer, Somerset	45 min
May 20, 5:24 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Middlesex, Morris, Somerset, Warren	51 min
May 20, 5:40 PM EDT	Flash Flood Warning	PHI	Burlington, Camden, Gloucester	3 hr
May 20, 5:41 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Mercer, Monmouth, Ocean	49 min
May 20, 5:52 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Hunterdon, Mercer, Middlesex, Monmouth, Ocean and 1 more	38 min
May 20, 6:01 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Gloucester	44 min
May 20, 6:04 PM EDT	Severe Thunderstorm Warning Considerable damage threat	PHI	Hunterdon, Middlesex, Monmouth, Morris, Somerset	56 min
May 20, 6:07 PM EDT	Special Marine Warning	PHI		53 min
May 20, 6:09 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Camden, Gloucester, Ocean	46 min
May 20, 6:12 PM EDT	Severe Thunderstorm Warning	PHI	Ocean	33 min
May 20, 6:17 PM EDT	Special Marine Warning	PHI		118 min
May 20, 6:23 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Mercer, Middlesex, Monmouth, Ocean, Somerset	56 min
May 20, 6:58 PM EDT	Severe Thunderstorm Warning	PHI	Ocean	32 min
May 20, 7:30 PM EDT	Special Marine Warning	PHI		90 min
May 19, 8:04 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery, Philadelphia	25 min
May 20, 3:57 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh	48 min
May 20, 4:00 PM EDT	Severe Thunderstorm Warning	PHI	Berks	45 min
May 20, 4:29 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester, Montgomery	46 min
May 20, 4:46 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Lehigh, Montgomery	44 min

Nearby

Severe Thunderstorm Warnings in New Jersey, 2026 Severe Thunderstorm Warnings in Pennsylvania, 2026 Severe Thunderstorm Warnings in Delaware, 2026 Every severe thunderstorm warning in 2026

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.