Alert archive / New Jersey / Severe Thunderstorm Warnings in 2026

Severe Thunderstorm Warning 48, NWS Philadelphia/Mount Holly

May 20, 2026Delaware County, Philadelphia County, Pennsylvania; 5 counties in New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 20, 2026, 6:09 PM EDT for Delaware County, Philadelphia County, Pennsylvania; 5 counties in New Jersey. It was in force for 46 min. 2 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, 6:09 PM EDT (22:09 UTC)
Expired
May 20, 2026, 6:55 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 Atlantic County, NJ, Burlington County, NJ, Camden County, NJ, Gloucester County, NJ, Ocean County, NJ, Delaware County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 40 km from the middle of the area, began a volume at 22:11 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
May 20, 6:10 PM EDTTSTM WND DMGMedford, NJWires down along Taunton Road and Himmelein Road in Medford, likely due to the outflow boundary. Time estimated from radar.
May 20, 6:10 PM EDTTSTM WND DMGMedford, NJWires down along Taunton Road and Himmelein Road in Medford, likely due to the outflow boundary. 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.

IssuedProductOfficeLasted
May 20, 2:10 PM EDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 10.2 hours before the alert went out and 204 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 12:00Z on 2026-05-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 31 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, Brookhaven, NY at 12:00Z on 2026-05-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 90 square meters per square second.193958Sfc1 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
31 J/kg
Mixed-layer CIN
-279 J/kg
Mixed-layer LCL
1524 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
90 m²/s²
0-3 km storm-relative helicity
80 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

168 
WUUS51 KPHI 202209
SVRPHI
NJC001-005-007-015-029-PAC045-101-202315-
/O.NEW.KPHI.SV.W.0048.260520T2209Z-260520T2315Z/

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

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northern Atlantic County in southern New Jersey...
  West central Ocean County in southern New Jersey...
  Camden County in southern New Jersey...
  Northeastern Gloucester County in southern New Jersey...
  Burlington County in southern New Jersey...
  Southwestern Philadelphia County in southeastern Pennsylvania...
  East central Delaware County in southeastern Pennsylvania...

* Until 715 PM EDT.

* At 609 PM EDT, a severe thunderstorm was located over Magnolia, or
  near 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, Gloucester City, Cherry Hill, Evesham, Mount
  Laurel, Deptford, Voorhees, Medford, West Deptford, Glassboro,
  Lindenwold, Hammonton, Lumberton, Bellmawr, Yeadon, Woodbury, Mount
  Holly, Pitman, and Berlin.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Wind damage with this storm will occur before any rain or lightning.
Do not wait for the sound of thunder before taking cover. SEEK
SHELTER IMMEDIATELY inside a sturdy structure and stay away from
windows.

&&

LAT...LON 3969 7441 3970 7495 3975 7531 3998 7527
      4000 7523 4000 7436
TIME...MOT...LOC 2209Z 272DEG 25KT 3988 7505 

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

$$

Fitzsimmons
2 follow-up statements
521 
WWUS51 KPHI 202237
SVSPHI

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

NJC015-PAC045-101-202247-
/O.CAN.KPHI.SV.W.0048.000000T0000Z-260520T2315Z/
Gloucester NJ-Philadelphia PA-Delaware PA-
637 PM EDT Wed May 20 2026

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN GLOUCESTER...
SOUTHWESTERN PHILADELPHIA AND EAST CENTRAL DELAWARE COUNTIES IS
CANCELLED...

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

A Severe Thunderstorm Watch remains in effect until 900 PM EDT for
southern New Jersey.

LAT...LON 3969 7441 3970 7496 3970 7498 3973 7502
      4000 7500 4000 7436
TIME...MOT...LOC 2237Z 272DEG 25KT 3987 7480 

$$

NJC001-005-007-029-202315-
/O.CON.KPHI.SV.W.0048.000000T0000Z-260520T2315Z/
Atlantic NJ-Ocean NJ-Camden NJ-Burlington NJ-
637 PM EDT Wed May 20 2026

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 715 PM EDT
FOR NORTHERN ATLANTIC...WEST CENTRAL OCEAN...CENTRAL CAMDEN AND
BURLINGTON COUNTIES...

At 637 PM EDT, a severe thunderstorm was located over Medford, or 16
miles east of Camden, 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...
Cherry Hill, Evesham, Mount Laurel, Voorhees, Medford, Lindenwold,
Hammonton, Lumberton, Mount Holly, Berlin, Tabernacle, Shamong,
Presidential Lakes Estates, Chesilhurst, Pemberton, Wrightstown,
Atsion, Barclay-Kingston, Marlton, and Leisuretowne.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Wind damage with this storm will occur before any rain or lightning.
Do not wait for the sound of thunder before taking cover. SEEK
SHELTER IMMEDIATELY inside a sturdy structure and stay away from
windows.

&&

LAT...LON 3969 7441 3970 7496 3970 7498 3973 7502
      4000 7500 4000 7436
TIME...MOT...LOC 2237Z 272DEG 25KT 3987 7480 

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

$$

Fitzsimmons
395 
WWUS51 KPHI 202255
SVSPHI

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

NJC001-005-007-029-202305-
/O.CAN.KPHI.SV.W.0048.000000T0000Z-260520T2315Z/
Atlantic NJ-Ocean NJ-Camden NJ-Burlington NJ-
655 PM EDT Wed May 20 2026

...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN ATLANTIC...WEST
CENTRAL OCEAN...CENTRAL CAMDEN AND BURLINGTON COUNTIES IS
CANCELLED...

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 has been cancelled.  However gusty winds and
heavy rain are still possible with this thunderstorm.

A Severe Thunderstorm Watch remains in effect until 900 PM EDT for
southern New Jersey.

LAT...LON 3969 7441 3970 7496 3970 7498 3973 7502
      4000 7500 4000 7436
TIME...MOT...LOC 2253Z 272DEG 25KT 3987 7463 

$$

Fitzsimmons

The office that day

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

IssuedProductOfficeCountiesLasted
May 19, 8:04 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery, Philadelphia25 min
May 20, 3:57 PM EDTSevere Thunderstorm WarningPHIBerks, Lehigh48 min
May 20, 4:00 PM EDTSevere Thunderstorm WarningPHIBerks45 min
May 20, 4:29 PM EDTSevere Thunderstorm WarningPHIBerks, Chester, Montgomery46 min
May 20, 4:43 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Lehigh, Northampton47 min
May 20, 4:46 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Lehigh, Montgomery44 min
May 20, 4:50 PM EDTSevere Thunderstorm WarningPHIChester, Delaware40 min
May 20, 5:10 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Montgomery, Philadelphia50 min
May 20, 5:15 PM EDTSevere Thunderstorm WarningPHIBucks, Chester, Montgomery, Philadelphia45 min
May 20, 5:24 PM EDTSevere Thunderstorm WarningPHIBucks, Northampton51 min
May 20, 5:29 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Philadelphia46 min
May 20, 5:40 PM EDTFlash Flood WarningPHIBucks, Delaware, Montgomery, Philadelphia3 hr
May 20, 5:41 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery, Philadelphia49 min
May 20, 5:52 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery, Philadelphia38 min
May 20, 6:01 PM EDTSevere Thunderstorm WarningPHIDelaware, Montgomery, Philadelphia44 min
May 20, 2:25 PM EDTSmall Craft AdvisoryPHI3 days
May 20, 5:01 PM EDTSpecial Marine WarningPHI86 min
May 20, 5:35 PM EDTSevere Thunderstorm WarningPHISalem40 min
May 20, 6:04 PM EDTSevere Thunderstorm Warning Considerable damage threatPHIHunterdon, Middlesex, Monmouth, Morris, Somerset56 min
May 20, 6:07 PM EDTSpecial Marine WarningPHI53 min
May 20, 6:12 PM EDTSevere Thunderstorm WarningPHIOcean33 min
May 20, 6:17 PM EDTSpecial Marine WarningPHI118 min
May 20, 6:23 PM EDTSevere Thunderstorm WarningPHIBurlington, Mercer, Middlesex, Monmouth, Ocean, Somerset56 min
May 20, 6:58 PM EDTSevere Thunderstorm WarningPHIOcean32 min
May 20, 7:30 PM EDTSpecial Marine WarningPHI90 min

Nearby

Severe Thunderstorm Warnings in New Jersey, 2026Severe Thunderstorm Warnings in Pennsylvania, 2026Every 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.