Alert archive / New Jersey / Severe Thunderstorm Warnings in 2026

Severe Thunderstorm Warning 41, NWS Philadelphia/Mount Holly

May 20, 2026Bucks County, Northampton County, Pennsylvania; 5 counties in New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 20, 2026, 5:24 PM EDT for Bucks County, Northampton County, Pennsylvania; 5 counties in New Jersey. It was in force for 51 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, 5:24 PM EDT (21:24 UTC)
Expired: May 20, 2026, 6:15 PM EDT
In force: 51 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Hunterdon County, NJ, Middlesex County, NJ, Morris County, NJ, Somerset County, NJ, Warren County, NJ, Bucks County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 74 km from the middle of the area, began a volume at 21:25 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, 6:11 PM EDT	TSTM WND DMG	Piscataway, NJ	Social media image of a large tree limb down. Time approximate from KDIX radar.
May 20, 6:11 PM EDT	TSTM WND DMG	Piscataway, NJ	Social media image of a large tree limb down. Time approximate from KDIX 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

Brookhaven, NY (KOKX), launched 12:00Z, 9.4 hours before the alert went out and 149 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: 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.

722 
WUUS51 KPHI 202124
SVRPHI
NJC019-023-027-035-041-PAC017-095-202215-
/O.NEW.KPHI.SV.W.0041.260520T2124Z-260520T2215Z/

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

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Hunterdon County in northwestern New Jersey...
  Southwestern Morris County in northern New Jersey...
  Southwestern Warren County in northwestern New Jersey...
  Somerset County in northern New Jersey...
  Northwestern Middlesex County in northern New Jersey...
  Northwestern Bucks County in southeastern Pennsylvania...
  Southeastern Northampton County in eastern Pennsylvania...

* Until 615 PM EDT.

* At 523 PM EDT, a severe thunderstorm was located over Milford, or
  11 miles southeast of Easton, moving east at 35 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  New Brunswick, Easton, Somerville, Somerset, East Brunswick,
  Bridgewater, North Brunswick, Forks, Middlesex, Bound Brook,
  Manville, Byram, Wilson, Washington, Mendham, Flemington, Tinicum,
  High Bridge, Clinton, and Harmony.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4041 7444 4043 7532 4075 7527 4076 7444
      4069 7444 4067 7446 4065 7444 4061 7444
      4060 7446 4059 7444
TIME...MOT...LOC 2123Z 271DEG 31KT 4057 7507 

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

$$

Fitzsimmons

1 follow-up statement

736 
WWUS51 KPHI 202143
SVSPHI

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

PAC017-095-202152-
/O.CAN.KPHI.SV.W.0041.000000T0000Z-260520T2215Z/
Bucks PA-Northampton PA-
543 PM EDT Wed May 20 2026

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN BUCKS AND
SOUTHEASTERN NORTHAMPTON 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
central, northern and northwestern New Jersey.

LAT...LON 4043 7505 4074 7504 4076 7444 4069 7444
      4067 7446 4065 7444 4061 7444 4060 7446
      4059 7444 4041 7444
TIME...MOT...LOC 2142Z 271DEG 31KT 4057 7485 

$$

NJC019-023-027-035-041-202215-
/O.CON.KPHI.SV.W.0041.000000T0000Z-260520T2215Z/
Hunterdon NJ-Morris NJ-Warren NJ-Somerset NJ-Middlesex NJ-
543 PM EDT Wed May 20 2026

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 615 PM EDT
FOR HUNTERDON...SOUTHWESTERN MORRIS...SOUTH CENTRAL WARREN...SOMERSET
AND NORTHWESTERN MIDDLESEX COUNTIES...

At 542 PM EDT, a severe thunderstorm was located near Flemington, or
12 miles west of Somerville, moving east at 35 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
New Brunswick, Somerville, Somerset, East Brunswick, Bridgewater,
North Brunswick, Middlesex, Bound Brook, Manville, Mendham,
Flemington, High Bridge, Clinton, Peapack And Gladstone, Glen
Gardner, Hampton, Lebanon, Califon, Far Hills, and Millstone.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4043 7505 4074 7504 4076 7444 4069 7444
      4067 7446 4065 7444 4061 7444 4060 7446
      4059 7444 4041 7444
TIME...MOT...LOC 2142Z 271DEG 31KT 4057 7485 

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 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, 4:43 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Lehigh, Northampton	47 min
May 20, 4:46 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Lehigh, Montgomery	44 min
May 20, 4:50 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware	40 min
May 20, 5:10 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	50 min
May 20, 5:15 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Chester, Montgomery, Philadelphia	45 min
May 20, 5:29 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware, Philadelphia	46 min
May 20, 5:40 PM EDT	Flash Flood Warning	PHI	Bucks, Delaware, Montgomery, Philadelphia	3 hr
May 20, 5:41 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery, Philadelphia	49 min
May 20, 5:52 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery, Philadelphia	38 min
May 20, 6:01 PM EDT	Severe Thunderstorm Warning	PHI	Delaware, Montgomery, Philadelphia	44 min
May 20, 6:09 PM EDT	Severe Thunderstorm Warning	PHI	Delaware, Philadelphia	46 min
May 20, 2:25 PM EDT	Small Craft Advisory	PHI		3 days
May 20, 5:01 PM EDT	Special Marine Warning	PHI		86 min
May 20, 5:35 PM EDT	Severe Thunderstorm Warning	PHI	Salem	40 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, 6:12 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

Nearby

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