Alert archive / New Jersey / Severe Thunderstorm Warnings in 2026

Severe Thunderstorm Warning 39, NWS Philadelphia/Mount Holly

May 20, 20264 counties in New Jersey; 4 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 20, 2026, 5:15 PM EDT for 4 counties in New Jersey; 4 counties in Pennsylvania. It was in force for 45 min. 13 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, 5:15 PM EDT (21:15 UTC)
Expired: May 20, 2026, 6:00 PM EDT
In force: 45 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Burlington County, NJ, Hunterdon County, NJ, Mercer County, NJ, Somerset County, NJ, Bucks County, PA, Chester County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 78 km from the middle of the area, began a volume at 21:16 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, 5:23 PM EDT	TSTM WND DMG	2 Ssw Doylestown, PA	Downed tree on PA 611 northbound between BRISTOL RD and ALMSHOUSE RD. There is a traffic disruption. Time estimated from radar.
May 20, 5:23 PM EDT	TSTM WND DMG	2 Ssw Doylestown, PA	Downed tree on PA 611 northbound between BRISTOL RD and ALMSHOUSE RD. There is a traffic disruption. Time estimated from radar.
May 20, 5:25 PM EDT	TSTM WND DMG	2 Nnw Montgomeryville, PA	Trees and wires down around Colmar. Time estimated from radar.
May 20, 5:25 PM EDT	TSTM WND DMG	2 Nnw Montgomeryville, PA	Trees and wires down around Colmar. Time estimated from radar.
May 20, 5:30 PM EDT	TSTM WND DMG	2 W Jamison, PA	A 12 inch diameter tree snapped at its base. Time checked from radar.
May 20, 5:43 PM EDT	TSTM WND DMG	1 Nw Levittown, PA	Large tree limbs down, some onto powerlines, on High Road. Time estimated from radar.
May 20, 5:50 PM EDT	TSTM WND DMG	Pennington, NJ	Two trees were blown down by a strong wind gust ahead of the rain starting.
May 20, 5:50 PM EDT	TSTM WND GST 62	2 Wnw Yardley, PA	Mesonet station 11379 1 WNW Yardley.
May 20, 5:54 PM EDT	TSTM WND GST 51	3 E Tullytown, PA	Mesonet station NBLP1 Newbold NOS.
May 20, 5:57 PM EDT	TSTM WND DMG	1 Ene Hopewell, NJ	Several trees and wires down around Hopewell. Time estimated from radar.
May 20, 5:57 PM EDT	TSTM WND DMG	1 Ene Hopewell, NJ	Several trees and wires down around Hopewell. Time estimated from radar.
May 20, 6:06 PM EDT	TSTM WND DMG	Bordentown, NJ	Several wires down across Bordentown and Chesterfield. Time estimated from radar.
May 20, 6:06 PM EDT	TSTM WND DMG	Bordentown, NJ	Several wires down across Bordentown and Chesterfield. 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

Brookhaven, NY (KOKX), launched 12:00Z, 9.3 hours before the alert went out and 210 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.

793 
WUUS51 KPHI 202115
SVRPHI
NJC005-019-021-035-PAC017-029-091-101-202200-
/O.NEW.KPHI.SV.W.0039.260520T2115Z-260520T2200Z/

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

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Southeastern Hunterdon County in northwestern New Jersey...
  Mercer County in central New Jersey...
  North central Burlington County in southern New Jersey...
  Southwestern Somerset County in northern New Jersey...
  Montgomery County in southeastern Pennsylvania...
  Bucks County in southeastern Pennsylvania...
  Northeastern Chester County in southeastern Pennsylvania...
  Northeastern Philadelphia County in southeastern Pennsylvania...

* Until 600 PM EDT.

* At 515 PM EDT, a severe thunderstorm was located over Chalfont, or
  19 miles north of Philadelphia, 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, Trenton, Ewing, Norristown, Phoenixville, Lansdale,
  West Norriton, East Norriton, Princeton, Florence, Bristol,
  Perkasie, Doylestown, Byram, Hatboro, Souderton, Ambler,
  Collegeville, Royersford, and Chalfont.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4010 7559 4042 7551 4042 7534 4043 7465
      4011 7468
TIME...MOT...LOC 2115Z 275DEG 26KT 4028 7520 

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

$$

Fitzsimmons

1 follow-up statement

375 
WWUS51 KPHI 202145
SVSPHI

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

PAC029-202154-
/O.CAN.KPHI.SV.W.0039.000000T0000Z-260520T2200Z/
Chester PA-
545 PM EDT Wed May 20 2026

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN CHESTER COUNTY 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, central, northern and northwestern New Jersey...and
southeastern Pennsylvania.

LAT...LON 4011 7522 4042 7521 4043 7465 4011 7468
TIME...MOT...LOC 2144Z 275DEG 26KT 4026 7492 

$$

NJC005-019-021-035-PAC017-091-101-202200-
/O.CON.KPHI.SV.W.0039.000000T0000Z-260520T2200Z/
Hunterdon NJ-Mercer NJ-Burlington NJ-Somerset NJ-Montgomery PA-
Bucks PA-Philadelphia PA-
545 PM EDT Wed May 20 2026

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 600 PM EDT
FOR SOUTHEASTERN HUNTERDON...MERCER...NORTH CENTRAL BURLINGTON...
SOUTHWESTERN SOMERSET...EAST CENTRAL MONTGOMERY...SOUTHEASTERN BUCKS
AND NORTHEASTERN PHILADELPHIA COUNTIES...

At 544 PM EDT, a severe thunderstorm was located over Newtown, or 8
miles west of Trenton, 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, Trenton, Ewing, Princeton, Florence, Bristol,
Doylestown, Byram, Hatboro, Ambler, Chalfont, Bordentown, Pennington,
New Hope, Yardley, Newtown, Dublin, Hopewell, Tullytown, and
Abington.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4011 7522 4042 7521 4043 7465 4011 7468
TIME...MOT...LOC 2144Z 275DEG 26KT 4026 7492 

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, 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, 5:24 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Middlesex, Morris, Somerset, Warren	51 min
May 20, 5:29 PM EDT	Severe Thunderstorm Warning	PHI	Camden, Gloucester, Salem	46 min
May 20, 5:35 PM EDT	Severe Thunderstorm Warning	PHI	Salem	40 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
May 20, 4:50 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware	40 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.