Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2026

Severe Thunderstorm Warning 35, NWS Philadelphia/Mount Holly

May 20, 2026Hunterdon County, Warren County, New Jersey; 4 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 20, 2026, 4:43 PM EDT for Hunterdon County, Warren County, New Jersey; 4 counties in Pennsylvania. It was in force for 47 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, 4:43 PM EDT (20:43 UTC)
Expired: May 20, 2026, 5:30 PM EDT
In force: 47 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Hunterdon County, NJ, Warren County, NJ, Berks County, PA, Bucks County, PA, Lehigh County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 119 km from the middle of the area, began a volume at 20:43 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, 4:59 PM EDT	TSTM WND DMG	3 Se Emmaus, PA	Downed utility on BEVERLY HILLS RD / CHURCHVIEW RD both directions between LIMEPORT PK and LAMOUR ST. All lanes now open. Time estimated from radar.
May 20, 4:59 PM EDT	TSTM WND DMG	3 Se Emmaus, PA	Downed utility on BEVERLY HILLS RD / CHURCHVIEW RD both directions between LIMEPORT PK and LAMOUR ST. All lanes now open. Time estimated from radar.
May 20, 5:22 PM EDT	TSTM WND DMG	1 Ene Kintnersville, PA	River Road closed between PA-611 and Narrows Hill Road due to trees and wires down. 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, 8.7 hours before the alert went out and 221 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.

579 
WUUS51 KPHI 202043
SVRPHI
NJC019-041-PAC011-017-077-095-202130-
/O.NEW.KPHI.SV.W.0035.260520T2043Z-260520T2130Z/

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

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Western Hunterdon County in northwestern New Jersey...
  Southwestern Warren County in northwestern New Jersey...
  Northeastern Berks County in eastern Pennsylvania...
  Lehigh County in eastern Pennsylvania...
  Northwestern Bucks County in southeastern Pennsylvania...
  Southern Northampton County in eastern Pennsylvania...

* Until 530 PM EDT.

* At 442 PM EDT, a severe thunderstorm was located over Coffeetown,
  or 7 miles west of Allentown, 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...
  Allentown, Easton, Bethlehem, Forks, Emmaus, Northampton,
  Quakertown, Byram, Wilson, Bedminster, Hellertown, Nazareth,
  Kutztown, Slatington, Tinicum, Bath, Harmony, Alpha, Walnutport,
  and Topton.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4071 7581 4072 7578 4077 7549 4075 7503
      4060 7501 4041 7505 4050 7584
TIME...MOT...LOC 2042Z 275DEG 32KT 4063 7560 

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

$$

Fitzsimmons

1 follow-up statement

523 
WWUS51 KPHI 202101
SVSPHI

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

PAC011-202110-
/O.CAN.KPHI.SV.W.0035.000000T0000Z-260520T2130Z/
Berks PA-
501 PM EDT Wed May 20 2026

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN BERKS 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
northwestern New Jersey...and eastern and southeastern Pennsylvania.

LAT...LON 4047 7552 4077 7551 4077 7549 4075 7503
      4060 7501 4041 7505 4044 7530
TIME...MOT...LOC 2100Z 275DEG 32KT 4062 7538 

$$

NJC019-041-PAC017-077-095-202130-
/O.CON.KPHI.SV.W.0035.000000T0000Z-260520T2130Z/
Hunterdon NJ-Warren NJ-Lehigh PA-Bucks PA-Northampton PA-
501 PM EDT Wed May 20 2026

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 530 PM EDT
FOR WESTERN HUNTERDON...SOUTHWESTERN WARREN...SOUTHEASTERN LEHIGH...
NORTHWESTERN BUCKS AND SOUTHERN NORTHAMPTON COUNTIES...

At 500 PM EDT, a severe thunderstorm was located over Lehigh
University, or near Allentown, moving east at 35 mph.

HAZARD...70 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect considerable tree damage. Damage is likely to mobile 
         homes, roofs, and outbuildings.

Locations impacted include...
Allentown, Easton, Bethlehem, Forks, Emmaus, Northampton, Quakertown,
Byram, Wilson, Bedminster, Hellertown, Nazareth, Tinicum, Bath,
Harmony, Alpha, Ferndale, Frenchtown, West Easton, and Milford.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4047 7552 4077 7551 4077 7549 4075 7503
      4060 7501 4041 7505 4044 7530
TIME...MOT...LOC 2100Z 275DEG 32KT 4062 7538 

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 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, 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, 5:29 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 Pennsylvania, 2026 Severe Thunderstorm Warnings in New Jersey, 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.