Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2026

Severe Thunderstorm Warning 348, NWS Philadelphia/Mount Holly

September 1, 20264 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Sep 1, 2026, 7:13 PM EDT for 4 counties in Pennsylvania. It was in force for 47 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Sep 1, 2026, 7:13 PM EDT (23:13 UTC)
Expired
Sep 1, 2026, 8:00 PM EDT
In force
47 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Berks County, PA, Chester County, PA, Lehigh County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 118 km from the middle of the area, began a volume at 23:16 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.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Sep 1, 4:32 PM EDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 11.2 hours before the alert went out and 225 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, Washington/Dulle, VA at 12:00Z on 2026-09-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 270 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, Washington/Dulle, VA at 12:00Z on 2026-09-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 104 square meters per square second.1939Sfc1 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
270 J/kg
Mixed-layer CIN
-74 J/kg
Mixed-layer LCL
1350 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
104 m²/s²
0-3 km storm-relative helicity
101 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

As transmitted.

897 
WUUS51 KPHI 012313
SVRPHI
PAC011-029-077-091-020000-
/O.NEW.KPHI.SV.W.0348.260901T2313Z-260902T0000Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
713 PM EDT Tue Sep 1 2026

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Eastern Berks County in eastern Pennsylvania...
  Northwestern Montgomery County in southeastern Pennsylvania...
  Central Lehigh County in eastern Pennsylvania...
  Northeastern Chester County in southeastern Pennsylvania...

* Until 800 PM EDT.

* At 713 PM EDT, a severe thunderstorm was located near Topton, or 12
  miles west of Allentown, moving south at 30 mph.

  HAZARD...60 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Minor damage to vehicles is possible. Wind damage to 
           roofs, siding, trees, and power lines is possible.

* Locations impacted include...
  Pottstown, Collegeville, Kutztown, Royersford, Fleetwood, Trappe,
  East Greenville, Topton, Schwenksville, Bally, Bechtelsville, Green
  Lane, Lyons, Pughtown, Ancient Oaks, Spring Mount, Claussville,
  Gilbertsville, Cedarville, and Skippack.

This includes Interstate 78 in Pennsylvania between mile markers 38
and 53.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4066 7561 4020 7536 4012 7574 4060 7587
TIME...MOT...LOC 2313Z 345DEG 24KT 4055 7570 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

DeSilva
2 follow-up statements
618 
WWUS51 KPHI 012338
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
738 PM EDT Tue Sep 1 2026

PAC011-029-077-091-020000-
/O.CON.KPHI.SV.W.0348.000000T0000Z-260902T0000Z/
Berks PA-Montgomery PA-Lehigh PA-Chester PA-
738 PM EDT Tue Sep 1 2026

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 800 PM EDT
FOR EAST CENTRAL BERKS...NORTHWESTERN MONTGOMERY...SOUTH CENTRAL
LEHIGH AND NORTH CENTRAL CHESTER COUNTIES...

At 738 PM EDT, a severe thunderstorm was located over Bally, or 14
miles south of Allentown, moving southeast at 25 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Minor damage to vehicles is possible. Wind damage to roofs, 
         siding, trees, and power lines is possible.

Locations impacted include...
Pottstown, Collegeville, Royersford, Trappe, East Greenville,
Schwenksville, Bally, Bechtelsville, Green Lane, Spring Mount,
Gilbertsville, Skippack, Boyertown, Pennsburg, Spring City, Macungie,
Red Hill, Alburtis, Pottsgrove, and Evansburg.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4048 7573 4053 7554 4020 7536 4014 7562
TIME...MOT...LOC 2338Z 336DEG 24KT 4040 7557 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

DeSilva
581 
WWUS51 KPHI 012351
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
751 PM EDT Tue Sep 1 2026

PAC011-029-077-091-020001-
/O.EXP.KPHI.SV.W.0348.000000T0000Z-260902T0000Z/
Berks PA-Montgomery PA-Lehigh PA-Chester PA-
751 PM EDT Tue Sep 1 2026

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL BERKS...
NORTHWESTERN MONTGOMERY...SOUTH CENTRAL LEHIGH AND NORTH CENTRAL
CHESTER COUNTIES WILL EXPIRE AT 800 PM EDT...

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 will be allowed to expire.

A Severe Thunderstorm Watch remains in effect until midnight EDT for
eastern and southeastern Pennsylvania.

LAT...LON 4048 7573 4053 7554 4020 7536 4014 7562
TIME...MOT...LOC 2351Z 345DEG 24KT 4033 7555 

$$

DeSilva

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 1, 2:30 AM EDTHeat AdvisoryPHIBucks, Chester, Delaware, Montgomery, Philadelphia18 hr
Sep 1, 5:45 PM EDTSevere Thunderstorm WarningPHIMonroe, Northampton45 min
Sep 1, 5:50 PM EDTSevere Thunderstorm WarningPHICarbon, Lehigh, Northampton40 min
Sep 1, 6:09 PM EDTSevere Thunderstorm WarningPHIBerks51 min
Sep 1, 6:21 PM EDTSevere Thunderstorm WarningPHIBerks39 min
Sep 1, 6:29 PM EDTSevere Thunderstorm WarningPHICarbon, Lehigh, Northampton46 min
Sep 1, 6:38 PM EDTFlash Flood WarningPHIBerks4 hr
Sep 1, 6:56 PM EDTSevere Thunderstorm WarningPHIBerks, Chester49 min
Sep 1, 6:58 PM EDTSevere Thunderstorm WarningPHIBerks34 min
Sep 1, 7:43 PM EDTSevere Thunderstorm WarningPHIBerks, Chester, Delaware47 min

Nearby

Severe 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.