Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2026

Severe Thunderstorm Warning 229, NWS Philadelphia/Mount Holly

July 27, 2026Chester County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 27, 2026, 3:01 PM EDT for Chester County, Montgomery County, Pennsylvania. It was in force for 44 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
Jul 27, 2026, 3:01 PM EDT (19:01 UTC)
Expired
Jul 27, 2026, 3:45 PM EDT
In force
44 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Chester County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 95 km from the middle of the area, began a volume at 19:02 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 nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 7.0 hours before the alert went out and 213 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 2026-07-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 87 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 2026-07-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 5 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
87 J/kg
Mixed-layer CIN
-53 J/kg
Mixed-layer LCL
1233 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
5 m²/s²
0-3 km storm-relative helicity
45 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

612 
WUUS51 KPHI 271901
SVRPHI
PAC029-091-271945-
/O.NEW.KPHI.SV.W.0229.260727T1901Z-260727T1945Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
301 PM EDT Mon Jul 27 2026

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Southwestern Montgomery County in southeastern Pennsylvania...
  Northeastern Chester County in southeastern Pennsylvania...

* Until 345 PM EDT.

* At 301 PM EDT, a severe thunderstorm was located over Collegeville,
  or 17 miles northeast of West Chester, moving southeast at 10 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Norristown, Phoenixville, West Norriton, East Norriton,
  Collegeville, Royersford, Trappe, Schwenksville, Valley Forge,
  Paoli, King Of Prussia, Skippack, Spring City, Malvern, Evansburg,
  Audubon, Chesterbrook, Eagleville, Trooper, and Blue Bell.

This includes the following highways...
 Pennsylvania Turnpike between mile markers 320 and 327.
 Northeast Extension near mile marker 23.
 Interstate 76 in Pennsylvania near mile marker 327.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4021 7559 4027 7549 4015 7528 4002 7551
TIME...MOT...LOC 1901Z 316DEG 10KT 4018 7547 

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

$$

Guzzo
2 follow-up statements
347 
WWUS51 KPHI 271920
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
320 PM EDT Mon Jul 27 2026

PAC029-091-271945-
/O.CON.KPHI.SV.W.0229.000000T0000Z-260727T1945Z/
Montgomery PA-Chester PA-
320 PM EDT Mon Jul 27 2026

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 345 PM EDT
FOR CENTRAL MONTGOMERY AND NORTHEASTERN CHESTER COUNTIES...

At 319 PM EDT, a severe thunderstorm was located over West Norriton,
or 15 miles northeast of West Chester, moving southeast at 20 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Norristown, Phoenixville, West Norriton, East Norriton, Collegeville,
Royersford, Trappe, Schwenksville, Valley Forge, Paoli, King Of
Prussia, Skippack, Spring City, Malvern, Evansburg, Audubon,
Chesterbrook, Eagleville, Trooper, and Blue Bell.

This includes the following highways...
 Pennsylvania Turnpike between mile markers 320 and 327.
 Northeast Extension near mile marker 23.
 Interstate 76 in Pennsylvania near mile marker 327.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4020 7558 4026 7548 4015 7528 4002 7551
TIME...MOT...LOC 1919Z 318DEG 17KT 4014 7542 

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

$$

Guzzo
312 
WWUS51 KPHI 271936
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
336 PM EDT Mon Jul 27 2026

PAC029-091-271945-
/O.EXP.KPHI.SV.W.0229.000000T0000Z-260727T1945Z/
Montgomery PA-Chester PA-
336 PM EDT Mon Jul 27 2026

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL MONTGOMERY AND
NORTHEASTERN CHESTER COUNTIES WILL EXPIRE AT 345 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.

LAT...LON 4020 7558 4026 7548 4015 7528 4002 7551
TIME...MOT...LOC 1935Z 316DEG 10KT 4011 7538 

$$

Guzzo

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 27, 2:15 PM EDTFlood WatchPHIBerks, Bucks, Carbon, Chester, Delaware, Lehigh and 4 more38 hr
Jul 27, 2:57 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery, Philadelphia48 min
Jul 27, 3:41 PM EDTSevere Thunderstorm WarningPHIMontgomery, Philadelphia49 min
Jul 27, 3:50 PM EDTSevere Thunderstorm WarningPHIMonroe, Northampton40 min
Jul 27, 3:58 PM EDTFlash Flood WarningPHIDelaware, Montgomery, Philadelphia3 hr
Jul 27, 5:25 PM EDTFlash Flood WarningPHILehigh2 hr
Jul 27, 5:51 PM EDTSevere Thunderstorm WarningPHIBerks, Lehigh23 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.