Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2026

Severe Thunderstorm Warning 211, NWS Philadelphia/Mount Holly

July 21, 20264 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 21, 2026, 4:23 PM EDT for 4 counties in Pennsylvania. It was in force for 52 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 21, 2026, 4:23 PM EDT (20:23 UTC)
Expired
Jul 21, 2026, 5:15 PM EDT
In force
52 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 75 km from the middle of the area, began a volume at 20:25 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.

The watch it was issued in

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

IssuedProductOfficeLasted
Jul 21, 2:06 PM EDTTornado WatchSPC7 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 8.4 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 2026-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 941 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 2026-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 68 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
941 J/kg
Mixed-layer CIN
-113 J/kg
Mixed-layer LCL
772 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
68 m²/s²
0-3 km storm-relative helicity
112 m²/s²
Significant tornado parameter
0.2
Supercell composite
0.9

Open this sounding in Storm Lab

The text

As transmitted.

262 
WUUS51 KPHI 212023
SVRPHI
PAC029-045-091-101-212115-
/O.NEW.KPHI.SV.W.0211.260721T2023Z-260721T2115Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
423 PM EDT Tue Jul 21 2026

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Southeastern Montgomery County in southeastern Pennsylvania...
  East central Chester County in southeastern Pennsylvania...
  Southwestern Philadelphia County in southeastern Pennsylvania...
  Delaware County in southeastern Pennsylvania...

* Until 515 PM EDT.

* At 423 PM EDT, a severe thunderstorm was located over Gradyville,
  or 7 miles east of West Chester, moving east at 25 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Philadelphia, Yeadon, Folcroft, Swarthmore, Narberth, National
  Park, East Lansdowne, Darby Township, Cheyney, Morris Park,
  Germantown, Bryn Mawr, Lima, Trout Lake, South Philadelphia, Radnor
  Township, Gradyville, Nether Providence Township, Broomall, and
  Newtown Square.

This includes the following highways...
 Interstate 95 in Pennsylvania between mile markers 11 and 18.
 Interstate 76 in Pennsylvania between mile markers 336 and 350.
 Interstate 676 in Pennsylvania between mile markers 0 and 1.
 Interstate 476 in Pennsylvania between mile markers 1 and 13.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 900 PM EDT for southern New
Jersey...and southeastern Pennsylvania.

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

A Tornado Watch remains in effect until 900 PM EDT for southern New
Jersey...and southeastern Pennsylvania.

&&

LAT...LON 4007 7515 3988 7515 3987 7520 3990 7555
      4001 7555
TIME...MOT...LOC 2023Z 266DEG 21KT 3997 7547 

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

$$

AKL
2 follow-up statements
008 
WWUS51 KPHI 212045
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
445 PM EDT Tue Jul 21 2026

PAC029-212054-
/O.CAN.KPHI.SV.W.0211.000000T0000Z-260721T2115Z/
Chester PA-
445 PM EDT Tue Jul 21 2026

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL 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 Tornado Watch remains in effect until 900 PM EDT for southern New
Jersey...and southeastern Pennsylvania.

LAT...LON 3993 7554 3992 7553 3994 7552 3996 7549
      3998 7535 4004 7532 4007 7515 3988 7515
      3987 7520 3990 7555
TIME...MOT...LOC 2044Z 265DEG 25KT 3998 7523 

$$

PAC045-091-101-212115-
/O.CON.KPHI.SV.W.0211.000000T0000Z-260721T2115Z/
Montgomery PA-Philadelphia PA-Delaware PA-
445 PM EDT Tue Jul 21 2026

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM EDT
FOR SOUTHEASTERN MONTGOMERY...SOUTHWESTERN PHILADELPHIA AND CENTRAL
DELAWARE COUNTIES...

At 444 PM EDT, a severe thunderstorm was located over Roxborough, or
near 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, Yeadon, Folcroft, Swarthmore, Narberth, National Park,
East Lansdowne, Darby Township, Cheyney, Morris Park, Germantown,
Bryn Mawr, Lima, South Philadelphia, Gradyville, Nether Providence
Township, Broomall, Roxborough, Philadelphia International Airport,
and Drexel Hill.

This includes the following highways...
 Interstate 95 in Pennsylvania between mile markers 11 and 18.
 Interstate 76 in Pennsylvania between mile markers 336 and 350.
 Interstate 676 in Pennsylvania between mile markers 0 and 1.
 Interstate 476 in Pennsylvania between mile markers 1 and 9.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 900 PM EDT for southern New
Jersey...and southeastern Pennsylvania.

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

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3993 7554 3992 7553 3994 7552 3996 7549
      3998 7535 4004 7532 4007 7515 3988 7515
      3987 7520 3990 7555
TIME...MOT...LOC 2044Z 265DEG 25KT 3998 7523 

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

$$

Staarmann
960 
WWUS51 KPHI 212105
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
505 PM EDT Tue Jul 21 2026

PAC045-091-101-212115-
/O.EXP.KPHI.SV.W.0211.000000T0000Z-260721T2115Z/
Montgomery PA-Philadelphia PA-Delaware PA-
505 PM EDT Tue Jul 21 2026

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN MONTGOMERY...
SOUTHWESTERN PHILADELPHIA AND CENTRAL DELAWARE COUNTIES WILL EXPIRE
AT 515 PM EDT...

The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire.  However heavy rain is still possible with this
thunderstorm.

A Tornado Watch remains in effect until 900 PM EDT for southern New
Jersey...and southeastern Pennsylvania.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Mount Holly NJ.

LAT...LON 3993 7554 3992 7553 3994 7552 3996 7549
      3998 7535 4004 7532 4007 7515 3988 7515
      3987 7520 3990 7555
TIME...MOT...LOC 2105Z 266DEG 21KT 3999 7508 

$$

Staarmann

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 21, 2:18 PM EDTSevere Thunderstorm WarningPHIBerks, Lehigh42 min
Jul 21, 2:57 PM EDTSevere Thunderstorm WarningPHIBucks, Lehigh, Northampton37 min
Jul 21, 3:37 PM EDTSevere Thunderstorm WarningPHIChester, Delaware53 min
Jul 21, 3:47 PM EDTSevere Thunderstorm WarningPHICarbon, Monroe43 min
Jul 21, 3:58 PM EDTSevere Thunderstorm WarningPHIChester, Delaware47 min
Jul 21, 4:31 PM EDTFlash Flood WarningPHIChester, Delaware96 min
Jul 21, 4:38 PM EDTFlash Flood Warning Considerable damage threatPHIChester, Delaware, Montgomery, Philadelphia4 hr
Jul 21, 4:43 PM EDTSevere Thunderstorm WarningPHIChester, Delaware47 min
Jul 21, 5:30 PM EDTSevere Thunderstorm WarningPHIDelaware45 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.