Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2026

Severe Thunderstorm Warning 210, NWS Philadelphia/Mount Holly

July 21, 2026New Castle County, Delaware; Chester County, Delaware County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 21, 2026, 3:58 PM EDT for New Castle County, Delaware; Chester County, Delaware County, Pennsylvania. It was in force for 47 min. 1 report 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
Jul 21, 2026, 3:58 PM EDT (19:58 UTC)
Expired
Jul 21, 2026, 4:45 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 New Castle County, DE, Chester County, PA, Delaware County, PA

The radar

The Dover AFB radar (KDOX), 116 km from the middle of the area, began a volume at 19:57 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

TimeReportWhereRemark
Jul 21, 4:02 PM EDTTSTM WND DMGEast Bradford Twp, PADowned tree on US 322 both directions between NORTH CREEK RD and COPELAND SCHOOL RD. There is a lane restriction. 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.

IssuedProductOfficeLasted
Jul 21, 2:06 PM EDTTornado WatchSPC7 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 8.0 hours before the alert went out and 155 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.

393 
WUUS51 KPHI 211958
SVRPHI
DEC003-PAC029-045-212045-
/O.NEW.KPHI.SV.W.0210.260721T1958Z-260721T2045Z/

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

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northwestern New Castle County in northern Delaware...
  Southwestern Chester County in southeastern Pennsylvania...
  Western Delaware County in southeastern Pennsylvania...

* Until 445 PM EDT.

* At 358 PM EDT, a severe thunderstorm was located over Wakefield, or
  15 miles north of Havre De Grace, moving east at 45 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Wilmington, Newark, West Chester, Elsmere, Kennett Square, New
  Castle, Oxford, Parkesburg, West Grove, Newport, Glen Roy,
  Homeville, Cochranville, Stanton, North Star, Wilmington Manor,
  Mount Vernon, Marshallton, Pike Creek, and Ashland.

This includes Interstate 95 in Delaware between mile markers 3 and
13.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 900 PM EDT for northern
Delaware...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.

A Tornado Watch remains in effect until 900 PM EDT for northern
Delaware...and southeastern Pennsylvania.

&&

LAT...LON 3974 7612 3973 7610 3974 7610 3976 7606
      3981 7603 3983 7604 3983 7602 3987 7601
      3987 7599 3995 7599 3998 7558 3964 7556
      3965 7579 3972 7579 3972 7613
TIME...MOT...LOC 1958Z 266DEG 40KT 3977 7616 

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

$$

AKL
1 follow-up statement
455 
WWUS51 KPHI 212027
SVSPHI

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

DEC003-PAC029-045-212045-
/O.CON.KPHI.SV.W.0210.000000T0000Z-260721T2045Z/
New Castle DE-Chester PA-Delaware PA-
427 PM EDT Tue Jul 21 2026

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 445 PM EDT
FOR NORTHWESTERN NEW CASTLE...SOUTHWESTERN CHESTER AND WESTERN
DELAWARE COUNTIES...

At 427 PM EDT, a severe thunderstorm was located over West Grove, or
11 miles north of Newark, 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...
Wilmington, Newark, West Chester, Elsmere, Kennett Square, New
Castle, Oxford, Parkesburg, West Grove, Newport, Glen Roy, Homeville,
Cochranville, Stanton, North Star, Wilmington Manor, Mount Vernon,
Marshallton, Pike Creek, and Ashland.

This includes Interstate 95 in Delaware between mile markers 3 and
13.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 900 PM EDT for northern
Delaware...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 3974 7612 3973 7610 3974 7610 3976 7606
      3981 7603 3983 7604 3983 7602 3987 7601
      3987 7599 3995 7599 3998 7558 3964 7556
      3965 7579 3972 7579 3972 7613
TIME...MOT...LOC 2027Z 269DEG 31KT 3984 7580 

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

$$

AKL

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 21, 4:38 PM EDTFlash Flood Warning Considerable damage threatPHINew Castle4 hr
Jul 21, 4:43 PM EDTSevere Thunderstorm WarningPHINew Castle47 min
Jul 21, 5:06 PM EDTSevere Thunderstorm WarningPHIKent39 min
Jul 21, 5:30 PM EDTSevere Thunderstorm WarningPHINew Castle45 min
Jul 21, 5:42 PM EDTSevere Thunderstorm Warning Considerable damage threatPHIKent48 min
Jul 21, 6:00 PM EDTSevere Thunderstorm WarningPHIKent, New Castle45 min
Jul 21, 6:53 PM EDTFlash Flood WarningPHIKent, New Castle3 hr
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, 4:23 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Montgomery, Philadelphia52 min
Jul 21, 4:31 PM EDTFlash Flood WarningPHIChester, Delaware96 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2026Severe Thunderstorm Warnings in Delaware, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.