Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2026

Severe Thunderstorm Warning 334, NWS Philadelphia/Mount Holly

August 27, 2026Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 27, 2026, 4:06 PM EDT for Chester County, Pennsylvania. It was in force for 39 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
Aug 27, 2026, 4:06 PM EDT (20:06 UTC)
Expired
Aug 27, 2026, 4:45 PM EDT
In force
39 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

County Chester County, PA

The radar

The Philadelphia radar (KDIX), 126 km from the middle of the area, began a volume at 20:09 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
Aug 27, 4:10 PM EDTTSTM WND DMG1 S Upper Oxford Twp, PATree damage between Oxford and Russellville. 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
Aug 27, 12:51 PM EDTSevere Thunderstorm WatchSPC9 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 8.1 hours before the alert went out and 170 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 2026-08-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 728 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 2026-08-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 145 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
728 J/kg
Mixed-layer CIN
-107 J/kg
Mixed-layer LCL
980 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
145 m²/s²
0-3 km storm-relative helicity
120 m²/s²
Significant tornado parameter
0.2
Supercell composite
2.7

Open this sounding in Storm Lab

The text

As transmitted.

714 
WUUS51 KPHI 272006
SVRPHI
PAC029-272045-
/O.NEW.KPHI.SV.W.0334.260827T2006Z-260827T2045Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
Issued by National Weather Service New York NY
406 PM EDT Thu Aug 27 2026

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Chester County in southeastern Pennsylvania...

* Until 445 PM EDT.

* At 406 PM EDT, a severe thunderstorm was located over Oxford, or 14
  miles northwest of Newark, moving northeast at 30 mph.

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

  SOURCE...Radar indicated.

  IMPACT...Minor hail damage to vehicles is possible. Expect wind 
           damage to trees and power lines.

* Locations impacted include...
  West Chester, Coatesville, Westtown, Downingtown, Kennett Square,
  Oxford, Parkesburg, West Grove, Honey Brook, Elverson, Homeville,
  Glen Roy, Cochranville, Cheyney, and Pughtown.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3980 7604 3982 7604 3983 7602 3985 7602
      3987 7599 3993 7600 3993 7598 3995 7599
      4004 7594 4009 7594 4012 7592 4014 7587
      4021 7576 4024 7568 3997 7547 3995 7551
      3993 7552 3972 7580 3973 7604 3977 7607
TIME...MOT...LOC 2006Z 238DEG 25KT 3981 7598 

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

$$

PHI
1 follow-up statement
240 
WWUS51 KPHI 272029
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
Issued by National Weather Service New York NY
429 PM EDT Thu Aug 27 2026

PAC029-272045-
/O.CON.KPHI.SV.W.0334.000000T0000Z-260827T2045Z/
Chester PA-
429 PM EDT Thu Aug 27 2026

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 445 PM EDT
FOR CHESTER COUNTY...

At 429 PM EDT, a severe thunderstorm was located near West Grove, or
11 miles southwest of West Chester, moving northeast at 30 mph.

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

SOURCE...Radar indicated.

IMPACT...Expect damage to trees and power lines.

Locations impacted include...
West Chester, Coatesville, Westtown, Downingtown, Kennett Square,
Oxford, Parkesburg, West Grove, Honey Brook, Elverson, Homeville,
Glen Roy, Cochranville, Pughtown, and Marshallton.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3985 7602 3987 7599 3993 7600 3993 7598
      3996 7599 4004 7594 4009 7594 4012 7592
      4014 7587 4021 7576 4024 7568 3997 7547
      3994 7552 3993 7553 3993 7554 3991 7555
      3986 7561 3976 7581 3976 7606
TIME...MOT...LOC 2029Z 238DEG 25KT 3989 7580 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

PHI

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 27, 11:38 AM EDTFlash Flood WarningPHIDelaware4 hr
Aug 27, 1:17 PM EDTFlash Flood WarningPHIBucks7 hr
Aug 27, 2:38 PM EDTFlash Flood WarningPHIDelaware, Philadelphia4 hr
Aug 27, 3:26 PM EDTAreal Flood WarningPHIDelaware5 hr
Aug 27, 4:52 PM EDTFlash Flood WarningPHINorthampton3 hr
Aug 27, 5:08 PM EDTFlash Flood WarningPHIChester, Montgomery4 hr
Aug 27, 7:00 PM EDTFlash Flood WarningPHIBucks, Delaware, Montgomery, Philadelphia3 hr

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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.