Alert archive / Pennsylvania / Tornado Warnings in 2026
Tornado Warning 27, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this tornado warning at Aug 20, 2026, 5:22 PM EDT for Chester County, Delaware County, Pennsylvania. It was in force for 38 min. 4 reports 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 20, 2026, 5:22 PM EDT (21:22 UTC)
- Expired
- Aug 20, 2026, 6:00 PM EDT
- In force
- 38 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Tornado
- Radar indicated
- Hail
- 0.75 in
Counties Chester County, PA, Delaware County, PA
The radar
The Philadelphia radar (KDIX), 107 km from the middle of the area, began a volume at 21:26 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
| Time | Report | Where | Remark |
|---|---|---|---|
| Aug 20, 5:25 PM EDT | TSTM WND DMG | Downington, PA | Basketball hoop knocked over. Estimated max wind gusts up to 80 mph. Time estimated from radar. |
| Aug 20, 5:33 PM EDT | TSTM WND DMG | East Brandywine Twp, PA | Report of power lines down in Guthriesville, East Brandywine Township. Time estimated from radar. |
| Aug 20, 5:40 PM EDT | TSTM WND DMG | Downington, PA | Report and photos via social media of at least 2 trees down along East Pennsylvania Avenue in Downingtown. One felled tree appears to have crushed a shed. Time estimated from radar. |
| Aug 20, 5:40 PM EDT | TORNADO | East Caln Twp, PA | A brief tornado occurred in East Caln Township. The first damage was noted just south of the intersection of East Lancaster Avenue and Quarry Road, where several small tree branches were broken. A path of more broken tree branches, some with diameters up to 5 |
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.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Aug 20, 2:31 PM EDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Aug 20, 2:58 PM EDT | Tornado Watch | SPC | 7 hr |
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 12:00Z, 9.4 hours before the alert went out and 189 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.
- Mixed-layer CAPE
- 97 J/kg
- Mixed-layer CIN
- -72 J/kg
- Mixed-layer LCL
- 1192 m above ground
- 0-6 km bulk shear
- 47 kt
- 0-1 km storm-relative helicity
- 115 m²/s²
- 0-3 km storm-relative helicity
- 230 m²/s²
- Significant tornado parameter
- -0.0
- Supercell composite
- -0.0
The text
As transmitted.
235
WFUS51 KPHI 202122
TORPHI
PAC029-045-202200-
/O.NEW.KPHI.TO.W.0027.260820T2122Z-260820T2200Z/
BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Mount Holly NJ
Issued by National Weather Service New York NY
522 PM EDT Thu Aug 20 2026
The National Weather Service in Mount Holly NJ has issued a
* Tornado Warning for...
Central Chester County in southeastern Pennsylvania...
Southwestern Delaware County in southeastern Pennsylvania...
* Until 600 PM EDT.
* At 522 PM EDT, severe thunderstorms capable of producing both
tornadoes and extensive straight line wind damage were located
along a line extending from Coatesville to 6 miles north of West
Grove, moving east at 45 mph.
HAZARD...Tornado.
SOURCE...Radar indicated rotation.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed.
Damage to roofs, windows, and vehicles will occur. Tree
damage is likely.
* Locations impacted include...
West Chester, Chester, Coatesville, Westtown, Downingtown, Kennett
Square, Parkesburg, Cheyney, Elam, Marshallton, Lima, Chelsea,
Lionville-Marchwood, Gradyville, and Paoli.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.
This line of thunderstorms is capable of producing tornadoes and
widespread significant wind damage. Do not wait to see or hear the
tornado. For your protection move to an interior room on the lowest
floor of a building.
Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4012 7549 3984 7536 3985 7582 3998 7592
4006 7591
TIME...MOT...LOC 2122Z 268DEG 40KT 3999 7584 3991 7580
TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
$$
Staarmann3 follow-up statements
570
WWUS51 KPHI 202134
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
Issued by National Weather Service New York NY
534 PM EDT Thu Aug 20 2026
PAC029-045-202200-
/O.CON.KPHI.TO.W.0027.000000T0000Z-260820T2200Z/
Chester PA-Delaware PA-
534 PM EDT Thu Aug 20 2026
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 600 PM EDT FOR EAST
CENTRAL CHESTER AND SOUTHWESTERN DELAWARE COUNTIES...
At 534 PM EDT, a severe squall line capable of producing both
tornadoes and extensive straight line wind damage was located along a
line extending from near Glenmoore to near Marshallton, moving east
at 45 mph.
HAZARD...Tornado.
SOURCE...Radar indicated rotation.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed. Damage
to roofs, windows, and vehicles will occur. Tree damage is
likely.
Locations impacted include...
West Chester, Chester, Coatesville, Westtown, Downingtown, Cheyney,
Elam, Marshallton, Lima, Chelsea, Lionville-Marchwood, Gradyville,
Paoli, Chester Springs, and Chester Township.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.
This line of thunderstorms is capable of producing tornadoes and
widespread significant wind damage. Do not wait to see or hear the
tornado. For your protection move to an interior room on the lowest
floor of a building.
Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4012 7549 3984 7536 3987 7574 3997 7580
4007 7581
TIME...MOT...LOC 2134Z 265DEG 38KT 4005 7574 3991 7565
TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
$$
Staarmann814
WWUS51 KPHI 202151
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
Issued by National Weather Service New York NY
551 PM EDT Thu Aug 20 2026
PAC029-045-202200-
/O.CON.KPHI.TO.W.0027.000000T0000Z-260820T2200Z/
Chester PA-Delaware PA-
551 PM EDT Thu Aug 20 2026
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 600 PM EDT FOR EAST
CENTRAL CHESTER AND SOUTHWESTERN DELAWARE COUNTIES...
At 551 PM EDT, a severe squall line capable of producing both
tornadoes and extensive straight line wind damage was located along a
line extending from near Lionville-Marchwood to Concordville, moving
east at 40 mph.
HAZARD...Tornado.
SOURCE...Radar indicated rotation.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed. Damage
to roofs, windows, and vehicles will occur. Tree damage is
likely.
Locations impacted include...
West Chester, Chester, Westtown, Downingtown, Cheyney, Lima, Chelsea,
Lionville-Marchwood, Gradyville, Paoli, Chester Springs, Chester
Township, Lionville, Concordville, and Nether Providence Township.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.
This line of thunderstorms is capable of producing tornadoes and
widespread significant wind damage. Do not wait to see or hear the
tornado. For your protection move to an interior room on the lowest
floor of a building.
Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4012 7549 3984 7536 3987 7557 3996 7562
3999 7568 4009 7570
TIME...MOT...LOC 2151Z 271DEG 36KT 4004 7560 3990 7551
TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
$$
Staarmann520
WWUS51 KPHI 202158
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
Issued by National Weather Service New York NY
558 PM EDT Thu Aug 20 2026
PAC029-045-202208-
/O.EXP.KPHI.TO.W.0027.000000T0000Z-260820T2200Z/
Chester PA-Delaware PA-
558 PM EDT Thu Aug 20 2026
...THE TORNADO WARNING FOR EAST CENTRAL CHESTER AND SOUTHWESTERN
DELAWARE COUNTIES WILL EXPIRE AT 600 PM EDT...
The tornado threat has diminished and the Tornado Warning has been
allowed to expired. However, damaging winds remain likely and a
Severe Thunderstorm Warning remains in effect for the area. Heavy
rain are still possible with these thunderstorms.
A Tornado Watch remains in effect until 1000 PM EDT for southeastern
Pennsylvania.
To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Mount Holly NJ.
LAT...LON 4012 7549 3984 7536 3987 7557 3996 7562
3999 7568 4009 7570
TIME...MOT...LOC 2158Z 268DEG 40KT 4004 7551 3990 7542
$$
StaarmannThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 20, 4:50 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Chester | 40 min |
| Aug 20, 4:59 PM EDT | Severe Thunderstorm Warning | PHI | Chester | 46 min |
| Aug 20, 5:27 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Bucks, Chester, Delaware, Montgomery, Philadelphia | 48 min |
| Aug 20, 5:39 PM EDT | Flash Flood Warning | PHI | Chester, Delaware, Montgomery, Philadelphia | 4 hr |
| Aug 20, 6:13 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Delaware, Montgomery, Philadelphia | 47 min |
| Aug 20, 6:26 PM EDT | Flash Flood Warning | PHI | Bucks, Montgomery, Philadelphia | 4 hr |
Nearby
Tornado Warnings in Pennsylvania, 2026Every tornado warning in 2026Tornadoes 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.