Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 270, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 27, 2021, 1:52 PM EDT for Chester County, Pennsylvania. It was in force for 53 min. 9 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 27, 2021, 1:52 PM EDT (17:52 UTC)
- Expired
- Aug 27, 2021, 2:45 PM EDT
- In force
- 53 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Hail
- 0.75 in
- Wind
- 60.0 mph
County Chester County, PA
The radar
The Philadelphia radar (KDIX), 116 km from the middle of the area, began a volume at 17:55 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 27, 2:04 PM EDT | TSTM WND DMG | 1 Nne Caln Twp, PA | MULTIPLE TREES DOWN ON OSBORNE ROAD. TIME ESTIMATED FROM RADAR. |
| Aug 27, 2:05 PM EDT | TSTM WND DMG | 1 Nnw Caln Twp, PA | SEVERAL TREES REPORTED DOWN AROUND CALN TOWNSHIP. TIME ESTIMATED FROM RADAR. |
| Aug 27, 2:10 PM EDT | TSTM WND DMG | 1 Nw Caln Twp, PA | SEVERAL LARGE BRANCHES DOWN BLOCKING TRAFFIC. TIME ESTIMATED FROM RADAR. |
| Aug 27, 2:13 PM EDT | TSTM WND DMG | 2 Sw East Brandywine Tw, PA | MULTIPLE TREES DOWN ON HURLEY ROAD. TIME ESTIMATED FROM RADAR. |
| Aug 27, 2:18 PM EDT | TSTM WND DMG | 1 Ese Wagontown, PA | SEVERAL TREES DOWN IN THE AREA OF PRATTS DAM ROAD. TIME ESTIMATED FROM RADAR. |
| Aug 27, 2:20 PM EDT | TSTM WND DMG | 2 Se East Brandywine Tw, PA | TREE AND POLE DOWN IN THE 900 BLOCK OF HORSESHOE PIKE. TIME ESTIMATED FROM RADAR. |
| Aug 27, 2:30 PM EDT | TSTM WND DMG | 1 N Coatesville, PA | TREES DOWN ALONG ROUTE 84 BETWEEN 30 BYPASS AND 30 BUSINESS JUST NORTH OF COATESVILLE. TIME ESTIMATED FROM RADAR. |
| Aug 27, 2:30 PM EDT | TSTM WND DMG | 1 Nne Coatesville, PA | MULTIPLE TREES DOWN AT ROUTE 30 BYPASS AND MOORE ROAD. TIME ESTIMATED. |
| Aug 27, 2:42 PM EDT | TSTM WND DMG | Valley Twp, PA | DOWNED TREE ON RAINBOW ROAD NEAR WEST LINCOLN HIGHWAY. TIME ESTIMATED FROM RADAR. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 12:00Z, 5.9 hours before the alert went out and 181 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
- 780 J/kg
- Mixed-layer CIN
- -92 J/kg
- Mixed-layer LCL
- 983 m above ground
- 0-6 km bulk shear
- 8 kt
- 0-1 km storm-relative helicity
- 13 m²/s²
- 0-3 km storm-relative helicity
- 41 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
159
WUUS51 KPHI 271752
SVRPHI
PAC029-271845-
/O.NEW.KPHI.SV.W.0270.210827T1752Z-210827T1845Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
152 PM EDT Fri Aug 27 2021
The National Weather Service in Mount Holly NJ has issued a
* Severe Thunderstorm Warning for...
Central Chester County in southeastern Pennsylvania...
* Until 245 PM EDT.
* At 152 PM EDT, a severe thunderstorm was located over Downingtown,
or near West Chester, and is nearly stationary.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Damage to roofs, siding, trees, and power lines is
possible.
* Locations impacted include...
West Chester, Coatesville, Downingtown, Lionville, Marshallton,
Lionville-Marchwood, West Goshen, South Coatesville, Modena, Exton
and Thorndale.
This includes Pennsylvania Turnpike between mile markers 308 and 313.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
In addition to damaging winds, frequent cloud to ground lightning is
occurring with this storm. Move indoors immediately. Remember, if
you can hear thunder, you are close enough to be struck by lightning.
&&
LAT...LON 3992 7585 4002 7590 4013 7568 3993 7557
TIME...MOT...LOC 1752Z 245DEG 2KT 4000 7571
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
Gorse2 follow-up statements
550
WWUS51 KPHI 271810
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
210 PM EDT Fri Aug 27 2021
PAC029-271845-
/O.CON.KPHI.SV.W.0270.000000T0000Z-210827T1845Z/
Chester PA-
210 PM EDT Fri Aug 27 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 245 PM EDT
FOR CENTRAL CHESTER COUNTY...
At 210 PM EDT, a severe thunderstorm was located near Downingtown, or
8 miles west of West Chester, and is nearly stationary.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Damage to roofs, siding, trees, and power lines is
possible.
Locations impacted include...
West Chester, Coatesville, Downingtown, Lionville, Marshallton,
Lionville-Marchwood, West Goshen, South Coatesville, Modena, Exton
and Thorndale.
This includes Pennsylvania Turnpike between mile markers 308 and 313.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
Frequent cloud to ground lightning is occurring with this storm. Move
indoors immediately. Lightning is one of nature's leading killers.
Remember, if you can hear thunder, you are close enough to be struck
by lightning.
&&
LAT...LON 3992 7585 4002 7590 4013 7568 3993 7557
TIME...MOT...LOC 1810Z 086DEG 1KT 3999 7575
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
Gorse593
WWUS51 KPHI 271820
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
220 PM EDT Fri Aug 27 2021
PAC029-271845-
/O.CON.KPHI.SV.W.0270.000000T0000Z-210827T1845Z/
Chester PA-
220 PM EDT Fri Aug 27 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 245 PM EDT
FOR CENTRAL CHESTER COUNTY...
At 220 PM EDT, a severe thunderstorm was located over Downingtown, or
7 miles west of West Chester, and is nearly stationary.
HAZARD...60 mph wind gusts. Trees reported down in Caln Township.
SOURCE...Law enforcement.
IMPACT...Damage to roofs, siding, trees, and power lines is
possible.
Locations impacted include...
West Chester, Coatesville, Downingtown, Lionville, Marshallton,
Lionville-Marchwood, West Goshen, South Coatesville, Modena, Exton
and Thorndale.
This includes Pennsylvania Turnpike between mile markers 308 and 313.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
Frequent cloud to ground lightning is occurring with this storm. Move
indoors immediately. Lightning is one of nature's leading killers.
Remember, if you can hear thunder, you are close enough to be struck
by lightning.
&&
LAT...LON 3992 7585 4002 7590 4013 7568 3993 7557
TIME...MOT...LOC 1820Z 245DEG 2KT 3999 7574
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
GorseThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 27, 1:20 PM EDT | Areal Flood Advisory | PHI | Carbon, Monroe | 2 hr |
| Aug 27, 1:33 PM EDT | Areal Flood Advisory | PHI | Bucks, Delaware, Philadelphia | 83 min |
| Aug 27, 1:36 PM EDT | Special Weather Statement | PHI | Monroe | 24 min |
| Aug 27, 2:12 PM EDT | Special Weather Statement | PHI | Northampton | 33 min |
| Aug 27, 2:18 PM EDT | Areal Flood Advisory | PHI | Chester | 93 min |
| Aug 27, 2:32 PM EDT | Severe Thunderstorm Warning | PHI | Carbon, Monroe, Northampton | 28 min |
| Aug 27, 2:33 PM EDT | Areal Flood Advisory | PHI | Carbon, Monroe, Northampton | 109 min |
| Aug 27, 2:42 PM EDT | Severe Thunderstorm Warning | PHI | Chester | 14 min |
| Aug 27, 3:07 PM EDT | Severe Thunderstorm Warning | PHI | Northampton | 24 min |
| Aug 27, 3:44 PM EDT | Special Weather Statement | PHI | Delaware | 31 min |
| Aug 27, 5:29 PM EDT | Areal Flood Advisory | PHI | Bucks, Montgomery | 3 hr |
| Aug 27, 6:29 PM EDT | Areal Flood Advisory | PHI | Berks | 3 hr |
| Aug 27, 6:41 PM EDT | Special Weather Statement | PHI | Berks | 34 min |
| Aug 27, 7:17 PM EDT | Flash Flood Warning | PHI | Berks | 3 hr |
Nearby
Severe Thunderstorm Warnings in Pennsylvania, 2021Every severe thunderstorm warning in 2021
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.