Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 196, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 17, 2021, 8:57 PM EDT for Chester County, Pennsylvania. It was in force for 48 min. 2 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
- Jul 17, 2021, 8:57 PM EDT (00:57 UTC)
- Expired
- Jul 17, 2021, 9:45 PM EDT
- In force
- 48 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), 111 km from the middle of the area, began a volume at 01:01 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 |
|---|---|---|---|
| Jul 17, 9:29 PM EDT | TSTM WND DMG | 2 Ene Landenberg, PA | TREE LIMBS BLOCKING THE ROAD ON KAOLIN RD AT LIMESTONE RD. TIME ESTIMATED FROM RADAR AND DISPATCH REPORT. |
| Jul 17, 9:32 PM EDT | TSTM WND DMG | 2 S Kennett Square, PA | TREE DOWN BLOCKING THE ROAD ON ROUND HILL RD AT KAOLI RD. TIME ESTIMATED FROM RADAR AND DISPATCH REPORT. |
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 |
|---|---|---|---|
| Jul 17, 1:13 PM EDT | Severe Thunderstorm Watch | SPC | 10 hr |
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 00:00Z, 1.0 hours before the alert went out and 184 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
- 933 J/kg
- Mixed-layer CIN
- -83 J/kg
- Mixed-layer LCL
- 1286 m above ground
- 0-6 km bulk shear
- 29 kt
- 0-1 km storm-relative helicity
- 163 m²/s²
- 0-3 km storm-relative helicity
- 172 m²/s²
- Significant tornado parameter
- 0.3
- Supercell composite
- 1.3
The text
As transmitted.
322
WUUS51 KPHI 180057
SVRPHI
PAC029-180145-
/O.NEW.KPHI.SV.W.0196.210718T0057Z-210718T0145Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
857 PM EDT Sat Jul 17 2021
The National Weather Service in Mount Holly NJ has issued a
* Severe Thunderstorm Warning for...
Chester County in southeastern Pennsylvania...
* Until 945 PM EDT.
* At 856 PM EDT, a severe thunderstorm was located over Cochranville,
or 15 miles west of West Chester, moving northeast at 30 mph.
HAZARD...60 mph wind gusts and quarter size hail.
SOURCE...Radar indicated.
IMPACT...Minor damage to vehicles is possible. Wind damage to
roofs, siding, trees, and power lines is possible.
* Locations impacted include...
West Chester, Phoenixville, Coatesville, Westtown, Downingtown,
Kennett Square, Royersford, Parkesburg, West Grove, Honey Brook,
Cochranville, Pughtown, Marshallton, Lionville-Marchwood, Valley
Forge, Glenmoore, Paoli, Chester Springs, Lionville and Ladenberg.
This includes Pennsylvania Turnpike between mile markers 304 and 324.
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 3997 7599 4004 7593 4010 7594 4020 7555
4015 7553 4016 7550 4014 7551 4013 7548
4002 7541 3990 7558 3985 7559 3981 7570
3977 7575 3972 7577 3972 7587 3991 7600
TIME...MOT...LOC 0056Z 245DEG 24KT 3992 7589
HAIL...1.00IN
WIND...60MPH
$$
JEO3 follow-up statements
559
WWUS51 KPHI 180116
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
916 PM EDT Sat Jul 17 2021
PAC029-180145-
/O.CON.KPHI.SV.W.0196.000000T0000Z-210718T0145Z/
Chester PA-
916 PM EDT Sat Jul 17 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 945 PM EDT
FOR CHESTER COUNTY...
At 916 PM EDT, a severe thunderstorm was located over Downingtown, or
near West Chester, moving northeast at 30 mph.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Damage to roofs, siding, trees, and power lines is
possible.
Locations impacted include...
West Chester, Phoenixville, Coatesville, Westtown, Downingtown,
Kennett Square, Royersford, Parkesburg, West Grove, Honey Brook,
Cochranville, Pughtown, Marshallton, Lionville-Marchwood, Valley
Forge, Glenmoore, Paoli, Chester Springs, Lionville and Ladenberg.
This includes Pennsylvania Turnpike between mile markers 304 and 324.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 3997 7590 4004 7593 4010 7594 4020 7555
4015 7553 4016 7550 4014 7551 4013 7548
4002 7541 3990 7558 3985 7559 3981 7570
3977 7575 3972 7577 3972 7587 3989 7598
TIME...MOT...LOC 0116Z 245DEG 24KT 3998 7573
HAIL...<.75IN
WIND...60MPH
$$
JEO686
WWUS51 KPHI 180130
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
930 PM EDT Sat Jul 17 2021
PAC029-180145-
/O.CON.KPHI.SV.W.0196.000000T0000Z-210718T0145Z/
Chester PA-
930 PM EDT Sat Jul 17 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 945 PM EDT
FOR CENTRAL CHESTER COUNTY...
At 930 PM EDT, a severe thunderstorm was located over
Lionville-Marchwood, or near West Chester, moving northeast 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...
West Chester, Phoenixville, Westtown, Downingtown, Kennett Square,
Royersford, West Grove, Pughtown, Marshallton, Lionville-Marchwood,
Valley Forge, Paoli, Chester Springs, Lionville, Ladenberg,
Kemblesville, North Star, West Goshen, Spring City and Malvern.
This includes Pennsylvania Turnpike between mile markers 311 and 324.
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 4002 7572 4017 7567 4020 7555 4015 7553
4016 7550 4014 7551 4013 7548 4002 7541
3990 7558 3985 7559 3981 7570 3977 7575
3972 7577 3972 7587 3982 7594
TIME...MOT...LOC 0130Z 245DEG 24KT 4002 7561
HAIL...<.75IN
WIND...60MPH
$$
Staarmann814
WWUS51 KPHI 180136
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
936 PM EDT Sat Jul 17 2021
PAC029-180146-
/O.EXP.KPHI.SV.W.0196.000000T0000Z-210718T0145Z/
Chester PA-
936 PM EDT Sat Jul 17 2021
...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL CHESTER COUNTY WILL
EXPIRE AT 945 PM EDT...
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.
A Severe Thunderstorm Watch remains in effect until 1100 PM EDT for
northern Delaware...and southeastern Pennsylvania.
To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Mount Holly NJ.
LAT...LON 4002 7572 4017 7567 4020 7555 4015 7553
4016 7550 4014 7551 4013 7548 4002 7541
3990 7558 3985 7559 3981 7570 3977 7575
3972 7577 3972 7587 3982 7594
TIME...MOT...LOC 0136Z 245DEG 24KT 4003 7558
$$
NCThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 17, 8:00 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Montgomery, Philadelphia | 45 min |
| Jul 17, 8:09 PM EDT | Flash Flood Warning | PHI | Bucks | 4 hr |
| Jul 17, 8:44 PM EDT | Areal Flood Advisory | PHI | Chester, Montgomery | 82 min |
| Jul 17, 9:15 PM EDT | Areal Flood Advisory | PHI | Delaware, Montgomery, Philadelphia | 2 hr |
| Jul 17, 9:27 PM EDT | Severe Thunderstorm Warning | PHI | Chester, Delaware, Montgomery, Philadelphia | 48 min |
| Jul 17, 9:36 PM EDT | Flash Flood Warning | PHI | Delaware, Montgomery, Philadelphia | 2 hr |
| Jul 17, 9:48 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Delaware, Montgomery, Philadelphia | 42 min |
| Jul 17, 10:21 PM EDT | Severe Thunderstorm Warning | PHI | Bucks | 54 min |
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.