Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 316, NWS Philadelphia/Mount Holly

October 25, 2021Berks County, Chester County, Delaware County, Pennsylvania; New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Oct 25, 2021, 6:57 PM EDT for Berks County, Chester County, Delaware County, Pennsylvania; New Castle County, Delaware. It was in force for 48 min. 7 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
Oct 25, 2021, 6:57 PM EDT (22:57 UTC)
Expired
Oct 25, 2021, 7:45 PM EDT
In force
48 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties New Castle County, DE, Berks County, PA, Chester County, PA, Delaware County, PA

The radar

The Philadelphia radar (KDIX), 117 km from the middle of the area, began a volume at 23:01 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

TimeReportWhereRemark
Oct 25, 7:13 PM EDTTSTM WND DMG1 Sw Winterthur, DEDOWNED TREE ON WALNUT GREEN ROAD. TIME ESTIMATED FROM RADAR.
Oct 25, 7:13 PM EDTTSTM WND DMG3 Wsw Brookfield, PATREE AND WIRES DOWN ON CENTER MILL RD. TIME ESTIMATED FROM RADAR.
Oct 25, 7:22 PM EDTTSTM WND DMG2 Ene Kennett Square, PADOWNED TREES AND WIRES NEAR SILLS MILL ROAD. TIME ESTIMATED FROM RADAR.
Oct 25, 7:30 PM EDTTSTM WND DMGCoatesville, PATREE DOWN ON WIRES NEAR COATESVILLE. TIME ESTIMATED FROM RADAR.
Oct 25, 7:35 PM EDTTSTM WND DMG1 Nw Downington, PADOWNED TREE OR LIMBS ONTO WIRES NEAR HILLTOP RD. SEVERAL OTHER POWER OUTAGE REPORTS IN THE GENERAL AREA. TIME ESTIMATED FROM RADAR.
Oct 25, 7:52 PM EDTTSTM WND DMG1 N West Vincent Twp, PADOWNED TREES AND WIRES NEAR HALF HILL ROAD. TIME ESTIMATED FROM RADAR.
Oct 25, 7:52 PM EDTTSTM WND DMG2 Wsw Pughtown, PADOWNED TREES AND WIRES NEAR MURRAYS SCHOOL ROAD. 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, 11.0 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.

Skew-T log-pSkew-T log-p diagram, Washington/Dulle, VA at 12:00Z on 2021-10-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2021-10-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 213 square meters per square second.19395878Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1230 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
213 m²/s²
0-3 km storm-relative helicity
196 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

135 
WUUS51 KPHI 252257
SVRPHI
DEC003-PAC011-029-045-252345-
/O.NEW.KPHI.SV.W.0316.211025T2257Z-211025T2345Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
657 PM EDT Mon Oct 25 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northern New Castle County in northern Delaware...
  Southern Berks County in eastern Pennsylvania...
  Chester County in southeastern Pennsylvania...
  Western Delaware County in southeastern Pennsylvania...

* Until 745 PM EDT.

* At 657 PM EDT, severe thunderstorms were located along a line
  extending from near Conowingo to Barksdale, moving north 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, West Chester, Chester, Phoenixville, Coatesville,
  Westtown, Downingtown, Elsmere, Kennett Square, Oxford, Parkesburg,
  West Grove, Honey Brook, Elverson, Arden, New Morgan, Glen Roy,
  Cheyney, Talleyville and Pughtown.

This includes the following highways...
 Pennsylvania Turnpike between mile markers 296 and 324.
 Interstate 95 in Pennsylvania between mile markers 0 and 3.
 Interstate 95 in Delaware between mile markers 15 and 23.
 Interstate 176 in Pennsylvania between mile markers 1 and 7.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3976 7606 3987 7599 3995 7600 4004 7593
      4011 7594 4014 7588 4021 7598 4025 7596
      4023 7559 4015 7553 4013 7546 4009 7546
      4006 7538 3983 7540 3976 7546 3972 7579
      3972 7613
TIME...MOT...LOC 2257Z 199DEG 41KT 3966 7625 3967 7582 

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

$$

JEO
2 follow-up statements
192 
WWUS51 KPHI 252325
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
725 PM EDT Mon Oct 25 2021

DEC003-252335-
/O.CAN.KPHI.SV.W.0316.000000T0000Z-211025T2345Z/
New Castle DE-
725 PM EDT Mon Oct 25 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN NEW CASTLE COUNTY IS
CANCELLED...

The storms which prompted the warning have moved out of the warned 
area. Therefore, the warning has been cancelled.

LAT...LON 3993 7598 3995 7600 4004 7593 4011 7594
      4014 7588 4021 7598 4025 7596 4023 7559
      4015 7553 4013 7550 4013 7546 4009 7546
      4006 7538 3983 7540 3985 7577 3984 7601
TIME...MOT...LOC 2325Z 199DEG 41KT 3995 7612 3995 7569 

$$

PAC011-029-045-252345-
/O.CON.KPHI.SV.W.0316.000000T0000Z-211025T2345Z/
Berks PA-Chester PA-Delaware PA-
725 PM EDT Mon Oct 25 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 745 PM EDT
FOR SOUTHERN BERKS...CHESTER AND WESTERN DELAWARE COUNTIES...

At 725 PM EDT, severe thunderstorms were located along a line
extending from near Quarryville to Marshallton, moving north 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...
West Chester, Chester, Phoenixville, Coatesville, Westtown,
Downingtown, Kennett Square, Parkesburg, Honey Brook, Elverson, New
Morgan, Cheyney, Pughtown, Elam, Marshallton, Chelsea, Gradyville,
Newtown Square, Chester Township and Homeville.

This includes the following highways...
 Pennsylvania Turnpike between mile markers 296 and 324.
 Interstate 95 in Pennsylvania between mile markers 2 and 3.
 Interstate 176 in Pennsylvania between mile markers 1 and 7.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3993 7598 3995 7600 4004 7593 4011 7594
      4014 7588 4021 7598 4025 7596 4023 7559
      4015 7553 4013 7550 4013 7546 4009 7546
      4006 7538 3983 7540 3985 7577 3984 7601
TIME...MOT...LOC 2325Z 199DEG 41KT 3995 7612 3995 7569 

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

$$

JEO
595 
WWUS51 KPHI 252339
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
739 PM EDT Mon Oct 25 2021

PAC011-029-045-252349-
/O.EXP.KPHI.SV.W.0316.000000T0000Z-211025T2345Z/
Berks PA-Chester PA-Delaware PA-
739 PM EDT Mon Oct 25 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN BERKS...CHESTER AND
WESTERN DELAWARE COUNTIES WILL EXPIRE AT 745 PM EDT...
            
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore, the warning will be allowed to expire.  However gusty
winds are still possible with these thunderstorms.

LAT...LON 3993 7598 3995 7600 4004 7593 4011 7594
      4014 7588 4021 7598 4025 7596 4023 7559
      4015 7553 4013 7550 4013 7546 4009 7546
      4006 7538 3983 7540 3985 7577 3984 7601
TIME...MOT...LOC 2339Z 199DEG 41KT 3995 7612 3995 7569 

$$

JEO

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 25, 6:33 PM EDTSevere Thunderstorm WarningPHIChester, Delaware42 min
Oct 25, 7:34 PM EDTSevere Thunderstorm WarningPHIDelaware, Philadelphia26 min
Oct 25, 7:43 PM EDTSpecial Weather StatementPHIBucks, Montgomery47 min
Oct 25, 4:15 PM EDTSpecial Weather StatementPHISussex30 min
Oct 25, 5:27 PM EDTSpecial Weather StatementPHIKent33 min
Oct 25, 6:27 PM EDTSpecial Weather StatementPHINew Castle33 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2021Severe Thunderstorm Warnings in Delaware, 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.