Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 194, NWS State College, PA

August 10, 2021Lancaster County, York County, Pennsylvania

NWS State College, PA issued this severe thunderstorm warning at Aug 10, 2021, 7:00 PM EDT for Lancaster County, York County, Pennsylvania. It was in force for 75 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 10, 2021, 7:00 PM EDT (23:00 UTC)
Expired
Aug 10, 2021, 8:15 PM EDT
In force
75 min
Issued by
NWS State College, PA
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Lancaster County, PA, York County, PA

The radar

The Dover AFB radar (KDOX), 134 km from the middle of the area, began a volume at 23:00 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 10, 7:39 PM EDTTSTM WND DMG5 E Quarryville, PAWIDESPREAD DOWNED POWERLINES AND WIRES.

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 143 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 2021-08-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 529 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 2021-08-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 37 square meters per square second.1939Sfc1 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
529 J/kg
Mixed-layer CIN
-120 J/kg
Mixed-layer LCL
1096 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
37 m²/s²
0-3 km storm-relative helicity
65 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

940 
WUUS51 KCTP 102300
SVRCTP
PAC071-133-110015-
/O.NEW.KCTP.SV.W.0194.210810T2300Z-210811T0015Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service State College PA
700 PM EDT Tue Aug 10 2021

The National Weather Service in State College PA has issued a

* Severe Thunderstorm Warning for...
  Southern Lancaster County in south central Pennsylvania...
  Southeastern York County in south central Pennsylvania...

* Until 815 PM EDT.

* At 700 PM EDT, severe thunderstorms were located along a line
  extending from near Leacock to near Shrewsbury, moving east at 30
  mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* Locations impacted include...
  Lancaster, Columbia, Millersville, Willow Street, Red Lion, New
  Holland, Dallastown, Leola, Paradise, Salunga-Landisville,
  Shrewsbury, Strasburg, Mountville, Marietta, Quarryville,
  Wrightsville, Stewartstown, Gap, Windsor and Delta.

This includes Interstate 83 from mile markers 0 to 7.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Very heavy rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3972 7675 4007 7653 4011 7594 4004 7594
      3997 7599 3986 7601 3973 7610 3974 7611
      3972 7614
TIME...MOT...LOC 2300Z 267DEG 25KT 4007 7626 3972 7666 

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

$$

Colbert
3 follow-up statements
089 
WWUS51 KCTP 102321
SVSCTP

Severe Weather Statement
National Weather Service State College PA
721 PM EDT Tue Aug 10 2021

PAC071-133-110015-
/O.CON.KCTP.SV.W.0194.000000T0000Z-210811T0015Z/
Lancaster PA-York PA-
721 PM EDT Tue Aug 10 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 815 PM EDT
FOR SOUTHERN LANCASTER AND SOUTHEASTERN YORK COUNTIES...

At 721 PM EDT, severe thunderstorms were located along a line
extending from New Holland to near Stewartstown, moving east at 30
mph.

HAZARD...70 mph wind gusts.

SOURCE...Trained weather spotters.

IMPACT...Expect considerable tree damage. Damage is likely to mobile 
         homes, roofs, and outbuildings.

Locations impacted include...
Lancaster, Columbia, Millersville, Willow Street, Red Lion, New
Holland, Dallastown, Leola, Paradise, Salunga-Landisville,
Shrewsbury, Strasburg, Mountville, Marietta, Quarryville,
Wrightsville, Stewartstown, Gap, Windsor and Delta.

This includes Interstate 83 from mile markers 0 to 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 3972 7675 4007 7653 4011 7594 4004 7594
      3997 7599 3986 7601 3973 7610 3974 7611
      3972 7614
TIME...MOT...LOC 2321Z 267DEG 25KT 4008 7609 3973 7649 

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...OBSERVED
MAX WIND GUST...70 MPH

$$

Colbert
822 
WWUS51 KCTP 102339
SVSCTP

Severe Weather Statement
National Weather Service State College PA
739 PM EDT Tue Aug 10 2021

PAC133-102349-
/O.CAN.KCTP.SV.W.0194.000000T0000Z-210811T0015Z/
York PA-
739 PM EDT Tue Aug 10 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN YORK COUNTY IS
CANCELLED...

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

LAT...LON 3973 7624 3977 7627 3987 7638 3991 7639
      3995 7648 3998 7650 4001 7645 4004 7594
      3997 7599 3986 7601 3973 7610 3974 7611
      3972 7614
TIME...MOT...LOC 2339Z 267DEG 25KT 4009 7593 3974 7633 

$$

PAC071-110015-
/O.CON.KCTP.SV.W.0194.000000T0000Z-210811T0015Z/
Lancaster PA-
739 PM EDT Tue Aug 10 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 815 PM EDT
FOR SOUTHEASTERN LANCASTER COUNTY...

At 739 PM EDT, severe thunderstorms were located along a line
extending from Honey Brook to Delta, moving east at 30 mph.

HAZARD...60 mph wind gusts.

SOURCE...Trained weather spotters.

IMPACT...Expect damage to roofs, siding, and trees.

Locations impacted include...
Millersville, Willow Street, Paradise, Strasburg, Quarryville, Gap,
Wakefield, Smithville, Safe Harbor, Holtwood, Shenks Ferry, Lampeter,
Intercourse, Conestoga, Christiana, Georgetown, Washington Boro,
Gordonville, Kirkwood and Little Britain.

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 3973 7624 3977 7627 3987 7638 3991 7639
      3995 7648 3998 7650 4001 7645 4004 7594
      3997 7599 3986 7601 3973 7610 3974 7611
      3972 7614
TIME...MOT...LOC 2339Z 267DEG 25KT 4009 7593 3974 7633 

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

$$

Colbert
135 
WWUS51 KCTP 110006
SVSCTP

Severe Weather Statement
National Weather Service State College PA
806 PM EDT Tue Aug 10 2021

PAC071-110016-
/O.EXP.KCTP.SV.W.0194.000000T0000Z-210811T0015Z/
Lancaster PA-
806 PM EDT Tue Aug 10 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN LANCASTER COUNTY
WILL EXPIRE AT 815 PM EDT...
    
The storms which prompted the warning have moved out of the area.
Therefore, the warning will be allowed to expire.

LAT...LON 3973 7624 3977 7627 3987 7638 3991 7639
      3995 7648 3998 7650 4001 7645 4004 7594
      3997 7599 3986 7601 3973 7610 3974 7611
      3972 7614
TIME...MOT...LOC 0006Z 267DEG 25KT 4010 7570 3975 7610 

$$

Colbert

The office that day

Everything else NWS State College, PA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 10, 12:55 PM EDTHeat AdvisoryCTPAdams, Columbia, Cumberland, Dauphin, Franklin, Juniata and 10 more30 hr
Aug 10, 12:55 PM EDTHeat AdvisoryCTPAdams, Bedford, Blair, Centre, Clinton, Columbia and 19 more54 hr
Aug 10, 2:21 PM EDTSpecial Weather StatementCTPDauphin, Lebanon24 min
Aug 10, 2:32 PM EDTSevere Thunderstorm WarningCTPDauphin, Lebanon43 min
Aug 10, 3:12 PM EDTSpecial Weather StatementCTPBedford, Blair, Cambria, Somerset33 min
Aug 10, 3:23 PM EDTSpecial Weather StatementCTPBerks37 min
Aug 10, 3:25 PM EDTSpecial Weather StatementCTPHuntingdon, Juniata50 min
Aug 10, 3:28 PM EDTSpecial Weather StatementCTPSchuylkill47 min
Aug 10, 4:14 PM EDTSpecial Weather StatementCTPJuniata31 min
Aug 10, 4:31 PM EDTSpecial Weather StatementCTPCentre29 min
Aug 10, 4:48 PM EDTSpecial Weather StatementCTPPerry27 min
Aug 10, 5:18 PM EDTSpecial Weather StatementCTPDauphin42 min
Aug 10, 5:50 PM EDTSpecial Weather StatementCTPAdams40 min
Aug 10, 5:52 PM EDTSpecial Weather StatementCTPLebanon38 min
Aug 10, 6:12 PM EDTSpecial Weather StatementCTPLancaster63 min
Aug 10, 6:17 PM EDTSevere Thunderstorm WarningCTPLancaster, Lebanon73 min
Aug 10, 6:29 PM EDTSevere Thunderstorm WarningCTPLancaster, York58 min
Aug 10, 7:33 PM EDTAreal Flood AdvisoryCTPLancaster2 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.