Alert archive / Pennsylvania / Tornado Warnings in 2021

Tornado Warning 11, NWS State College, PA

September 1, 2021York County, Pennsylvania

NWS State College, PA issued this tornado warning at Sep 1, 2021, 3:05 PM EDT for York County, Pennsylvania. It was in force for 23 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Sep 1, 2021, 3:05 PM EDT (19:05 UTC)
Expired
Sep 1, 2021, 3:28 PM EDT
In force
23 min
Issued by
NWS State College, PA
Area
Storm-based polygon
Tornado
Radar indicated
Hail
0.0 in

County York County, PA

The radar

The Sterling radar (KLWX), 128 km from the middle of the area, began a volume at 19:09 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.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Sep 1, 12:40 PM EDTTornado WatchSPC9 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 7.1 hours before the alert went out and 125 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 2021-09-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 558 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 2021-09-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 122 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
558 J/kg
Mixed-layer CIN
-21 J/kg
Mixed-layer LCL
575 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
122 m²/s²
0-3 km storm-relative helicity
223 m²/s²
Significant tornado parameter
0.4
Supercell composite
2.6

Open this sounding in Storm Lab

The text

As transmitted.

822 
WFUS51 KCTP 011905
TORCTP
PAC133-011945-
/O.NEW.KCTP.TO.W.0011.210901T1905Z-210901T1945Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service State College PA
305 PM EDT Wed Sep 1 2021

The National Weather Service in State College PA has issued a

* Tornado Warning for...
  Southeastern York County in south central Pennsylvania...

* Until 345 PM EDT.
    
* At 305 PM EDT, a severe thunderstorm capable of producing a tornado
  was located near Shrewsbury, moving north at 35 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.

* This dangerous storm will be near...
  Stewartstown around 310 PM EDT.
  Cross Roads around 320 PM EDT.
  Red Lion, Dallastown, Spry, Windsor, Yoe, Brogue, East York, Tyler 
  Run-Queens Gate and Valley View around 330 PM EDT.

Other locations impacted by this tornadic thunderstorm include
Winterstown, Felton and Loganville.

This includes Interstate 83 between mile markers 0 and 12...and from
mile markers 16 to 17.

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.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3996 7669 3994 7645 3991 7640 3990 7640
      3972 7658 3972 7672
TIME...MOT...LOC 1905Z 195DEG 28KT 3973 7665 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...0.00 IN

$$

Colbert
1 follow-up statement
195 
WWUS51 KCTP 011928
SVSCTP

Severe Weather Statement
National Weather Service State College PA
328 PM EDT Wed Sep 1 2021

PAC133-011936-
/O.CAN.KCTP.TO.W.0011.000000T0000Z-210901T1945Z/
York PA-
328 PM EDT Wed Sep 1 2021

...THE TORNADO WARNING FOR SOUTHEASTERN YORK COUNTY IS CANCELLED...
    
The tornado threat has diminished and the Tornado Warning has been 
cancelled. However, damaging winds remain likely and a Severe 
Thunderstorm Warning remains in effect for the area.

A Tornado Watch remains in effect until 1000 PM EDT for south central
Pennsylvania.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
State College PA.

Torrential rain is also occuring and a flash flood warning remains 
in effect. Turn Around, Don't Drown. 

LAT...LON 3996 7669 3994 7645 3991 7640 3990 7640
      3972 7658 3972 7672
TIME...MOT...LOC 1924Z 195DEG 28KT 3989 7659 

$$

Colbert

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 1, 8:54 AM EDTFlash Flood Warning Considerable damage threatCTPBedford, Blair, Cambria, Centre, Clearfield, Fulton and 3 more8 hr
Sep 1, 9:37 AM EDTFlash Flood Warning Considerable damage threatCTPCambria, Clearfield, Somerset6 hr
Sep 1, 9:45 AM EDTAreal Flood AdvisoryCTPAdams, Columbia, Cumberland, Dauphin, Franklin, Juniata and 10 more2 hr
Sep 1, 11:04 AM EDTRiver Flood WarningCTPSnyder, Union17 hr
Sep 1, 11:04 AM EDTRiver Flood WarningCTPCambria17 hr
Sep 1, 11:04 AM EDTRiver Flood WarningCTPHuntingdon23 hr
Sep 1, 11:04 AM EDTRiver Flood WarningCTPJuniata, Mifflin20 hr
Sep 1, 11:04 AM EDTRiver Flood WarningCTPBedford, Huntingdon30 hr
Sep 1, 11:04 AM EDTRiver Flood WarningCTPDauphin55 hr
Sep 1, 12:04 PM EDTFlash Flood Warning Considerable damage threatCTPAdams, Columbia, Cumberland, Dauphin, Franklin, Juniata and 10 more6 hr
Sep 1, 1:09 PM EDTFlash Flood Warning EmergencyCatastrophic damage threatCTPCambria5 hr
Sep 1, 2:07 PM EDTSevere Thunderstorm WarningCTPAdams53 min
Sep 1, 2:28 PM EDTSevere Thunderstorm WarningCTPYork77 min
Sep 1, 3:25 PM EDTSevere Thunderstorm WarningCTPLancaster, York35 min
Sep 1, 3:34 PM EDTAreal Flood WarningCTPCambria, Clearfield, Somerset6 hr
Sep 1, 4:21 PM EDTSevere Thunderstorm WarningCTPLancaster39 min
Sep 1, 4:24 PM EDTFlash Flood Warning EmergencyCatastrophic damage threatCTPAdams, York4 hr
Sep 1, 4:40 PM EDTAreal Flood WarningCTPBedford, Blair, Cambria, Centre, Clearfield, Franklin and 4 more6 hr
Sep 1, 5:41 PM EDTAreal Flood WarningCTPAdams, Centre, Columbia, Cumberland, Dauphin, Franklin and 15 more14 hr

Nearby

Tornado Warnings in Pennsylvania, 2021Every tornado warning in 2021Tornadoes 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.