Alert archive / Pennsylvania / Snow Squall Warnings in 2021

Snow Squall Warning 4, NWS State College, PA

February 22, 202115 counties in Pennsylvania

NWS State College, PA issued this snow squall warning at Feb 22, 2021, 8:15 AM EST for 15 counties in Pennsylvania. It was in force for 90 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: Feb 22, 2021, 8:15 AM EST (13:15 UTC)
Expired: Feb 22, 2021, 9:45 AM EST
In force: 90 min
Issued by: NWS State College, PA
Area: Storm-based polygon

Counties Columbia County, PA, Cumberland County, PA, Dauphin County, PA, Lancaster County, PA, Lebanon County, PA, Lycoming County, PA, Montour County, PA, Northumberland County, PA, Perry County, PA, Schuylkill County, PA, Snyder County, PA, Sullivan County, PA, Tioga County, PA, Union County, PA, York County, PA

The radar

The State College radar (KCCX), 125 km from the middle of the area, began a volume at 13:14 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 nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 1.3 hours before the alert went out and 228 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1420 m above ground
0-6 km bulk shear: 91 kt
0-1 km storm-relative helicity: 461 m²/s²
0-3 km storm-relative helicity: 475 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

914 
WWUS51 KCTP 221318
SQWCTP

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Snow Squall Warning
National Weather Service State College PA
815 AM EST Mon Feb 22 2021

PAC037-041-043-071-075-081-093-097-099-107-109-113-117-119-133-
221445-
/O.NEW.KCTP.SQ.W.0004.210222T1315Z-210222T1445Z/
Lancaster PA-Northumberland PA-Dauphin PA-Snyder PA-Columbia PA-
Union PA-Tioga PA-Cumberland PA-Perry PA-Schuylkill PA-York PA-
Montour PA-Lycoming PA-Sullivan PA-Lebanon PA-
815 AM EST Mon Feb 22 2021

The National Weather Service in State College PA has issued a

* Snow Squall Warning for...
  Northwestern Lancaster County in south central Pennsylvania...
  Northumberland County in central Pennsylvania...
  Dauphin County in south central Pennsylvania...
  Eastern Snyder County in central Pennsylvania...
  Columbia County in central Pennsylvania...
  East central Union County in central Pennsylvania...
  Southeastern Tioga County in north central Pennsylvania...
  Eastern Cumberland County in south central Pennsylvania...
  Northeastern Perry County in south central Pennsylvania...
  Schuylkill County in central Pennsylvania...
  Northwestern York County in south central Pennsylvania...
  Montour County in central Pennsylvania...
  Eastern Lycoming County in north central Pennsylvania...
  Sullivan County in north central Pennsylvania...
  Lebanon County in south central Pennsylvania...

* Until 945 AM EST.

* At 815 AM EST, a dangerous snow squall was along the leading edge 
  of a band of heavy snow moving rapidly across central 
  Pennsylvania. The leading edge of intense snow was located along a 
  line extending from near Ralston to near Hughesville to 
  Selinsgrove to near Mount Holly Springs to near Aspers, moving 
  northeast at 45 mph. Road condiditions will quickly go from dry to 
  snow covered, with the potential for flash freezes on interstate 
  highways. Avoid travel if possible until this weather system 
  passes.

  HAZARD...Whiteout conditions. Zero visibility in heavy snow and 
           blowing snow. 

  SOURCE...Radar indicated.

  IMPACT...Dangerous life-threatening travel.

* For those driving on Interstate 80, this includes areas between the
  Milton-Williamsport and Nescopek exits, specifically from mile
  markers 212 to 247.

This includes the following Interstates...
 The Pennsylvania Turnpike from mile markers 225 to 285.
 Interstate 78 from mile markers 0 to 8.
 Interstate 81 from mile markers 47 to 139.
 Interstate 83 from mile markers 30 to 50.
 Interstate 180 from mile markers 1 to 17.
 Interstate 283 from mile markers 0 to 2.

Locations impacted include...
Harrisburg, Lebanon, Carlisle, Lower Allen, Bloomsburg, Pottsville,
Hershey, Colonial Park, Elizabethtown, Berwick, Sunbury, Progress,
Mechanicsburg, Middletown, Camp Hill, Shamokin, Palmyra, New
Cumberland, Milton and Linglestown.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Consider avoiding or delaying travel until the snow squall passes
your location. If you must travel, use extra caution and allow extra
time. Rapid changes in visibility and slick road conditions may lead
to accidents.

&&

LAT...LON 4053 7620 4049 7644 4029 7611 4022 7609
      4002 7726 4061 7703 4064 7696 4064 7700
      4120 7679 4153 7719 4169 7689 4160 7687
      4154 7623 4120 7632 4113 7627 4114 7623
      4095 7621 4090 7600 4085 7600
TIME...MOT...LOC 1315Z 238DEG 41KT 4153 7702 4126 7669 4079 7688 4004
7717 4003 7718

$$

DeVoir/Guseman

The office that day

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

Issued	Product	Office	Counties	Lasted
Feb 22, 8:28 AM EST	Snow Squall Warning	CTP	Adams, Lancaster, York	47 min

Nearby

Snow Squall Warnings in Pennsylvania, 2021 Every snow squall 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.