Alert archive / Pennsylvania / Snow Squall Warnings in 2021

Snow Squall Warning 5, NWS State College, PA

February 22, 2021Adams County, Lancaster County, York County, Pennsylvania

NWS State College, PA issued this snow squall warning at Feb 22, 2021, 8:28 AM EST for Adams County, Lancaster County, York County, Pennsylvania. It was in force for 47 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, 8:28 AM EST (13:28 UTC)
Expired
Feb 22, 2021, 9:15 AM EST
In force
47 min
Issued by
NWS State College, PA
Area
Storm-based polygon

Counties Adams County, PA, Lancaster County, PA, York County, PA

The radar

The Sterling radar (KLWX), 147 km from the middle of the area, began a volume at 13:27 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, 1.5 hours before the alert went out and 145 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 2021-02-22Temperature 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 2021-02-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 461 square meters per square second.1939587897117136Sfc1 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
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.

627 
WWUS51 KCTP 221330
SQWCTP

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

PAC001-071-133-221415-
/O.NEW.KCTP.SQ.W.0005.210222T1328Z-210222T1415Z/
Lancaster PA-Adams PA-York PA-
828 AM EST Mon Feb 22 2021

The National Weather Service in State College PA has issued a

* Snow Squall Warning for...
  Lancaster County in south central Pennsylvania...
  Southeastern Adams County in south central Pennsylvania...
  York County in south central Pennsylvania...

* Until 915 AM EST.

* At 828 AM EST, a dangerous snow squall was located along the 
  leading edge of an area of heavy snow extending from near Dover to 
  near Littlestown, moving east at 40 mph.

  HAZARD...Extremely poor visibility in heavy snow and blowing snow. 
           Possible flash freezes.
         
  SOURCE...Radar indicated.

  IMPACT...Dangerous life-threatening travel.

* This includes the following Interstates...
   The Pennsylvania Turnpike from mile markers 286 to 295.
   Interstate 83 from mile markers 0 to 34.

Locations impacted include...
Lancaster, York, Hanover, Ephrata, Weigelstown, Elizabethtown,
Columbia, Lititz, Millersville, Willow Street, Mount Joy, Parkville,
Red Lion, New Holland, Spry, Manheim, East Petersburg, Dallastown,
Akron and Shiloh.

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 4014 7696 4016 7675 4012 7672 4016 7670
      4015 7668 4017 7663 4023 7601 4017 7593
      4000 7596 3996 7599 3987 7599 3973 7610
      3974 7611 3972 7614 3972 7705
TIME...MOT...LOC 1328Z 271DEG 36KT 4007 7692 3970 7699 

$$

DeVoir/Guseman

The office that day

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

IssuedProductOfficeCountiesLasted
Feb 22, 8:15 AM ESTSnow Squall WarningCTPColumbia, Cumberland, Dauphin, Lancaster, Lebanon, Lycoming and 9 more90 min

Nearby

Snow Squall Warnings in Pennsylvania, 2021Every 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.