Alert archive / Utah / Snow Squall Warnings in 2021

Snow Squall Warning 9, NWS Salt Lake City, UT

December 27, 2021Uinta County, Wyoming; 4 counties in Utah

NWS Salt Lake City, UT issued this snow squall warning at Dec 27, 2021, 5:02 PM MST for Uinta County, Wyoming; 4 counties in Utah. It was in force for 43 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
Dec 27, 2021, 5:02 PM MST (00:02 UTC)
Expired
Dec 27, 2021, 5:45 PM MST
In force
43 min
Issued by
NWS Salt Lake City, UT
Area
Storm-based polygon

Counties Morgan County, UT, Rich County, UT, Summit County, UT, Weber County, UT, Uinta County, WY

The radar

The Salt Lake City radar (KMTX), 91 km from the middle of the area, began a volume at 00:04 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
Dec 27, 5:20 PM MSTNON-TSTM WND GST 55Salt Lake City, UTSR-65 AT BIG MOUNTAIN PASS - 7433 FT

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Salt Lake City I, UT (KSLC), launched 00:00Z, 0.0 hours before the alert went out and 65 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, Salt Lake City I, UT at 00:00Z on 2021-12-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 33 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Salt Lake City I, UT at 00:00Z on 2021-12-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 219 square meters per square second.1939587897Sfc1 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
33 J/kg
Mixed-layer CIN
-42 J/kg
Mixed-layer LCL
1606 m above ground
0-6 km bulk shear
69 kt
0-1 km storm-relative helicity
219 m²/s²
0-3 km storm-relative helicity
252 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.7

Open this sounding in Storm Lab

The text

As transmitted.

398 
WWUS55 KSLC 280002
SQWSLC

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Snow Squall Warning
National Weather Service Salt Lake City UT
502 PM MST Mon Dec 27 2021

UTC029-033-043-057-WYC041-280045-
/O.NEW.KSLC.SQ.W.0009.211228T0002Z-211228T0045Z/
Weber UT-Rich UT-Morgan UT-Summit UT-Uinta WY-
502 PM MST Mon Dec 27 2021

The National Weather Service in Salt Lake City has issued a

* Snow Squall Warning for...
  Northeastern Weber County in northern Utah...
  Southern Rich County in northern Utah...
  Morgan County in northern Utah...
  Northwestern Summit County in northern Utah...
  West central Uinta County in southwestern Wyoming...

* Until 545 PM MST

* At 502 PM MST, a dangerous snow squall was located along a line
  extending from 18 miles southwest of Woodruff to Farmington, moving
  east at 45 mph.

  HAZARD...Extremely poor visibility in heavy snow and blowing snow. 
           Wind gusts greater than 30 mph. 

  SOURCE...Radar indicated. 

  IMPACT...Rapid snow accumulation on area roadways resulting in 
           dangerous travel. 

* This includes the following highways...
   Interstate 84 between mile markers 101 and 119.
   Interstate 80 in Utah between mile markers 161 and 196.

Locations impacted include...
Morgan, Coalville, Woodruff, East Canyon State Park, Henefer,
Portersville, Echo, Stoddard, Richville, Echo Reservoir, Wahsatch,
Emory, Causey Reservoir, Croydon and Castle Rock.

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.

Reduce your speed and turn on headlights! During snow squalls, the
visibility may suddenly drop to near zero in whiteout conditions.

&&

LAT...LON 4158 11104 4097 11104 4081 11164 4094 11171
      4135 11173
TIME...MOT...LOC 0002Z 262DEG 41KT 4137 11146 4097 11188 

$$

MPS
2 follow-up statements
600 
WWUS55 KSLC 280020
SQWSLC

Snow Squall Warning
National Weather Service Salt Lake City UT
520 PM MST Mon Dec 27 2021

UTC029-033-043-057-WYC041-280045-
/O.CON.KSLC.SQ.W.0009.000000T0000Z-211228T0045Z/
Weber UT-Rich UT-Morgan UT-Summit UT-Uinta WY-
520 PM MST Mon Dec 27 2021

...A SNOW SQUALL WARNING REMAINS IN EFFECT UNTIL 545 PM MST FOR
NORTHEASTERN WEBER...SOUTHERN RICH...MORGAN...NORTHWESTERN SUMMIT AND
WEST CENTRAL UINTA COUNTIES...

At 520 PM MST, a dangerous snow squall was located along a line
extending from 9 miles south of Woodruff to near Morgan, moving east
at 45 mph.

HAZARD...Extremely poor visibility in heavy snow and blowing snow. 
         Wind gusts greater than 40 mph. 

SOURCE...Radar indicated. 

IMPACT...Dangerous life-threatening travel. 

This includes the following highways...
 Interstate 84 between mile markers 101 and 119.
 Interstate 80 in Utah between mile markers 161 and 196.

Locations impacted include...
Morgan, Coalville, Woodruff, East Canyon State Park, Henefer,
Portersville, Echo, Stoddard, Richville, Echo Reservoir, Wahsatch,
Emory, Causey Reservoir, Croydon and Castle Rock.

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.

Reduce your speed and turn on headlights! During snow squalls, the
visibility may suddenly drop to near zero in whiteout conditions.

&&

LAT...LON 4158 11104 4097 11104 4081 11164 4094 11171
      4135 11173
TIME...MOT...LOC 0020Z 262DEG 41KT 4140 11121 4100 11163 

$$

MPS
551 
WWUS55 KSLC 280053
SQWSLC

Snow Squall Warning
National Weather Service Salt Lake City UT
553 PM MST Mon Dec 27 2021

UTC029-033-043-057-WYC041-280103-
/O.EXP.KSLC.SQ.W.0009.000000T0000Z-211228T0045Z/
Weber UT-Rich UT-Morgan UT-Summit UT-Uinta WY-
553 PM MST Mon Dec 27 2021

...THE SNOW SQUALL WARNING FOR NORTHEASTERN WEBER...SOUTHERN RICH...
MORGAN...NORTHWESTERN SUMMIT AND WEST CENTRAL UINTA COUNTIES HAS
EXPIRED...

The snow squall which prompted the warning has exited the area.
Therefore, the snow squall warning has been allowed to expire. Roads 
will remain snow covered, and additional snowfall will continue 
through the evening hours. 

LAT...LON 4158 11104 4097 11104 4081 11164 4094 11171
      4135 11173
TIME...MOT...LOC 0053Z 262DEG 41KT 4144 11080 4104 11122 

$$

MPS

The office that day

Everything else NWS Salt Lake City, UT issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 27, 5:24 PM MSTSnow Squall WarningSLCUinta66 min
Dec 28, 3:42 PM MSTWinter Weather AdvisorySLCUinta4 days
Dec 27, 5:45 PM MSTSnow Squall WarningSLCSalt Lake, Summit, Tooele, Utah, Wasatch60 min
Dec 27, 6:51 PM MSTSpecial Weather StatementSLCUtah, Wasatch39 min
Dec 28, 3:19 AM MSTWinter Storm WatchSLCBeaver, Box Elder, Cache, Carbon, Davis, Duchesne and 18 more12 hr

Nearby

Snow Squall Warnings in Utah, 2021Snow Squall Warnings in Wyoming, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.