Alert archive / Utah / Snow Squall Warnings in 2021

Snow Squall Warning 3, NWS Salt Lake City, UT

December 24, 2021Box Elder County, Utah

NWS Salt Lake City, UT issued this snow squall warning at Dec 24, 2021, 3:08 PM MST for Box Elder County, Utah. It was in force for 52 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
Dec 24, 2021, 3:08 PM MST (22:08 UTC)
Expired
Dec 24, 2021, 4:00 PM MST
In force
52 min
Issued by
NWS Salt Lake City, UT
Area
Storm-based polygon

County Box Elder County, UT

The radar

The Salt Lake City radar (KMTX), 62 km from the middle of the area, began a volume at 22:08 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

Salt Lake City I, UT (KSLC), launched 12:00Z, 10.1 hours before the alert went out and 133 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 12:00Z on 2021-12-24Temperature 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 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 12:00Z on 2021-12-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -13 square meters per square second.1939587897117136156175Sfc1 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
1233 m above ground
0-6 km bulk shear
82 kt
0-1 km storm-relative helicity
-13 m²/s²
0-3 km storm-relative helicity
-59 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

199 
WWUS55 KSLC 242208
SQWSLC

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Snow Squall Warning
National Weather Service Salt Lake City UT
308 PM MST Fri Dec 24 2021

UTC003-242300-
/O.NEW.KSLC.SQ.W.0003.211224T2208Z-211224T2300Z/
Box Elder UT-
308 PM MST Fri Dec 24 2021

The National Weather Service in Salt Lake City has issued a

* Snow Squall Warning for...
  North central Box Elder County in northern Utah...

* Until 400 PM MST

* At 305 PM MST, a dangerous snow squall was located along a line
  extending from near Holbrook Summit to 13 miles south of Park 
  Valley, moving east at 35 mph. At 250 PM Curlew Junction 
  visibility dropped to 1/4 mile with wind gusts of 37 mph.

  HAZARD...Extremely poor visibility in heavy snow and wind gusts up 
           to 40 mph.

  SOURCE...Radar and mesonet station indicated. 

  IMPACT...Dangerous life-threatening travel. 

* This includes the following highways...
   Interstate 84 between mile markers 0 and 25.
   Utah Route 30 between mile markers 56 and 90.

Locations impacted include...
Snowville, Howell, Great Salt Lake North of the Causeway, Curlew
Junction and Locomotive Springs.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4151 11272 4157 11356 4200 11314 4200 11228
TIME...MOT...LOC 2205Z 267DEG 30KT 4215 11275 4163 11325 

$$

Church
2 follow-up statements
310 
WWUS55 KSLC 242228
SQWSLC

Snow Squall Warning
National Weather Service Salt Lake City UT
328 PM MST Fri Dec 24 2021

UTC003-242300-
/O.CON.KSLC.SQ.W.0003.000000T0000Z-211224T2300Z/
Box Elder UT-
328 PM MST Fri Dec 24 2021

...A SNOW SQUALL WARNING REMAINS IN EFFECT UNTIL 400 PM MST FOR NORTH
CENTRAL BOX ELDER COUNTY...

At 327 PM MST, a dangerous snow squall was located along a line
extending from near Holbrook Summit to 18 miles southeast of Park
Valley, moving east at 35 mph.

HAZARD...Extremely poor visibility in heavy snow and blowing snow. 
         Wind gusts up to 40 mph. 

SOURCE...Radar, surface observations, and webcams. 

IMPACT...Dangerous life-threatening travel. 

This includes the following highways...
 Interstate 84 between mile markers 0 and 25.
 Utah Route 30 between mile markers 69 and 90.

Locations impacted include...
Snowville, Howell, Curlew Junction and Locomotive Springs. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4163 11261 4170 11317 4200 11308 4200 11228
TIME...MOT...LOC 2227Z 267DEG 30KT 4216 11256 4164 11306 

$$

Church
343 
WWUS55 KSLC 242302
SQWSLC

Snow Squall Warning
National Weather Service Salt Lake City UT
402 PM MST Fri Dec 24 2021

UTC003-242312-
/O.EXP.KSLC.SQ.W.0003.000000T0000Z-211224T2300Z/
Box Elder UT-
402 PM MST Fri Dec 24 2021

...THE SNOW SQUALL WARNING FOR NORTH CENTRAL BOX ELDER COUNTY HAS
EXPIRED...

The snow squall which prompted the warning has weakened and exited
the area. Therefore, the snow squall warning has been allowed to
expire. Roads will remain snow covered.

LAT...LON 4163 11261 4170 11317 4200 11308 4200 11228
TIME...MOT...LOC 2302Z 267DEG 30KT 4217 11223 4165 11273 

$$

Church

The office that day

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

IssuedProductOfficeCountiesLasted
Dec 24, 7:14 AM MSTAreal Flood WarningSLCIron, Kane, Washington9 hr

Nearby

Snow Squall Warnings in Utah, 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.