Alert archive / Utah / Winter Weather Advisories in 2021

Winter Weather Advisory 23, NWS Salt Lake City, UT

December 15, 202115 counties in Utah

NWS Salt Lake City, UT issued this winter weather advisory at Dec 15, 2021, 2:44 PM MST for 15 counties in Utah. It took effect at Dec 16, 2021, 2:00 AM MST. It was in force for 30 hr.

The area

The counties it named.

The facts

Issued: Dec 15, 2021, 2:44 PM MST (21:44 UTC)
In effect from: Dec 16, 2021, 2:00 AM MST
Expired: Dec 17, 2021, 8:00 AM MST
In force: 30 hr
Issued by: NWS Salt Lake City, UT

Counties Box Elder County, UT, Cache County, UT, Carbon County, UT, Davis County, UT, Duchesne County, UT, Emery County, UT, Juab County, UT, Morgan County, UT, Rich County, UT, Salt Lake County, UT, Sanpete County, UT, Summit County, UT, Utah County, UT, Wasatch County, UT, Weber County, UT

The radar

The Salt Lake City radar (KMTX), 109 km from the middle of the area, began a volume at 21:44 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

Grand Junction, CO (KGJT), launched 12:00Z, 9.7 hours before the alert went out and 305 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: 755 m above ground
0-6 km bulk shear: 98 kt
0-1 km storm-relative helicity: -252 m²/s²
0-3 km storm-relative helicity: -57 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this winter weather advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Salt Lake City, UT wrote its last area forecast discussion before this winter weather advisory went out at Dec 14, 4:20 PM MST, 22 hours 24 minutes earlier.

Area forecast discussion, Dec 14, 4:20 PM MST, 22 hours 24 minutes before

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Nearby

Winter Weather Advisories in Utah, 2021 Every winter weather advisory 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.