Winter Storm in Utah, December 23 to 26, 2016

Area Forecast Discussion
National Weather Service Salt Lake City UT
1045 AM MST Fri Dec 23 2016

.SYNOPSIS...A moist and cold storm will slowly cross the Great
Basin during the weekend.

&&

.DISCUSSION...A short wave ridge is centered over UT this
morning downstream from the deepening trof in the ern Pac.
Extensive stratus developed in the valleys across much of the CWA
under this ridge from the low level moisture left behind from
yesterdays snow. Low level southerly flow has started ahead of the
incoming trof and this has been lifting the stratus into the
terrain across srn UT and generating a little light rain and snow.
Areas of fog have also formed across portions of the CWA.

The ridge shifts east this aftn and the extensive mid and high
clouds upstream of the axis spread into the CWA. Expect the
southerly flow to increase this aftn as well and this should
disrupt the stratus as the low levels start to mix out. The low
clouds could persist in upslope areas such as Dixie and Castle
Country. Light upslope precip could also develop over higher
terrain this aftn as the low level moisture is lifted out.

The ern Pac trof moves inland tonight and precip looks to become
more widespread late tonight into Sat morning. It will still
be more likely in the areas favored by southerly flow and temps
look a little warm for snow in the Wasatch Front valleys.
Especially if we mix out as well as forecast. The swrn UT valleys
will be closer to the snow level in the morning but it should fall
in the aftn with travel impacts beginning.

The ern valleys around Price will likely not mix out and could
also see snow starting as early as late today continuing thru Sat
with significant travel impacts along US-6 thru that area.

The trof digs a bit farther south in this mornings model runs with
the cold air surging east into AZ and far srn UT Sat aftn before
it gets into the rest of wrn UT. This delays the arrival of the
cold front into the Wasatch Front until Sat eve but it also keeps
heavy snow potential for this area going longer into Sunday...with
snow possibly not tapering off until aftn.

Some snow could linger over the far north Sun night into early Mon
before the system moves off to the east with a break for Mon aftn
into Tue.

Updated earlier to add mention of fog and local upslope precip
this morning and kept the mention of local upslope precip going
into the aftn. Made some adjustments to sky cover as well. Current
Winter Storm Warning looks on track.

&&

.AVIATION...VFR conditions are expected at the SLC terminal
through the afternoon with increasing high and mid level clouds.
Light northwest winds are expected to becoming prevailing
southerly by 20Z, but there is a 40 percent chance of northwest
winds persisting longer or shifts from southerly to northwest
during the day.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Winter Storm Warning from 8 PM this evening to 4 AM MST Monday
     for UTZ001>012-014>016-020-517-518.

WY...Winter Storm Warning from 8 PM this evening to 4 AM MST Monday
     for WYZ021.

&&

Wilensky/Traphagan

For more information from NOAA's National Weather Service visit...
http://weather.gov/saltlakecity

For frequently asked questions about the Area Forecast Discussion
visit...
http://weather.gov/saltlakecity/general/afd_faqs.php

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
258 AM MST FRI DEC 23 2016

UTZ001>016-019>021-517-518-WYZ021-241300-
CACHE VALLEY/UTAH PORTION-NORTHERN WASATCH FRONT-
SALT LAKE AND TOOELE VALLEYS-SOUTHERN WASATCH FRONT-
GREAT SALT LAKE DESERT AND MOUNTAINS-WASATCH MOUNTAIN VALLEYS-
WASATCH MOUNTAINS I-80 NORTH-WASATCH MOUNTAINS SOUTH OF I-80-
WESTERN UINTA MOUNTAINS-WASATCH PLATEAU/BOOK CLIFFS-
WESTERN UINTA BASIN-CASTLE COUNTRY-SAN RAFAEL SWELL-
SANPETE/SEVIER VALLEYS-WEST CENTRAL UTAH-SOUTHWEST UTAH-
UTAHS DIXIE AND ZION NATIONAL PARK-SOUTH CENTRAL UTAH-
GLEN CANYON RECREATION AREA/LAKE POWELL-CENTRAL MOUNTAINS-
SOUTHERN MOUNTAINS-SOUTHWEST WYOMING-
258 AM MST FRI DEC 23 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN TWO THIRDS OF
UTAH AND SOUTHWEST WYOMING.

.DAY ONE...TODAY AND TONIGHT

LIGHT VALLEY RAIN AND SNOW AND MOUNTAIN SNOW...AS WELL AS GUSTY
SOUTH WINDS WILL DEVELOP TONIGHT. WINTER DRIVING CONDITIONS MAY
DEVELOP ACROSS MOUNTAIN PASSES AND COLDER VALLEYS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

A WINTER STORM WILL IMPACT THE OUTLOOK AREA DURING THE UPCOMING
HOLIDAY WEEKEND. GENERALLY 4 TO 8 INCHES OF VALLEY SNOWFALL AND 1
TO 3 FEET IN THE MOUNTAINS CAN BE EXPECTED. SIGNIFICANT TRAVEL
IMPACTS ARE LIKELY THROUGH THE HOLIDAY WEEKEND. THOSE PLANNING
TRAVEL ACROSS THE AREA DURING THIS TIME ARE ENCOURAGED TO ADJUST
TRAVEL PLANS IF POSSIBLE...PLAN FOR WINTER DRIVING CONDITIONS...AND
CARRY A WINTER SURVIVAL KIT.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

ROGOWSKI

FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY

FOR INFORMATION ON POTENTIAL ROAD TRAVEL IMPACTS VISIT...
HTTP://WWW.UDOTTRAFFIC.UTAH.GOV/ROADWEATHERFORECAST.ASPX