Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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FXUS65 KSLC 270359

Area Forecast Discussion
National Weather Service Salt Lake City UT
859 PM MST Sat Nov 26 2016

.SYNOPSIS...A series of increasingly cold Pacific storm systems
will cross the area beginning late tonight and continuing on
into Tuesday.


.SHORT TERM (Through 12Z Tuesday)...Light showers/virga beginning
to show up across western Utah as mid-level temps cool and weak
low-level cold advection forms ahead of the advancing trough
currently exiting southern California. This precip will expand in
areal coverage overnight as the air mass continues to destabilize
and the upper trough enters western Utah late tonight.

Solid dynamic lift along with abundant cold air and deep layer
moisture should make for widespread and at time heavy precip
throughout Sunday morning. Significant accumulations are expected
across the mountains, with the central and northern mountains
likely to receive the lions share. Snow levels will drop to most
valley locations Sunday morning, though accumulations will
generally be on the light side as rain could mix in at times.

Looking for a bit of a lull in the snow Sunday afternoon ahead of
a weak secondary shortwave move through late Sunday afternoon and
early evening. A trailing shortwave ridge Sunday night will again
limit precip through the balance of the overnight hours.

Moist low-level warm advection supported by steadily cooler temps
in the mid-levels will generate fairly strong lift and a return
to organized precip across northwest Utah late Sunday night
through early Monday. This precip will turn more widespread and
intense during the morning as the cold and quite energetic trough
will move southeast from the Pacific Northwest and into the
eastern/northern Great Basin. Looking for the heaviest snow of
this long duration precip event on Monday. The persistent cyclonic
northwest flow over northern Utah will create ideal conditions for
heavy snow for the mountains and adjacent windward valleys. The
potential for heavy snows will continue into Monday night, though
the focus will shift farther south along the I-15 corridor and to
the south of the GSL as the mean layer flow turns northerly during
the evening.

.PREVIOUS LONG TERM (After 12Z Tuesday)...Showers could continue
through the day Tuesday, particularly in mountain locations, as
the moist northwesterly flow persists through the day. Conditions
will become more stable Tuesday night as the trough axis finally
shifts eastward and temperatures warm aloft. Wednesday could be a
particularly cold morning, depending on how quickly the clouds
clear overnight.

Shortwave ridging on Wednesday is short-lived, as the next trough
drops into the Great Basin Wednesday night. While this system is
just as cold as the ones preceding it, this trough looks to be far
less productive precipitation-wise across Utah. The best energy
swings through California and Nevada, then eventually pushes
southeast across Arizona. On the whole, the storm also looks to tap
into less moisture than previous storms. For now, have kept isolated
to widely scattered showers in the forecast across most of the area
Thursday and Friday, with continued cold temperatures. Current model
runs advertise quieter weather for next weekend.


.AVIATION...Showers developing ahead of the advancing Pacific
storm system will impact the terminal beginning around 08Z.
Ceilings late tonight will lowering to around 7000 feet, then drop
down to around 4000-5000 feet during the early and mid-morning
hours Sunday. MVFR ceiling/visibility conditions will develop by
early Sunday afternoon.


UT...Winter Storm Warning until 5 AM MST Tuesday for UTZ007>010-517-

     Winter Storm Watch from late Sunday night through Monday evening
     for UTZ001>004-006.




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