Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 280432
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
932 PM MST Sun Nov 27 2016

.SYNOPSIS...A cold Pacific storm system will cross the region late
tonight through Monday. A trailing cold northerly flow will follow
through midweek, with another storm system possible late in the
week.

&&

.SHORT TERM (After 12Z Wednesday)...The weak mid-level trough
heading into the eastern half of Utah this evening will maintain
scattered snow showers across the central/southern/northeast
mountains, with isolated showers for the valleys until shortly
after midnight. Trailing the trough a weak shortwave ridge will
bring a short period of minimal precip activity through late
tonight.

The next, and most potent, round of precip will return to far
northwest and west-central Utah late tonight. A 3-6 hour period
of strong and quite moist deep layer warm advection ahead of the
cold core upper trough digging southeast from the Pacific
Northwest will bring widespread snow back into the north late
tonight. This precip will spread south by early Monday morning,
though the precip intensity should remain on the lighter side as
the lift from the warm advection become a bit less organized.

Snow will become heavy over a fairly broad area of the north
during Monday morning as strong deep layer cold advection develops
in associated with the rather energetic trough sweeping southeast
into the northern/western Great Basin during the morning. This
trough will enter northern Utah around midday and maintain
enhanced snowfall through the afternoon as it continue southeast
across and eventual out of Utah by Tuesday evening.

The deep layer moisture working with the strong thermal/dynamic
lift generated by the trough will lead to widespread accumulating
snows, with heavy snow for the mountains and many of the adjacent
valleys west of the mountains along the I-15 corridor. Orographic
enhancement will also be in play, with the Wasatch range and a
good portion of the central mountains receiving enhanced snowfall
totals.

The deep layer northerly flow behind the exiting trough will drive
a period of heavy snow along the I-15 and I-70 corridors in
central and southwest Utah Tuesday night. Further north cold air
instability showers will linger overnight as the coldest air
associated with the trough lags back across much of western Utah.

Lake effect snows also in play late Monday night/Tuesday morning.
Trajectories will take the best chance for snow squalls south
through western Salt Lake, northern Utah, and northeast Tooele
counties. Lake effect showers will gradually dissipate beginning
late Tuesday morning or early afternoon, with all convective snow
showers finally winding down Tuesday evening as warming/drying
aloft take hold across the entire region.

.PREVIOUS LONG TERM (After 12Z Wednesday)...The trough continues
to exit to the east on Wednesday, with shortwave ridging building
over the Great Basin. Any warming of temperatures is not expected
to be significant, especially since the next trough in the mean
northwest flow pushes into the region starting Wednesday night.

The bulk of the mid and upper level energy stays west and south of
the area Thursday and Friday, though Utah does get some weak and
moist cold advection. This could kick off some light shower activity
across the state, especially on Thursday and Thursday night. Have
continued to slowly increase POPs and sky cover through this period,
though precipitation totals do not look significant at this time.

Most of the trough is south of Utah by Friday night, with a more
stable anticyclonic flow setting up over the Great Basin. The
weekend still looks primarily dry across the area, though increased
cloud cover is possible across the north as the ridge flattens and
increased moisture moves over Idaho.

&&

.AVIATION...The KSLC terminal sits in a lull in precipitation
ahead the next cold and energetic weather disturbance scheduled to
arrive around mid-morning Monday. Light rain/snow will return to
the terminal area after 11z with ceilings running between 4000 to
5000 feet. IFR conditions will develop quickly as the storm
settles in between 15z and 16Z. IFR and brief periods of LIFR
conditions will exist in snow through the day Monday. Lake effect
bands that would impact the terminal could form early in the
evening, then shift off to the west around mid-evening.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Winter Storm Warning until 5 AM MST Tuesday for UTZ007>010-517-
     518.

     Winter Storm Warning from 2 AM to 11 PM MST Monday for
     UTZ001>004-006.

     Winter Weather Advisory from 2 AM to 11 AM MST Monday for UTZ005.

     Winter Weather Advisory from 11 AM to 11 PM MST Monday for
     UTZ014>016.

WY...None.
&&

$$

Conger/Schoening

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http://weather.gov/saltlakecity

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


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