844
FXUS65 KSLC 272045
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
245 PM MDT Sat Apr 27 2024

.SYNOPSIS...Cool conditions will continue into Sunday with a few
lingering showers as an upper low exits the area. Temperatures
will then gradually warm through Monday before a series of mostly
dry cold fronts impact the region beginning midweek.

&&

.SHORT TERM (Through 12Z/6AM Monday)...A broad upper low appears
to be centered just east of the Four Corners region this
afternoon, resulting in cool and unsettled conditions over Utah
and southwest Wyoming. In this airmass, temperatures are averaging
10-15F below seasonal normals with widespread cloud cover.
Precipitation earlier was most widespread with an area of upper
level divergence near and west of the Great Salt Lake, producing
some significant water totals and some issues with standing water
in that area. With the eastward movement of the low, associated
precipitation has tended to diminish and the focus has shifted
east a bit. Showers over central and southern Utah have become
spotty at best, so have cancelled the Winter Weather Advisory for
that area. With a bit better coverage of showers over northern
portions of the forecast area, have allowed that advisory to
continue for a bit longer.

Remaining showers are expected to all but diminish overnight as
the low continues to pull away from the area. However, northern
Utah is expected to see some redevelopment of showers during the
day Sunday with the passage of a trailing weak shortwave. Warm
advection in the airmass behind the low will allow temperatures to
become less cool, averaging 5-7F below normal for this time of
year. Any lingering showers are expected to diminish by Sunday
evening.

.LONG TERM (After 12Z/6AM Monday)...While the long term forecast
features a somewhat active and uncertain progression, there is a
low chance of any impactful weather through the period.

For Monday and Tuesday, confidence remains high in an active storm
track through the northern Rockies / Montana with generally zonal
flow across Utah. On Monday a shortwave will graze northern Utah
allowing temperatures to increase slightly ahead of the wave Monday,
invigorate some showers across northern Utah (especially the
mountains), followed by a slight cooling/drying trend into Tuesday
behind the wave passage. Temperatures will be fairly unremarkable,
for northern Utah, running a few degrees above average on Monday and
a few degrees below average on Tuesday. Meanwhile southern/central
Utah remains displaced enough from the shortwave passage to support
continued dry and slightly above normal temperatures south of the
boundary.

By Wednesday, a trailing wave is forecast to move through the
Pacific Northwest and into the intermountain West. However, per
cluster analysis about 50% of ensemble solutions maintain a
shallower wave that ejects more eastward which allows for
maintenance of zonal flow across Utah and continued drier, near
seasonal conditions. Meanwhile the other 50% of solutions dig the
wave further southward, swinging the wave through Utah. These
solutions feature cooler temperatures across the Great Basin and
through Utah as a cold front is force across the region. However,
as far as sensible weather impacts go, that is about it, as these
further south solutions are also moisture starved. At most, would
expect a few scattered showers, mainly in the northern Utah
terrain.

For Thursday through Saturday, the ensemble mean solution is a fair
nondescript zonal flow across the western US and Great Basin.
Breaking this down via the cluster analysis reveals about 25% of
solutions develop a deeper trough over the western US, just upstream
from Utah. Another 25% develop some very weak ridging over the
western US, while the remaining 50% of solutions in the middle have
some sort of weak troughing to nearly zonal flow across the area.
Picking apart the clusters further, its really only the upper
echelon (10%) of the deeper trough clusters that produce any
significant precipitation across the area, which would manifest as
valley rain and accumulating mountain snow. Otherwise, the vast
majority of most solutions support roughly seasonal temperatures
with some occasional passing showers.

&&

.AVIATION...KSLC...Shower activity expected to continue to gradually
diminish as system departs, but periods of CIGS generally to MVFR
will remain possible with any shower activity over the terminal.
Otherwise, will see some mountain obscuration from cloud cover, but
trend will be towards partial clearing late evening into the
overnight hours. Aside from influence of nearby showers, anticipate
winds to largely follow a typical diurnal pattern. An isolated
shower or two may redevelop Sunday, but activity much less
widespread.

.REST OF UTAH AND SOUTHWEST WYOMING...Active weather system will
continue to depart the region, with shower activity gradually
diminishing late evening into the overnight hours accordingly.
Reduced CIGS (generally to MVFR) possible during periods of showers,
but otherwise should also see something of a partial clearing trend.
Winds will also start to relax some late evening into the overnight,
with a bit more diurnally typical winds expected Sunday. Some
redevelopment of isolated showers will remain possible (~20% chance)
on Sunday.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Winter Weather Advisory until 6 AM MDT Sunday for UTZ111-112.

WY...None.
&&

$$

SHORT TERM...Traphagan
LONG TERM...Church
AVIATION...Warthen

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