884
FXUS65 KSLC 182141
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
341 PM MDT Fri Apr 18 2025

.SYNOPSIS...A late season cold airmass will gradually exit the
region through the overnight period, with rapid stabilization of
the environment expected through Saturday morning. The pattern
remains progressive across the northern area through the upcoming
week, though warming temperatures are generally expected across
Utah and southwest Wyoming.

&&

.SHORT TERM (Through 12Z/6AM Sunday)...As of 3:15PM the center of
the low/ mid-level trough associated with the current storm
system is located over southern Utah, helping to aid in increased
coverage of showers and isolated thunderstorms this afternoon.
This low will meander south and east through the overnight hours
with a transient ridge building into the region through the
morning and afternoon hours on Saturday. Ahead of this ridge,
rapid stabilization of the environment is expected to spread from
north to south through the overnight hours. Skies will clear
across the region through the overnight which, with the cold
airmass in place, will lead to the coldest night of the week. For
many lower elevation valley areas across Utah and southwest
Wyoming, temperatures will drop into the 20 to 30 degree range by
sunrise tomorrow. If you`ve already got small gardens set up, be
sure to cover them or migrate sensitive plants/ crops indoors.

The influence of the aforementioned shortwave ridge will be
widespread by tomorrow, with skies expected to be largely clear
across the region. A few clouds may linger in southeast Utah, as
well as the southern mountains. Modest warming of overhead
temperatures is expected as the coldest airmass departs the
region, however, temperatures will still run around 5 degrees
below average for this time of year.

A weak shortwave trough translates through Utah and southwest
Wyoming during the overnight hours on Saturday into early Sunday,
bringing an increase in mid-level and high-level cloud cover. Much
warmer overnight temperatures are expected due to the warming
airmass and increased cloud coverage across the region. Enough
moisture may be present to generate light snow showers in the high
terrain of far northern Utah (including the Uinta Mountains),
however, little to no accumulation is expected.


.LONG TERM (After 12Z/6AM Sunday)...A transient ridge tracking in
from the northwest Saturday night into Sunday will bring dry
conditions through much of Sunday. A longwave trough will be exiting
the region as the transient ridge builds in, so temperatures will be
5-15F warmer from Saturday to Sunday. Highs Sunday will be in the
mid to upper 60s for most valleys.

The transient ridge will quickly slide eastward later Sunday as a
longwave trough digs into the PacNW. Ensembles are in good agreement
that the trough will not dig far to the south, but rather start to
slide eastward near the U.S. and Canada border. It will come close
enough for a weak baroclinic zone to slide in from the northwest
late Sunday into Monday. The front will bring limited cold air
advection, but enough forcing and moisture for scattered valley rain
and mountain snow showers above roughly 7000 feet through early
Monday. As the associated trough slides east, the boundary will
lift, with showers ending through the afternoon.

Zonal flow Tuesday will transition to west to southwest Wednesday.
Both days will be largely dry, but weak shortwave energy will keep
isolated to scattered showers for southwest Wyoming and northern
Utah. Conditions will warmer further Wednesday, as winds become
southwest. Valley highs will be into the 70s and 80s, with similar
values through later in the week.

There is good confidence that a longwave trough will dig into the
eastern Pacific Thursday. This will bring an increase in southwest
flow by Thursday for southern Utah and Friday throughout southwest
Wyoming and Utah. An upper diffluent set up will bring more showers
for southwest Wyoming and northern Utah.

Although there are daily chances for precipitation for southwest
Wyoming and northern Utah, there will be plenty of dry time. Total
valley rainfall and mountain snowfall through the week will be
minimal.

&&

.AVIATION...KSLC...Northerly winds will continue through the
afternoon, likely becoming lighter and northwesterly after 04-05z.
Winds may be light and variable at times overnight, but is looking
more likely to go light and southeasterly after 09z. VFR conditions
will prevail with clearing skies after 00z.

.REST OF UTAH AND SOUTHWEST WYOMING...Showers will largely diminish
heading into the evening hours, first across northern UT after 02z,
and after most of southern Utah by 05z. Showers will be strongest
across southern Utah producing intermittent MVFR conditions and even
IFR where snow is falling (>~5000ft). Across the north, winds will
become light and terrain-driven late in the evening; across southern
Utah, this transition will be more gradual, with breezy northerly
winds hanging on near higher terrain until 09-12z or so. Skies will
clear from northwest to southeast across the area overnight.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Winter Weather Advisory until 9 PM MDT this evening for UTZ117.

     Winter Weather Advisory until midnight MDT tonight for UTZ125.

WY...None.
&&

$$

SHORT TERM...Webber
LONG TERM...Wilson
AVIATION...Cunningham

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