388
FXUS65 KSLC 130958
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
358 AM MDT Tue May 13 2025

.SYNOPSIS...Gusty winds redevelop across east Utah as a cold front
progresses Tuesday. Cooler and unsettled conditions largely persist
through the rest of the work week, with potential for another
stronger and more widespread system by the upcoming weekend.

&&

.SHORT TERM (Through 12Z/6AM Thursday)...Morning water vapor loop
shows a broad trough continuing to dig southward into the Great
Basin. Area observations as well as SPC mesoanalysis data show
that the surface front and low level baroclinic zone associated
with this trough has already progressed through much of the
Wasatch Front. Moderately strong cold air advection behind the
front has resulted in some maintained modest wind gusts, though
comfortably below advisory criteria aside from an occasional
localized gust here and there. As such, allowed the prior
headlines to expire on schedule. Aside from the winds, the cold
air advection behind the front is resulting in temperatures around
15F to 25F colder than at this time 24 hours ago. With deeper
moisture lagging the front, just starting to see area radars pick
up on precipitation shifting into northwest Utah.

Moving into the day Tuesday, the broad trough will continue to
deepen through the Great Basin and gradually start to cut off a
bit from the northern stream. The low level front will continue on
a southeastward trajectory throughout the course of the day, with
another day of strong prefrontal wind gusts developing across
eastern valley locations mid morning on through the afternoon.
Maintained the associated Wind Advisory headline as-is for fairly
widespread south to southwesterly gusts in excess of 40 mph, but
given the degree to which Monday seemed to overachieve
expectations, will certainly need to keep an eye on conditions.
Following frontal passage Tuesday evening, winds will begin to
gradually relax.

As mentioned, better precipitation chances with the system will
lag the front. A more marked embedded shortwave will round the
base of the trough with associated energy advecting into Utah
through the morning. In combination with moisture, CAM guidance
shows a fairly widespread band of precipitation developing through
the morning as far south as Millard County or so, slowly
progressing eastward in the hours following sunrise. Forcing with
this impulse becomes a bit more nebulous as the core of the trough
continues to work in by early afternoon, and in turn showery
precipitation trends a bit more scattered in nature. With the
colder near-surface air and marginally steeper lapse rates, meager
diurnal destabilization will also support a few thunderstorms.

Over the remainder of the short term forecast, the broad trough
will slowly continue to shift through overhead, with limited
moisture and weaker embedded impulses within the cyclonic flow
maintaining unsettled and cooler conditions. In general, coverage
will tend to be a little higher during the day given the aid of
daytime heating. Given that the moisture is somewhat meager with
the system, QPF totals aren`t too impressive, but many across the
area (especially those further north) will have favorable odds to
pick up at least a little bit of measurable precipitation. Given
the cooler air associated with the core of the trough, snow levels
actually briefly drop to around 6750-7250 ft Wednesday morning,
but actual late season accumulations are more likely to be limited
to areas generally at/above 8500 ft or so. Even then, outside of
some of the highest peaks, accumulations look to be pretty light
and minimally impactful.

.LONG TERM (after 12Z/6AM Thursday)...Between Thursday and
Friday, our region remains wedged between an area of low pressure
over the Baja Peninsula and a deep trough traversing the northern
Plains. This pattern will support continued cool and unsettled
conditions through this period as west-northwesterly flow develops
across the region. Temperatures are expected to gradually warm
near to just below to climatological normals by Friday,
translating to highs in the mid-upper 60s for most valley
locations except lower Washington county where highs nudge into
the 80s.

A reinforcing shortwave digging into the Great Basin on Thursday
will provide enough instability for widely scattered showers and
thunderstorms to develop across northern Utah and southwest
Wyoming on Thursday afternoon. Precipitation chances dwindle on
Friday, with additional afternoon shower chances remaining
generally less than 20% areawide.

An upper-level trough deepens across the Pacific Northwest on
Saturday, introducing increased southwesterly flow across the
region and warm advection aloft. As such, temperatures are
expected to jump an additional 5-10 degrees on Saturday, mainly
across the northern portion of the forecast area. Gusty
southwesterly winds are expected to develop mainly across
southwestern Utah, with widespread gusts 20- 30 mph. Ensemble
clusters support this trough digging into the Great Basin late
Saturday, cutting off directly over our region late Sunday, then
lingering overhead before ejecting eastward late Monday. This
pattern will support widespread showers between late Saturday into
early Monday, with a cooling trend back below seasonal averages.
Additionally, significant cooling aloft will allow for some
snowfall accumulations mainly above 8000-9000 feet between this
period.

&&

.AVIATION...KSLC...Dust lofted off of the Great Salt Lake Desert
from the frontal passage continues to hang around the Salt Lake
Valley early this morning, resulting in MVFR VIS. This dust will
likely linger across the valley this morning until a band of post
frontal precipitation moves through this afternoon, though VIS may
fluctuate between MVFR/VFR during this period. Have opted to err
on the pessimistic side for latest TAF package given current
observations. Regardless, slantwise visibility reductions will
continue until precipitation flushes out remaining dust this
afternoon. High resolution guidance suggests the aforementioned
precip band will impact the terminal roughly between 20-00z this
afternoon, with more showery conditions through the remainder of
the evening. While showers will be generally light, expect CIG
reductions with resultant mountain obscuration after 18z.

.REST OF UTAH AND SOUTHWEST WYOMING...Winds across the
northern portion of the airspace have tapered off as
northwesterly post-frontal winds prevail. Some BLDU still lingers
across areas downstream of desert sinks this morning, resulting in
deteriorated VIS. Behind this front, a band of light
precipitation traverses the northern portion of the airspace early
this afternoon, which will clear out any lingering dust. Strong
southerly winds persist for southern Utah terminals as they remain
ahead of the front this morning. Expect winds to finally ease and
shift west-northwest as the front passes through southern Utah
late this afternoon.

&&

.FIRE WEATHER...A strong trough and associated cold frontal
boundary will continue to gradually work southeast through Utah
Tuesday. Ahead of the front, primarily east of Utah`s high
terrain, strong gusty south to southwest winds will redevelop and
afternoon humidity values will remain in the high single digits to
mid teens. Winds will trend west to northwesterly behind the
front and remain more modestly gusty for a period of time. Showers
and a few thunderstorms will accompany the front, with forcing
and moisture sufficient to then maintain shower chances behind the
front into midweek as the broader/deeper system shifts through
overhead. Some light snow accumulation will be possible at high
elevation locations generally above 9000 feet. A series of weaker
reinforcing waves will help keep an unsettled pattern continue
through the remainder of the work week, especially for northern
Utah. Another fairly deep and moist system then remains favored to
impact Utah through the weekend.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Wind Advisory from 9 AM this morning to 9 PM MDT this evening
     for UTZ120-121-126>131.

WY...None.
&&

$$

SHORT TERM...Warthen
LONG TERM...Whitlam
AVIATION...Whitlam
FIRE WEATHER...Warthen

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