004
FXUS65 KSLC 200934
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
334 AM MDT Sun Jul 20 2025

.SYNOPSIS...Limited amounts of moisture maintain isolated to
scattered daytime convection chances, especially across southern
Utah and elsewhere along Utah`s high terrain. From midweek onward,
a drying and warming trend is largely expected.

&&

.SHORT TERM (Through 12Z/6AM Tuesday)...This morning`s satellite
water vapor analysis looks quite similar to that of 24 hours
prior. Currently, a fairly broad longwave trough is continuing to
very slowly deepen through the PacNW, while a weaker cutoff system
continues to churn near the California/Mexico border. Main
difference is an evident intrusion of slightly drier air, or at
least a more muted moisture return, and thus also seeing fairly
clear conditions across the area. Despite the clear skies though,
temperatures at most locations appear to be running a bit above
where they were at this time last night.

For Sunday, another fairly weak system and its associated
moisture will start to shift northward through Mexico, approaching
the cutoff system, while the cutoff system moves minimally.
Meanwhile, the broader longwave trough will continue to very
slowly deepen. Locally, the pattern doesn`t shift significantly,
and PWAT values near normal will support the development of
isolated to scattered and largely terrain initiated convection
through the afternoon into the evening hours. H7 temps nudge
upwards a bit, so most locations will also see afternoon highs a
degree or two higher than Saturday.

Sunday night into Monday the cutoff low will begin interacting
with the approaching moisture plume and start to be tugged
northeastward towards Utah due to the deepening of the broader
longwave trough. This will lead to some potential for shower
activity overnight into sunrise especially across southern Utah.
Moisture will continue to then spread further northward through
the day, with the motion of the system supporting best moisture
and associated convective coverage outside of southern Utah
generally along/east of the I-15 corridor and south of the I-80
corridor. While not as prolific as some prior moisture surges, any
storm that manages to drift over a rain sensitive area such as a
slot canyon, typically dry wash, or burn scar will have some
possibility of being impactful. Showers and thunderstorms will
then decrease in coverage/strength from later Monday evening on
into the overnight hours.

.LONG TERM (After 12Z/6AM Tuesday)...A longwave trough to the
northwest will lift Tuesday. Drier southwest flow will build in,
as remnant moisture from a system to the southwest that will track
through Monday will also exit the area. There will be lower
relative humidity values than Monday, generally ranging in the
teens. The lifting storm system will bring a downtrend in wind
speeds, but gusts will top 30 mph throughout southwest Wyoming and
25 mph for portions of southwest Utah. These conditions will come
with some enhancement in wildfire danger.

Almost all ensemble members from the GEFS, EPS, and GEPS indicate
that a closed low will break off the positively-tilted system to
the northwest. It will likely be positioned off the coast of
California much of the week, lifting later in the week with
minimal or no effects for southwest Wyoming and Utah. An expansive
ridge throughout the southeast U.S. will retrograde much of the
week. As it does, conditions throughout southwest Wyoming and Utah
will trend slightly warmer and drier.

Isolated to scattered afternoon showers and thunderstorms will
primarily be around mountainous terrain from Tuesday through
Thursday. As high pressure builds west, there will be fewer
showers and thunderstorms Friday into the weekend.

Valley temperatures for much of Utah will reach the low 90s early
in the week, with more mid 90s later in the week. Lower
Washington County will trend from the upper 90s to around 100F.

&&

.AVIATION...KSLC...Clear conditions with light southeast winds will
last through the morning. There is uncertainty on wind direction
into the afternoon, as nearby showers will be capable of gusty,
erratic outflow winds. Winds will prevail from the southeast into
the afternoon, with a transition to light northwest flow possible
around 21Z, depending on where showers track.

.REST OF UTAH AND SOUTHWEST WYOMING...Clear conditions with light
winds will last through the morning. Southwest winds will gust
between 20-30 knots for southwest Wyoming and much of Utah from
18- 03Z. Directions and speeds could be altered by showers capable
of gusty, erratic outflow winds, primarily for southwest Wyoming
and northern Utah.

&&

.FIRE WEATHER...A similar forecast evolution is expected on
Sunday to that of Saturday, with isolated convection developing
after around 1300 and diminishing after around 2100. Coverage is
expected to be less than that of yesterday, and generally
maximized along Utah`s high terrain. Once again, what does develop
will have the potential for moderate rain, lightning, and gusty
erratic outflow winds up to around 40 mph or so. Moisture
increases on Monday, especially across southern Utah, resulting in
a brief upward RH trend. It will also allow for some potential of
morning showers across southern utah, and increased convective
coverage moving through the afternoon hours. While general daytime
southwesterly wind gusts will nudge upwards, the increase in RH
should abate widespread critical fire weather conditions, and
rather expect more general elevated fire weather conditions with
some potential for locally critical areas. From midweek onward,
while there will be limited enough moisture to result in a few
isolated high-based terrain showers and thunderstorms, most of the
area will see a warming and drying trend.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...None.
WY...None.
&&

$$

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

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http://weather.gov/saltlakecity