820
FXUS65 KSLC 142159
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
359 PM MDT Sun Sep 14 2025

.SYNOPSIS...High pressure departs and gives way to a quick grazing
system and associated cold front to start the week. This will
bring cooler temperatures and some light precipitation to N UT and
SW WY. A drying and warming trend then sets in through midweek,
with moisture and precipitation chances returning late in the
week.

&&

.SHORT TERM (Through 12Z/6AM Tuesday)...Afternoon water vapor loop
shows a transient ridge shifting through the Great Basin and into
the Intermountain West as the trough which brought a period of
unsettled weather continues to depart to the east. This ridge is
bringing much quieter conditions to Utah and southwest Wyoming
today, with little of note on radar. Visible satellite however is
picking up on a fair bit of cumulus developing along the northern
high terrain and eastward. Overall though, pretty pleasant
conditions across the area with afternoon temperatures running
fairly close to normal for mid September.

As quickly as the ridge shifted in, it will depart tonight as it
gives way to an approaching PacNW trough. This trough will push an
associated cold frontal boundary southward into Utah and
southwest Wyoming, accompanied by some showers and potentially a
thunderstorm or two given modest instability with pockets of
MUCAPE around 100 J/kg or so. With the grazing nature of the
trough, the front won`t advance too far southward, with
precipitation generally along/north of the I-80 corridor or so. As
the day progresses precipitation chances will actually gradually
decrease, becoming more focused over southwest Wyoming and the
Uinta Mountains by the afternoon. At locations behind the front
across northern Utah and southwest Wyoming, afternoon high
temperatures dip around 3-7F in comparison to Sunday.

Overnight into Tuesday morning a reinforcing lobe of the trough
will pivot through and help reinvigorate some low end (~10-30%)
chances of showers across some of the high northern terrain,
particularly the Uinta Mountains. Otherwise, it`ll be a cooler
night at areas where the front passed, with some potential for
patchy frost noted across some of the higher mountain valleys like
the Wasatch Back.

.LONG TERM (After 12Z/6AM Tuesday), Issued 341 AM MDT...
A shortwave ejecting to the east will leave conditions dry on
Tuesday with temperatures near normal along with temperatures a
few degrees above normal further south. A ridge builds into the
area on the heels of this shortwave with temperatures gradually
warming a few degrees above normal Wednesday and Thursday.
Temperatures across lower Washington county will be in the upper
90s to near 100 degrees.

The ridge starts to break down a bit late in the week with
southerly flow advecting moisture back into the area. This will
help to develop diurnal convection through the weekend. A trough
off the west coast will bring upper level diffluence to provide
more lift for convection across the area on Saturday. ~56% of
ensemble members are on the wetter side of the solution, while the
remaining 44% of members are on the drier side of the solution
space. Additionally, guidance does hint at some shortwaves ejected
out ahead of the parent trough over the weekend that could
enhance lift and promote more convection. This pattern will favor
temperatures near normal given the absence of any cooler
continental airmasses.

&&

.AVIATION...KSLC...VFR conditions are expected through the TAF
period under clearing skies through the evening. Light
northwesterly winds are expected this evening, transitioning back
to southerly flow around 02-03Z. Clouds will increase again
through the overnight hours but remain around 10kft or higher,
with around a 20-30% chance of light rain around 11-12Z.

.REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions are expected
across Utah and southwest Wyoming through the TAF period. Gusty
west to southwest winds will persist through sunset, reverting
back to diurnally driven flows thereafter. Across northern Utah
and southwest Wyoming, an area of light showers is anticipated to
develop after 05Z, bringing isolated to scattered precipitation
from KSLC northward through 14-15Z.

&&

.FIRE WEATHER...Sunday`s high pressure and dry conditions will
depart and give way to a grazing system Sunday night into early
next week. An associated cold front will be pushed southward into
northern Utah, bringing some chances of light showers. Instability
will be limited but non-zero, so cannot entirely rule out a
thunderstorm or two. Precipitation chances will be highest along
and north of the I-80 corridor, with a reinvigoration of low end
precipitation chances Monday night into Tuesday as a reinforcing
system grazes the area. Thereafter into the middle portions of the
week a drying and warming trend is noted, with widespread daytime
minimum humidity values in the teens at most lower elevation
areas. Moisture is then favored to return to the area from Friday
into the weekend, bringing a corresponding return of precipitation
chances.


&&

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

$$

SHORT TERM...Warthen
LONG TERM...Mahan
AVIATION...Webber
FIRE WEATHER...Warthen

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