879
FXUS65 KSLC 101835
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
1235 PM MDT Thu Sep 10 2026

.KEY MESSAGES, Issued 1137 AM MDT Thu Sep 10 2026...


- Flash Flooding is possible again starting Friday afternoon
  across southern Utah where a Marginal Risk (level 1 of 4) of
  Excessive Rainfall is in place. An isolated flash flood threat
  will continue across southern and eastern Utah through the
  weekend and likely into next week.

- There is a ~50% chance the western valleys will see wind gusts
  in excess of 45 mph for 3 or more hours Saturday evening into
  late Saturday night ahead of a strong cold front.

- Temperatures will warm through Saturday ahead of an approaching
  cold front. The cold front will usher in cooler temperatures
  across northern Utah early next week (Sunday through Tuesday)
  while southern Utah will remain on the warm side of the
  boundary.

&&

.DISCUSSION, Issued 1137 AM MDT Thu Sep 10 2026...

High pressure centered south of Las Vegas currently will keep
Utah under dry northwesterly flow again today, supporting another
day of clear skies and seasonable temperatures. The ridge will
become suppressed to our south tonight as cyclonic flow over the
Pacific Northwest increases with a shortwave trough pushing
through the northern Rockies overnight. Models have trended up
slightly in producing some scattered light showers across northern
Utah overnight tonight as a weak boundary is pushed southward
through the area. Given the limited moisture in place and marginal
moisture transport along this leading shortwave coverage will be
widely scattered and precipitation totals very light.

By Friday afternoon the flow across Utah becomes more zonal again,
but at the low-levels some modest moisture is drawn northward
into southern Utah. An isolated flash flood threat will develop
Friday afternoon where storms develop over the higher terrain of
southern Utah, aided by convergence along the washed out boundary,
with preference for tracking eastward off the terrain the zonal
background flow. This pattern favors more of the eastern basins
like the upper Escalante River Basin, Capitol Reef and slot canyon
terrain south of Hanksville around the Henry Mountains, although
other favored southern Utah flash flood prone locations cannot be
completely ruled out.

By Saturday the ridge starts to re-develop and amplify over New
Mexico, while a trough carves out over the Pacific Northwest. This
will start to increase the pressure gradient across Utah, with
increasing southwesterly winds. There remains between a 30-60%
chance of exceeding wind advisory criteria (45 mph) on Saturday
across western Utah. There remains some slight variation in the
exact timing and location of the upstream trough, which will
matter for how quickly the winds ramp up and how strong the winds
will become. Also with the ridge position, the better monsoon
moisture will be shunted a bit eastward into far eastern Utah and
Colorado. However, if the moisture settles into the eastern Utah
basins well on Friday, this moisture can be stubborn to leave, and
a few longer range high resolution models show the potential for
a few organized stronger storms developing over the Uinta Basin
and San Rafael Swell given the increase in shear. Any organized
supercells that can develop are always extremely efficient heavy
rain producers. This is a good example of a low confidence, but
potentially high impact event if these storms can develop and
track over a vulnerable slot canyon. Have ensured the Flash Flood
Potential Rating is carrying `Possible` for the Swell and Capitol
Reef on Saturday for this potential. The potential looks very
similar into Sunday as the upstream trough tracks into the
Northern Rockies, and the core of the monsoon plume remains east
of the area into far eastern Utah and Colorado.

Otherwise, as the through move through the Northern Rockies, a
generally dry cold front will be pushed south through northern
Utah, which may come through a in a couple of pushes. This will
bring temperatures trending down by Sunday, and especially by
Monday, with high temperatures trending down from the 90s on
Saturday to the 70s by Monday across Northern Utah valleys.
Meanwhile, southern Utah will see almost no change in airmass, and
will continue to see seasonably warm temperatures continue into
next week.

Through the rest of next week, temperatures will slowly rebound
across northern Utah back to seasonable values. Meanwhile, with
the ridge placement to our southeast, the door will remain open to
moisture moving in from the south supporting daily shower and
thunderstorm chances, especially across southern and eastern Utah.



&&

.AVIATION...

KSLC...VFR conditions will persist at the KSLC terminal this
afternoon into the evening. Thursday evening into Friday morning, a
weak system will bring chances of isolated showers and thunderstorms
with the increase of some cloud cover. Aside from any precipitation
influence, winds are expected to follow a diurnally typical pattern,
shifting NW ~19-20Z Thursday afternoon, back SE ~02-04Z this
evening, and back to NW ~17-18Z.

REST OF UTAH AND SOUTHWEST WYOMING...VFR Conditions will persist at
the northern terminals into this evening; a weak system will bring
isolated shower chances and increased cloud cover Thursday evening
through Friday morning. Otherwise, benign weather is expected to
continue. Areawide, terminals are largely expected to see diurnally
normal winds with fairly light magnitudes.

&&

.FIRE WEATHER, Issued 507 AM MDT Thu Sep 10 2026...
Generally benign weather persists much of Thursday as
the area remains placed in a dry and stable deep westerly flow. A
system will graze by north of Utah roughly Thursday evening into
Friday morning, bringing widely isolated shower chances along with
increased cloud cover and moisture. For the southern half of
Utah, isolated redevelopment of convection will be possible Friday
afternoon.

Saturday will see a more potent system deepen through the Pacific
Northwest and towards Utah. Ahead of this system, deep
southwesterly flow will increase. This will bring widespread wind
gusts around 20 to 35 mph, with the higher gusts over portions of
Utah`s West Desert region. Models continue to then support this
system slipping by the region, pushing a cold front southward
through Utah most likely some time Sunday, though of note some
models have slowed more in the Sunday night to early Monday time
range. Models have however maintained consensus in this frontal
passage being overwhelmingly dry, with the best low end chances of
precipitation noted across portions of southern to eastern Utah.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...None.
WY...Red Flag Warning until 9 PM MDT this evening for WYZ277.

&&

$$

PUBLIC...Church
AVIATION...Tekoe
FIRE WEATHER...Warthen

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