630
FXUS65 KSLC 271135
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
535 AM MDT Sun Sep 27 2026

.KEY MESSAGES, Issued 1038 PM MDT Sat Sep 26 2026...


- Increasing moisture aloft ahead of an approaching system will
  result in scattered showers and thunderstorms across southwest
  Wyoming, the Utah mountains, and the eastern half of Utah on
  Sunday.

- An upper-level disturbance moving across the Desert Southwest
  will draw deep tropical moisture from Hurricanes Odalys and
  Polo into the region Monday into Tuesday, bringing an increased
  risk for flash flooding across portions of southern and eastern
  Utah.

- Drier, more seasonable conditions develop mid-week and persist
  through at least Friday.

&&

.DISCUSSION, Issued 1038 PM MDT Sat Sep 26 2026...
A dry southwesterly flow remains in place over Utah
this evening. Upstream, an upper trough is strengthening off the
PacNW coast. Meanwhile, Hurricanes Odalys and Polo continue to
spin in the eastern Pacific.

The upstream trough will carve south towards the northern/central
California coast on Sunday, with southwest flow continuing over
Utah. Meanwhile, a weak vort lobe originating near Hurricane
Odalys will become absorbed into the southwesterlies and lift
across Utah during the afternoon. This weak disturbance will bring
increased moisture and isolated to scattered showers and
thunderstorms to Utah by Sunday afternoon, generally focused over
and near the spine of Utah.

As the trough develops into a closed low over southern California
and far southern Nevada on Monday, Hurricane Polo will track
northeast, moving into Baja California. Moisture from the
hurricane will become ingested into the southwesterly flow ahead
of the closed low and increase into southern Utah. This will
continue to bring the potential for widespread and locally heavy
rain, especially across southern and eastern Utah as the closed
low crosses from California into Arizona Monday through Tuesday.

Model QPF continues to creep up for the Monday-Tuesday timeframe,
especially notable on the lower end of the probabilistic spectrum
(NBM 25th percentile values now in excess of 0.6 inches for the
bulk of south-central and southeast Utah), which increases
confidence in wet conditions. A good portion of south-central
through southeast Utah has a 60-70% chance of exceeding 1 inch
Monday through Tuesday, highest along the Arizona border.
Precipitation amounts will decrease farther north and east into
Utah, with east-central Utah having a 60-70% chance of exceeding
0.5 inches, and areas farther north and east with a 30% chance or
less.

The heavy rain will bring an increased risk of flooding/flash
flooding to the area. The WPC Excessive Rainfall Outlook now has
a Moderate Risk across portions of southern Utah, and the Slight
Risk now extends into central and portions of northeast Utah.
Although model instability is increasing, especially across
southwest Utah, precipitation may well end up as largely
stratiform with embedded convective elements, and the strength and
coverage of these convective elements will most likely determine
the extent of any significant flash flooding.

Cooler temperatures will spread into the area Monday and Tuesday,
with afternoon maxes falling to around 4-10 degrees below normal
and largely failing to rise above the low to mid 70s in most
valleys. Temperatures will slowly rebound midweek as the storm
system exits the area. There is still some model spread with
regards to the large-scale pattern for the latter part of the
week. Some models have been trying to bring a trough back into the
area, but based on cluster analysis of global ensembles, it
appears that any trough may end up being relatively weak.



&&

.AVIATION...

KSLC...The SLC terminal will see VFR conditions throughout the day
with some high clouds. Generally light winds are expected to become
prevailing southerly by 15Z, becoming gusty this afternoon into the
early evening. There is a 10-20 percent chance of outflow from
showers developing east of the terminal to bring a period of gusty
and erratic winds, most likely between 00Z and 04Z.

REST OF UTAH AND SOUTHWEST WYOMING...The airspace will see VFR
conditions throughout the day, with southerly winds gradually
increasing during the day. Some moisture will start to spread
northward into the area today, bringing 20-30 percent coverage of
showers and thunderstorms for the higher terrain east of I-15 late
this afternoon into the early evening. Coverage of showers will
increase more noticeably over southern Utah beginning Monday
morning, with coverage spreading northward during the day Monday.

&&

.FIRE WEATHER, Issued 439 AM MDT Sun Sep 27 2026...
A Pacific storm system will move onshore over
California today. As it does, southerly winds across the area will
continue to increase, particularly for western Utah where a few
gusts could reach 40 mph this afternoon. The southerly winds will
start to draw moisture back northward, but will stream in
substantially Monday as the storm system crosses Utah, bringing
much cooler temperatures as well as widespread coverage of showers
and thunderstorms for the southeastern three-quarters of the
state with a high chance of wetting rainfall. The system is
expected to linger across the Desert Southwest Tuesday, keeping
the potential for precipitation in place for southern Utah. Drier
conditions are expected to move in by midweek with temperatures
gradually warming to near seasonal normals.

&&

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

$$

PUBLIC...Cheng
AVIATION...Traphagan
FIRE WEATHER...Traphagan

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