615
FXUS65 KSLC 281122
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
522 AM MDT Wed Oct 28 2026

.KEY MESSAGES, Issued 1021 PM MDT Tue Oct 27 2026...


- Generally dry and seasonable conditions will persist through
  Thursday, with a weak grazing system tonight bringing light
  precipitation to northern Utah and southwest Wyoming.

- Moisture will increase over the area beginning Friday, bringing
  an increasing threat of flash flooding. The area will see a more
  substantial increase in moisture and instability and thus the
  potential for flooding Sunday into Monday as a strong Pacific
  storm crosses the area.

- Much cooler temperatures will accompany the system for early
  next week, allowing snow levels to potentially drop as low as
  7500 feet by Monday morning.

&&

.DISCUSSION, Issued 1021 PM MDT Tue Oct 27 2026...
A weakening shortwave trough is currently swinging
across northern Nevada and will cross far northern Utah tonight.
Much like last night, this fast-moving wave will push a
reinforcing cold front into northern Utah, bringing valley rain
showers and light mountain snow once again. Precipitation is
already ongoing near remnants of the existing boundary and will
continue through late tonight. The boundary and associated
precipitation is expected to remain north of around Utah County.
Expect precipitation to wind down well before sunrise.

Fairly benign weather is expected on Wednesday and Thursday under
a southwesterly flow aloft. Temperatures should cool slightly
from today across northern Utah owing the the cold front, then
rebound for Thursday. Models do depict yet another weakening
trailing shortwave disturbance crossing Utah late Wednesday
afternoon into Wednesday evening. The dynamics associated with
that looks to be very insignificant, so very little if any
precipitation is expected.

Main focus continues to be the storm system for the end of the
week through the weekend. A low pressure system will slowly make
its way to the PacNW coast on Thursday. On Friday, a subtle
disturbance rounding the base of this low and lifting across Utah
will start to spread some moisture into the area. However, with
weak dynamics, expect mainly isolated to scattered showers and a
few thunderstorms to develop. Main focus for heavier
precipitation will be southwest Utah, otherwise amounts are
expected to remain relatively light elsewhere. The 25th percentile
of the NBM has no measurable precipitation for the vast majority
of the forecast area and only a few hundredths of an inch in
portions of southwest Utah. However, the 75th percentile has
between 0.5-1 inch over portions of southwest Utah, so cannot rule
out some heavier showers and isolated potential for flash
flooding. On Saturday, the storm system will begin to move inland.
This will maintain unsettled weather over the area, but with the
better large-scale dynamics still upstream, expect generally
isolated to scattered showers and isolated thunderstorms once
again.

The storm system is expected to cross Utah on Sunday, although
there is still some uncertainty regarding how deep it will carve
into the area. This storm will also phase with a southern stream
system that will be associated with an atmospheric river. The
moisture plume will punch inland across far southern California
and northern Baja. Some of this moisture will make it into Utah,
with IVT anomalies in the 97th-99th percentile of climatology.
However, there is still enough model spread regarding how much
precipitation will develop over Utah. While the spread has
decreased from what models were showing 24 hours ago, we are still
looking at NBM 25th-75th percentile differences of 1-2 inches in
areas favored in southwest flow and 0.5-1 inch elsewhere.
Regardless, Sunday is expected to see the heaviest precipitation
of this storm cycle, with the potential for widespread and
moderate to heavy precipitation with an increased flash flood
threat.

A cold front will also push into Utah on Sunday, bringing lowering
snow levels. Snow amounts will be dependent on the strength of the
trough and precipitation amounts, of which, as mentioned, there
is still significant uncertainty. However, a general 3-6 inches
with locally 10 inches or more in higher elevation sites such as
near Brian Head, in the Tushars, the upper Cottonwoods, and high
Uintas seem reasonable at this time.

Precipitation looks to mostly wind down Monday morning, leaving a
cool northerly flow in place over the area. Models then start to
diverge on the large-scale pattern, with how quickly the storm
continues to progress east out of the area and whether a strong
ridge builds into the area behind it or whether another storm
system manages to move into the area midweek.


&&

.AVIATION...

KSLC...A brief period of light southerly to variable winds expected
Wednesday morning, shifting back northwesterly late morning to early
afternoon (~16-19Z). VFR cloud cover will linger through the day,
thickening some overnight into Thursday.

REST OF UTAH AND SOUTHWEST WYOMING...A weak cold frontal boundary
will continue to wash out over northern Utah and southwest Wyoming.
Associated cloud cover will decrease through the day, though
mid/upper level moisture will bring a corresponding increase to VFR
cloud cover later Wednesday afternoon onward. Winds will tend to be
light and at times variable, or modest (~5-15 kts) and follow a
diurnally typical directional pattern.

&&

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

$$

PUBLIC...Cheng
AVIATION...Warthen

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http://weather.gov/saltlakecity