574
FXUS65 KSLC 261730
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
1130 AM MDT Sat Sep 26 2026

.KEY MESSAGES, Issued 1034 PM MDT Fri Sep 25 2026...


- It is increasingly likely that deep tropical moisture from
  Hurricane Odalys and/or Hurricane Polo will be drawn northward
  ahead of a strong disturbance Monday into Tuesday.

- A slight risk (level 2/4) for excessive rainfall has been issued
  by the Weather Prediction Center for southern Utah between 12Z
  Monday and 12Z Tuesday.

- This will bring an increased risk for flash flooding across
  national parks and recreation areas across southern through
  east-central Utah on Monday and potentially into Tuesday.

&&

.DISCUSSION, Issued 1034 PM MDT Fri Sep 25 2026...
A weak shortwave ridge is building into Utah this
evening ahead of a shortwave trough ejecting across the PacNW and
Idaho, and as subtle low pressure over eastern Utah earlier today
lifts northeast away from the area. Convection from earlier this
afternoon has mostly waned, leaving patchy midlevel clouds.
Meanwhile, the trough to the northwest will continue to eject into
western Montana. This will push a cold front into northern Utah
tonight, dropping temperatures a few degrees there through
Saturday. The weather will be otherwise benign on Saturday, with
drier and more stable conditions under a somewhat breezy
southwest flow.

Models are still consistent in lifting a vort max originating
near Hurricane Odalys through Utah on Sunday. This will bring
increased moisture to the area, leading to isolated to widely
scattered convection, mainly over the higher terrain. This will
start priming the airmass for the next storm system Monday and
Tuesday, which looks increasingly likely to tap tropical
moisture.

Cluster analysis of global ensembles are coming together on the
idea of the splitty solution with a closed low tracking across
Arizona on Tuesday. Meanwhile, models are also favoring Hurricane
Polo to cross into northwest Mexico Tuesday morning before its
remnants move into New Mexico. The pattern favors tropical
moisture being ingested into the southwesterlies ahead of the
closed low, and model QPF has been increasing. However, the
question is how much of this moisture makes it into Utah, given
the southerly track of the low. While the bulk of the moisture
will remain south and east of Utah, there are indications that
portions of southern and southeast Utah will likely receive
widespread precipitation and potentially significant amounts. The
latest NBM has 25th percentile amounts Monday through Tuesday of a
third to a half an inch across southern through southeast Utah,
while the 75th percentile has widespread 1.25-1.5 inches with
locally greater than 1.75 inches between St George and Kanab.
Looking at it a different way, the southern third of Utah has
roughly a 30-55% chance of exceeding 1 inch of rain between 12z
Monday and 12z Wednesday. There is a Slight Risk for Excessive
Rainfall in that area Monday morning through Monday night.
Meanwhile, northern Utah currently has less than a 30% chance of
seeing even 0.5 inches over the same period (except over
mountains). Will continue to monitor developments to see if any
hydro highlights are needed for southern Utah in the near future.

Cooler temperatures are expected areawide Monday through Tuesday,
with afternoon maxes falling to 3-10 degrees below normal.
Temperatures should rebound as the low exits the area Wednesday
afternoon. However, there are uncertainties regarding the large-
scale pattern for the latter half of the week, with ensembles
split between another trough moving into the area and ridging or
zonal flow patterns.




&&

.AVIATION, Issued 528 AM MDT Sat Sep 26 2026...


KSLC...The SLC terminal will see VFR conditions throughout the day
with some high clouds. Northwest winds are expected to become light
and variable or light southerly between 13Z and 15Z before returning
to the northwest between 19Z and 21Z.

REST OF UTAH AND SOUTHWEST WYOMING...The airspace will see VFR
conditions throughout the day with some high clouds. Generally light
winds are expected through mid-morning before increasingly breezy
southerly winds develop, particularly for western Utah.

&&

.FIRE WEATHER...Increasing southerly flow aloft through the
remainder of the weekend will result in gusty afternoon winds
developing across the western portion of the state through Sunday,
with widespread gusts 25-30 mph. While conditions remain dry
today, especially across portions of southern Utah where daytime
RH values dip to near-critical, improving overnight recoveries
tonight will limit the fire weather risk overall. Moisture
associated with two tropical systeams in the Eastern Pacific will
increase steadily on Sunday, with best moisture availability focused
across southern and eastern Utah. This will result in scattered
showers and thunderstorms developing across these areas on Sunday
afternoon, with the main threat being gusty and erratic outflow
winds as lower levels remain relatively dry. Deep moisture
overspreads the region Monday into Tuesday; concurrently, an
upper-level wave traversing the western US will result in ample
instability developing across southern and eastern Utah on Monday
afternoon. This increasing instability will interact with deep
tropical moisture, resulting in more widespread showers and
thunderstorms capable of producing heavy rainfall and better
chances for widespread wetting rains through Tuesday morning.

&&

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

$$

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

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