747
FXUS65 KSLC 260434
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
1034 PM MDT Fri Sep 25 2026

.KEY MESSAGES...

- 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...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...
KSLC...VFR conditions will continue through the TAF period.
Southeast wind will persist overnight through Saturday morning,
however there is a 30% chance for a temporary switch to northwest
during the 10-14Z window, before southeasterly winds become
reestablished late tonight. A return to northwest winds will occur
during the 18-19Z timeframe Saturday.

REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions will continue
through the TAF period at all terminals. Light, diurnally driven
winds through Saturday morning will be followed by gusty south to
southwest winds by midday Saturday at most terminals.

&&

.FIRE WEATHER, Issued 1219 PM MDT Fri Sep 25 2026...
Afternoon convection will continue to develop across
the higher terrain and adjacent valleys of southern Utah this
afternoon and evening, bringing gusty and erratic winds near
thunderstorms. As a strong Pacific disturbance approaches the
region, gusty southerly winds will develop across western Utah
Saturday, with gusts up to 30 mph expected. These winds will
combine with humidities near 15% to bring elevated to locally
critical fire weather conditions to western Utah Saturday
afternoon and evening. These winds will redevelop Sunday afternoon
and evening, with gusts to 35 mph...and humidities again near
15%, bringing locally critical fire conditions to a similar area
Sunday afternoon and evening.

There is an increasing potential for tropical moisture from
either/both Hurricanes Polo and Odalys to spread northeast into
the Great Basin ahead of the previously mentioned upper level
system. This would bring an extended period of moderate to heavy
rain across southern and eastern Utah Monday into early Tuesday
morning. While the other 25% of guidance keeps any tropical
moisture away from the region, it still brings widespread wetting
rains as the upper level system crosses the area.

&&

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

$$

PUBLIC...Cheng
AVIATION...Seaman
FIRE WEATHER...Kruse

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