857
FXUS65 KSLC 062158
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
358 PM MDT Mon Oct 6 2025

.SYNOPSIS...A warming and drying trend will spread across Utah and
southwest Wyoming through the first half of the week. Moisture
begins to increase by Thursday, and especially by Friday, with a
cold trough anticipated to bring another round of widespread
precipitation and cooler temperatures across the area.

&&

.DISCUSSION...Through the remainder of the evening and overnight
hours, the remnants of the trough associated with the most recent
storm system will depart the region, allowing high pressure to
build back into Utah and southwest Wyoming. Remnant cold air from
this trough will stay in place for one more night across the
northern half of Utah and southwest Wyoming, bringing cold
overnight temperatures and patchy fog for some of the smaller/
colder valley areas across this region. Heading into Tuesday,
however, overhead temperatures will warm slowly, marking the
beginning of a warming trend that is expected area-wide through
Wednesday across the southern area and through Thursday across the
northern area. Through Wednesday, anticipate conditions to dry at
the surface, potentially reaching elevated to near critical fire
weather conditions across a portion of southern Utah (minus the
fuels) as winds increase ahead of the next storm system.

By Thursday, conditions begin to change across the southern half
of the area as moisture increases ahead of the next storm system.
There is generally moderate to high confidence that remnant
moisture from Hurricane Priscilla will spread across central and
southern Utah Friday and Saturday, interacting with our next
cold-core storm system which is anticipated to bring impacts
across northern and central Utah/ southwest Wyoming.

Key Messages / Impacts from this upcoming storm:

- A significant moisture increase across central and southern Utah
  will bring an increased risk of flash flooding due to heavy
  rainfall, especially in the typically prone areas (slot canyons,
  burn scars, etc.) on Friday

- A moisture rich low pressure system will progress into northern
  Utah/ southwest Wyoming on Saturday, bringing a period of
  potentially heavy rainfall along the associated cold frontal
  boundary on Saturday.

- Cold air behind the associated cold front will bring a
  significant cool-down across the area, bringing well below
  normal temperatures for this time of year.


As mentioned above, confidence is high in a cold trough moving
into the western U.S. late next week/ early in the weekend. This
trough is expected to interact with the aforementioned tropical
moisture, bringing increased potential for heavy rainfall and
flash flooding across central and southern Utah (where the
moisture is most likely to be maximized) on Friday. Right now, the
details of the precise locations to be impacted by heavy rainfall
are not yet within reach, however, moisture (and the extreme high
end forecasts from the ECMWF) points toward the most likely
locations to be east of the I-15 corridor and south of the Uinta
Mountains.

During this time, a deep, cold, and progressive trough is
expected to begin moving inland from Friday evening through
Sunday. The associated cold front is most likely to move through
the Wasatch Front sometime between Saturday morning and early
Saturday evening. Along said front, strong lift will pair with the
moisture increasing from the trough itself (and a touch of
moisture from the tropical influence) and bring a period ripe for
moderate to heavy precipitation. Again, the potential is there,
however, the precise locations expected to be impacted are a bit
uncertain at this time. Continue to monitor forecasts through the
week as confidence in the specific impacts will likely increase.

By Sunday, model guidance suggests with fairly high confidence
that a broad trough will remain draped across the region through
the first half of next week. As such, colder temperatures will
remain in place across the region alongside potential for
unsettled weather, though no significant precipitation events are
expected at this time.


&&

.AVIATION...KSLC...VFR conditions will persist for the KSLC terminal
through the period. Dry conditions with clear skies will continue
with light diurnally driven winds.

.Rest of Utah and Southwest Wyoming...VFR conditions will persist
for most terminals through the period. Dry conditions and clear
skies will continue with light diurnally driven winds. Fog
development is possible overnight across the higher valleys of
the northern airspace that could reduce categories to IFR.

&&

.FIRE WEATHER...An area of high pressure will build back into
Utah through the first half of the upcoming week, allowing
temperatures to increase area-wide. In addition to temperatures
rising back to above normal temperatures across Utah, significant
drying is expected through Wednesday. By this time, afternoon
relative humidity is expected to fall as low as 10 to 15 percent
across the lower lying areas of southern Utah. Increasing
southwesterly winds are anticipated ahead of the next storm system
(expected Thursday through Sunday), with gusts possibly exceeding
30 mph in areas across southern Utah where humidity will be
critically low (15-30% chance). As such, anticipate at least
elevated fire weather conditions on Wednesday afternoon before
moisture begins to increase again on Thursday.

Thursday forward, a significant increase in moisture is expected
to spread over Utah. The greatest moisture increase, at this point
in time, is anticipated through the second half of Thursday
through at least early Saturday as tropical moisture works its way
into Utah. Overall trend to expect from this will be a
significant increase in afternoon minimum humidity on Thursday (up
15-25 percent) and especially Friday (up 25-40 percent), high
probability of wetting rains (45-65 percent), and cooler
temperatures... especially across the southern half of Utah. For
northern Utah, expect a more significant drop in temperatures from
Saturday into Sunday with moisture also increasing Friday and
Saturday. While this area is not expected to see tropical
moisture, we`ll see an increase in moisture from a stout low
pressure system that is expected to bring a strong cold front and
an area of potentially heavy rainfall and high elevation snow
along the front.

&&

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

$$

DISCUSSION...Webber
AVIATION...Mahan
FIRE WEATHER...Webber

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