White City Utah Weather Forecast Discussion

138
FXUS65 KSLC 081002
AFDSLC
Area Forecast Discussion
National Weather Service Salt Lake City UT
402 AM MDT Wed Oct 8 2025
.SYNOPSIS...Another day of dry and calm conditions continue today
ahead of a surge of tropical moisture from the south on Thursday.
Wet conditions persist Thursday through the weekend with flash
flooding possible across southern UT, particularly on Friday and
Saturday. Following this active stretch, a cold front will push
through bringing cooler and drier conditions to the forecast area
with mountain snow across higher elevations.
&&
.DISCUSSION...Key Messages:
* Generally dry conditions persist today with gusty winds across the
  majority of the state ahead of an approaching system.
* Tropical moisture from Hurricane Priscilla begins to push up from
  the south on Thursday resulting in widespread chances for rain
  across southern UT.
* Chances for rain become increasingly widespread across nearly the
  entirety of the forecast area Friday and Saturday as moisture
  continues to surge north.
* Chances for flash flooding exist Thursday through Saturday with a
  particular emphasis on southern UT where higher quality moisture
  exists. Additionally, Friday and Saturday appear to possess the
  highest threat for flash flooding across southern UT as well.
Ridging aloft persists today ahead of an approaching trough from the
Pacific NW. Generally dry conditions are expected to persist as
large-scale subsidence aloft persists across the forecast area,
though enhanced southwest flow aloft looks to develop in the
afternoon hours with the approaching trough to our northwest. As a
result, winds are expected to mix to the surface with gusty winds
ranging from 20-30mph developing across southern UT, central UT,
higher elevations of northern UT, and southwest WY. Most lower
elevations are expected to decouple from the boundary layer
following sunset with gusts subsiding as a result, though higher
elevations should continue gusting throughout the evening hours into
Thursday morning.
In the early morning hours on Thursday, PoPs begin to see an
increase as moisture associated with Hurricane Priscilla begins to
move north into the state. While Priscilla remains well to our
south, moisture aloft is expected to advect northeast toward the
forecast area as the pressure gradient tightens aloft with the
approaching trough from the Pacific NW. This stream of moisture is
expected to persist through at least Sunday, continually increasing
in quality as Priscilla eventually phases into the mean flow with
more robust moisture arriving to the forecast area on Friday and
Saturday. PWATs with this system certainly raise eyebrows given
guidance indicates a PWAT anomaly across the majority of UT and SW
WY around 0.5" above normal for this time of year. If that wasn`t
enough, guidance also indicates that PWAT anomalies across
Washington county and areas adjacent to Lake Powell range from 0.75"
up to 1" above normal. For Thursday, the WPC currently has a
Marginal Risk (level 1 of 4) of flash flooding outlined across
southern UT and the entirety of eastern UT.
Regarding Friday and Saturday, moisture quality looks to increase
with increasingly favorable ascent as the upper trough continues to
move east. Assuming cloud cover isn`t overly persistent allowing
instability to build somewhat, some storms may be longer-lived and
with deeper moisture in place, may result in an increased flash
flooding threat compared to Thursday, particularly across southern
UT. Additionally, moisture will continue surging north with
increasingly favorable ascent across the entirety of the forecast
area increasing PoPs across northern UT and SW WY. At this time, it
appears that the strongest signal for heavy rainfall through the
duration of this event appears to be across southwestern UT where
the most favorable overlap of deep moisture and favorable dynamics
overlap. On Friday, the WPC has a Marginal Risk (level 1 of 4)
encompassing central UT with the majority of southern UT now
outlined in a Slight Risk (2 of 4) of flash flooding. On Saturday,
the WPC has expanded the Marginal Risk (1 of 4) to include the
majority of UT and SW WY with a Slight Risk (level 2 of 4)
encompassing southeast UT. This appears to be evolving into a pretty
impressive rainfall event for the forecast area, particularly across
southern UT. With this impressive parameter space, it is worth
noting that the flash flooding threat appears somewhat concerning
for slot canyons, recent burn scars, dry washes, and slickrock
areas. If you are planning on venturing out to flood prone areas in
southern UT, be sure to keep up to date with recent forecasts and
remain situationally aware. Remember, turn around, don`t drown!
On Sunday, a cold front looks to sweep across the forecast area as
the trough begins to depart to our east. Lingering mid-upper level
moisture with snow levels decreasing in the wake of the cold front
will result in snowfall across higher elevations, particularly above
~7500ft. Chances for rain continue into early next week as long-
range guidance indicates another upper trough will slide down toward
the Pacific NW keeping conditions unsettled across the forecast area
through the foreseeable future.
&&
.AVIATION...KSLC...The SLC terminal will see VFR conditions
throughout the day with mostly clear skies. Southeast winds are
expected to shift to the northwest between 20Z and 22Z.
.REST OF UTAH AND SOUTHWEST WYOMING...The entirety of the airspace
will see VFR conditions and mostly clear skies throughout the day.
Winds will be generally light and terrain driven this morning, with
some increase in southerly winds during the afternoon hours.
&&
.FIRE WEATHER...Dry conditions are expected to persist
across UT through the remainder of today, though gusty winds ranging
from 20-30mph out of the south appear possible ahead of an
approaching storm system. Conditions begin to deteriorate early
Thursday morning as tropical moisture begins to push up from the
south increasing humidities and chances for rain, primarily across
southern UT. A wet trend will persist through the weekend providing
multiple chances for a wetting rain across the majority of the
state. Conditions look to clear out on Sunday as a cold front sweeps
through the area bringing cooler and drier air to the state via
northwest flow. Additionally, snow appears possible on Sunday across
higher elevations as snow levels drop following the passage of the
cold front.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...None.
WY...None.
&&
$$
PUBLIC...Worster
AVIATION...Traphagan
FIRE WEATHER...Worster
For more information from NOAA`s National Weather Service visit...
http://weather.gov/saltlakecity

NWS SLC Office Area Forecast Discussion