295
FXUS65 KSLC 090929
AFDSLC
Area Forecast Discussion
National Weather Service Salt Lake City UT
329 AM MDT Tue Sep 9 2025
.SYNOPSIS...A slow moving upper level low will bring gusty
southwest winds to the region through Wednesday, followed by a
chance of precipitation across northern and eastern Utah Friday.
The active pattern will continue into next week.
&&
.DISCUSSION...A breezy couple of days is in store for the region
as a slow moving upper level trough interacts with the Interior
West through Saturday. Early morning upper air and satellite
analysis indicates an upper level low is currently center near the
Oregon/California state-line. Deep southwest flow stretches across
the Great Basin, with general upper level diffluence across
portions of northern and eastern Utah.
A rather energetic shortwave trough ejecting ahead of the parent
low has shifted across northern Utah overnight. Strong
thunderstorms developed near the Delle area in the Great Salt Lake
Desert, with rather pronounced updrafts. This area of convection
is now crossing through Uinta County, WY at press time.
Upper level diffluence will remain in place across portions of
eastern Utah this afternoon and evening. This will help to support
convection across portions of northern and eastern Utah. HREF mean
SBCAPE values range from around 300-600 J/kg in this area with
around 25 kts or so of deep layer shear.
Meanwhile, across western Utah, southwest flow will increase.
700mb winds near 35kts or so will combine with humidities near to
below 15 percent to bring locally critical fire weather conditions
to western Utah this afternoon and evening.
As the upper level low shifts eastward Wednesday, centered near
Reno, 700mb flow will increase further. This will again bring
areas of locally critical fire weather conditions to western Utah.
With 700mb winds near 40kts across western Utah, gusts may
approach wind advisory criteria. Right now, there is a 25% chance
of wind advisory criteria being met across the western valleys, in
particular western Millard, western Beaver and western Iron County
as well as portions of the Great Salt Lake Desert. Given the low
probs, won`t be issuing any products on this shift, but something
to monitor moving forward.
As the upper level low reaches the Interior West Thursday with the
low centered somewhere around the Idaho/Nevada/Oregon triple
point, the majority of the ensemble members shift a dry slot into
portions of western and southern Utah. Meanwhile, the majority of
members support at least light precipitation across portions of
northern and eastern Utah Friday afternoon and evening. It should
be noted however that the ensemble members have shifted over the
last few runs toward a more pronounced dry slot across
Utah...which may eventually eat away at any precipitation chances
even for portions of northern Utah.
By Saturday, the upper level low will finally be kicking out the
region as another upper level trough approaches the Pacific Coast.
Depending on how fast shortwave ridging crosses the state, lapse
rates look steep enough to allow for convection across portions of
northern and eastern Utah. And this progressive, fall-like pattern
looks to continue beyond the weekend.
&&
.AVIATION...KSLC...Light southeast winds will last through 15Z.
Winds will transition to the south, with gusts around 25 knots
from 15-00Z. Conditions will be dry, with scattered to broken
clouds in VFR range. Winds will transition to southeast and
decrease some after 00Z, but speeds around 15 knots will continue.
.REST OF UTAH AND SOUTHWEST WYOMING...South to southwest winds
will be enhanced throughout southwest Wyoming and most of Utah.
Winds will increase through the morning, with peak gusts from
15-00Z. Gusts will prevail around 30 knots for southwest Wyoming
and southwest Utah and around 25 knots for much of Utah. Dry
conditions will prevail, but there will be isolated to scattered
rain showers and thunderstorms. There is around a 30% chance that
these track into KEVW. Gusty, erratic outflow winds are likely
with showers and thunderstorms. Winds will decrease some after
00Z, with speeds around 15 knots continuing for many locations.
&&
.FIRE WEATHER...A slow moving upper level system will bring
gradually increasing southwesterly winds, with humidities near to
below 15% across western Utah today. Winds will increase further
as this system shifts slowly eastward Wednesday. Expect locally
critical fire weather conditions where fuels are sufficiently dry
across western Utah both days. By Thursday, winds will
decrease...with humidities remaining near critical levels across
much of Utah. Guidance has trended toward a drier solution for
Thursday into Friday, with a dry slot keeping conditions dry
across southern and portions of western Utah.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...None.
WY...None.
&&
$$
Kruse/Wilson
For more information from NOAA`s National Weather Service visit...
http://weather.gov/saltlakecity
