997
FXUS65 KSLC 312152
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
352 PM MDT Thu Jul 31 2025

.SYNOPSIS...Southwesterly flow will maintain a very dry airmass
across the region through the upcoming weekend and into early next
week.

&&

.SHORT TERM (Through 12Z/6AM Saturday)...A hot and very dry
airmass remains in place across the forecast area this afternoon.
Daytime temperatures are running near to slightly above normal
for late July, while afternoon RH values are running in the
single digits. A shortwave trough ejecting across the northern
Great Basin is enhancing the general southwesterly flow across the
forecast area, resulting in gusty winds across much of central
and southern Utah, resulting in fairly widespread critical fire
weather conditions. Ascent associated with this ejecting wave is
also providing sufficient forcing for high based convection across
the terrain of eastern Nevada, as well as off the Uintas in
northeast Utah. Given the deeply mixed and very dry boundary
layer, strong outflow winds and isolated lightning can be expected
with these storms which will quickly diminish around sunset.

The northern Great Basin trough will lift into the northern
Rockies Friday, allowing the general southwesterly flow to relax
a bit across the forecast area, as well as allow for a slight
cooling trend across the north. Hardly a monsoon surge, but a
slight increase in mid level moisture will temporarily spread
into southern Utah Friday afternoon, allowing for a slight chance
of high based showers and dry thunderstorms mainly across the
higher terrain of southern Utah east of Highway 89s. Otherwise a
very dry boundary layer will continue to result in single digit RH
values with poor overnight recoveries.

.LONG TERM (After 12Z/6AM Saturday), Issued 345 AM MDT...The
long-term period will begin generally quiescent as the region
remains under the influence of a broad ridge and dry southwesterly
flow. Despite these dry conditions, a weak upper-level
disturbance moving into the Great Basin on Saturday will allow
some isolated showers and thunderstorms to develop during the
afternoon across far northwestern Utah. Dry microbursts will be
the main threat, given extremely dry lower levels. Ridging builds
back in across the region on Sunday, cutting off potential for any
additional shower activity.

The pattern turns a bit more active early next week as a shortwave
trough digs into the Great Basin on Monday. This system will
introduce increased southwesterly flow across the region, resulting
in heightened fire weather concerns on Monday afternoon. See the
fire weather section below for additional details. Ensembles are
supportive of a Four Corners high developing as early as Tuesday,
which would allow moisture to be drawn up into the region from the
south. As such, could see afternoon shower and thunderstorm chances
returning as early as Tuesday, especially across southern Utah.

&&

.AVIATION...KSLC...VFR conditions are expected to prevail through
the forecast period with southerly winds becoming west to northwest
from about 00Z through 04-05Z. There is about a 25% chance that
winds do not shift at all and remain south, and also about a 25%
chance that winds shift as early as 23Z. Once south winds
reestablish after sundown, this will be the dominant flow pattern
through the night.

.REST OF UTAH AND SOUTHWEST WYOMING...Gusty southwest winds are
expected across a majority of the area under largely clear skies
(excluding Uinta Co., WY and far northwest Utah). High-based showers
and isolated thunderstorms are currently noted (as of 2145Z) across
northwestern Utah and Uinta Co., WY, and will bring a threat for
gusty and erratic outflow winds so long as these showers exist.
Following sunset, gusty southwest winds are expected to diminish,
with terrain driven flows prevailing through the overnight period.
High-based showers should diminish by sundown, with largely clear
skies persisting through the overnight.

&&

.FIRE WEATHER...Hot, very dry and unstable southwesterly flow
will continue to bring critical fire weather conditions to much of
central and southern Utah through this evening. Meanwhile, high
based showers and thunderstorms developing across eastern Nevada
will bring isolated dry lightning and gusty outflow winds to
northwest Utah through this evening.

This hot and very dry airmass will remain in place through the
weekend and into early next week, with widespread single digit
RH during the afternoon, and marginal to poor overnight recovery.
Southwesterly flow across the area will weaken a bit, with critical
fire weather conditions mainly over the central and southern
mountains, with a more localized threat elsewhere. Just enough
high based moisture will spread into southern Utah Friday afternoon
to bring a couple of isolated high based showers or dry
thunderstorms east of Highway 89.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Red Flag Warning until 10 PM MDT this evening for UTZ483-484-489-
     492-494-495-497-498.

     Red Flag Warning until 10 PM MDT Saturday for UTZ493-496.

WY...None.
&&

$$

SHORT TERM...Seaman
LONG TERM...Cunningham
AVIATION...Webber
FIRE WEATHER...Seaman

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