West Valley City, Utah 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

430
FXUS65 KSLC 122059
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
259 PM MDT Tue Aug 12 2025

.SYNOPSIS...Hot temperatures Wednesday will transition to somewhat
cooler temperatures through the weekend as a weak monsoon surge
impacts the region. Hot temperatures are likely to return for the
second half of the weekend into early next week.

&&

.SHORT TERM (Through 12Z Thursday)...A warming trend will continue
through the short term, with the hottest day of the stretch
expected Wednesday. Temperatures will near or exceed 100F for the
Wasatch Front. Those without adequate hydration or cooling will be
at risk for heat related illness. For the Glen Canyon/Lake Powell
area, temperatures will be sufficient to reach widespread major
HeatRisk levels. In coordination with WFO FGZ, we have issued an
Excessive Heat Warning for this area for Wednesday.

Aside from the hot temperatures, isolated thunderstorms are
possible for both the northwestern portion of the state and
southern mountains Wednesday afternoon and evening. CAMS have
shown a propensity for strong outflow winds in excess of 50 mph
across northwestern Utah, which will need to be monitored. Given
a very dry subcloud environment, any high-based convection will
have a threat of gusty and erratic winds. Similar conditions will
be at play across the southern mountains.

.LONG TERM (After 12Z Thursday), Issued 437 AM MDT... The
beginning of the long term period will feature a trough situated
along the Sierra/western Great Basin, with an upper ridge centered
across the central/southern High Plains. This will induce a
general southwesterly flow aloft across the forecast area through
the latter portion of the week and into the upcoming weekend.
Unlike recent southwesterly flow events which spread very dry air
across the forecast area, this round will feature a modest influx
of predominantly mid level moisture, which will support an
increasing chance for showers and thunderstorms Thursday through
Friday. The majority of ensemble members from both the GEFS and
EPS suggest this moisture lingers into the weekend, maintaining a
chance for showers and thunderstorms through Saturday. With this
increase in moisture, temperatures will trend cooler through the
latter portion of the week, returning to near climo by Friday.

Given the very dry airmass currently in place across the region
region as a whole, and the lack of a better defined low level
surge of higher dew points (model forecasts keep dew points in the
30s through Thursday with PW values generally around 0.5"), the
most likely scenario Thursday afternoon/evening is a round of high
based, predominantly dry convection accompanied by dry lightning
and strong microburst winds, but little in the way of measurable
rainfall. By Friday, with the column moistening from the top down,
the chance for wetting rainfall (0.10" or more) and perhaps
isolated heavy rainfall will increase with afternoon/evening
convection.

The consensus through the weekend and into early next week is for
the airmass to trend drier as the region comes under the
influence of large scale subsidence associated with an amplifying
ridge across the central and southern Rockies. There is some
spread in model guidance with respect to how quickly this drying
trend manifests itself, but the overall downward trend in NBM PoPs
from scattered coverage of terrain driven convection Saturday, to
more isolated coverage Sunday into Monday seems to handle this
well. This amplifying ridge looks to become the dominant weather
feature across the region throughout next week.

&&

.AVIATION...KSLC...Northwesterly winds will continue until
roughly 03-04z, gradually veering to light and southeasterly for
the overnight hours. Clear skies and VFR conditions will continue.

.REST OF UTAH AND SOUTHWEST WYOMING...Winds will become light and
terrain-driven overnight, increasing out of the west to southwest
with gusts to 15-25kts by Wednesday afternoon. Clear skies and VFR
conditions will continue outside of areas affected by wildfire smoke.

&&

.FIRE WEATHER...As a disturbance crosses the north side of the
building area of high pressure, gusty west winds will combine with
low humidity to bring an area of critical fire weather conditions
to the Wasatch Mountains. Southerly flow will begin to increase
mid- level (at first) moisture across southern Utah Wednesday
shifting north Thursday. Isolated high-based thunderstorms with an
attendant risk of gusty and erratic winds will be possible across
southern Utah Wednesday. This risk will spread through much of
the higher terrain and adjacent valleys Thursday, with more
widespread risk of lightning. Given many areas have not seen
appreciable precipitation in a significant period of time and
fuels are very dry, wildfire starts are possible with any
lightning strikes. A Fire Weather Watch has been issued for these
areas for Thursday afternoon and evening.

Current expectation is thunderstorms will transition to a more
wet state Friday across at least southern Utah. Thunderstorms are
likely to continue through at least Saturday before drier air
builds into the region once again.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Red Flag Warning from noon to 9 PM MDT Wednesday for UTZ479.

     Fire Weather Watch from Thursday afternoon through Thursday
     evening for UTZ480-481-483-484-488-489-493-494-496-498.

     Extreme Heat Warning from noon to 8 PM MDT Wednesday for UTZ131.

WY...Red Flag Warning from noon to 8 PM MDT Wednesday for WYZ277.

&&

$$

Kruse/Seaman/Cunningham

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