796
FXUS65 KSLC 131025
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
425 AM MDT Sun Jul 13 2025

.SYNOPSIS...Hot and mostly dry conditions continue this week, with
chances for isolated high-based showers and thunderstorms returning
from Monday onward.

&&

.SHORT TERM (THROUGH 12Z TUESDAY)...High pressure centered over
the SoCal coast will build more into Utah today. This will maintain
dry conditions in place while temperatures will continue to trend
warmer. Expect afternoon highs to reach into the mid to upper 90s in
the northern valleys and near to above 100F in the valleys of west-
central through southern Utah. Temperatures will then continue to
climb slightly higher tomorrow as a west to northwest flow
increases. HeatRisk continues to highlight lower Washington County
tomorrow (where highs will be near 110 and overnight lows in the
upper 70s to low 80s) as far as impactful heat, and an Excessive
Heat Warning remains in place. While higher HeatRisk is slightly
less widespread across Zion NP, due to similar conditions, have
decided to add that zone to the warning as well.

Despite the dry airmass (PWATs around 0.4-0.5 inches), there should
be enough midlevel moisture in place to combine with the strong
surface heating to allow for some cumulus buildups and weak, very
isolated high-based showers to develop mainly over the southern
mountains and high Uintas this afternoon. Tomorrow, a modest increase
in midlevel moisture is expected (with PWATs reaching 0.6-0.7 inches
across southern and western Utah), which will allow for a bit more
coverage of showers and thunderstorms, including some developing
more into northwest Utah. Showers and thunderstorms will remain high-
based, with the greatest threat being gusty outflow winds

.LONG TERM (After 12Z/6AM Tuesday)...Ridging aloft remains over the
area, though may slide south somewhat as an upper trough passes to
our north. Another day of notably hot temperatures across the CWA is
expected on Tuesday with valley floors seeing temperatures just shy
of or exceeding 100F. On Wednesday, the aforementioned upper trough
will have passed through with an attendant frontal boundary sweeping
the area as well. Given meager moisture across the area and weak
forcing, little is expected in the way of precipitation, though it
will "cool" the area down by around 5 degrees.

Modest moisture return will occur through the long term period with
PWATs generally ranging from around 0.5-0.7" across the majority of
UT and southwest WY. This will be enough moisture to spark isolated
showers and thunderstorms across our typical higher terrain spots
each afternoon due to weak synoptic forcing in play. With heights
building over the forecast area, hot temperatures are expected
areawide throughout the duration of the long term with our valley
locations seeing temperatures in the upper 90s to low 100s each day.
Additionally, lower Washington county will see temperatures nearing
and perhaps exceeding 110F each day. Be sure to drink plenty of
water, limit time in the sun, and dress appropriately!

Guidance continues to indicate that an upper low may develop off the
coast of CA near the Baja Peninsula late Wednesday evening into
Thursday morning. Current consensus is that more robust moisture
could push into southern UT as early as Thursday which would
increase PoPs to just shy of 50% across a large portion of southern
UT. This unsettled pattern appears to last at least into Saturday
and bears watching given its more widespread nature. Unfortunately,
northern UT and southwest WY appear to remain quite dry as moisture
quality and forcing further north leave much to be desired in this
solution.

&&

.AVIATION...KSLC...VFR conditions will persist at the KSLC terminal
through the TAF period. Typical diurnal wind shifts are expected to
northwesterly around 17z and southeasterlies once again around 04-
05z.

.REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions are expected to
persist through the TAF period. Generally diurnal winds will take
hold as overall flow remains light across UT and southwest WY.

&&

.FIRE WEATHER...High pressure will continue to build into Utah
today, resulting in continued warming along with dry conditions.
Afternoon humidities will remain in the single digits across
central/southern Utah valleys with poor overnight recoveries.
Despite the dry airmass, cumulus buildups and very isolated high-
based showers along with an outside chance of thunderstorms will be
possible over the higher terrain of southern Utah as well as the
high Uintas, with the main threat being brief, localized gusty
outflow winds.

Modest midlevel moisture is expected to spread into the area on
Monday, bringing an increased threat of high-based showers and
thunderstorms. Coverage is expected to remain generally isolated to
widely scattered for much of the week, but the threat of gusty
outflow winds and dry lightning will exist near showers and
thunderstorms. Additionally, with some increase in westerly flow,
marginal/isolated critical fire weather conditions will be possible
mainly across northeast Utah on Monday and southern Utah on Tuesday.
Deeper moisture looks to work its way into the area by the weekend,
increasing the coverage of showers and thunderstorms and bringing
the potential for wetting rain, though there is still uncertainty in
how robust the moisture stream will be.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Extreme Heat Warning from noon to 10 PM MDT Monday for
     UTZ123-124.

WY...None.
&&

$$

Cheng/Worster

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