Severe Thunderstorm Warning 42, NWS Salt Lake City, UT

Area Forecast Discussion...CORRECTED
National Weather Service Salt Lake City UT
454 AM MDT Fri Sep 12 2025

.SYNOPSIS...A slow moving upper level low will impact the region
through Saturday. Short-lived high pressure Sunday will transition
to a cold front crossing the state Monday into Tuesday.

&&

.DISCUSSION...A slow moving upper level will continue to impact
much of Utah through Saturday. Early morning upper air and
satellite analysis indicates an upper level low is centered
north of Reno, NV. Southwest flow remains across Utah, while a
series of shortwave troughs rotate around the parent low across
Oregon and Nevada. Light showers continue across portions of
northern Utah in association with subtle jet enhancement.

By this afternoon, a shortwave trough ejecting ahead of the main
circulation in southwest flow will provide support for convection
across the eastern half of Utah. HREF mean SBCAPE across Utah will
range from around 250-500 J/kg, with deep layer shear around
40-50kts. Expect showers and a few thunderstorms to develop
through the afternoon and evening from roughly I-15 eastward.

Similar conditions are expected Saturday as the trough axis
finally passes overhead.

By Sunday, shortwave ridging will shift across the region. The
next upper level low is expected to slowly cross the northern
Intermountain Region Monday through Wednesday. This system will
likely push a cold front slowly through the state Monday into
Tuesday.

Around 30% of the ensemble members bring light precipitation to
northern Utah (mainly Provo and northward) with this front, while
70% indicate this front is sufficiently removed from any forcing
to be dry. More probable is the reduction of temperatures by at
least 2-3 degrees Monday and another 2-3 degrees Tuesday, mainly
across northern and central Utah.

&&

.AVIATION...KSLC...VFR conditions will persist for the KSLC
terminal through the period. Variable winds will gradually switch
over to light southerly winds that will become gusty during the
day. Conditions will remain dry with some scattered mid level
clouds.

.REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions will persist
for the entire airspace through the period. Mostly dry conditions
and some mid level clouds will continue with afternoon convection
staying confined to far eastern portions of the airspace unlikely
to impact any terminals. Southerly winds will increase during the
day.

&&

.FIRE WEATHER...A slow moving upper level system (that we've been
talking about for days) will continue to shift across the Great
Basin through Saturday. Expect showers and thunderstorms to
develop Friday and Saturday afternoon and evening across the
eastern half of Utah.

After a brief period of high pressure Sunday, another slow moving
upper level low will cross the northern Intermountain Region
Monday into Wednesday. This will bring a cold front slowly through
the state Monday into Tuesday. Around 30% of the ensemble members
bring light precipitation into northern Utah with this cold
front, while the remainder indicate a largely dry front.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...None.
WY...None.
&&

Kruse/Mahan

For more information from NOAA's National Weather Service visit...
http://weather.gov/saltlakecity

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