318
FXUS65 KSLC 182208
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
408 PM MDT Fri Jul 18 2025

.SYNOPSIS...One last day of more widespread convection will shift
to more isolated storms Saturday. A drying trend will bring little
threat of precipitation early next week.

&&

.SHORT TERM (Through 12Z Sunday)...While not as active as
Thursday, convection continues to develop across much of the CWA
this afternoon. Mesoanalysis indicates SBCAPE values near 500-1000
J/kg across much of Utah...though weak CIN remains in place. The
best forcing for convection remain north of a line from roughly
Cedar city to Hanksville.

The main threats today will be strong, gusty winds, particularly
near the Nevada and Idaho borders across northern Utah...and
isolated flash flooding near persistent storms over burn scars and
other prone locations. Convection will gradually weaken after 8
PM.

Saturday looks to be a day with much more isolated convection as
the best forcing for precipitation slides eastward.

.LONG TERM (After 12Z Sunday)...Issued 342 AM MDT

A longwave trough will dig into the PacNW Sunday, while a ridge
will be in place for the southern plains and southeast U.S. As the
ridge tracks closer to southwest Wyoming and Utah, southwest flow
will enhance. Gusts will likely exceed 20 mph for portions of
southwest Utah, with the southwest flow advecting drier conditions
in. Showers and thunderstorms will be much more isolated than the
start of the weekend and largely be near mountainous terrain.
Southwest winds will likely not warrant Red Flag Warnings, but
with the stronger winds and afternoon relative humidity in the
teens, fire danger will increase.

The longwave trough to the northwest will become positively-tilted
Monday. That will bring an increase in southwest winds, while
relative humidity remains low. Critical fire weather conditions
become likely Monday afternoon, with west to southwest winds gusting
in excess of 25 mph throughout southwest Wyoming and most of western
Utah. Relative humidity values will likely range from the single
digits to teens. Shower and thunderstorm chances will lower further
from Saturday, with only isolated showers and thunderstorms in the
mountains.

The longwave trough will lift northward Tuesday. That will bring a
slight downtrend in winds, but continued gusts in excess of 20 mph
and low relative humidity will bring potential Red Flag conditions
to the same locations.

There is good model agreement that the ridge that will prevail to
the southeast will retrograde much of the week. As high pressure
builds in from the southeast, southwest Wyoming and Utah will keep
largely dry conditions with lighter winds.

High temperatures through the week will be in the low or mid 90s for
valleys, which is near normal for the time of year.

&&

.AVIATION...KSLC...VFR conditions will prevail for the KSLC terminal
through the period. There is a 40% chance of showers and
thunderstorms impacting the terminal between 00-04z which could be
capable of producing lightning, brief moderate rain which may reduce
visibilities, and gusty and erratic outflow winds. Outside of
showers and thunderstorms, northwest winds will prevail,
transitioning to southeasterly later this evening.

.REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions will prevail
for most of the airspace through the period. scattered convection
will continue through the evening, becoming focused more across
central and portions of northern Utah through the evening. These
showers and thunderstorms will be capable of producing lightning,
moderate to heavy rain briefly reducing VIS, and gusty and erratic
outflow winds.

&&

.FIRE WEATHER...One last day of relatively widespread thunderstorms
will trend much more isolated Saturday. A drier airmass will
build into the region, with a disturbance approaching the Pacific
Coast by Monday. This will bring areas of gusty winds and low
humidities to western Utah Monday and Tuesday afternoon and
evening...with the potential for critical fire weather conditions
in these areas both days.

&&

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

$$

Kruse/Wilson/Cheng

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