613
FXUS65 KSLC 220351
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
951 PM MDT Sun Jun 21 2026

.KEY MESSAGES

- High pressure will bring a warming trend early this week.
  Daytime temperatures will run 5 to 10 degrees above normal by
  Tuesday, with hot conditions continuing through at least
  Thursday. The potential for heat related illness will increase
  across valley locations by the middle of the week.

- Moisture spreading northward will bring an increased threat of
  high-based showers and thunderstorms Wednesday and Thursday to
  southern Utah. Lightning associated with these storms may
  result in new fire starts.

- Strengthening and drying southwesterly flow ahead of an
  approaching cold front will bring the return of widespread
  critical fire weather conditions Friday into the weekend.

&&

.DISCUSSION...Generally westerly flow remains across the region
this evening. A few high-based showers have developed near the
Utah/Nevada border, however given lack of instability across Utah,
have generally remained near the border with little progress
further east. Smoke from local fires including the Hastings,
Bonneville, Iron and Sawmill fires as well as fires in Nevada and
Arizona will continue to impact Utah. Low-level smoke is most
likely in valley locations adjacent to the above fires through
Monday.

As high pressure remains in place across the 4-Corners states,
temperatures will warm to around 5 to 10 degrees above normal.
These hot conditions may impact those most prone to heat including
the elderly as well as unsheltered populations and those without
adequate cooling and hydration. Please remember to properly
hydrate during outdoor activities, including carrying enough water
on hikes. Current temperature forecasts fall short of heat
advisory criteria, so no advisories will be issued with this
package.

By Wednesday, the majority of ensemble members bring PWs around
95 to 98 percent of normal into southern Utah as moisture
advection from the eastern Pacific/Baja streams northward ahead of
the next Pacific trough. This moisture surge looks to remain
largely aloft, with mid-level moisture advection sufficient to
bring the threat of high-based convection to portions of southern
Utah as early as Wednesday afternoon.

Mid-level moisture may shift far enough north by Thursday to
impact portions of northern and central Utah, though, again,
convection looks to remain mainly high-based with the ever present
threat of microburst winds in excess of 50 mph.

The previously mentioned trough will shift into the Pacific
Northwest by Friday, bringing a dry, hot and windy pattern into
Utah...with an increasing probability of widespread critical fire
weather conditions across nearly all zones with critical fuels
Friday and Saturday.

In reality, there is a very low chance of precipitation for most
locations over the next 7 days outside of briefly heavy rain under
a stronger thunderstorm Wednesday or Thursday.

&&

.AVIATION...Light variable or southeasterly winds will persist
through the night into Monday morning, becoming northwesterly
after 17-18z. VFR conditions will likely prevail, however smoke
from nearby wildfires could produce brief periods of MVFR VIS,
particularly around sunrise/sunset.

REST OF UTAH AND SOUTHWEST WYOMING...Typical diurnal winds can be
expected across much of the area through Monday. Although many
sites will experience VFR conditions, wildfire smoke could result
in reductions in slantwise VIS, particularly around
sunrise/sunset.

&&

.FIRE WEATHER...High pressure will strengthen across the area
during the first half of the week, resulting in a return to hot
and very dry conditions by Tuesday. Daytime temperatures Tuesday
and Wednesday will run 5-10 degrees above normal with very low
daytime RH and marginal to poor overnight recovery. With this
strengthening high, general winds will remain fairly light from
the west to southwest. The exception will be portions of south
central and east central Utah, where gusts may locally exceed 25
mph and result in pockets of locally critical fire weather
conditions in zones 482, 489 and 498

High based moisture will begin to increase Wednesday afternoon
across southern and potentially central Utah, bringing a chance
for high based showers and dry thunderstorms. This moisture looks
to increase on Thursday, bringing a mixture of wet and dry
thunderstorms. A dry and strengthening southwesterly flow will
follow Friday into Saturday as this ridge breaks down, which will
likely bring a return to critical fire weather conditions across
much of the area.

&&

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

$$

Kruse/Cheng/Seaman

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