Severe Thunderstorm Warning 69, NWS Salt Lake City, UT

Area Forecast Discussion
National Weather Service Salt Lake City UT
135 PM MDT Sat Aug 22 2026

.KEY MESSAGES...

- There is a Marginal Risk (level 1/4) for excessive rainfall
  across most of the region through the weekend.

- There is a Marginal Risk (level 1/5) for severe thunderstorms
  across portions of northwestern Utah today. There is a 5-10%
  chance of wind gusts in excess of 58 mph in this area through
  the evening.

- A Slight Risk (level 2/5) for severe thunderstorms is outlooked
  for Sunday afternoon and evening across much of northern Utah.
  There is a 10% chance of wind gusts in excess of 70 mph with
  these thunderstorms Sunday afternoon and evening.

&&

.DISCUSSION...Increased moisture across the region will support
thunderstorms capable of heavy rainfall rates. With relatively
slow storm motions today, already seeing convection anchored on
terrain training in locations and producing localized flooding of
small streams and dry washes. Will need to continue to monitor
central and southern Utah through the evening as rainfall rates in
excess of 0.50-0.75 inches per hour have been observed. The most
prone locations will be slot canyons, normally dry washes, slick
rock areas, areas with poor drainage and of course the numerous
recent burn scars across the region.

Across northwestern Utah, CAMS suggest the threat of strong to
severe microburst winds. One inhibiting factor will be the mid-
morning to early afternoon convection that moved across
northwestern Utah. This likely stabilized the atmosphere a
bit...and additional convective potential may be suppressed for
several hours. While earlier runs of the HRRR showed significant
wind gusts impacting northwestern Utah and perhaps the Wasatch
Front in the 21Z-02Z timeframe, later runs have largely shifted
away from this solution. Mesoanalysis correlates a fair amount of
inhibition...and guidance suggests this CIN may not be overcome by
the end of peak heating.

Sunday looks to be a potentially interesting day convection-wise.
A weak area of convergence associated with a Pacific trough will
shift into northwestern Utah. Mean HREF SBCAPE values will near
1000 J/kg across much of northern Utah by noon to 1 PM. This
combined with deep layer shear around 25-30 kts and general
synoptic scale lift will support convective development across
much of Utah after noon. The most intense convection will likely
be across northern Utah. HREF suggests a neighborhood probability
of wind gusts in excess of 55 mph around 15-25%, especially near
and west of the Great Salt Lake, and 10% or so in excess of 60
mph. The Storm Prediction Center has outlooked this area with a
slight risk (level 2/5) for Sunday afternoon and evening including
the Wasatch Front.

Across central and southern Utah, another day of thunderstorms
with the threat of heavy rainfall is expected. Peak rainfall rates
in guidance are notably lower than Saturday, correlating well with
a net drying trend. That said, the threat of at least isolated
flash flooding in the most prone locations will continue Sunday
afternoon and evening, especially across central and southern
Utah.

The Pacific trough will finally shift into the northern High
Plains, shifting any large scale forcing for convection to the
east. Given there wasn't a front to sweep out the low-level
moisture in the low desert areas, expect the threat of isolated
flash flooding to persist in any areas that develop convection
through at least Monday...if not longer.

&&

.AVIATION...

KSLC...There is low confidence in wind direction this afternoon and
evening, particularly near any storms. High-based showers and
thunderstorms will begin to develop over the Oquirrh Mountains after
20z, with storms potentially moving over the terminal after 21z or
so, resulting in gusty and erratic outflow winds reaching 40kts for
a brief period (10% chance). BLDU may result in brief VIS
reductions. The threat of showers will linger well into the
evening/overnight hours (until 09-10z), with a continued threat of
outflow winds.

REST OF UTAH AND SOUTHWEST WYOMING...High-based showers and
thunderstorms will continue to develop across much of the area (all
but KCDC-KSGU) this afternoon, first over higher terrain. These
storms will be capable of producing gusty and erratic outflow winds
up to 40kts (up to 50kts across NW-UT). Storms will likely subside
across southern UT between 02-04z, though showers are likely to
linger through the overnight hours across the rest of the
area...gradually weakening through the night. Outflow winds will
result in low confidence in wind direction through much of the valid
TAF period.

&&

.FIRE WEATHER...Afternoon and evening showers and thunderstorms
will become more isolated through early Monday, and largely tied
to terrain. Any showers and thunderstorms this weekend will have
the threat of strong, gusty microburst winds.

Over the work-week, valley humidities will fall slowly each day,
reaching near critical to critical levels as early as Monday.
There is little sign of an additional monsoon surge after this
weekend until after the next weekend.

&&

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

Kruse/Cunningham

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

Special Weather Statement
National Weather Service Salt Lake City UT
138 PM MDT Sat Aug 22 2026

UTZ113-114-222030-
Western Uinta Basin UT-Wasatch Plateau/Book Cliffs UT-
138 PM MDT Sat Aug 22 2026

...A strong thunderstorm will impact portions of central Duchesne
County through 230 PM MDT
...

At 137 PM MDT, Doppler radar was tracking a strong thunderstorm 9
miles southwest of Starvation Reservoir, or 10 miles southwest of
Duchesne, moving northeast at 20 mph.

HAZARD...Wind gusts of 50 to 55 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Roosevelt, Duchesne, Myton, Starvation Reservoir, Altamont, Upalco,
Arcadia, Cedarview, Bridgeland, Utahn, and Neola.

This includes the following highways...
 US Route 40 between mile markers 72 and 115.
 Utah Route 35 between mile markers 56 and 62.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 3994 11060 4016 11073 4050 11010 4034 10998
      4017 10997
TIME...MOT...LOC 1937Z 241DEG 19KT 4007 11055

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...55 MPH

CRK