045
FXUS65 KSLC 202322
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
522 PM MDT Thu Aug 20 2026

.KEY MESSAGES, Issued 136 PM MDT Thu Aug 20 2026...



- Strong high pressure will bring hot temperatures to much of Utah
  on Thursday and Friday, especially across northern and central
  Utah where little relief from heat is expected.

- Monsoonal moisture will surge into Utah and southwest Wyoming
  Friday and Saturday, persisting through at least early next
  week. This will bring an increased threat of showers and
  thunderstorms capable of producing flash flooding.

&&

.DISCUSSION, Issued 136 PM MDT Thu Aug 20 2026...
Minor, but noteworthy increases in atmospheric
moisture and instability are noted across the region today as
afternoon satellite and radar imagery reveal isolated showers and
thunderstorms spread across the high terrain features of Utah.
That said, early afternoon mesoanalysis shows a finger of elevated
(1+ inch) PWAT values just barely sneaking into far southwest
Utah. Therefore, it appears the current environment is only
supportive of isolated heavy rainfall with slower moving storms.
Additionally, with a ridge of high pressure cresting over the
region today, heat is also expected to maximize across the region
with high temperatures on the Wasatch Front, and other western
valley areas, around 100 degrees. With overnight lows in this
region only expected to recover to around 70 to 75 degrees,
prolonged exposure to the heat may bring an increased risk for
heat related illness in vulnerable populations. This heat is
expected to remain in place across northern Utah on Friday while
waning across central and southern Utah.

The center of the high pressure will shift into the Four Corners
region on Friday, aiding in the advection of monsoonal moisture
into southern and central Utah. As such, the coverage of showers
and thunderstorms will expand farther north on Friday afternoon,
with similar risks of heavy rainfall and flash flooding expanding
into southern and central Utah. Particular areas of concern for
flash flooding will be recent burn scars, slot canyons, dry
washes, and steep terrain.

The position of the high will shift farther east on Saturday,
altering the trajectory of the moisture plume into northern Utah
and southwest Wyoming, thus expanding the threat of showers and
thunderstorms capable of producing heavy rainfall and flash
flooding. Models do indicate a dry slot working into southwest and
west-central Utah on Saturday and Sunday, which may act to limit
storm potential in this region of Utah while areas in the north
see an increase in coverage. The position of the high goes
relatively unchanged through early next week, bringing daily
shower and thunderstorm coverage over the high terrain features of
Utah, as well as potential for heavy rainfall and flash flooding
to typically prone areas.



&&

.AVIATION...

KSLC...The SLC terminal will see VFR conditions through the
overnight hours with some scattered clouds. Northwest winds are
expected to return to the south between 03Z and 05Z with tomorrow`s
shift to the north most likely occurring between 19Z and 21Z. With
increasing moisture, there is a 30 percent chance of the terminal
seeing a period of gusty and erratic thunderstorm winds, with the
most likely time during the late afternoon and early evening.

REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions will prevail
across the airspace through the overnight hours. Scattered showers
and thunderstorms have been focused over the higher terrain and will
continue into the early evening before dissipating. Any storms that
develop will have the potential to produce gusty and erratic winds,
lightning, and brief mountain obscurations. With moisture increasing
tomorrow, coverage of showers and thunderstorms will become a bit
more widespread tomorrow afternoon, with similar potential aviation
impacts as today. Away from thunderstorms, generally light and
terrain driven winds will prevail.

&&

.FIRE WEATHER, Issued 136 PM MDT Thu Aug 20 2026...
Monsoonal moisture is expected to increase across Utah
through the weekend, bringing increased coverage of showers and
thunderstorms across the high terrain in the region. In addition
to shower and thunderstorm activity, a trend of increasing
humidity is expected areawide. That said, lower elevations of
western, eastern, and southern Utah will continue to see minimum
relative humidity values in the mid- to upper-teens. For the
higher terrain areas, minimum values may only fall into the 25 to
35 percent range with good to excellent recovery expected
areawide. While probability for wetting rains will be relatively
high over the mountainous terrain (up to 45-60 percent chance),
lower lying adjacent valley areas will see far lower chances (15
percent or less). On Friday in particular, developing storms will
bring potential for strong outflow winds over central and northern
Utah. Daily shower and thunderstorm chances will be maintained through
at least Tuesday next week, with storms expected to develop over the
high terrain features each afternoon.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Heat Advisory until 7 AM MDT Saturday for UTZ101>106.

     Heat Advisory until 7 AM MDT Friday for UTZ115-116.

WY...None.
&&

$$

PUBLIC...Webber
AVIATION...Traphagan
FIRE WEATHER...Webber

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