509
FXUS65 KSLC 120409 CCA
AFDSLC

Area Forecast Discussion...CORRECTED
National Weather Service Salt Lake City UT
1009 PM MDT Fri Sep 11 2026

.UPDATE...Ongoing convection across far southeastern portions of
the CWA near Halls Creek Narrows and additional convection near
several burn scars precludes a full discussion this evening.
Expect this convection to continue through at least 09-10Z during
the overnight hours. Occasional rainfall rates in or near 100% of
flash flood guidance for areas near Capitol Reef has occurred as
well as around 0.30-0.35"/hour rates near several susceptible burn
scars.

Moving into Saturday, additional convection is likely across
portions of eastern and southern Utah. The flash flood potential
rating was updated to include possibles for additional eastern and
southern Utah parks and rec areas.

&&

.KEY MESSAGES...

- A marginal risk (level 1/4) for excessive rainfall is in place
  across portions of southern Utah through Tuesday.

- Gusty winds up to 45 mph will develop across portions of
  northern Utah Saturday night into early Sunday morning. Wind
  gusts to 40 mph will continue behind the cold front through
  Sunday evening.

&&

.DISCUSSION, Issued 225 PM MDT Fri Sep 11 2026...
While an increase in moisture is noted across the central and
southern portions of Utah this afternoon, the coverage of showers
and thunderstorms is rather dismal as originally anticipated. That
said, it is evident that the environment is conducive to
thunderstorms and heavy rainfall as SPC mesoanalysis suggests
upwards of 1500-2000J/kg of CAPE paired with PWAT values around 1
inch in southern Utah. One singular storm moving across the
southern area has been able to tap into this instability and
maintain itself while the remainder of the thunderstorm activity
has been rather short-lived. In any case, moisture has positioned
itself in place across the southern half of Utah and will continue
to increase subtly over the next couple of days.

Coverage of showers and thunderstorms is anticipated to be just as
isolated on Saturday as weak subsidence in the wake of the current
shortwave inhibits widespread thunderstorm activity. The more
noteworthy widespread weather that Saturday will feature will be
an increase in southwest winds across much of the region, with the
strongest winds targeting west-central and southwest Utah, as well
as southwest Wyoming. In these areas, afternoon wind gusts will
reach upwards of 30-35 mph as a trough remains over the PacNW
region. This trough is slated to progress inland and graze
northern Utah through the second half of Sunday and into Monday
morning, introducing a cold front to the northern area. Behind the
cold front, a brief period of stronger west to northwest winds can
be expected in northern Utah on the lee sides of mountain ranges.

Cooler temperatures are expected in the wake of the cold front on
Monday across the northern area, with warm southerly return flow
bringing a gradual warming trend into the middle of the week. For
southern Utah, some level of moisture will remain in place from
now through next week, bringing at least a chance for showers and
thunderstorms each afternoon.



&&

.AVIATION...

KSLC...The SLC terminal will see VFR conditions through the
overnight hours with mostly clear skies. Southerly winds will
continue through the morning, shifting to the northwest between 19Z
and 21Z.

REST OF UTAH AND SOUTHWEST WYOMING...The entire airspace will see
VFR conditions through the overnight hours. The northern two-thirds
of the airspace is expected to remain dry with mostly clear skies
and terrain driven winds. A few showers and storms continue over
southern Utah this evening, with a line from near Milford to near
Hanksville expected to see some showers continuing overnight. Any
storms that develop will have the potential to produce gusty and
erratic thunderstorm winds. Some storms are then expected to develop
Saturday afternoon, primarily focused over eastern portions of the
airspace.

&&

.FIRE WEATHER, Issued 225 PM MDT Fri Sep 11 2026...
Moisture increases across the southern and eastern
portions of Utah through the upcoming weekend, bringing potential
for shower and thunderstorm development over the high terrain in
these areas, particularly today and Sunday. While moisture will be
increased across the south and east, the northern and western
portions of Utah will remain largely dry with minimum relative
humidity continuing to fall to near 15% (or slightly below) each
afternoon. Breezy southwest winds ahead of a late weekend cold
front will pair with the borderline critically dry conditions in
western Utah, creating near-critical to isolated critical fire
weather conditions on Saturday and Sunday afternoon.

A cold front will graze across northern Utah Sunday evening
through Monday morning, bringing shifting winds across the
northern third of the area. Localized strong winds may be possible
on the lee sides of mountain ranges in northwest Utah during the
overnight hours. In the wake of the cold front, much cooler
temperatures will spread over the area, though humidity will not
see much improvement. Through the remainder of the week, southerly
return flow will bring an increase in temperatures across the
northern area while southern Utah will see little change in the
atmospheric moisture content. As it stands, the greatest concern
for fire weather conditions over the next 7 days will exist across
western and northern Utah while conditions remain moderated in
the southern and eastern area.

&&

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

$$

Kruse/Webber/Traphagan

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