397
FXUS65 KSLC 291907
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
107 PM MDT Tue Sep 29 2026

.KEY MESSAGES...

- Thunderstorms capable of heavy rainfall are expected to develop
across southern UT this afternoon with conditions gradually
improving into Wednesday morning.

- Quiescent weather looks to develop Wednesday as zonal flow
develops, persisting into early next week.

- While chances remain low at this time (~20% or less), there is
potential for moisture to return to southern UT early next week as
another trough moves across the area.


&&

.DISCUSSION... A closed upper low continues to progress east across
AZ and NM today with the left-exit region of an upper jet streak
nudging its way into southern UT this afternoon. While ascent
remains modest across southern UT through much of the event, cool
mid-level temperatures (-10C to -12C) coupled with left-exit region
jet periphery favoring diffluence across southern UT will favor
convective development this afternoon. At the surface, a low will
continue progressing east across southern AZ into southern NM,
phasing in with the remnants of Hurricane Polo through the day. This
will yield modest wrap around moisture return, serving to raise
PWATs to the 0.8-1.0" range, with some areas seeing localized values
to 1.2" of water. This raises some concern for flash flooding across
southern UT this afternoon into the evening hours, though
uncertainty does exist given lack of widespread deep moisture
profiles and weaker ascent potentially resulting in widespread light
stratiform rain versus deeper convection capable of heavy rainfall.
Regardless, the SPC has much of southern UT outlined within a
moderate risk (level 3/4) for excessive rainfall this afternoon.

Following today, zonal flow looks to build in with height rises
occurring across much of the Four Corners region. This will bring
quiescent weather to the area with dry and mild conditions expected
through at least Sunday. Temperatures Wednesday and Thursday
afternoons will run near-normal before increasing to broadly 10F
above normal Friday into early next week.

Long-range guidance does hint at some troughing looking to occur
early next week, potentially ushering in another instance of active
weather. This is a particularly hairy forecast to iron out given the
active EPAC, as any storm that forms within the basin could impact
moisture return across the forecast area. At this time, it appears
that there is a low (~20% or less) chance that we see moisture make
it up to southern UT at least with the next system, though this
forecast will more than likely change through the next several days.

&&

.AVIATION, Issued 1231 PM MDT Tue Sep 29 2026...


KSLC...VFR conditions will persist for the KSLC terminal through the
period. Dry and stable conditions with mostly clear skies will
continue. Light northerly winds will continue through most of the
period with only a brief and light southerly flow overnight, if at
all, between 09-13Z.

REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions will persist for
the entire airspace through the period. Dry and stable with mostly
clear skies across the northern airspace with light northerly winds
will continue. Cloud cover with some lingering moisture across the
southern airspace throughout the day with ~30% chance of rain
showers impacting southern terminals.

&&

.FIRE WEATHER...Showers and thunderstorms will continue to develop
across primarily southern UT through 12-2PM and persist through
the late evening hours as tropical moisture continues to work its
way north. The threat for flash flooding exists across southern UT
once again today, with a particular emphasis for interests located
along the AZ border, such as the Telegraph Flats.

Starting tomorrow, high pressure builds in bringing mild
and dry conditions to UT. This is forecast to persist through the
weekend, with temperatures warming slightly above normals as well.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Flood Watch until midnight MDT tonight for UTZ123>131.

WY...None.
&&

$$

PUBLIC...Worster
AVIATION...Mahan
FIRE WEATHER...Worster

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