198
FXUS65 KSLC 161002
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
402 AM MDT Wed Jul 16 2025

.SYNOPSIS...More seasonable temperatures are expected across Utah
and southwest Wyoming today behind an exiting cold front. Moisture
will increase over the area beginning Thursday, bringing a
heightened threat of showers and thunderstorms, particularly for
southern Utah, through at least the first half of the weekend.

&&

.SHORT TERM (Through 12Z/6AM Friday)...High pressure has been
nudged southward into Arizona by the grazing Pacific Northwest
low, putting Utah and southwest Wyoming under a zonal flow this
morning. Earlier convective activity has all but dissipated, with
just a few showers hanging on along I-70 in the vicinity of the
cold front. Behind that front, temperatures will be noticeably
cooler across the area, running right around normal for this time
of year.

With the flow aloft remaining out of the west to northwest today,
little change in the amount of moisture over the area is expected.
There will be enough moisture and instability for isolated to
widely scattered showers and thunderstorms, primarily focused over
the higher terrain and over southern Utah. With the better
dynamics removed from the area with the exit of the grazing
trough, northern Utah convection will be limited at best, a change
from yesterday. Given the dry lower levels, little rain is
expected with storms that develop, with gusty winds and isolated
dry lightning the main threats of the day.

By Thursday morning, the flow aloft is expected to shift to a more
southerly direction as the ridge axis re-amplifies over the Great
Basin and a closed low starts to move northward along the Baja
California coast. This will draw moisture northward into the area,
resulting in a substantial increase in afternoon/evening storms,
particularly over southern Utah. This moisture should make its way
into the lower levels as well, increasing the chance of wetting
rains. Thus concerns start to shift to the potential for flash
flooding as the moisture increases.

.LONG TERM (After 12Z/6AM Friday)...An upper cutoff low is forecast
to move north slowly over the Baja Peninsula, eventually ending up
over southern CA before eventually phasing into the mean flow by the
end of the weekend. This low will result in a period of unsettled
weather beginning Thursday resulting in widespread precipitation
across southern UT, perhaps extending further into northern UT
Friday and Saturday

Moisture return continues through the long term period as the
aforementioned upper low churns to our southwest. PWATs have
increased somewhat, generally ranging from 0.7" to 0.9" of water.
Some locally higher amounts are evident across the GFS, EURO, NAM,
and RRFS, although inconsistency is high at this time. Guidance
Guidance continues to trend more robust moisture further north
resulting in some higher rainfall totals and higher PoPs appearing
possible across northern UT as well with the Uintas appearing to be
an area of interest. With this setup, some locally heavy rainfall
amounts appear possible with an emphasis on southern UT and perhaps
the Uintas. Details remain inconsistent at best with where this
rainfall will occur, though it bears watching.

The aforementioned upper low looks to phase into the mean flow late
in the period as a trough moves in from the Pacific Northwest around
Monday. Guidance has somewhat flipped with what may occur over our
area with this trough as it now puts the trough axis directly over
our area which would limit ascent across the area. This would not be
favorable for rain as limited ascent would likely keep precipitation
limited to the higher terrain despite ample moisture remaining over
the area from the now dissipated upper low. Naturally, guidance
remains inconsistent at this timeframe and things may chance in
upcoming forecasts.

&&

.AVIATION...KSLC...VFR conditions will persist at the KSLC terminal
through this period. Drainage flow is currently taking hold with
northwesterly winds expected to develop around 18-19z. Following
this, drainage flow will occur once again around 04z.

.REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions are settling in
across all terminals this morning. While VFR conditions will persist
across the majority of our TAF sites, particularly KBCE and KCDC
following 19z. Isolated showers and thunderstorms are possible near
these sites with gusty and erratic winds possible at and near the
terminals. Following sunset, VFR conditions will settle in across
all sites once again.

&&

.FIRE WEATHER...Behind an exiting cold front, Utah will be under a
westerly flow today with lighter winds but little change in
moisture. Enough moisture and instability will exist for another
round of showers and thunderstorms, primarily focused over the
higher terrain and over southern Utah. Storms will be scattered in
nature today, increasing in coverage Thursday into Friday as
monsoonal moisture is drawn northward. As the moisture increases,
the chance of wetting rains increases, particularly over southern
Utah. The moist airmass will persist into the first part of the
weekend before drier air moves in for early next week. Away from
thunderstorms, winds will be generally light over the next few
days with temperatures near or just above seasonal normals.

&&

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

$$

SHORT TERM/FIRE WEATHER...Traphagan
LONG TERM/AVIATION...Worster

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