220
FXUS65 KSLC 292137
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
337 PM MDT Mon Apr 29 2024

.SYNOPSIS...A cold front will cross northern Utah and southwest
Wyoming through the early evening before stalling over central
Utah. A secondary cold front will cross the area Tuesday night
bringing much cooler temperatures for Wednesday. A warming trend
is expected late in the week and into the upcoming weekend.

&&

.SHORT TERM (Through 12Z/6AM Wednesday)...Seeing a breezy
southwest flow across Utah and southwest Wyoming this afternoon as
a Pacific Northwest trough moves into far northwest Utah. This
trough is accompanied by a fairly potent upper level jet, bringing
increasing instability. In this environment, scattered showers and
a few thunderstorms have developed over northern Utah and
southwest Wyoming. Temperatures remain very much on the mild side
areawide, with maxes running 5-8F above seasonal normals.

The previously mentioned trough is on track to slide across
northern portions of the forecast area this evening and into the
overnight hours, bringing a frontal boundary through as it does
so. Thus, associated showers and thunderstorms will hang on into
the evening, with a low chance (20 percent) of a few hanging on
during the overnight hours. Given the dry lower levels in the
airmass currently over the area, cannot rule out microburst winds
with any storms that develop, something to watch through the
evening.

The passage of the system will have a more noticeable
impact on temperatures, however, with maxes over the northern half
of the area expected to run near seasonal normals while southern
Utah remains quite mild, up to 10F above climo. Behind the exiting
trough, the region will be under a drier and more stable zonal
flow, keeping conditions dry.

.LONG TERM (After 12Z/6AM Wednesday)...A broad trough centered over
southern Saskatchewan will slowly meander through the end of the
week. Our area will be on the southern periphery of this trough
resulting in some shortwave troughs grazing by the northern portion
of the CWA. Moisture will be lacking with these shortwaves, so the
biggest impacts will be cooler than normal temperatures along with
gusty winds over eastern Utah on Wednesday along the lee side of the
mountains. The first of these shortwaves arrives Wednesday morning
with southwest flow transitioning to northwest flow behind a mostly
dry cold front. A few showers are possible across the high terrain,
but little to no measurable precipitation is expected.
Temperatures will drop about 10 degrees Wednesday compared to
Tuesday. Far southern Utah will see a less dramatic temperature
fall ~5 degrees which will keep temperatures near normal across
lower Washington county and areas near the Arizona border. Post
frontal northwest winds across eastern Utah will accelerate along
the lee side of the terrain. Some locations could flirt with
advisory level winds with probability of exceeding 50 mph ~70%
across lee side valleys of Carbon, Emery, and Duchesne counties.
Probability of exceeding 58 mph is much lower, ~<30% chance. A
second shortwave arrives on Friday with slightly better moisture,
but still little to no measurable precipitation is expected
outside of the highest terrain of northern Utah/SW Wyoming.

The broad trough ejects further east by the weekend and a
shortwave ridge builds across the Great Basin. This will keep
conditions dry with warming temperatures a few degrees above normal.
Guidance starts to differ by early next week when a trough moves
into the western CONUS. 70% of guidance brings this trough into the
Great Basin by Monday. Moisture won`t be lacking with this trough
given its maritime origin. However, 30% of members suggest a slower
progression of the trough with its placement further west on Monday
and mostly dry conditions across the Great Basin until later in the
week.

&&

.AVIATION...KSLC...Quick impulse will nudge a cold frontal boundary
through Monday evening. If not already switched, this will push
winds NW, with some likely gusts accompanying the front. While
mostly dry, some isolated to scattered shower activity is possible,
though largely expect VFR conditions to prevail. Winds begin to
relax Monday night and are generally favored to remain out of the NW
into the day Tuesday, though guidance hints at a brief period of
light VRB to S flow possible in the morning (best likelihood
currently indicated ~14z-18z).

.REST OF UTAH AND SOUTHWEST WYOMING...A quick system will push a
cold front through northern terminals Monday evening into the early
overnight hours. Front is fairly dry, but will likely trigger some
isolated to scattered showers. Even then, VFR conditions generally
expected to persist. Front will also likely cause a period of gusty
winds (generally NW) before relaxing moving further into the night.
Following the front, anticipate remaining VFR cloud cover to largely
clear. At southern terminals, expect mostly clear skies with some
modestly gusty conditions Monday becoming lighter overnight into
Tuesday.

&&

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

$$

SHORT TERM...Traphagan
LONG TERM...Mahan
AVIATION...Warthen

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