488
FXUS65 KSLC 232134
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
334 PM MDT Thu May 23 2024

.SYNOPSIS...A cool, stable airmass across northern Utah will
transition to a more active pattern Friday. Widespread
precipitation is expected north of I-70 late Friday into Saturday
evening. A cool, stable airmass will shift into the area for
Sunday, followed by a warming trend early next week.

&&

.SHORT TERM (Through 12Z Sunday)...It`s May but we are feeling
very April here today in the Beehive State. A mainly dry cold
front is currently across southern Utah. Afternoon upper air and
satellite analysis indicates an upper level low pulling away from
the area across northeastern Wyoming. Several additional shortwave
troughs are noted upstream and will bring additional rounds of
precipitation to the region through Saturday.

The previously mentioned cold front will continue to weaken as the
upper level support shifts away from the region. This front will
shift northward Friday, nearing central Utah by afternoon.
Meanwhile, a combination of PVA ahead of the next shortwave trough
and preferential jet dynamics will support the development of
convection across much of the state. Looking at the 12Z CAMS,
sufficient instability is expected across the bulk of the members
to support isolated convection as far south as southern Utah, with
the highest likelihood from near the boundary north. The strongest
potential for any impacts, and the highest potential for heavy
rain will be north of I-70.

By Friday night, a weak boundary will now be across portions of
northern and central Utah as yet another shortwave trough will
shift into the region. With a period of frontogenesis expected
Saturday morning into Saturday afternoon, widespread precipitation
is expected. Heaviest precipitation will again be north of I-70.

By late Saturday, this shortwave trough will be lifting out of the
area, bringing a cool, stable airmass into the area by Sunday
morning.

For those planning to venture into the higher terrain Friday into
Sunday morning, expect winter-like conditions with accumulating
snow above about 8500 feet, especially for the western Uinta
Mountains. Be careful out there!

.LONG TERM (After 12Z Sunday)...
Issued 409 AM MDT
Through Sunday, should see precipitation
tapering off as the system from the prior day(s) departs eastward.
Temperatures will warm from that of Saturday, but afternoon highs
areawide will remain below seasonal normal for late May.

Deterministic and ensemble model guidance continues to show good
consensus in support of a building ridge from Memorial Day on into
midweek. This will yield dry conditions and a warming trend, with
afternoon highs likely near normal on Monday, increasing to above
normal moving into the middle of the week. In comparison to prior
forecasts, NBM has backed off slightly on the potential for the
first 90F or higher day Wednesday afternoon (down to 22% now at
KSLC). This appears to be due to potential for an amplifying
trough in the PacNW to flatten the ridge or shunt the ridge axis a
bit more east of the area, seemingly supported by ~50% of
ensemble members. Generally would just anticipate this to result
in slightly cooler (but still above normal) temperatures, though
something more aggressive/amplified like what the deterministic
GFS depicts would certainly be more interesting. This split in
ensemble scenarios carries on into Thursday as well, though even
then there is ~25% of ensemble membership which support a
continued strong ridge. Overall though, looks favorable for a
period of more summer-like weather with several days with highs in
the low to mid 80s across much the Wasatch Front, and mid to
upper 90s in Lower Washington County. While beyond the forecast
period, CPC 8 to 14 day also leans in favor of warmer/drier
conditions in comparison to normal, so some sort of ridge
dominated pattern seems favored to largely persist.

&&

.AVIATION...KSLC...Northwest winds are expected to gradually
decrease late this afternoon and into the early evening hours.
Expect a shift back to southerly by around 04z. The south winds
will likely persist into the early afternoon hours Friday along
with VFR conditions before showers begin to develop for the second
half of the afternoon.

.REST OF UTAH AND SOUTHWEST WYOMING...Generally VFR conditions
with west to northwest winds will persist across the forecast area
into this evening. Winds will then decouple and become more
terrain-driven by late this evening though the overnight hours.
Near the Idaho border, CIGS of 11-12kft MSL will continue until
around 01- 02z. Friday by around 19-20z, showers are expected to
begin developing across central Utah, increasing in coverage and
expanding into portions of northern and southern Utah through the
rest of the afternoon and into the evening hours.

&&

.FIRE WEATHER...Warm, dry, and breezy conditions continue across
southern Utah this afternoon as a cold front gradually weakens
across southern Utah. This boundary will lift north Friday, with
the highest potential for wetting rain near and north of the
boundary across central and northern Utah. Most of the showers and
thunderstorms will trend toward high-based given the dry
antecedent conditions. By Saturday, another stronger trough will
bring widespread precipitation across northern and central Utah
with a much higher chance of wetting rain. Southern Utah will see
more isolated, high-based convection. An abnormally cool airmass
will be in place statewide Sunday...with a significant warm- up
expected into early next week.

&&

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

$$

Kruse/Warthen/Cheng

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