910
FXUS65 KSLC 052127
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
327 PM MDT Sun May 5 2024

.SYNOPSIS...A cold, unsettled pattern will continue through
midweek across much of the region...bringing significant northern
mountain snow accumulations. A gradual warming and drying trend is
expected across northern Utah late in the week. This warm-up may
be slower across southern Utah as a remnant low remains in place
across the area.

&&

.SHORT TERM (Through 12Z Tuesday)...It`s feeling a lot more like
March than May, especially across northern Utah as snow is being
reported along the Wasatch Front as low as 4200 feet. Afternoon
upper air and satellite analysis indicates and large, potent upper
level low near the Idaho/Oregon/Nevada triple point. With 700mb
temperatures near -7 to -8C, precipitation has changed over to
snow as low as 4000 feet or so in association with a band of
heavy precipitation near and behind a strong cold front.

Strong, gusty winds to 55 mph continue across the eastern and
southern valleys this afternoon. The cold front has progressed
east of the I-15 corridor however, so allowed the wind advisories
for west central and southwest Utah to expire. Wind advisories
continue through the mid to late evening for more eastern and
southern valleys...and this looks to be on track based on current
observation and model trends.

This upper level low will gradually shift across the region
through Monday morning. Expect the band of moderate to heavy
precipitation to gradually decrease in intensity (but not end)
this evening. With the loss of precipitation intensity, expect
snow levels to gradually rise again to around 5000-5500 feet or
so overnight tonight.

The longwave trough will remain across the northern United States,
with reinforcing waves moving into the Great Basin through Tuesday
morning. This will bring periods of valley rain and mountain snow
and much cooler than normal temperatures through the remainder of
the short term forecast period.

Current winter storm warning for the northern mountains remains on
track. Will need to monitor the central mountains...as an advisory
may be needed there. Otherwise, no changes are noted for the going
winter headlines.

.LONG TERM (After 12Z Tuesday)...A persistent period of broad
cyclonic flow across northern portions and periodic low/mid level
moisture advection will be maintained into Wednesday. Result,
continued northern mountain snow accums, and potential for lake
enhanced precip downstream of the GSL. Model consensus continues
to key in on reinforcement of the mean long wave trough from the
northern Great Basin region north across the northern Rockies with
additional short wave energy and CAA phasing Tuesday, prior to
the trough trending more into a shearing regime Wed on, this due
to rapidly building heights on the lee side across the PacNW. Snow
impacts still pointing to the high terrain, but temps/lapse rates
will also support snow levels down into the valleys at times,
especially with any convectively enhanced (higher) PI periods.
Details as always a lower probability forecast, but the set up is
there.

Noting ensembles favoring increased ridge influence across
northern portions by late week, this owing to a fairly notable
warming trend focused Friday on. The southern portions however
will still be influenced by a baggy closed low, though this will
be filling in time. Trapped mid level moisture is likely to be
retained within this regime, along with potential for diurnally
driven convective showers forced by thermal input along and
adjacent to terrain.

Forecast temp trends across the period see-sawing from 20 below
climo at their coldest Tuesday, to roughly 10 degrees above climo
later next weekend. The spring roller coaster continues...

&&

.AVIATION...KSLC...Persistent rain-snow mix will diminish through
the early evening, transitioning to vicinity shower activity
until 04Z with another round of showers thereafter. MVFR to IFR
CIGs and VIS will prevail under areas of precipitation. After 07Z,
showers clear the terminal but continue over surrounding terrain,
allowing for obscuration of mountainous terrain through the
overnight hours. Gusty northwest winds will diminish through the
early evening, switching to a light south flow after 02Z. After
There is a 35% chance that winds remain light out of the west to
northwest through the overnight.

.REST OF UTAH AND SOUTHWEST WYOMING...A winter storm system will
bring a mix of conditions across the forecast area through the
remainder of the evening, with MVFR to IFR conditions across the
northern half of the area and MVFR to VFR conditions across the
south. Gusty winds will diminish behind the cold front west of the
central mountain spine, while areas across eastern Utah will
remain under strong southwesterly flow. Mountain obscuration is
expected across the northern half of the area through the
overnight hours while the southern half of the area sees clearing
skies after midnight.

&&

.FIRE WEATHER...A potent late season storm will bring mountain
snow...with occasional snow as low as 4200 feet through the
evening. Mountain snow will continue across northern and central
Utah into Wednesday. Long term into next weekend, the main
question is how quickly a warming/drying trend will build into the
state. For northern Utah...guidance is consistent in a warming
and drying trend. For southern Utah, around 50% of the guidance
suggests a similar warming and drying trend, while 50% of the
guidance suggests a remnant, weakening upper level low may slow
the warming trend through next weekend.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Winter Storm Warning until noon MDT Tuesday for UTZ110>112.

     Wind Advisory until 10 PM MDT this evening for UTZ114-120-121-
     126>131.

     Wind Advisory until 3 PM MDT Monday for UTZ115.

     Wind Advisory until 6 PM MDT this evening for UTZ119.

     Wind Advisory until 3 PM MDT this afternoon for UTZ122.

WY...None.
&&

$$

Kruse/Merrill/Webber

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