006
FXUS65 KSLC 071020
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
420 AM MDT Tue May 7 2024

.SYNOPSIS...Northern and central Utah will remain cold and
unsettled through Wednesday while southern Utah stays dry and
warmer. A warming and drying trend will commence late Wednesday
with isolated showers and storms remaining possible across central
and southern Utah through the weekend.

&&

.SHORT TERM (Through 12Z/6AM Thursday)...Current radar shows
valley rain and mountain snow ongoing across northern Utah and the
central Utah mountains. This precipitation will continue through
the morning as a shortwave trough moves through the region. This
will bring a reinforcing shot of cold air with H7 temperatures
dropping to ~-10C by the afternoon. Precipitation will gradually
diminish throughout the day as it turns into a more showery regime
with isolated thunder possible (~30% chance). Given steep lapse
rates and the cold air aloft these showers will be capable of
dragging snow levels down to valley floors as well as containing
graupel and locally gusty winds under any heavier cores that
become established. In addition to the showers, post-frontal
northwesterly flow will be gusty throughout the day for most
regions, but gusts should remain below advisory criteria. Given
the continued snow across the northern mountains, winter storm
warnings continue through 06Z Wednesday for 4-8 inches of
additional snow, with higher amounts up to 12 inches possible in
the Cottonwoods and high Uintas.

A cold light northwest flow will remain established through
Wednesday morning that could result in lake effect snow south and
east of the GSL. This is noted in all of the hi-res models, but
the extent and duration of this lake band is fairly small so
limited impacts are anticipated across valley locations.
Additionally, sub-freezing temperatures are expected across
agriculture zones of Tooele, Box Elder, and Utah counties along
with portions of The Swell. As a result, freeze warnings have been
issued for these areas through Wednesday morning.

A following shortwave arrives on Wednesday afternoon which will
bring a boost in moisture and more widespread showery
precipitation across northern Utah with little to no additional
snow accumulations across the mountains. This diurnal
precipitation will subside during the evening with cold
temperatures remaining, but most valley locations will have
slightly warmer temperatures Thursday morning so the freeze threat
is lower compared to Wednesday morning.

.LONG TERM (After 12Z/6AM Thursday)...Models are in good agreement
with the synoptic pattern at the beginning of the long term period,
temporarily building a large scale blocking pattern across the
western CONUS. A broad upper ridge will become established across
the Pacific Northwest/northern Rockies region beginning Thursday and
persisting through much of the weekend, while a cutoff low develops
and parks across the Great Basin/Colorado Plateau region.  This
setup looks to persist through at least Saturday, before model
guidance begins to diverge with respect to how quickly this low
exits the region.

Initially, easterly flow along the northern periphery of the
developing upper low will spread across northern Utah/southwest
Wyoming by early Thursday morning, and persist through at least
Friday, resulting in a favorable setup for enhanced easterlies along
the northern Wasatch Front and eastern Cache Valley. Uncertainty
centers around the magnitude of the cold advection, as well as the
strength of the easterly flow aloft. At this point it`s not looking
like a significant downslope event, but rather gusts predominantly
in the 40-55 mph range.

With the upper low and associated cold pool aloft residing across
the region, diurnal convection can be expected through at least
Saturday, and potentially beyond depending on how quickly the upper
low exits the region. 00Z guidance has trended slower with respect
to eventually lifting this low out of the region, which would
maintain the threat for daily convection into early next week. The
current forecast trends temperatures warmer heading into the
weekend and early next week as the airmass modifies.

&&

.AVIATION...KSLC...Periods of rain will occasional MVFR CIGS
through the morning hours, with a 20% chance of brief IFR CIGS
through 18Z. Scattered showers will linger around the terminal into
the afternoon hours as predominant VFR conditions take hold. Winds
throughout the day will remain northwesterly, but may become briefly
erratic near passing showers.

.REST OF UTAH AND SOUTHWEST WYOMING...Areas of precipitation with
snow levels around 4500 feet will continue across northern Utah and
southwest Wyoming through the morning hours. Periods of MVFR CIGS
are expected within these areas of precipitation, with IFR to LIFR
within periods of snow above 4500 feet. Conditions across southern
Utah will remain predominantly VFR. Winds across the region will
remain predominantly northwesterly throughout the day today, but may
become erratic near passing showers.

&&

.FIRE WEATHER...A trough will move through the region Tuesday bringing
reinforcing cold air to central and northern Utah along with more
valley rain and mountain snow. Snow levels will be down to valley
floors, at times, with 6-12" of accumulating snow across the high
terrain. Northwest winds will be gusty areawide on Tuesday behind
a cold front. Showers will linger through Wednesday morning across
the north before drier and warmer conditions develop.

This trough shifts east by Thursday, but an area of low pressure
will be left in its wake that will linger across southern Utah
resulting in isolated afternoon showers through the weekend. But
the primary result of this low will be an increase in cloud
coverage and higher relative humidity.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Freeze Watch from late tonight through Wednesday morning for
     UTZ102-103-106-121.

     Winter Storm Warning until midnight MDT tonight for UTZ110>112.

WY...None.
&&

$$

SHORT TERM...Mahan
LONG TERM...Seaman
AVIATION...Seaman
FIRE WEATHER...Mahan

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