Winter Weather in Utah, February 13, 2024

Area Forecast Discussion
National Weather Service Salt Lake City UT
426 AM MST Tue Feb 13 2024

.SYNOPSIS...Several weak disturbances crossing the area through
Friday may bring accumulating snow to the northern mountains. A
potentially more active and moist pattern is expected late this
weekend into next week.

&&

.SHORT TERM (THROUGH 12Z THURSDAY)...A near-zonal flow is in place
this morning over the interior West while an upper trough is noted
upstream across the PacNW. This trough will weaken before it grazes
northern Utah tonight into tomorrow morning. Modest H7 warm
advection will allow temperatures to continue to climb today, with
afternoon maxes expected to reach near to slightly above
climatological normals. Otherwise, patchy mid and high clouds will
continue to cross Utah, increasing later this afternoon into this
evening ahead of the aforementioned trough.

The trough passage tonight will push a weak H7 baroclinic zone
through northern Utah. Models indicate that it could bring some
precipitation to mainly the northern mountains late tonight into
tomorrow morning. Weak dynamics and relative lack of moisture
suggest that precipitation should be on the light side. However, it
should be noted that the HREF QPF spans a fairly large range, with a
spread of less than 0.01 inches in the ensemble min to over 1.3
inches in the Provo area mountains in the ensemble max. Diving into
the individual members, it appears that the NAMNest is the main
contributor to the high-end values, with some help from the HRW
NSSL. The rest of the ensemble members have relatively low QPF such
that the ensemble mean does not exceed 0.3 inches at any given
point, with most northern mountain areas remaining under 0.2 inches.
This should translate to light snow with little impact across the
northern mountains. Valleys closer to the Idaho border could see
dusting of snow tonight, while farther south, snow levels are
expected to remain higher resulting in less chance of any
accumulating snow.

As the trough exits the area tomorrow afternoon, H7 warm advection
will quickly return. This could maintain some light precipitation
across northern Utah, otherwise expect precipitation trends to
decrease until closer to Thursday morning with the arrival of the
next trough.

.LONG TERM (After 12Z/5AM Thursday)...The shortwave on Thursday is
still on track, but H7 flow seems to be trending slightly more
northwesterly, favoring terrain that does best in this flow regime.
The storm will primarily impact the northern Utah mountains. The
25th-75th percentile QPF totals range from 0.3"-0.75" with the
highest amounts across the Bear River range. This will translate to
roughly 4"-8" of snow across the highest terrain with amounts near a
foot across the Bear River range. Snow levels will start around 5kft
before rising to ~5500ft during the day on Thursday given the lack
of CAA. By Friday morning, snow levels will drop close to valley
floors near the Idaho border. Moisture will remain in place so
valley snow is possible across far northern Utah. The shortwave
moves east by Friday afternoon as a ridge moves in from the west.
Some light snow may linger in the mountains Friday afternoon. A
shortwave with an associated jet streak will be passing by to our
north during the day on Friday, bringing snow to eastern Idaho and
Wyoming. But one development amongst several GFS ensemble members
has been to bring this band of precipitation further south into
northern Utah which would enhance orographic snowfall. This is
something to monitor as hi-res guidance begins to come into frame.

The aforementioned ridge centers itself over Utah by the weekend,
allowing conditions to dry and temperatures to rise several degrees.
Temperatures are forecast to reach the low 50s Saturday through
Tuesday across the Wasatch Front. Southwesterly flow increases on
Saturday ahead of our next storm that will be arriving in the form
of a quick moving shortwave trough on Sunday afternoon. This will be
another relatively warm storm with valley rain and mountain snow.
The northern half of Utah will be the favored region for highest QPF
totals, but this storm has the potential to deliver precipitation
further south compared to the Thursday/Friday storm.

Another shortwave ridge temporarily provides a break in
precipitation on Monday before more moisture starts to stream into
the Great Basin on Tuesday as a coastal low tries to push inland.
Ensemble guidance doesn't have a good grasp on how quickly this low
moves ashore. Right now 22% of members keep this low spinning off
the California coast through Tuesday, which would keep us dry on
Tuesday. But the remaining 78% of members suggest this low tracks
further east, which would reintroduce precipitation back into the
region by Tuesday.

&&

.AVIATION...KSLC...VFR conditions will persist across the KSLC
terminal throughout the period as conditions remain dry with some
high clouds. Winds will remain light and diurnally driven.

.REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions will persist
across the entire airspace as conditions remain dry with some high
clouds. Winds will be light and diurnally driven areawide.

&&

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

Cheng/Mahan

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