A winter storm system moved through Utah in late November, producing heavy snowfall.
Every event with a place to put it; 2 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS SLC wrote it up.
A winter storm system moved through Utah in late November, producing heavy snowfall.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Salt Lake City, UT wrote its last area forecast discussion before the first event at Nov 23, 3:47 PM MST, 8 hours 13 minutes earlier.
Area Forecast Discussion
National Weather Service Salt Lake City UT
347 PM MST Thu Nov 23 2023
.SYNOPSIS...A slow moving low pressure system will cross the
region through Friday. A dry and cold northerly flow will follow
for the weekend into early next week.
&&
.SHORT TERM (Through 12Z/5AM Saturday)...An upper low digging
into the northern Great Basin this afternoon will slowly make its
way across the forecast area through the short term period. The
surface front has pushed through the Wasatch Front as of mid
afternoon, stretching from roughly Heber City to Milford, while
the trailing 700mb baroclinic zone resides across northwest and
west central Utah. Meanwhile, a backdoor front is noted across
southwestern WY, accompanied by gusty easterly winds.
As the upper low continues slowly southward near the Utah/Nevada
border tonight, the aforementioned 700mb baroclinic zone will
spread east into the Wasatch Front and adjacent terrain this
evening. This feature will be weakening with time as the flow
aloft weakens substantially, but nonetheless will be accompanied
by widespread generally light precipitation. Snow levels will
fall to the benches by mid evening, with some uncertainty
regarding when snow levels reach the valley floors. Given valley
inversions in place with fairly isothermal low level lapse rates,
and the fact inversions will likely be slow to mix out given
light flow and slowly cooling temperatures aloft, anticipate a
quicker turnover to snow along the northern valley floors this
evening. That said, fairly weak synoptic forcing will likely
result in only light precipitation minor at best accumulation.
The backdoor front across southwest WY will progress westward as
the low center drops south, enhancing cold advection across
northeastern Utah. Models have been trending away from a stronger
downslope wind event, with the stronger 700mb cold advection now
largely confined to Cache/Rich/Uinta counties, and hi-res guidance
largely supporting an advisory level event. As such have gone with
an wind advisory for downslope-prone areas along the northern
Wasatch Front/Cache Valley. These winds will also impact the Bear
River Valley, however a winter wx advisory is already in effect
for this location, and have included the wind threat within this
headline.
As the upper low pivots east late tonight through Friday, the
stronger synoptic forcing will shift into central and southern
Utah, and anticipate fairly widespread and continuous snowfall
from the Wasatch Plateau southwestward. As such, have expanded the
going winter wx advisory into the southern mountains, and will
need to keep an eye on the I-15 corridor through central/southwest
Utah, where a somewhat favorable window for orographic enhancement
will set up through the day Friday. Meanwhile, very light flow
followed by a turn to northerly flow across northern Utah will
largely limit the potential for anything more than light snowfall
across the higher terrain. As the upper low progresses east into
the central Rockies Friday night, a deformation axis/wrap around
precip band may linger from the central mountains eastward across
the eastern deserts. Have trended PoPs upward accordingly across
this area, while the remainder of the forecast area sees precip
come to a gradual end.
.LONG TERM (After 12Z Saturday)...A trough axis will be positioned
near the Utah and Colorado border Saturday morning. Northerly
synoptic flow, low level moisture, and a sufficient lake-700 mb
temperature difference sets up lake effect and lake enhancement snow
chances for the western Salt Lake valley, Oquirrh Mountains, and
Tooele valley. Model soundings show the main limiting factor being a
near isothermal layer from roughly 5000-1000 ft. which would limit
lift to get snow going. Probabilities are limited to around 15%
because of that.
Snow will be ending for southwest Wyoming and much of Utah, with
snow lasting into Saturday afternoon for higher terrain in central
Utah. Snow will diminish into the evening there.
Overnight lows into Sunday will be around 10F cooler than normal,
with the Bear River and Cache valleys into the single digits, teens
and 20s for much of the urban corridor, and teens for most southern
valleys.
Valley inversions will start to build Sunday and get better
established into the week as there is high confidence in a ridge
through at least Tuesday. Models are in general agreement on a
trough once the ridge tracks east, but confidence is low on timing
or snowfall accumulation.
&&
.AVIATION...KSLC...A broader, heavier round of precipitation
will reach KSLC around 23-01z. Expect CIGs to drop to low-end MVFR,
even down to IFR overnight (40% chance). Exact timing of the
transition to snowfall is uncertain, though will most likely occur
between 03-06z. Locally heavier precipitation could make this
transition even earlier. Winds will remain northwesterly and fairly
light (<7kts), though note that surface winds on the east side of
the valley will be breezy out of the east. KSLC itself is unlikely
to see these winds.
.REST OF UTAH AND SOUTHWEST WYOMING...Beginning with rain/snow
category impacts, a storm system will bring widespread valley rain
and mountain snow to much of the area. This will cause widespread
MVFR to IFR CIGs/VIS, especially across the northern two-thirds of
Utah and Uinta Co., WY. Blowing snow will likely cause LIFR
conditions at KEVW overnight. Northern/central valleys are expected
to transition to snow late this evening. Sites along the northern
Wasatch Front, Cache Valley, and Bear River Valley may see CIGs rise
and precipitation drop off earlier in the night due to easterly
downslope winds.
Speaking of downslope winds, expect strong winds out of the east
tonight just downwind of terrain in the aforementioned areas, plus
Uinta Co., WY. KLGU will see the biggest impacts out of our TAF
sites. It is not 100% certain that KLGU will see these easterly
gusts. If KLGU does see these winds (40% chance), expect gusts
around 35-45kts at the surface and approaching 50kts at 1000ft AGL.
If easterly winds don't quite reach KLGU (60% chance), surface winds
will be light out of the west most likely, with very strong LLWS
between the surface and 1000ft AGL...nearly 50kts of shear. KOGD may
see occasional gusts out of the east, though these strong downslope
winds typically do not reach KOGD.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Wind Advisory from 8 PM this evening to 11 AM MST Friday for
UTZ104-107.
Winter Weather Advisory until 5 PM MST Friday for UTZ108-109.
Winter Storm Warning until 5 PM MST Friday for UTZ110.
Winter Weather Advisory until 11 PM MST Friday for UTZ111-112.
Winter Weather Advisory until 11 PM MST Friday for UTZ113.
Winter Weather Advisory from 11 PM this evening to 11 PM MST
Friday for UTZ114.
Winter Weather Advisory until 5 AM MST Saturday for UTZ117-125.
WY...Winter Storm Warning until 5 PM MST Friday for WYZ021.
&&
Seaman/Wilson/Cunningham
For more information from NOAA's National Weather Service visit...
http://weather.gov/saltlakecityThe national radar mosaic for the moment the first event began.
2 heavy snow. Local standard time, as filed.
Several SNOTEL stations including Big Flat, Sunflower Flat, and Midway Valley recorded 0.7 to 0.9 inches of snow water equivalent, resulting in approximately 12 to 15 inches of snow.
Several SNOTEL stations including Pickle Keg, Farnsworth Lake, and GBRC HQ recorded around 0.7 to 1.1 inches of snow water equivalent, resulting in approximately 12 to 18 inches of snow.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Utah in 2023Every state in 2023This day in weather historyWarnings in Utah, November 2023
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1146231, 1146229.