709
FXUS65 KSLC 201053
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
353 AM MST SAT DEC 20 2025
KEY MESSAGES
- ANOTHER IMPULSE OF MOISTURE WILL PASS THROUGH NORTHERN UTAH FROM
SUNDAY THROUGH TUESDAY, BRINGING ANOTHER ROUND OF HIGH ELEVATION
SNOW AND VALLEY RAIN, PRIMARILY FOR AREAS NORTH OF THE I-80
CORRIDOR.
- BREEZY SOUTHWEST WINDS ARE EXPECTED EACH AFTERNOON FROM SUNDAY
THROUGH AT LEAST THURSDAY AS UTAH AND SOUTHWEST WYOMING REMAIN
SOUTHEAST OF A BROAD UPPER LEVEL TROUGH POSITIONED OFFSHORE OF
THE PACIFIC NORTHWEST.
- AFTER A RELATIVE LULL IN ACTIVE WEATHER EARLY NEXT WEEK, ANOTHER
PACIFIC STORM WILL BRING ANOTHER ROUND OF VALLEY RAIN AND
MOUNTAIN SNOW CHRISTMAS EVE AND CHRISTMAS DAY.
SHORT TERM (THROUGH 12Z/5AM WEDNESDAY)
LINGERING MOISTURE
ACROSS THE NORTHERN PORTION OF UTAH AND SOUTHWEST WYOMING WILL
REMAIN IN PLACE THROUGH AT LEAST THE MID-TO-LATE MORNING HOURS
TODAY WHICH WILL HELP TO FAVOR HIGH ELEVATION SNOW SHOWERS ALONG
THE WASATCH, BEAR RIVERS, AND ADJACENT VALLEY AREAS TO THE EAST.
ADDITIONAL SNOWFALL ACCUMULATIONS ARE NOT EXPECTED TO BE
IMPACTFUL, LARGELY DUE TO CONTINUED HIGH SNOW LEVELS IN THE
WASATCH (AROUND 7,500FT). THOUGH SNOW LEVELS WILL BE LOWER
(~5,500FT) IN THE BEAR RIVERS, COVERAGE OF SNOW SHOWERS WILL BE
QUITE LIMITED. RAIN/SNOW SHOWERS ARE EXPECTED TO CONTINUE THROUGH
AROUND 10AM BEFORE THE BEST MOISTURE AVAILABILITY OF THE DAY
DEPARTS THE REGION AND ALLOWS PRECIPITATION TO DECLINE THEREAFTER.
A COOLER DAY, ALBEIT WELL ABOVE NORMAL, WILL EXIST ACROSS THE
NORTHERN HALF OF THE AREA TODAY AS A COOLER AIRMASS REMAINS DRAPED
OVER THE AREA. THAT SAID, UPPER LEVEL FLOW WILL GRADUALLY REVERT
BACK TO A SOUTHWEST FLOW REGIME AND INTRODUCE WARMING TEMPERATURES
OVERHEAD WHICH WILL LEAD TO AN OVERALL WARMING TREND THROUGH AT
LEAST THE MIDDLE OF THE WEEK.
UPSTREAM OF THE FORECAST AREA, ANOTHER WAVE OF MOISTURE IS
EXPECTED TO PUSH ACROSS THE GREAT BASIN REGION, HOWEVER, THE
CENTER OF THE MOISTURE AXIS IS EXPECTED TO REMAIN ACROSS NORTHERN
NEVADA/ CENTRAL IDAHO. AS WE WILL FIND OURSELVES ON THE SOUTHERN
PERIPHERY OF THE MOISTURE, EXPECTING GENERALLY LIGHT PRECIPITATION
ACROSS THE NORTHERN UTAH MOUNTAINS AND ADJACENT VALLEY AREAS FROM
ROUGHLY THE I-80 CORRIDOR NORTHWARD. AS OVERHEAD TEMPERATURES WARM
BACK TO NEAR 0C AT 700MB (~10,000FT), SNOW LEVELS WILL REMAIN VERY
HIGH, BRINGING VIRTUALLY NO CHANCE OF VALLEY SNOWFALL FOR NORTHERN
UTAH/ SOUTHWEST WYOMING. THIS MOISTURE STREAM WILL INTRODUCE
ITSELF INTO THE REGION BY SUNDAY MORNING, ALLOWING FOR HIGH
ELEVATION SNOW (AND EVEN RAIN) AS EARLY AS 9AM ON SUNDAY. THE
STREAM OF MOISTURE IS EXPECTED TO LINGER ACROSS THE NORTHERN AREA
THROUGH TUESDAY MORNING, WITH BRIEF LULL IN PRECIPITATION OVER
THE NORTHERN MOUNTAINS EXPECTED FROM MONDAY EVENING THROUGH EARLY
TUESDAY MORNING BEFORE A TRAILING WAVE KICKS OFF ONE LAST PERIOD
OF LIGHT PRECIPITATION ACROSS THE NORTHERN MOUNTAINS.
AS THE REGION REMAINS ON THE SOUTHERN PERIPHERY OF THE MOISTURE
AND THE ASSOCIATED MID-LEVEL TROUGH, AN INCREASE IN SOUTHWESTERLY
FLOW IS EXPECTED ACROSS UTAH AND SOUTHWEST WYOMING. ANTICIPATE
BREEZY SOUTHWEST WINDS EACH AFTERNOON, WITH THE STRONGER WINDS
(GUSTS 25-35 MPH) CONCENTRATED TO WEST-CENTRAL UTAH.
LONG TERM (AFTER 12Z/5AM WEDNESDAY)
ENSEMBLE GUIDANCE REMAINS
IN GREAT AGREEMENT WITH ENHANCED SOUTHWESTERLIES ALOFT
OVERSPREADING THE REGION AHEAD OF TROUGH WHICH IS EXPECTED TO
MEANDER OFF THE PACIFIC COAST. THIS WILL RESULT IN AN ATMOSPHERIC
RIVER TRANSPORTING AMPLE MOISTURE TO THE REGION RESULTING IN
PERSISTENT AND WIDESPREAD PRECIPITATION ACROSS THE FORECAST AREA
WEDNESDAY THROUGH AT LEAST FRIDAY.
ON WEDNESDAY, WINDS LOOK TO INCREASE IN MAGNITUDE ACROSS THE REGION
AS A DEEPENING SHORTWAVE EMBEDDED WITHIN THE MEAN FLOW TRAVERSES
ACROSS NORTHERN UT THROUGHOUT THE DAY. ADDITIONALLY, THIS SHORTWAVE
IS EXPECTED TO OVERLAP WITH THE ARRIVAL OF MOISTURE WITHIN THE
ATMOSPHERIC RIVER WHICH IS EXPECTED TO KICK OFF OUR PROLONGED PERIOD
OF PRECIPITATION ACROSS THE FORECAST AREA. GIVEN THE WARM NATURE OF
ATMOSPHERIC RIVERS, SNOW LEVELS ARE FORECAST TO REMAIN HIGH KEEPING
SNOW CONTAINED TO HIGHER ELEVATION LOCATIONS. WITH THIS SETUP,
VALLEY LOCATIONS ACROSS THE FORECAST AREA CAN EXPECT RAIN AS THE
MAIN PRECIPITATION TYPE THROUGH THE DURATION OF THE EVENT. THIS
GENERAL PATTERN IS EXPECTED TO PERSIST THROUGH AT LEAST THURSDAY AS
THE UPPER TROUGH REMAINS PARKED OFF THE PACIFIC COAST.
COME FRIDAY AND SATURDAY, ENSEMBLES BEGIN TO DIVERGE SOMEWHAT WHICH
WILL IMPACT STORM COVERAGE, ACCUMULATIONS, AND TIMING. ROUGHLY ~40%
OF GUIDANCE ERODES THE UPPER RIDGE OVER THE CENTRAL U.S., ENABLING
THE TROUGH TO EJECT INLAND ON FRIDAY RESULTING IN AN EARLIER ARRIVAL
TIME OF HIGHER PRECIPITATION RATES. THE OTHER ~60% OF GUIDANCE,
HOWEVER, MAINTAINS THE RIDGE OVER THE CENTRAL U.S. AND CONTINUES TO
STALL THE TROUGH OFF THE WEST COAST RESULTING IN WEAKER
PRECIPITATION RATES, THOUGH MUCH MORE PROLONGED. ON SATURDAY,
ENSEMBLES DIVERGE FURTHER WITH AROUND ~40% OF ALL MEMBERS
MAINTAINING HIGHER GEOPOTENTIAL HEIGHTS TO OUR NORTH, RESULTING IN
THE TROUGH EJECTING INLAND AND PERHAPS DEVELOPING A CUTOFF LOW TO
OUR SOUTH. THE OTHER ~60% KEEP A BROAD OPEN WAVE AS IT PUSHES
INLAND, THOUGH THERE ARE STILL SOME TIMING DIFFERENCES THAT ARE
EVIDENT WITHIN THE ENSEMBLES. WHILE THERE REMAINS CONSIDERABLE
UNCERTAINTY PAST D6, CONFIDENCE REMAINS HIGH IN A RELATIVELY ACTIVE
AND POTENTIALLY SIGNIFICANT PERIOD OF WEATHER FOR THE FORECAST AREA
DEVELOPING AS EARLY AS WEDNESDAY, LASTING INTO THE WEEKEND.
LASTLY, THIS FORECASTER HATES TO BE THE BEARER OF BAD NEWS, BUT THIS
PATTERN GENERALLY SETS US UP FOR A "WET" CHRISTMAS RATHER THAN A
"WHITE" CHRISTMAS. WITH TEMPERATURES WEDNESDAY THROUGH FRIDAY
RUNNING ROUGHLY 15-20F ABOVE AVERAGE ACROSS THE MAJORITY OF OUR
VALLEY LOCATIONS, CONDITIONS WILL BE DREARY AND WET FOR MOST OF THE
POPULATION OF OUR FORECAST AREA. FORTUNATELY FOR US, HOWEVER, A
WHITE CHRISTMAS IS STILL ATTAINABLE, GRANTED YOU FEEL THE URGE TO
DRIVE UP TO HIGHER TERRAIN.
AVIATION...KSLC
NORTHERLY WINDS APPEAR WELL ESTABLISHED NOW
THROUGH THE MAJORITY OF THE PERIOD, THOUGH BRIEF DIRECTIONAL CHANGES
TO SOUTHERLY MAY BE POSSIBLE OVER THE NEXT COUPLE HOURS. ISOLATED
SHOWERS ARE POSSIBLE NEAR THE TERMINAL IN THE AFTERNOON HOURS,
THOUGH CONFIDENCE REMAINS LOW AT THIS TIME REGARDING IMPACTS TO THE
TERMINAL. BORDERLINE MVFR CIGS WITH MOUNTAIN OBSCURATIONS WILL
PERSIST THROUGH 13Z BEFORE CLEARING UP SOMEWHAT AND RAISING.
OTHERWISE, VFR CONDITIONS PERSIST WITH A SOUTHERLY WIND SHIFT AROUND
02Z.
REST OF UTAH AND SOUTHWEST WYOMING... ISOLATED SHOWERS ARE POSSIBLE
THIS MORNING AND EARLY AFTERNOON ACROSS OUR NORTHERN UT SITES,
CLEARING UP BY THE LATE AFTERNOON. ADDITIONALLY, MOUNTAIN
OBSCURATIONS WILL PERSIST THROUGH 13-14Z BEFORE CLEARING UP
SOMEWHAT. REGARDING KEVW, GUSTS GREATER THAN 20KTS WILL PERSIST
THROUGH THE TAF PERIOD WITH OCCASIONAL SHOWERS AND MVFR CIGS THROUGH
THE NEXT COUPLE HOURS.
SLC WATCHES/WARNINGS/ADVISORIES
UT...WINTER WEATHER ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR UTZ112.
WY...NONE.
SHORT TERM...WEBBER
LONG TERM...WORSTER
AVIATION...WORSTER
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY
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