132
FXUS65 KSLC 152240
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
340 PM MST SAT FEB 15 2025
SYNOPSIS
AFTER A RELATIVE LULL, A SERIES OF SHORTWAVE IMPULSES
WILL RESULT IN ANOTHER PERIOD OF ACTIVE WEATHER SUNDAY AFTERNOON
INTO TUESDAY, BRINGING ADDITIONAL ACCUMULATING SNOW TO THE NORTHERN
MOUNTAINS.
SHORT TERM (THROUGH 00Z WEDNESDAY/5PM TUESDAY)
AFTER AN ACTIVE
PERIOD COURTESY OF A MOIST ATMOSPHERIC RIVER, THE WEATHER IS
STARTING TO SETTLE DOWN. A FEW LIGHT SNOW SHOWERS REMAIN ONGOING
ACROSS THE HIGH TERRAIN GIVEN CONTINUED UPSLOPE FLOW, BUT MOISTURE
IS BECOMING INCREASINGLY LIMITED. AS SUCH, ANTICIPATE REMAINING
SHOWERS TO GENERALLY CONTINUE TO DECREASE IN COVERAGE AND
INTENSITY HERE MOVING INTO THE EVENING. OUTSIDE OF THE TERRAIN,
MOST LOCATIONS THIS AFTERNOON ARE SEEING MOSTLY CLEAR SKIES AND
TEMPERATURES RUNNING AROUND 5 TO 10 DEGREES BELOW CLIMATOLOGICAL
NORMAL.
OVERNIGHT INTO SUNDAY A MID LEVEL RIDGE WILL SHIFT OVERHEAD,
GRADUALLY FLATTENING AS IT DOES SO. ENOUGH MOISTURE WILL STILL BE
CARRIED WITH THE RIDGE TO ACTUALLY SEE AN INCREASE IN CLOUD COVER
OVERNIGHT, WHICH IN COMBINATION WITH WARMING H7 TEMPERATURES WILL
RESULT IN LOWS NEAR TO A LITTLE ABOVE NORMAL IN MOST SPOTS.
LATER SUNDAY ON THROUGH TUESDAY LOOKS TO BE ANOTHER ACTIVE PERIOD
AS A SERIES OF MID LEVEL SHORTWAVE IMPULSES PIVOT THROUGH A
BROADER LONGWAVE TROUGH. SNOW LEVELS SUNDAY LOOK TO START LOW
ENOUGH TO ALLOW FOR A PERIOD OF VALLEY SNOW, BUT WILL INCREASE TO
AROUND 5500- 6000 FT MSL SUNDAY EVENING INTO THE OVERNIGHT. SNOW
LEVELS THEN DROP NEAR TO BELOW VALLEY FLOORS AGAIN MONDAY AS A
BAROCLINIC ZONE SLOWLY SAGS SOUTHWARD, WITH FURTHER
COOLING/LOWERING THEREAFTER INTO MONDAY NIGHT. GIVEN HOW CLOSE
SNOW LEVELS WILL BE TO VALLEY FLOORS, CERTAINLY WOULDN'T RULE OUT
SOME LOW ELEVATION ACCUMULATION POTENTIAL, ESPECIALLY ON BENCHES,
THOUGH RATES ARE GENERALLY EXPECTED TO BE PRETTY LOW THROUGHOUT
THE EVENT. THE HIGHEST RATE PERIOD LOOKS TO BE THROUGH THE DAY
MONDAY AS THE BAROCLINIC ZONE SAGS THROUGH IN CONJUNCTION WITH A
PERIOD OF STRONGER PVA AND JET SUPPORT. ANY PERIODS WHERE RATES DO
PICK UP A BIT WILL HAVE A CHANCE TO HELP DRIVE COOLER AIR DOWN
AND LOWER SNOW LEVELS, SO THINKING THAT'LL BE THE MOST FAVORABLE
PERIOD FOR LOWER ELEVATION IMPACTS. CURRENTLY, ONLY CARRYING SOME
LIGHT (T-1.0" OR SO) ACCUMULATIONS FOR PORTIONS OF THE NORTHERN
WASATCH FRONT, CACHE VALLEY, BEAR RIVER VALLEY, AND UINTA COUNTY
(HIGHER AMOUNTS ON THE NORTH SLOPES OF THE UINTAS). THAT SAID, NBM
75TH PERCENTILE CARRIES ACCUMULATING SNOW AS FAR SOUTH AS UTAH
VALLEY. DEFINITELY A FORECAST TO WATCH FOR TRENDS TOWARDS
WARMER/COOLER, GIVEN THE PRECARIOUS NATURE OF EXACT SNOW LEVELS.
FOR MOUNTAINS, THIS ONCE AGAIN APPEARS TO BE A SERIES OF IMPULSES
WITH A TRAJECTORY THAT WILL MORE FAVOR TERRAIN ACROSS THE
NORTHERN HALF OF THE FORECAST REGION. SNOW ACCUMULATIONS CURRENTLY
SIT IN A GENERAL 6-12" OR SO FOR MUCH OF THE NORTHERN MOUNTAINS,
WITH HIGHER AMOUNTS NOTED IN LOCALLY FAVORED SPOTS SUCH AS THE
UPPER COTTONWOODS AND BEAR RIVER RANGE, AND OTHERS THAT SEE
FAVORABLE OROGRAPHIC ENHANCEMENT OUT OF PROLONGED WEST TO
NORTHWESTERLY FLOW REGIMES. WITH LINGERING MOUNTAIN SNOW CURRENTLY
ONGOING (ALBEIT LIGHT), OPTED TO MAINTAIN THE WINTER STORM
WARNINGS, WITH PLANS TO LIKELY ISSUE ADVISORIES FOR THE NEXT STORM
AFTER THEY ARE EXPIRED.
LONG TERM (AFTER 00Z WEDNESDAY/5PM TUESDAY)
AS WE FIND THE
FORECAST AREA ON THE WESTERN PERIPHERY OF A DEPARTING TROUGH, WE'LL
SEE CONTINUED SHOWERS OF SNOW ACROSS THE MOUNTAINOUS TERRAIN OF
NORTHERN UTAH AND ADJACENT VALLEY AREAS BEFORE CONDITIONS STABILIZE
UNDER THE INFLUENCE OF A SHORTWAVE RIDGE. ADDITIONAL SNOW
ACCUMULATIONS THROUGH TUESDAY EVENING ARE EXPECTED TO BE OF
GENERALLY LOW IMPACT, AND MAY ONLY ACCUMULATE UPWARDS OF 1 INCH NEAR
THE UTAH/IDAHO BORDER.
SHORTLY THEREAFTER, YET ANOTHER SHORTWAVE TROUGH FOLLOWS DIRECTLY IN
THE HEELS OF THE TRANSIENT RIDGE AND OPENS THE DOOR TO ANOTHER ROUND
OF MOUNTAIN SNOWFALL AND MIXED VALLEY PRECIPITATION WEDNESDAY
AFTERNOON THROUGH THURSDAY EVENING. WHILE THE EXISTENCE OF THIS
TROUGH IS WELL AGREED UPON BY MODELS, THERE IS A SIGNIFICANT AMOUNT
OF UNCERTAINTY REVOLVING AROUND THE OVERALL STRENGTH OF THE FEATURE.
NEARLY 55% OF MEMBERS SUPPORT A LOWER AMPLITUDE TROUGH, WITH ABOUT
40% OF THE TOTAL ENSEMBLE MEMBERS ONLY SUPPORTING A GRAZING
SHORTWAVE. THE REMAINING 45% ARE IN SUPPORT OF A DEEPER TROUGH, WITH
ONLY 14% OF THE TOTAL MEMBERS SUPPORTING A TROUGH DEEP ENOUGH TO
ALLOW PRECIPITATION TO SPREAD INTO THE FAR SOUTHERN REACHES OF UTAH.
THE BIG PICTURE TAKEAWAY HERE IS THAT A LOWER AMPLITUDE TROUGH WOULD
LIKELY BRING LOWER PRECIPITATION AMOUNTS, LESS COLD AIR, AND A LOWER
IMPACT THAN A DEEPER TROUGH WOULD.
CURRENT MOST-LIKELY SNOW AMOUNTS (25TH-75TH PERCENTILE) FOR THE
RANGE FROM A TRACE TO 1.5 INCHES ON THE WASATCH FRONT AND CACHE
VALLEY, WITH 1 TO 4 INCHES ON THE WASATCH BACK (LOCALLY UP TO 6 IN
THE PARK CITY AREA). HIGH END SNOW ACCUMULATION POTENTIAL (90TH
PERCENTILE) FOR THE VALLEY AREAS OF NORTHERN UTAH RANGE FROM 1-3
INCHES FOR THE LOWER ELEVATIONS (WASATCH FRONT, CACHE) AND UINTA
COUNTY, WITH UPWARDS OF 4-8 FOR THE WASATCH BACK. FOR THE MOUNTAINS,
ESPECIALLY IN NORTHERN UTAH, ANYWHERE FROM 2-8 INCHES FALLS WITHIN
THE MOST-LIKELY RANGE, WITH UPWARDS OF 6 INCH ACCUMULATIONS POSSIBLE
(25% CHANCE) IN THE CENTRAL UTAH MOUNTAINS. HIGH END ACCUMULATIONS
JUMP UP TO 10+ INCHES FOR THE NORTHERN MOUNTAINS, WITH SNOW
ACCUMULATION POTENTIAL ALSO REACHING INTO THE BRIAN HEAD AREA.
AGAIN, THERE IS A SIZABLE AMOUNT OF UNCERTAINTY WITH THIS FORECAST,
BUT THE ANTICIPATED POTENTIAL IMPACTS SEEM TO BE LIMITED TO THE
NORTHERN UTAH MOUNTAINS AND HIGHER ELEVATION VALLEY AREAS. WILL NEED
MODELS TO COME INTO BETTER ALIGNMENT, BUT MOVING PAST THIS TRAILING
TROUGH THERE IS INCREASING CONFIDENCE THAT A BROADER RIDGE WILL
BUILD INTO THE WESTERN U.S., BRINGING A SIZABLE BREAK IN
PRECIPITATION AND ACTIVE WEATHER.
AVIATION...KSLC
LIGHT NORTHWEST WINDS WILL TRANSITION TO THE
SOUTHEAST AROUND 03Z. MOSTLY CLEAR CONDITIONS WILL PREVAIL INTO THE
EVENING, BUT CLOUDS WILL BE LOW ENOUGH FOR MOUNTAIN OBSCURATION.
CLOUDS WILL INCREASE AFTER 03Z AHEAD OF A STORM SYSTEM. SNOW OR RAIN
MIXED WITH SNOW WILL BUILD IN AROUND 19-20Z, WITH PRECIPITATION
TRANSITIONING TO RAIN BY 00Z. CONDITIONS WILL LIKELY BE IN MVFR
RANGE WITH SNOW OR RAIN MIXED WITH SNOW, WITH VFR CONDITIONS WITH
RAIN.
REST OF UTAH AND SOUTHWEST WYOMING
LIGHT WINDS WITH MOSTLY CLEAR
CONDITIONS WILL PREVAIL INTO THE EVENING, BUT CLOUDS WILL INCREASE
AFTER 03Z FOR SOUTHWEST WYOMING AND NORTHERN UTAH AHEAD OF A STORM
SYSTEM. SNOW WILL BUILD INTO FAR NORTHERN UTAH AROUND 15Z AND INTO
SOUTHWEST WYOMING AND OTHER PORTIONS OF NORTHERN UTAH AROUND 19-20Z.
SNOW WILL TRANSITION TO RAIN FOR UTAH VALLEYS LATER INTO THE
AFTERNOON. MVFR OR IFR CONDITIONS WILL PREVAIL WITH SNOW, WITH A
TRANSITION TO VFR CONDITIONS ONCE SNOW TRANSITIONS TO RAIN.
PRECIPITATION WILL PRIMARILY BE IN SOUTHWEST WYOMING AND NORTHERN
UTAH, WITH DRY CONDITIONS ELSEWHERE.
SLC WATCHES/WARNINGS/ADVISORIES
UT...WINTER STORM WARNING UNTIL 5 PM MST THIS AFTERNOON FOR
UTZ110>113-117.
WY...NONE.
SHORT TERM...WARTHEN
LONG TERM...WEBBER
AVIATION...WILSON
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY
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