299
FXUS65 KSLC 171019
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
319 AM MST MON FEB 17 2025
SYNOPSIS
MULTIPLE DISTURBANCES WILL RESULT IN PERIODS OF
PRECIPITATION THROUGH TUESDAY, BRINGING ACCUMULATING MOUNTAIN SNOW.
AFTER A BRIEF BREAK, ANOTHER STORM SYSTEM IS EXPECTED TO MOVE
THROUGH THE AREA LATE WEDNESDAY INTO THURSDAY, WITH A DRIER
PATTERN DEVELOPING THEREAFTER.
SHORT TERM (THROUGH 12Z/5AM WEDNESDAY)
SEEING SCATTERED
PRECIPITATION, PRIMARILY SNOW, OVER NORTHERN UTAH AND SOUTHWEST
WYOMING THIS MORNING AS SOUTHERN UTAH REMAINS DRY WITH SOME HIGH
CLOUDS. THE PRECIPITATION IS ASSOCIATED WITH THE LATEST IN A
SERIES OF WEAK WEATHER DISTURBANCES TO MOVE THROUGH THE AREA
THROUGH TUESDAY. THIS WAVE IS EXPECTED TO EXIT THE AREA MID-
MORNING, WITH INSTABILITY FOR SNOW SHOWERS BEING PRIMARILY
PROVIDED BY OROGRAPHICS UNTIL ANOTHER WAVE ARRIVES LATE
AFTERNOON/EARLY EVENING. THAT WAVE WILL BE FOLLOWED BY THE
TRAILING TROUGH EARLY TUESDAY, WITH HIGH PRESSURE MOVING IN
THEREAFTER. OVERALL, HEADLINES COVER THE THREAT OF MOUNTAIN TRAVEL
DIFFICULTIES WITH THIS SNOW WELL.
SOME UNCERTAINTY REMAINS WITH REGARD TO VALLEY PRECIPITATION TYPE
AS THESE VARIOUS WAVES MOVE THROUGH. CURRENTLY, SALT LAKE VALLEY
FLOORS HAVE BEEN SEEING A MIX OF RAIN AND GRAUPEL, WITH VALLEY
SNOW BECOMING MORE DOMINANT MOVING CLOSER TO THE IDAHO BORDER.
WITH COLDER AIR CONTINUING TO MOVE IN DURING THE DAY, WILL SEE
SOME CHANGEOVER TO SNOW, PRIMARILY RATE DEPENDENT.
LONG TERM (AFTER 12Z/5AM WEDNESDAY)
* ACCUMULATING MOUNTAIN SNOW FOR NORTHERN AND CENTRAL UTAH LATE
WEDNESDAY THROUGH THURSDAY, WITH RAIN AND SNOW MIX IN THE NORTHERN
AND CENTRAL UTAH VALLEYS
* HIGH CONFIDENCE IN A STRETCH OF DRY AND WARMING CONDITIONS THIS
COMING WEEKEND INTO NEAR EARLY NEXT WEEK
A TAIL END SHORTWAVE WILL MOVE ACROSS UTAH LATE WEDNESDAY THROUGH
LATE THURSDAY BRINING ANOTHER ROUND OF PRECIPITATION ACROSS MUCH OF
NORTHERN AND CENTRAL UTAH. EXAMINING THE CLUSTERS OF ENSEMBLE
SOLUTIONS, THERE IS HIGH CONFIDENCE IN THIS SHORTWAVE TROUGH
PASSAGE, BUT WITH ANY DIFFERENCES IN EVOLUTION LARGELY RELATED TO
THE SPEED AT WHICH THE TROUGH AXIS CROSSES THE AREA AND THE DEPTH OF
THE TROUGH WHEN IT CROSSES THE REGION. THE SMALL VARIANCES IN TIMING
YIELD LITTLE APPRECIABLE CHANGE IN THE OVERALL PRECIPITATION TOTALS
ACROSS NORTHERN UTAH, WITH GENERALLY AROUND INCH OF WATER IN THE
COTTONWOODS, AND AROUND 0.75 INCHES IN THE BEAR RIVER RANGE.
HOWEVER, ABOUT 20% OF SOLUTIONS TAKE THE TROUGH A BIT FARTHER SOUTH
AS IT STARTS TO CUT OFF GOING TOWARD THE FOUR CORNERS REGION, AND
THIS SOLUTION WOULD YIELD THE DRIER OUTCOME, WITH TOTALS DROPPING TO
AROUND 0.75 INCHES IN THE COTTONWOODS AND LESS THAN 0.5 INCHES IN
THE BEAR RIVER RANGE. TRANSLATING THIS INTO MEANINGFUL SNOWFALL
RANGES FOR THE MOUNTAINS, THE 25TH TO 75TH PERCENTILE ACCUMULATIONS
ARE AROUND 3 TO 7 INCHES ACROSS THE NORTHERN MOUNTAINS, WITH LOCALLY
UP TO 8 TO 20 INCHES IN THE UPPER COTTONWOODS AND 5-13 INCHES IN THE
NORTHERN BEAR RIVER MOUNTAINS. FOR THE CENTRAL UTAH MOUNTAINS, THE
SPREAD HAS NARROWED SOME TO AROUND 2-6 INCHES, WHICH IS LARGELY DUE
TO THE UNCERTAINTY IN THE DEPTH OF THE TROUGH. OVERALL, THE NORTHERN
MOUNTAINS ARE MORE LIKELY TO SEE ANY MEANINGFUL IMPACT FROM THIS
STORM, ESPECIALLY IN THE NORTHERN BEAR RIVER MOUNTAINS AND CENTRAL
WASATCH.
OTHERWISE, FOR VALLEY LOCATIONS EXPECT TO SEE SOME LIGHT SNOWFALL
BEFORE WARM ADVECTION FORCES A TRANSITION OVER TO RAIN OR A RAIN/
SNOW MIX. SNOW WILL BE MORE PERSISTENT THROUGH THE DURATION OF THE
EVENT ALONG THE WASATCH BACK FROM PARK CITY NORTHWARD TO THE OGDEN
VALLEY. HOWEVER, EVEN THERE, TEMPERATURES WILL WARM TO AROUND
FREEZING ON THURSDAY, COMBINED WITH DAYTIME SOLAR WILL HELP REDUCE
ACCUMULATION EFFICIENCY. THESE MORE MARGINAL TEMPERATURES IN THE
WASATCH BACK HAVE CONTINUED TO TREND DOWN TOTALS IN THE FORECAST
SLIGHTLY, WITH GENERALLY AROUND 2-6 INCHES, ESPECIALLY IN THE PARK
CITY AREA. OTHERWISE, THE WASATCH FRONT AND CACHE VALLEY MAY
STRUGGLE TOO MUCH WITH TEMPERATURES TO SEE MORE THAN T-2 INCHES
(CLOSER TO 2 ONLY REALLY POSSIBLE IN THE CACHE).
THIS COMING WEEKEND INTO EARLY NEXT WEEK WILL FEATURE A BUILDING
RIDGE ACROSS THE WESTERN US THAT WILL RESULT IN STRENGTHENING
SUBSIDENCE OVER THE AREA ALONG WITH A WARMING TREND THAT WILL
PERSIST INTO EARLY NEXT WEEK. THIS WILL USHER IN A DRY STRETCH OF
WEATHER FOR ABOUT 5-6 DAYS, ALONG WITH TEMPERATURES TRENDING ABOVE
NORMAL BY NEXT WEEK. AS WE ARE GETTING INTO LATE FEBRUARY, SOME
LIMITED INVERSION IMPACTS MAY BE NOTED, BUT LARGELY THE INCREASING
SUN ANGLE THIS TIME OF YEAR SHOULD HELP PREVENT THE INVERSIONS FROM
BECOMING TOO WELL ESTABLISHED.
AVIATION...KSLC
OCCASIONAL LIGHT RAIN SHOWERS, POSSIBLY MIXED
WITH SNOW OR GRAUPEL, WILL DIMINISH THROUGH MID-MORNING, BUT BRIEF
MVFR CONDITIONS ARE POSSIBLE IN THOSE SHOWERS UNTIL THEY SUBSIDE.
AFTER A BREAK THROUGH MIDDAY, MORE SCATTERED SHOWERS ARE EXPECTED
TO DEVELOP LATER THIS AFTERNOON THROUGH THIS EVENING, WITH
ADDITIONAL MVFR RESTRICTIONS POSSIBLE. WINDS ARE EXPECTED TO
TRANSITION FROM SOUTHERLY THIS MORNING TO NORTHERLY THIS
AFTERNOON. AS SHOWERS DEVELOP LATER THIS AFTERNOON AND EVENING,
WINDS MAY BE A BIT ERRATIC, AS THEY COULD TURN BACK TO THE SOUTH
BRIEFLY THIS EVENING BEFORE A WEAK FRONTAL PASSAGE WITH
ACCOMPANYING SHOWERS REINFORCE A NORTH WIND THIS EVENING INTO THE
OVERNIGHT HOURS TONIGHT.
REST OF UTAH AND SOUTHWEST WYOMING
RAIN AND SNOW SHOWERS WILL
CONTINUE IN SOUTHWEST WYOMING AND MUCH OF NORTHERN UTAH THIS
MORNING, WITH A BIT OF A BREAK THROUGH EARLY AFTERNOON, THEN A
REDEVELOPMENT OF SHOWERS AGAIN LATER THIS AFTERNOON THROUGH THIS
EVENING. SHOWERS WILL PRODUCE MOUNTAIN OBSCURATIONS, AND LIFR/IFR
CONDITIONS FOR HIGHER ELEVATION LOCATIONS WITH PREDOMINATE SNOW, AND
LARGELY MVFR CONDITIONS FOR LOWER ELEVATION LOCATIONS WHERE
PRECIPITATION WILL REMAIN LARGELY RAIN. SOUTHERN UTAH WILL REMAIN
DRY WITH VFR CONDITIONS THROUGH THE PERIOD.
SLC WATCHES/WARNINGS/ADVISORIES
UT...WINTER WEATHER ADVISORY UNTIL NOON MST TUESDAY FOR UTZ110>112.
WY...NONE.
SHORT TERM...TRAPHAGAN
LONG TERM/AVIATION...CHURCH
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY
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