789
FXUS65 KSLC 162251
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
351 PM MST SUN FEB 16 2025
SYNOPSIS
MULTIPLE DISTURBANCES WILL RESULT IN PERIODS OF
PRECIPITATION THROUGH TUESDAY, BRINGING ACCUMULATING MOUNTAIN SNOW.
AFTER A BRIEF BREAK, ANOTHER STORM SYSTEM THEN LOOKS POISED TO
FOLLOW LATE IN THE WORK WEEK.
SHORT TERM (THROUGH 00Z WEDNESDAY/5PM TUESDAY)
THE FIRST OF
SEVERAL SHORTWAVE IMPULSES EMBEDDED WITHIN A BROADER SCALE TROUGH
HAS BEEN RIPPLING THROUGH THE FORECAST REGION TODAY. THIS HAS
RESULTED IN FAIRLY EXPANSIVE COVERAGE OF PRECIPITATION ACROSS THE
NORTHERN HALF OF THE FORECAST REGION, WITH INITIAL SNOW LEVELS
SUPPORTING LOW ELEVATION SNOW. THAT SAID, ASIDE FROM PLACES CLOSER
TO THE ID BORDER LIKE THE FAR NORTHERN WASATCH FRONT AND CACHE
VALLEY, HAVE SEEN MINIMAL SNOW ACCUMULATING OUTSIDE OF SOME GRASSY
SURFACES. MOUNTAINS AND ASSOCIATED PASSES HAVE STARTED TO SEE
ACCUMULATING SNOW THOUGH, SO THOSE PLANNING TRAVEL ACCORDINGLY
SHOULD BE PREPARED TO ENCOUNTER WINTER DRIVING CONDITIONS AS THE
EVENT CONTINUES. SNOW LEVELS WILL GRADUALLY RISE THROUGH THE
EVENING, WITH LOWER ELEVATIONS SEEING INCREASING ODDS OF RAIN MIXING
IN, IF NOT FULLY SWITCHING OVER TO RAIN FOR A PERIOD.
MOVING INTO TONIGHT, GUIDANCE SUGGESTS MAYBE A BRIEF PERIOD OF LESS
COVERAGE GIVEN SLIGHTLY WEAKER MID/UPPER SUPPORT AND SLIGHTLY DRIER
AIR. HIGH RESOLUTION GUIDANCE ALSO HONES IN ON THIS IDEA, WITH MOST
MODELS SHOWING SHOWERS GETTING MORE SHOWERY IN NATURE, ASIDE FROM
THE MOUNTAINS WHICH SHOULD CONTINUE TO DO WELL WITH THE CONTINUED
UPSLOPE FLOW. PRIOR TO SUNRISE, A FAIRLY ILL DEFINED BAROCLINIC ZONE
WILL START SAGGING SOUTHWARD INTO THE REGION, WITH DECREASING H7
TEMPERATURES PULLING SNOW LEVELS BACK DOWN. THROUGH THE DAY, AREAS
CLOSER TO THE ID BORDER WILL BE MORE FAVORED TO SEE A MORE SNOW
DOMINANT PRECIP TYPE, WITH A BIT MORE UNCERTAINTY AT AREAS FURTHER
SOUTH. FORECAST SNOW LEVELS THROUGH THE DAY WILL RANGE FROM ABOUT
4500 FT IN THE OGDEN AREA, TO AROUND 5000 FT ACROSS SALT LAKE AND
UTAH VALLEY. HIGH RES GUIDANCE CONTINUES TO SUGGEST PRECIP MORE
SHOWERY IN NATURE (WITH POTENTIAL FOR A BIT MORE DEFINITION ALONG
THE BAROCLINIC ZONE), AND ANY PERIODS OF HEAVIER RATES WILL HAVE
POTENTIAL TO PULL SNOW LEVELS DOWN TO VALLEY FLOORS. BENCHES WILL
SEE BETTER ODDS FOR MORE SNOW, AND THE NORTHERN MOUNTAINS WILL
CONTINUE TO SEE A GOOD UPSLOPE FLOW COMPONENT TO HELP MAINTAIN
HIGHER SNOW CHANCES.
A FINAL DISTURBANCE NOTED WITHIN THE BROAD TROUGH WILL APPROACH AND
PIVOT THROUGH THE AREA MONDAY EVENING THROUGH EARLY TUESDAY. THIS
WILL HELP TRIGGER ANOTHER PERIOD WITH A BIT MORE COVERAGE OF SNOW
SHOWERS, AND HELP FURTHER REINFORCE STRONGER NORTHWESTERLY DEEP
LAYER FLOW AND ASSOCIATED MOUNTAIN UPSLOPE COMPONENT. THROUGH THE
DAY TUESDAY, DRIER AIR WILL GRADUALLY START TO WORK INTO THE REGION
AND STRONGER MID/UPPER SUPPORT WILL BEGIN TO WANE. AS SUCH, EXPECT
TO SEE DECREASING COVERAGE OF PRECIPITATION, ESPECIALLY AT LOWER
ELEVATIONS, WITH MOUNTAIN SNOW ALSO EVENTUALLY CEASING LATE IN
THE DAY DUE TO THE INCREASE OF DRY AIR.
OVERALL, THIS WINTER STORM CHARACTERIZED BY MULTIPLE WAVES AND
PERIODS OF PRECIPITATION WILL BRING THE BULK OF IMPACTS TO THE
MOUNTAINS AND HIGHER MOUNTAIN ROUTES, PARTICULARLY ACROSS NORTHERN
UTAH. GENERAL NORTHERN MOUNTAIN STORM TOTAL SNOW ACCUMULATION HASN'T
CHANGED SIGNIFICANTLY, WITH AROUND 10-20" INCLUDING WHAT HAS
ALREADY FALLEN HERE TODAY. AS TYPICAL, SOME LOCALLY FAVORED SPOTS
SUCH AS THE UPPER COTTONWOODS, AND ESPECIALLY THE BEAR RIVER RANGE
THIS TIME AROUND, WILL SEE POTENTIAL FOR LOCALLY HIGHER AMOUNTS.
FOR THE FAR NORTHERN WASATCH FRONT AND CACHE VALLEY, EXPECTING
TOTALS CLOSER TO THE 1-2" RANGE. TOTALS FURTHER SOUTH ALONG THE
WASATCH FRONT ARE MORE UNCERTAIN GIVEN THE AFOREMENTIONED
UNCERTAINTY ON SNOW LEVELS, WITH 0.5-1" OR SO POSSIBLE IF RATE
DRIVEN COOLING CAN INDEED PULL THEM DOWN. OVERALL, BIGGEST CONCERN
FOR THIS STORM REMAINS POTENTIAL TO ENCOUNTER WINTER DRIVING
CONDITIONS ALONG SOME OF THOSE HIGHER ROUTES AND PASSES.
LONG TERM (AFTER 00Z WEDNESDAY/ 5PM TUESDAY)
SHORTWAVE RIDGING
WILL NOSE INTO THE REGION IN THE HEELS OF THE DEPARTING TROUGH,
BRINGING A TEMPORARY DRYING AND STABILIZING TREND ACROSS THE REGION.
FOLLOWING QUICKLY BEHIND THE TRANSIENT RIDGE WILL BE YET ANOTHER
SHORTWAVE TROUGH WHICH WILL BRING ANOTHER ROUND OF MOUNTAIN SNOW AND
MIXED VALLEY PRECIPITATION. MODELS HAVE SEEMINGLY COME INTO BETTER
AGREEMENT THIS AFTERNOON, HOWEVER, THERE STILL EXISTS SOME
UNCERTAINTY ON THE OVERALL DEPTH OF THIS TROUGH. THE DEPTH OF THE
FEATURE WILL ULTIMATELY DETERMINE THE INTENSITY OF PRECIPITATION AND
THE AREAL EXTENT ACROSS UTAH AND SOUTHWEST WYOMING.
THE GENERAL TREND OF THIS STORM WILL FEATURE THE ONSET OF
PRECIPITATION WEDNESDAY AFTERNOON WHILE COLDER AIR NEAR THE SURFACE
LINGERS. FOR VALLEY AREAS ACROSS NORTHERN UTAH AND SOUTHWEST
WYOMING, THIS SHOULD HELP TO FAVOR SNOWFALL IN THE VALLEYS BEFORE
WARM ADVECTION FORCES A TRANSITION OVER TO RAIN OR A RAIN/ SNOW MIX.
AREAS THAT MAY HAVE A BETTER CHANCE AT SEEING SNOWFALL THROUGH THE
DURATION OF THE EVENT INCLUDE THE CACHE VALLEY AND AREAS ALONG THE
WASATCH BACK FROM PARK CITY NORTHWARD. THAT SAID, A MAJORITY OF THE
MOISTURE ASSOCIATED WITH THE TROUGH WILL ARRIVE IN THE WARM SECTOR,
BRINGING THE MOST LIKELY SNOW ACCUMULATIONS ON THE WASATCH FRONT AND
CACHE VALLEY DOWN FROM PREVIOUS RUNS FROM TRACE TO 3 INCHES TO TRACE
TO 1.5/2 INCHES. AREAS ON THE WASATCH BACK (WHERE COLD AIR WILL BE
MORE LOCKED IN PLACE NEAR THE SURFACE) WILL SEE POTENTIAL FOR
ANYWHERE FROM 1 TO 4 INCHES WITH LOCALLY UP TO 6 TO 10 INCHES IN THE
PARK CITY AREA.
FOR THE MOUNTAINS, 25TH TO 75TH PERCENTILE ACCUMULATIONS HAVE MADE A
SIGNIFICANT JUMP TO 5 TO 9 INCHES ACROSS THE NORTHERN MOUNTAINS,
WITH LOCALLY UP TO 15 TO 25 INCHES IN THE UPPER COTTONWOODS AND
NORTHERN BEAR RIVER MOUNTAINS. FOR THE CENTRAL UTAH MOUNTAINS THERE
IS STILL QUITE A BIT OF SPREAD (2-10 INCHES) IN THE 25TH TO 75TH
PERCENTILE WHICH IS LARGELY DUE TO THE UNCERTAINTY IN THE DEPTH OF
THE TROUGH. BOTTOM-LINE, THE NORTHERN MOUNTAINS ARE MUCH MORE LIKELY
TO SEE ANY MEANINGFUL IMPACT FROM THIS STORM, ESPECIALLY IN THE
NORTHERN BEAR RIVER MOUNTAINS AND CENTRAL WASATCH.
BY LATE THURSDAY/ EARLY FRIDAY, THE AXIS OF THE MID-LEVEL TROUGH
SHOULD START DEPARTING THE REGION. ENSEMBLE GUIDANCE IS IN GOOD
AGREEMENT ON THIS SETUP, THOUGH SNOW SHOWERS WILL STILL BE POSSIBLE
(20-30% CHANCE) IN THE NORTHERN MOUNTAINS THROUGH THE DAY ON FRIDAY
AS NORTHWESTERLY FLOW FAVORS LINGERING UPSLOPE PRECIPITATION. AFTER
FRIDAY, MODELS ARE IN PRETTY CLEAR AGREEMENT THAT A SIGNIFICANT
RIDGE WILL DEVELOP ACROSS THE INTERIOR WESTERN U.S., HELPING TO
BRING STABILIZING CONDITIONS AND WARMING TEMPERATURES. GIVEN THE
TIME OF YEAR AND STRENGTH OF THE SUN (EQUIVALENT TO MID-LATE
OCTOBER), DON'T THINK WE'LL HAVE TO WORRY TOO MUCH ABOUT POTENTIAL
INVERSION CONDITIONS.
AVIATION...KSLC
LIGHT RAIN OR RAIN MIXED WITH SNOW WILL BECOME
MORE SHOWERY, WITH DRY CONDITIONS PREVAILING MUCH OF THE EVENING.
SCATTERED SHOWERS WILL BE CAPABLE OF MVFR CONDITIONS. MOUNTAIN SNOW
WILL BRING MOUNTAIN OBSCURATION MUCH OF THE TAF PERIOD. LIGHT
SOUTHEAST WINDS WILL PREVAIL, BUT DIRECTION COULD CHANGE WITH
SHOWERS.
REST OF UTAH AND SOUTHWEST WYOMING
RAIN AND SNOW SHOWERS WILL
CONTINUE IN SOUTHWEST WYOMING AND MUCH OF NORTHERN UTAH. VFR
CONDITIONS WILL PREVAIL WHEN CONDITIONS ARE DRY, BUT LIFR OR LIFR
CONDITIONS ARE LIKELY WITH SNOW. MOUNTAIN SNOW WILL BRING MOUNTAIN
OBSCURATION FOR THESE LOCATIONS. DRY CONDITIONS WITH LIGHT WINDS ARE
LIKELY ELSEWHERE WITH MOSTLY CLOUDY CONDITIONS IN VFR RANGE.
SLC WATCHES/WARNINGS/ADVISORIES
UT...WINTER WEATHER ADVISORY UNTIL NOON MST TUESDAY FOR UTZ110>112.
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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