305
FXUS65 KSLC 212116
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
316 PM MDT TUE OCT 21 2025
SYNOPSIS
HIGH PRESSURE OVER UTAH AND SOUTHWEST WYOMING WILL
SHIFT EAST OF THE AREA DURING THE DAY WEDNESDAY. A PACIFIC LOW
WILL TRACK ACROSS THE DESERT SOUTHWEST LATE WEDNESDAY INTO FRIDAY,
BRINGING SCATTERED SHOWERS AND THUNDERSTORMS TO THE SOUTHERN HALF
OF THE AREA. HIGH PRESSURE WILL RETURN LATER FRIDAY INTO SATURDAY
BEFORE AN EARLY SEASON WINTER STORM IMPACTS PRIMARILY NORTHERN
PORTIONS OF THE AREA EARLY NEXT WEEK.
SHORT TERM (THROUGH 12Z/6AM FRIDAY)
SEEING CLEAR SKIES ACROSS
UTAH AND SOUTHWEST WYOMING THIS AFTERNOON UNDER THE INFLUENCE OF
HIGH PRESSURE. AFTER AN UNSEASONABLY COLD START TO THE MORNING,
WITH MANY VALLEYS SEEING LOWS NEAR TO BELOW FREEZING, TEMPERATURES
HAVE WARMED TO WITHIN 5F OF SEASONAL NORMALS.
THE RIDGE WILL REMAIN IN PLACE TONIGHT, SHIFTING EAST DURING THE
DAY TOMORROW AS A BROAD LOW PRESSURE SYSTEM MOVES ONSHORE ALONG
THE CALIFORNIA COAST. THIS SYSTEM WILL TRACK EASTWARD ACROSS THE
DESERT SOUTHWEST LATE WEDNESDAY INTO FRIDAY, A STORM TRACK WE SAW
SEVERAL TIMES DURING THE COURSE OF THE SUMMER.
THERE IS A HIGH CHANCE THAT THE NORTHERN HALF OF THE FORECAST
AREA WILL STAY DRY DURING THIS TIME, WITH SCATTERED SHOWERS WITH A
FEW THUNDERSTORMS DEVELOPING OVER SOUTHERN UTAH. CHANCES WILL BE
HIGHEST FOR SOUTHWEST UTAH WEDNESDAY NIGHT INTO EARLY THURSDAY,
WITH THE BEST COVERAGE SHIFTING EAST DURING THE DAY THURSDAY WITH
THE TRACK OF THE LOW AND ITS ASSOCIATED MOISTURE AND INSTABILITY.
GIVEN THE RELATIVELY WARM NATURE OF THIS SYSTEM, IT SHOULD NOT
HAVE A SIGNIFICANT IMPACT ON TEMPERATURES, THOUGH BY THURSDAY
MAKES ARE EXPECTED TO RETURN TO VALUES JUST BELOW SEASONAL
NORMALS.
LONG TERM (AFTER 12Z/6AM FRIDAY)
A TRANSIENT RIDGE OF HIGH
PRESSURE WILL TRACK ACROSS UTAH FRIDAY. THERE WILL BE DRY
CONDITIONS, WITH TEMPERATURES AROUND 5F WARMER THAN NORMAL.
AS AN ATMOSPHERIC RIVER TRACKS INTO THE PACNW AND THE AFOREMENTIONED
RIDGE SLIDES EAST, CLOUDS AND ENHANCED WINDS WILL BUILD INTO
SOUTHWEST WYOMING AND UTAH. SOUTHWEST FLOW WILL BE STRONGEST FOR
SOUTHWEST WYOMING AND SOUTHWEST UTAH WITH GUSTS AROUND 30 MPH. CLEAR
CONDITIONS FRIDAY WILL TRANSITION TO MOSTLY CLOUDY FROM NORTHWEST TO
SOUTHEAST INTO SATURDAY. DESPITE THAT, THE SOUTHWEST WINDS AND WARM
AIR ADVECTION WILL ALLOW TEMPERATURES TO BE NEAR OR SLIGHTLY WARMER
THAN FRIDAY. THE LONGWAVE TROUGH AND MOISTURE WITH THE ATMOSPHERIC
RIVER WILL DIG FROM THE NORTHWEST THROUGH SATURDAY, BUT DRY
CONDITIONS WILL CONTINUE FOR ALL BUT FAR NORTHERN UTAH.
ENSEMBLES ARE IN GOOD AGREEMENT ON THE TRACK OF THE LONGWAVE TROUGH,
WITH SOME UNCERTAINTY ON TIMING OF THE ASSOCIATED COLD FRONT. THERE
IS GOOD AGREEMENT THAT THE STORM SYSTEM WILL COME IN MULTIPLE WAVES,
WITH THE INITIAL COLD FRONT SUNDAY, THEN SHORTWAVE ENERGY AND MORE
COLD AIR ADVECTION MONDAY. BETWEEN THOSE, PRECIPITATION WOULD LIKELY
CONTINUE, ESPECIALLY FOR NORTHERN MOUNTAIN LOCATIONS WITH UPSLOPE
OROGRAPHIC ENHANCEMENT FROM THE WEST TO NORTHWEST. THERE IS GOOD
CONFIDENCE THAT THE EVENT WILL PRIMARILY IMPACT SOUTHWEST WYOMING
AND NORTHERN UTAH, WITH MUCH LOWER PRECIPITATION TOTALS SOUTH OF THE
WASATCH MOUNTAINS. SNOW LEVELS AS THE EVENT STARTS WILL BE AROUND
9500 FEET, BUT LOWER THROUGH MONDAY TO AROUND 5000 FEET AS
PRECIPITATION TAPERS OFF. THE MOST SNOW ACCUMULATION WILL BE IN THE
BEAR RIVER RANGE, WASATCH MOUNTAINS, AND UINTA MOUNTAINS. AS THE
STORM SYSTEM TRACKS EAST EARLY IN THE WEEK, CONDITIONS WILL BE GOOD
FOR LAKE-EFFECT OR LAKE-ENHANCED PRECIPITATION, WHICH WOULD BRING
ADDITIONAL MOUNTAIN SNOW AND BE THE MOST LIKELY TIME RANGE FOR
VALLEY SNOW.
CONFIDENCE IN SNOW ACCUMULATIONS IS RELATIVELY LOW, AND ENSEMBLE
MEMBERS HAVE A RANGE OF TOTALS, BUT CONFIDENCE IS HIGH IN MUCH
COOLER CONDITIONS ALONG WITH MOUNTAIN SNOW AFFECTING ACTIVITIES
THROUGHOUT THE NORTHERN MOUNTAINS SUNDAY AND MONDAY.
AVIATION...KSLC
VFR CONDITIONS WILL PERSIST FOR THE KSLC TERMINAL
THROUGH THE PERIOD. DRY CONDITIONS AND CLEAR SKIES WILL CONTINUE
WITH LIGHT NORTHERLY FLOW TRANSITIONING TO LIGHT SOUTHERLY FLOW
THIS EVENING A BIT LATER THAT NORMAL, EXPECTED BETWEEN 04-05Z.
REST OF UTAH AND SOUTHWEST WYOMING
VFR CONDITIONS WILL PERSIST
FOR THE ENTIRE AIRSPACE THROUGH THE PERIOD. FOR SOUTHERN UTAH
AIRPORTS, DRY CONDITIONS AND MOSTLY CLEAR SKIES WILL GIVE WAY TO
DEVELOPING CLOUDS OVERNIGHT AND VICINITY SHOWERS AFTER 10Z.
SLC WATCHES/WARNINGS/ADVISORIES
UT...NONE.
WY...NONE.
SHORT TERM...TRAPHAGAN
LONG TERM...WILSON
AVIATION...VERZELLA
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY
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