207
FXUS65 KSLC 122215
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
315 PM MST MON JAN 12 2026
KEY MESSAGES
- HIGH PRESSURE WILL KEEP INVERSIONS IN PLACE IN PRONE VALLEYS
THROUGH AT LEAST LATE IN THE WEEK. THIS WILL RESULT IN
DECREASING AIR QUALITY AND VISIBILITY WITH AN INCREASE IN
NOCTURNAL FOG FOR THE VALLEYS OF NORTHERN UTAH.
DISCUSSION
STRONG HIGH PRESSURE REMAINS CENTERED OVER THE WEST
COAST THIS AFTERNOON, RESULTING IN CLEAR AND DRY CONDITIONS ACROSS
UTAH AND SOUTHWEST WYOMING. WHILE HIGHER ELEVATION TEMPERATURES
ARE QUITE MILD, THE VALLEYS OF NORTHERN UTAH REMAIN MUCH COLDER,
NEAR SEASONAL NORMALS, DUE TO BUILDING INVERSIONS. THIS IS ALSO
RESULTING IN DECREASING AIR QUALITY AND VISIBILITY. THERE IS HIGH
CONFIDENCE THAT THIS RIDGE WILL CONTINUE TO BUILD THROUGH THE
MIDDLE OF THE WEEK, ALLOWING PARTICULATES TO CONTINUE TO
ACCUMULATE IN THE VALLEYS PRONE TO INVERSION CONDITIONS. NOCTURNAL
FOG WHICH, SO FAR, HAS BEEN CONFINED TO THE BEAR LAKE AREA, IS
LIKELY TO EXPAND IN COVERAGE INTO THE CACHE VALLEY AND PORTIONS OF
THE WASATCH FRONT.
GUIDANCE CONTINUES TO INDICATE SOME COOLING ALOFT FRIDAY INTO
SATURDAY AS A BROAD TROUGH DIVES SOUTH IN THE CENTRAL UNITED
STATES. ENSEMBLE GUIDANCE, WHICH PREVIOUSLY INDICATED THE EFFECTS
OF THIS SYSTEM WOULD MORE LIKELY THAN NOT BE ABLE TO MIX OUT THE
INVERSIONS, NOW ONLY SHOW A 30 PERCENT CHANCE OF THE SYSTEM MOVING
WESTWARD ENOUGH FOR THIS TO HAPPEN. THE MORE LIKELY SCENARIO IS
FOR THE SYSTEM TO BRING SOME MODEST WEAKENING OF THE INVERSIONS,
THOUGH THEY WILL REMAIN IN PLACE. THEREAFTER, THERE IS RELATIVELY
HIGH CONFIDENCE THAT HIGH PRESSURE WILL REBUILD, WITH THE NEXT
CHANCE OF LOSING THE VALLEY INVERSIONS NOT EXPECTED UNTIL LATE
NEXT WEEK.
AVIATION...KSLC
VISIBILITY IN THE LOW END VFR RANGE AT THE
TERMINAL IS EXPECTED TO DETERIORATE INTO THE MVFR RANGE AFTER
SUNSET, MOST LIKELY IN THE 03Z TO 05Z TIMEFRAME, DUE TO
ACCUMULATION OF PARTICULATES FROM VALLEY INVERSIONS. THERE IS A
30 PERCENT CHANCE OF FOG DEVELOPING OVERNIGHT, RESULTING IN
PERIODS OF VISIBILITY IN THE IFR/LIFR RANGE. NORTHERLY WINDS ARE
EXPECTED TO RETURN TO THE SOUTHEAST BETWEEN 03Z AND 05Z.
REST OF UTAH AND SOUTHWEST WYOMING
THE MAJORITY OF THE AIRSPACE
WILL SEE VFR CONDITIONS THROUGH THE EVENING WITH MOSTLY CLEAR
SKIES. THE EXCEPTION TO THIS WILL BE IN VALLEYS PRONE TO INVERSION
CONDITIONS, WHERE ACCUMULATION OF PARTICULATES WILL RESULT IN LOW
END VFR TO HIGH END MVFR VISIBILITIES THROUGH THE OVERNIGHT HOURS.
DEVELOPMENT OF FOG AND STRATUS WILL RESULT IN IFR CONDITIONS IN
THE BEAR LAKE AREA OVERNIGHT, WITH A 30 PERCENT CHANCE OF
OVERNIGHT FOG REDUCING VISIBILITIES INTO THE IFR/LIFR RANGE IN
OTHER AREAS SEEING INVERSION CONDITIONS, INCLUDING THE CACHE
VALLEY AND WASATCH FRONT.
SLC WATCHES/WARNINGS/ADVISORIES
UT...NONE.
WY...NONE.
TRAPHAGAN
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY
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