994
FXUS65 KSLC 121048
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
348 AM MST MON JAN 12 2026
KEY MESSAGES
- A PROLONGED INVERSION EVENT WILL LAST THROUGH AT LEAST LATE IN
THE WEEK. THIS WILL ALLOW FOR AN INCREASE IN HAZE, NOCTURNAL
FOG, AND A DEGRADATION IN AIR QUALITY FOR NORTHERN VALLEYS.
DISCUSSION
HIGH PRESSURE WILL BE POSITIONED OVER THE WESTERN
U.S. THROUGH THE WEEK, WITH SOUTHWEST WYOMING AND UTAH ON THE
EASTERN PERIPHERY OF THE RIDGE. THAT WILL KEEP CONDITIONS DRY WITH
FAIRLY LIGHT WINDS. VALLEY INVERSIONS WILL STRENGTHEN,
PARTICULARLY FOR NORTHERN VALLEYS. THIS WILL RESULT IN MORE HAZE
AND FOG.
REGARDING HAZE, IT WILL BE A CONTINUOUS INCREASE UNTIL THE NEXT
SYSTEM COMES CLOSE ENOUGH OR PUSHES THROUGH AND BRINGS SUFFICIENT
COOLING OR WIND TO MIX OUT VALLEY INVERSION CONDITIONS. HAZE WILL
BE MOST DENSE FOR THE URBAN CORRIDOR OF NORTHERN UTAH, BUT
VALLEYS THROUGHOUT UTAH WILL LIKELY HAVE SOME REDUCTION IN
VISIBILITY FROM HAZE.
FOG WILL BE MORE LIKELY FOR VALLEYS WITH INVERSION CONDITIONS.
MINIMAL FOG WILL DEVELOP THROUGH MONDAY, BUT HREF GUIDANCE
INDICATES HIGHER PROBABILITIES STARTING TUESDAY. LIKELIHOOD
RANGES FROM 40-50% FOR THE URBAN CORRIDOR FROM SALT LAKE CITY TO
BRIGHAM CITY AND LOCATIONS WEST TO THE GREAT SALT LAKE AND FOR THE
CACHE VALLEY. FOG WILL BE MORE LIKELY THROUGH THE WEEK FOR THOSE
PLACES.
TEMPERATURES WILL BE NEAR TO SLIGHTLY BELOW NORMAL FOR VALLEYS
AFFECTED BY INVERSIONS. THE RIDGE WILL BRING WARMER CONDITIONS
ELSEWHERE, WITH TEMPERATURES OF 5-15F WARMER THAN NORMAL.
THERE WILL BE AN INCREASING TREND FOR FOG AND HAZE UNTIL VALLEY
INVERSIONS ARE ELIMINATED. MODELS AND ENSEMBLES ARE IN GOOD
AGREEMENT THAT IT WILL TAKE SEVERAL DAYS BEFORE A LONGWAVE TROUGH
THAT WILL TRACK INTO THE PLAINS COULD BE CLOSE ENOUGH TO WEAKEN
OR ELIMINATE VALLEY INVERSIONS. IT WILL DEPEND ON WESTWARD EXTENT,
WITH A MORE WESTWARD TRACK TO BRING MORE COOLING AND BETTER FLOW
TO ASSIST WITH ERODING OR ELIMINATING VALLEY INVERSIONS. IF
INVERSIONS DO NOT MIX OUT FRIDAY, THEN THEY WOULD LAST INTO NEXT
WEEK.
AVIATION...KSLC
VALLEY HAZE WILL BRING SLANTWISE VISIBILITY
REDUCTIONS AT TIMES, WITH INTERMITTENT 6SM OR LOWER VISIBILITY
LIKELY FROM AROUND 12Z TO 18Z AND A LOWER CHANCE (20-40%) FOR THE
REMAINDER OF THE DAYLIGHT HOURS. PATCHY FOG MAY ALSO DEVELOP IN THE
MORNING AND CONTRIBUTE TO VISIBILITY RESTRICTION (20-30% CHANCE). BY
SUNSET, CHANCES OF VISIBILITY UNDER 6SM INCREASES TO 60-80% FROM A
COMBINATION OF HAZE AND FOG. LIGHT SOUTHEAST WINDS OF 5KTS OR LESS
WILL TRANSITION TO NORTHWESTERLY AFTER 19Z AND RETURN SOUTHEAST
AFTER 4Z.
REST OF UTAH AND SOUTHWEST WYOMING
VALLEY HAZE, ESPECIALLY
ACROSS THE WASATCH FRONT AND ADJACENT VALLEYS, WILL RESULT IN
SLANTWISE VISIBILITY REDUCTIONS. OTHERWISE, CLEAR SKIES ACROSS THE
AIRSPACE WILL ALLOW VFR CONDITIONS TO PERSIST FOR ALL REGIONAL
TERMINALS THROUGH THE PERIOD. WINDS REMAIN GENERALLY LIGHT AND
TERRAIN DRIVEN.
SLC WATCHES/WARNINGS/ADVISORIES
UT...NONE.
WY...NONE.
PUBLIC...WILSON
AVIATION...VAN CLEAVE
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY
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