767
FXUS65 KSLC 091027
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
327 AM MST FRI JAN 9 2026
KEY MESSAGES
- STRONG WASHINGTON COUNTY GAP WINDS WILL CONTINUE THROUGH
SUNRISE, WITH GUSTS TO 60 MPH IMPACTING THE I-15 CORRIDOR
THROUGH BLACK RIDGE CANYON INCLUDING ADJACENT AREAS NEAR
TOQUERVILLE, LA VERKIN AND PORTIONS OF HURRICANE. THERE IS A
20% CHANCE WIND GUSTS WILL EXCEED 65 MPH IN THESE AREA. WINDS
WILL DECREASE AFTER 8-9 AM THIS MORNING.
- A LAKE EFFECT SNOW BAND WILL CONTINUE TO AFFECT FAR WESTERN
SALT LAKE VALLEY, EASTERN TOOELE VALLEY, AND NORTHWEST UTAH
COUNTY NEAR EAGLE MOUNTAIN. AN ADDITIONAL 1 TO 3 INCHES OF SNOW
IS POSSIBLE IN THESE AREAS BEFORE THIS BAND DISSIPATES BY MID
MORNING.
- FREEZING FOG WILL BE POSSIBLE ACROSS THE CACHE VALLEY THROUGH
THIS MORNING.
- A POTENTIALLY PROLONGED INVERSION CYCLE WILL SET UP THIS
WEEKEND ACROSS NORTHERN AND CENTRAL UTAH, AND PERSIST THROUGH
MOST OF NEXT WEEK. THIS WILL RESULT IN AN INCREASE IN URBAN
HAZE, NOCTURNAL FOG, AND DEGRADING AIR QUALITY ACROSS PRONE
VALLEYS INCLUDING THE WASATCH FRONT.
DISCUSSION
THE UPPER TROUGH WHICH PASSED THROUGH THE REGION
THURSDAY IS GRADUALLY MAKING ITS WAY THROUGH THE CENTRAL AND
SOUTHERN ROCKIES EARLY THIS MORNING, LEAVING A COLD NORTHERLY FLOW
IN ITS WAKE ACROSS THE FORECAST AREA. WITHIN THIS FLOW, SHORTWAVE
RIDGING IS CURRENTLY BUILDING ACROSS THE EASTERN GREAT BASIN,
RESULTING IN INCREASING SUBSIDENCE ACROSS NORTHERN UTAH. AS THIS
CONTINUES OVER THE NEXT FEW HOURS, THE LINGERING LAKE BAND
EMANATING OFF THE GSL SHOULD CONTINUE TO WEAKEN AND LIKELY
DISSIPATE BY SUNRISE. EXTENDED THE GOING WINTER WX ADVISORY FOR
AREAS SOUTH OF THE LAKE, BUT ONCE THIS BAND WINDS DOWN SHOULD BE
ABLE TO DROP THIS HEADLINE.
ELSEWHERE, STRATUS REMAINS IN PLACE ALONG NORTHERN/WESTERN SLOPES
OF THE HIGHER TERRAIN ACROSS NORTHERN AND CENTRAL UTAH. THIS
STRATUS EXTENDS UPSTREAM INTO SOME VALLEY LOCATIONS SUCH AS THE
CACHE, AND HAS THUS FAR DETERRED FOG FORMATION, HOWEVER THE
POTENTIAL REMAINS FOR QUICK FOG DEVELOPMENT IF SKIES CLEAR, AND
WILL HOLD ONTO THE FREEZING FOG ADVISORY FOR THE CACHE VALLEY FOR
THE TIME BEING. MEANWHILE, A TIGHT PRESSURE GRADIENT IN THE WAKE
OF THE DEPARTING SYSTEM IS MAINTAINING STRONG GAP WINDS ACROSS
FAVORED AREAS OF WASHINGTON COUNTY. THUS FAR PEAK GUSTS HAVE
REACHED THE LOW-MID 50 MPH RANGE, AND THESE WINDS WILL PERSIST FOR
A FEW MORE HOURS BEFORE THE GRADIENT WEAKENS THIS MORNING.
WITH THIS COLD NORTHERLY FLOW IN PLACE (-15C AIRMASS AT 700MB PER
RAP ANALYSIS), MAX TEMPS TODAY WILL STRUGGLE TO REACH THE FREEZING
MARK ACROSS WESTERN VALLEYS INCLUDING THE WASATCH FRONT, WHILE
LOWER ELEVATIONS OF SOUTHERN UTAH WILL REACH THE LOW 40S. CLEAR
SKIES TONIGHT WILL ALLOW TEMPS TO FALL INTO THE TEENS, WITH SINGLE
DIGITS IN SHELTERED LOCATIONS SUCH AS THE CACHE AND BEAR RIVER
VALLEYS.
BEYOND TONIGHT, WE TRANSITION INTO A POTENTIALLY PROLONGED
INVERSION CYCLE FOR MOST NORTHERN AND CENTRAL VALLEYS. A DOMINANT
MID LEVEL RIDGE WILL BEGIN SPREADING INTO THE FORECAST AREA
TONIGHT, WITH LONGWAVE RIDGING REMAINING IN PLACE ACROSS THE
REGION THROUGH MOST IF NOT ALL OF NEXT WEEK. WITH WARMING ALOFT
OVERNIGHT, VALLEY INVERSIONS WILL QUICKLY DEVELOP SATURDAY AS THE
COLD AIRMASS CURRENTLY IN PLACE ACROSS THE REGION BECOMES TRAPPED
WITHIN MOST NORTHERN AND CENTRAL UTAH BASINS INCLUDING THE WASATCH
FRONT. AS SUCH EXPECT AN INCREASE IN URBAN HAZE BY MONDAY (IF NOT
OVER THE WEEKEND), ALONG WITH OVERNIGHT FOG AND STRATUS BECOMING
INCREASINGLY COMMON BY EARLY NEXT WEEK. UNDERCUT GUIDANCE THROUGH
MUCH OF NEXT WEEK TO REFLECT A MORE STAGNANT TREND IN
TEMPERATURES ACROSS THE NORTHERN VALLEYS. LATE NEXT WEEK WOULD
BRING THE FIRST CHANCE FOR DISLODGING THESE STAGNANT AIRMASSES
RESULTING FROM A BACKDOOR FRONT ASSOCIATED WITH A POTENTIAL
TROUGH DIGGING THROUGH THE ROCKIES, HOWEVER CONFIDENCE IS PRETTY
LOW AT THIS POINT IN THIS SCENARIO.
AVIATION...KSLC
RELATIVELY LIGHT NORTHWEST WINDS WILL LAST
THROUGH 03Z WHEN WINDS TRANSITION TO LIGHT SOUTHEAST. BROKEN TO
OVERCAST CLOUDS IN VFR RANGE WILL BECOME MORE SCATTERED, WITH MOSTLY
CLEAR CONDITIONS BY 21Z.
REST OF UTAH AND SOUTHWEST WYOMING
WINDS WILL PREVAIL FROM THE
NORTHWEST AND BE RELATIVELY LIGHT. THE MAIN EXCEPTIONS WILL BE AT
KPVU AND KSGU, WHERE DOWNSLOPE FLOW FROM THE NORTH WILL ENHANCE
WINDS. LOCALLY STRONGER GUSTS AROUND 30 KNOTS AT THOSE LOCATIONS WILL
CONTINUE THROUGH ROUGHLY 00Z. BROKEN TO OVERCAST CLOUDS IN VFR RANGE
FOR SOUTHWEST WYOMING AND NORTHERN UTAH WILL BECOME MORE SCATTERED,
WITH MOSTLY CLEAR CONDITIONS BY 21Z.
SLC WATCHES/WARNINGS/ADVISORIES
UT...WINTER WEATHER ADVISORY UNTIL 8 AM MST THIS MORNING FOR UTZ102-
105-106.
FREEZING FOG ADVISORY UNTIL 9 AM MST THIS MORNING FOR UTZ107.
HIGH WIND WARNING UNTIL 8 AM MST THIS MORNING FOR UTZ123.
WY...NONE.
PUBLIC...SEAMAN
AVIATION...WILSON
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY
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