542
FXUS65 KSLC 082202
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
302 PM MST SAT NOV 8 2025
SYNOPSIS
HIGH PRESSURE WILL BECOME THE DOMINANT WEATHER FEATURE
OVER THE FORECAST AREA FOR THE NEXT SEVERAL DAYS, KEEPING DRY AND
MILD CONDITIONS IN PLACE FOR UTAH AND SOUTHWEST WYOMING. THERE IS
GENERALLY HIGH CONFIDENCE THAT A STORM SYSTEM WILL MOVE ACROSS THE
WESTERN U.S. LATE IN THE WEEK AND OVER THE WEEKEND, THOUGH IMPACTS
ARE YET TO BE DETERMINED AT THIS TIME.
DISCUSSION
KEY MESSAGES:
- A RIDGE OF HIGH PRESSURE WILL BUILD INTO THE WESTERN U.S.
THROUGH THE NEXT SEVERAL DAYS, KEEPING DRY AND STABLE CONDITIONS
SPREAD ACROSS UTAH AND SOUTHWEST WYOMING THROUGH AT LEAST
WEDNESDAY.
- THERE IS HIGH CONFIDENCE (75% CHANCE) THAT A TROUGH WILL MOVE
INTO THE WESTERN U.S. LATE IN THE WEEK/ OVER THE WEEKEND,
BRINGING POTENTIALLY WIDESPREAD PRECIPITATION ACROSS THE AREA,
AS WELL AS COOLER TEMPERATURES.
TODAY WE FIND THE REGION ON THE EASTERN PERIPHERY OF AN UPSTREAM
RIDGE, LEAVING COOL AND DRY CONDITIONS AREAWIDE. WITH SURFACE HIGH
PRESSURE INTENSIFYING ON THE EASTERN EDGE OF THIS RIDGE, A N-S
ORIENTED PRESSURE GRADIENT HAS AIDED IN LIGHT NORTH WINDS ACROSS
MUCH OF THE AREA. THE GRADIENT WILL TIGHTEN ACROSS SOUTHWEST UTAH
THIS EVENING, HELPING TO FORCE NORTHERLY WINDS THROUGH THE CANYONS
ACROSS IRON AND WASHINGTON COUNTY. AS SUCH, ANTICIPATE A PERIOD OF
GUSTY NORTH WINDS ALONG THE I-15 CORRIDOR BETWEEN CEDAR CITY AND
ST. GEORGE DURING THE OVERNIGHT HOURS, WITH PEAK GUSTS OF 35-40
MPH IN SOME OF THE MORE EXPOSED AREAS.
THIS RIDGE IS EXPECTED TO BUILD OVER THE WESTERN U.S. OVER THE
NEXT SEVERAL DAYS, HELPING TO INCREASE TEMPERATURES OVERHEAD WHILE
MAINTAINING DRY CONDITIONS. THE RESULTING TREND ACROSS THE REGION
WILL BE GRADUALLY WARMING TEMPERATURES THROUGH AT LEAST THURSDAY.
AN INNOCUOUS WEATHER PATTERN TO SAY THE LEAST. VALLEY INVERSIONS
ARE, HOWEVER, LIKELY TO DEVELOP UNDER THE INFLUENCE OF THE RIDGE
AND WILL ALLOW FOR PARTICULATES TO ACCUMULATE THROUGH THE WORK
WEEK (SEE AIR.UTAH.GOV FOR OFFICIAL AIR QUALITY FORECASTS).
BY THURSDAY, THE AXIS OF THE AFOREMENTIONED RIDGE WILL BE EAST OF
THE FORECAST AREA WHILE A DEEP TROUGH DEVELOPS OVER THE NORTHEAST
PACIFIC. INCREASED FLOW OVERHEAD ALONGSIDE BETTER ATMOSPHERIC
MIXING POTENTIAL WILL ALLOW FOR INCREASINGLY BREEZY SOUTHWEST
WINDS ACROSS THE AREA ON THURSDAY AFTERNOON. SOME RELIEF MAY BE
SEEN FROM ANY DEVELOPED VALLEY INVERSIONS, THOUGH FULL RELIEF WILL
LIKELY NOT ARRIVE UNTIL THE WEEKEND.
THIS TAKES US TO OUR NEXT WEATHER SYSTEM. AT THIS TIME, THERE IS
GENERALLY HIGH CONFIDENCE (75% CHANCE) THAT A TROUGH WILL MOVE
INTO THE WESTERN U.S. SOME TIME BETWEEN FRIDAY AND SUNDAY,
BRINGING A POTENTIALLY SIGNIFICANT AREAWIDE COOL DOWN AND A ROUND
OF GENERALLY WIDESPREAD PRECIPITATION. BREAKING DOWN MODEL
GUIDANCE FURTHER REVEALS A SIZABLE AMOUNT OF UNCERTAINTY
REVOLVING AROUND THE OVERALL DEPTH OF THE TROUGH AS WELL AS THE
PHASE OF THE FEATURE. WHILE THE SLIGHT MAJORITY OF MODEL GUIDANCE
(60%) FAVORS THE TROUGH AXIS MOVING INLAND BY FRIDAY EVENING,
THERE IS STILL AROUND 40% OF GUIDANCE THAT KEEPS THE FEATURE
OFFSHORE. ONCE THE TROUGH CREEPS ONSHORE, PRECIPITATION CHANCES GO
UP. IF IT STAYS OFFSHORE, PRECIPITATION CHANCES WILL BE NEAR
ZERO. THIS IS ONE OF THE BIGGEST UNCERTAINTIES OF THE FORECAST AT
THIS TIME ("WHEN IS GOING TO START?"). FURTHERMORE, IF THIS TROUGH
BECOMES TOO DEEP OFFSHORE, THERE IS ABOUT A 55% CHANCE THAT WE
SEE THE DEVELOPMENT OF A CUTOFF LOW WHILE THE NORTHERN BRANCH
DETACHES FROM THE FEATURE... AIDING IN A MORE SOUTHERLY STORM
TRACK (CURRENTLY SUPPORTED BY ECMWF DETERMINISTIC). THE REMAINING
45% OF GUIDANCE FAVORS BETTER STRUCTURE OF THE TROUGH, THUS
INTRODUCING A MORE NORTHERN TRACK AND A GREATER ABUNDANCE OF COLD
AIR.
REMEMBER, THERE ARE STILL ABOUT 20-25% OF MODELS THAT DO NOT
SUPPORT THIS TROUGH MOVING INTO THE AREA. SO CONTINUE TO MONITOR
FORECASTS AS WE HEAD THROUGH THE WEEK.
AVIATION...KSLC
VFR CONDITIONS WILL PERSIST THROUGH THE PERIOD
FOR THE KSLC TERMINAL. DRY STABLE CONDITIONS WITH A FEW HIGH CLOUDS
WILL CONTINUE WITH LIGHT NORTHERLY WINDS TRANSITIONING TO LIGHT
SOUTHERLY WINDS OVERNIGHT.
REST OF UTAH AND SOUTHWEST WYOMING
VFR CONDITIONS WILL PERSIST
FOR THE ENTIRE AIRSPACE THROUGH THE PERIOD. DRY STABLE CONDITIONS
WITH A FEW HIGH CLOUDS WILL CONTINUE WITH LIGHT DIURNALLY DRIVEN
WINDS.
SLC WATCHES/WARNINGS/ADVISORIES
UT...NONE.
WY...NONE.
PUBLIC...WEBBER
AVIATION...MAHAN
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY
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