524
FXUS65 KSLC 092222
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
322 PM MST SUN NOV 9 2025
SYNOPSIS
HIGH PRESSURE REMAINS IN PLACE THROUGH THE NEXT
SEVERAL DAYS, BRINGING DRY AND MILD CONDITIONS ACROSS THE FORECAST
AREA THROUGH AT LEAST THURSDAY. A PATTERN CHANGE ARRIVES LATE IN
THE WEEK, BRINGING POTENTIAL FOR MUCH COLDER TEMPERATURES AND
WIDESPREAD PRECIPITATION ACROSS UTAH AND SOUTHWEST WYOMING.
DISCUSSION
KEY MESSAGES:
- HIGH PRESSURE WILL REMAIN IN CONTROL OF THE REGION THROUGH
WEDNESDAY AND WILL HELP TO MAINTAIN ABOVE NORMAL TEMPERATURES
THROUGH AT LEAST THURSDAY.
- THERE IS GENERALLY HIGH CONFIDENCE (70-80% CHANCE) THAT A
POTENTIALLY SIGNIFICANT COLD TROUGH MOVES INTO THE WESTERN U.S.
LATE IN THE WEEK, BRINGING A VARIETY OF IMPACTS TO THE FORECAST.
WHILE THERE IS UNCERTAINTY IN HOW THE STORM UNFOLDS, POTENTIAL
IMPACTS INCLUDE: STRONG WINDS THURSDAY (30% CHANCE FOR GUSTS
GREATER THAN 45 MPH), SIGNIFICANT MOUNTAIN SNOW (25-50% CHANCE
OF 9+ INCHES), AND A LOW CHANCE (10-25% CHANCE) FOR WASATCH
FRONT SNOW ACCUMULATIONS OF AROUND AN INCH.
ASIDE FROM A FEW HIGH LEVEL CLOUDS FLOATING AROUND THE EASTERN
GREAT BASIN REGION, UTAH AND SOUTHWEST WYOMING HAVE SEEN LARGELY
CLEAR SKIES TODAY THANKS TO A STOUT UPPER LEVEL RIDGE. WHILE ONLY
SLIGHT WARMING OF SURFACE TEMPERATURES HAVE BEEN SEEN THROUGHOUT
THE FORECAST AREA TODAY, THE TREND OVER THE NEXT SEVERAL DAYS WILL
BE INCREASINGLY MILD TEMPERATURES AS THE RIDGE CONTINUES TO USHER
IN WARMER AIR ALOFT. THOUGH MODEST INVERSION CONDITIONS WILL
DEVELOP THANKS TO THESE WARMER OVERHEAD TEMPERATURES, WARM
SOUTHERLY FLOW WILL HELP TO BOOST DAYTIME HIGH TEMPERATURES UP TO
5-10 DEGREES ABOVE CLIMATOLOGICAL NORMALS BY THE MIDDLE OF THE
WORK WEEK.
COME EARLY THURSDAY, THE AXIS OF THE AFOREMENTIONED RIDGE WILL BE
POSITIONED EAST OF THE FORECAST AREA WHICH WILL ALLOW FOR DEEPER
ATMOSPHERIC MIXING. UPSTREAM, OUR NEXT POTENTIAL STORM SYSTEM WILL
DEEPEN OFFSHORE OF THE U.S. WEST COAST, INCREASINGLY THE OVERALL
FLOW ALOFT. PAIRED WITH THE DEEPER MIXING, STRONGER OVERHEAD WINDS
WILL ATTEMPT TO SURFACE DURING THE AFTERNOON HOURS ON THURSDAY. AT
THE VERY LEAST, WE'LL SEE A NOTABLE UPTICK IN SOUTHWEST WINDS WITH
GUSTS APPROACHING 30 TO 35 MPH ACROSS THE WESTERN UTAH VALLEYS AND
25 TO 30 MPH ALONG THE WASATCH FRONT. CURRENTLY, THERE IS AROUND A
30% CHANCE THAT WIND GUSTS IN THE WESTERN UTAH VALLEYS EXCEED THE
45 MPH THRESHOLD, WHICH WOULD INCREASE THE OVERALL IMPACT OF THE
PRE-STORM ENVIRONMENT.
AS MENTIONED ABOVE, THERE IS HIGH CONFIDENCE THAT A STORM SYSTEM
WILL PUSH INTO THE FORECAST AREA LATE IN THE WEEK/ OVER THE
WEEKEND. THAT SAID, THERE IS STILL A CONSIDERABLE AMOUNT OF
UNCERTAINTY TO WORK THROUGH WITH THIS STORM, PARTICULARLY WITH HOW
THE TROUGH PHASES OVER THE REGION. AT THIS POINT IN TIME, THERE IS
A SLIGHT MAJORITY OF ENSEMBLE GUIDANCE (~55%) THAT FAVORS AN OPEN
WAVE WHICH WOULD HELP TO INTRODUCE A MUCH COLDER AIRMASS OVER UTAH
AND SOUTHWEST WYOMING. THE REMAINING 45% OF GUIDANCE DEVELOPS THE
FEATURE INTO A CUTOFF LOW AS THE TROUGH POTENTIALLY DEEPENS
OFFSHORE, FAVORING A WARMER (BUT STILL COLD) AIRMASS OVER THE
REGION. OF THAT 45%, 10% KEEP THE FEATURE OFFSHORE AND ALLOW THE
ABNORMALLY WARM AIRMASS TO LINGER. FOR REFERENCE, THE OVERALL
SPREAD IN 25TH TO 75TH PERCENTILE HIGH TEMPERATURE FORECASTS FOR
SLC RANGES FROM 40 DEGREES TO 53 DEGREES. EXPANDING THIS TO THE
10TH TO 90TH PERCENTILE REVEALS 25 DEGREES (!) OF SPREAD (FROM 37
DEGREES TO 62 DEGREES).
WITH A VAST MAJORITY OF ENSEMBLE GUIDANCE FAVORING THE
INTRODUCTION OF THE TROUGH, GENERALLY WIDESPREAD PRECIPITATION
SEEMS TO BE A CERTAINTY WITH THIS SYSTEM. THE BIG QUESTION(S)
THEN BECOMES "WHAT KIND OF PRECIPITATION? AM I GOING TO GET SNOW?
HOW MUCH?". THE ANSWER IS ABOUT AS COMPLEX AND UNCERTAIN AS HOW
THIS TROUGH IS INTRODUCED INTO THE REGION, BUT EACH OF THE ABOVE
LISTED SCENARIOS WILL HAVE ITS OWN RESULT.
- SCENARIO 1 (45% CHANCE): TROUGH PUSHES INTO THE REGION INTACT,
INTRODUCING COLDER AIR AND A MORE POTENT COLD FRONT. THE MORE
POTENT COLD FRONT FORCES HEAVIER PRECIPITATION ALONG THE BOUNDARY,
ALLOWING FOR SIGNIFICANT (6-8+ INCHES) SNOW IN THE MOUNTAINOUS
TERRAIN AND MEASURABLE VALLEY SNOW AFTER TRANSITIONING FROM RAIN.
WIDESPREAD PRECIPITATION.
- SCENARIO 2 (45% CHANCE): TROUGH FORMS INTO A CUTOFF LOW AND THE
FEATURE TRACKS FARTHER SOUTH. WIDESPREAD PRECIPITATION STILL
LIKELY. MOUNTAIN SNOW IS STILL INTRODUCED, BUT ACCUMULATIONS ARE
NOT AS GREAT AND WARMER TEMPERATURES FAVOR HIGHER SNOW LEVELS AND
VALLEY RAIN.
- SCENARIO 3 (10% CHANCE): TROUGH DEVELOPS INTO A CUTOFF LOW
OFFSHORE, SLOWING THE PROGRESSION OF THE FEATURE AND DECREASING
THE STRENGTH OF THE COLD POOL BY THE TIME IT SHIFTS INLAND.
HIGH SNOW LEVELS WITH LIGHT MOUNTAIN SNOW IN THE HIGHEST TERRAIN
(LESS THAN 3 INCHES). LIGHT VALLEY RAINFALL, PRIMARILY ACROSS
NORTHERN UTAH AND SOUTHWEST UTAH.
MUCH MORE TO COME FROM THESE DISCUSSIONS OVER THE NEXT SEVERAL
DAYS, SO CONTINUE MONITORING FORECASTS FOR MORE UP TO DATE
INFORMATION.
AVIATION...KSLC
VFR CONDITIONS WILL PERSIST FOR THE KSLC TERMINAL
THROUGH THE PERIOD. DRY STABLE CONDITIONS WILL CONTINUE WITH A FEW
HIGH CLOUDS. LIGHT NORTHERLY WINDS WILL TRANSITION 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
WILL A FEW HIGH CLOUDS AND LIGHT DIURNALLY DRIVEN WINDS WILL
CONTINUE.
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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