788
FXUS65 KSLC 021045
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
345 AM MST TUE DEC 2 2025
SYNOPSIS
A STORM SYSTEM WILL BRING LIGHT VALLEY AND MOUNTAIN
SNOW TO MUCH OF UTAH AND SOUTHWEST WYOMING TODAY AND WEDNESDAY.
DRY CONDITIONS ARE EXPECTED ON THURSDAY, THOUGH WILL BE SHORT
LIVED AS AN ATMOSPHERIC RIVER BRINGS POTENTIAL FOR MORE
CONSIDERABLE VALLEY RAIN AND NORTHERN MOUNTAIN SNOW FRIDAY INTO
THE WEEKEND.
SHORT TERM (THROUGH 12Z/5AM THURSDAY)
A COLD STORM IS STILL
ON TRACK TO IMPACT UTAH AND SOUTHWEST WYOMING TODAY INTO
WEDNESDAY. GIVEN H7 TEMPERATURES DROPPING TO AROUND -10C TODAY,
THE PRECIPITATION TYPE THROUGH THIS EVENT WILL BE PREDOMINANTLY
SNOW. HIGH RESOLUTION MODELS NOW CAPTURING THE ENTIRE EVENT
HEAVILY SUGGEST THIS SYSTEM WILL BE MUCH DRIER THAN PREVIOUSLY
EXPECTED, THUS SNOW TOTALS HAVE GONE DOWN ACROSS THE BOARD AS A
RESULT. GIVEN ITS ORIGINS FROM INTERIOR CANADA, THE CONTINENTAL
AIRMASS MOVING IN WITH THIS SYSTEM WILL BE TOO MOISTURE DEPRIVED.
REGARDLESS, THERE IS A GOOD (>70%) CHANCE FOR THE FIRST
MEASURABLE SNOW OF THE SEASON FOR NORTHERN AND CENTRAL UTAH
VALLEYS THAT MISSED OUT FROM OUR PREVIOUS STORM, INCLUDING KSLC.
AS AN INTERESTING CLIMATE TIDBIT -- IF WE RECEIVE 0.1 INCHES OR
MORE OF SNOW TODAY OR TOMORROW AT KSLC, IT WILL HAVE BEEN THE
16TH LATEST MEASURABLE SNOWFALL SINCE RECORDKEEPING BEGAN IN 1885.
SNOW SHOWERS ARE EXPECTED TO MOVE IN FROM THE NORTH THIS
AFTERNOON, THOUGH COVERAGE WILL BE MORE DISORGANIZED AND
SCATTERED. THUS, MOST VALLEY LOCATIONS COULD SEE ANYWHERE FROM
NOTHING TO AROUND HALF AN INCH OF SNOW THROUGH WEDNESDAY. ACROSS
THE NORTHERN AND CENTRAL MOUNTAINS, CURRENT FORECAST HOLDS AROUND
2 TO 4 INCHES FOR MOST LOCATIONS, LOCALLY UP TO 6 INCHES. FOR THE
WASATCH BACK, LIGHT SNOW EXPECTED, WITH LOCALIZED AREAS SEEING
AROUND AN INCH. SNOW FALLING OVERNIGHT MAY RESULT IN A TRICKY
MORNING COMMUTE ON WEDNESDAY, SO MAKE SURE TO CHECK ROAD
CONDITIONS BEFORE YOU GO AND TAKE IT SNOW IN ICE AND SNOW.
SNOW TAPERS OFF AS IT MOVES SOUTHWARD THROUGH WEDNESDAY, WITH DRY
CONDITIONS SETTLING IN ACROSS THE ENTIRE FORECAST AREA BY THE LATE
AFTERNOON.
LONG TERM (AFTER 12Z THURSDAY)
A HIGH AMPLITUDE MID LEVEL RIDGE
WILL RESIDE ACROSS THE EASTERN PACIFIC/GULF OF ALASKA AT THE
BEGINNING OF THE LONG TERM PERIOD, MAINTAINING A COOL NORTHWESTERLY
FLOW DOWNSTREAM ACROSS THE EASTERN GREAT BASIN. THIS WILL MAINTAIN A
COOL AND STABLE AIRMASS ACROSS THE FORECAST AREA ON THURSDAY. MAX
TEMPERATURES THURSDAY WILL RUN SLIGHTLY BELOW CLIMO, REMAINING IN
THE MID TO UPPER 30S ACROSS MOST NORTHERN/CENTRAL VALLEYS, AND 40S
TO LOW 50S ACROSS SOUTHERN UTAH.
THIS UPSTREAM RIDGE WILL BEGIN TO FLATTEN BEGINNING FRIDAY, ALLOWING
FOR A QUASI-ZONAL FLOW TO SPREAD INLAND ACROSS THE INTERIOR PACIFIC
NORTHWEST, NORTHERN ROCKIES AND NORTHERN GREAT BASIN. ENSEMBLES
REMAIN IN GOOD AGREEMENT WITH THE OVERALL LARGE SCALE PATTERN
TRANSITION WITH FAIRLY SMALL SPREAD IN THE GUIDANCE THROUGH SATURDAY
ALLOWING FOR RELATIVELY HIGH CONFIDENCE IN THE FORECAST HEADING INTO
THE UPCOMING WEEKEND.
AS THE UPPER JET SPREADS INLAND, AN PLUME OF LOW LEVEL WARM
AIR/MOISTURE ADVECTION WILL SPREAD ACROSS NORTHERN UTAH/SOUTHWEST
WYOMING AS EARLY AS LATE THURSDAY NIGHT, THEN PERSIST THROUGH FRIDAY
BRINGING PERIODS OF PRECIPITATION MAINLY TO AREAS NORTH OF I-80, AND
HEAVIEST/MOST PERSISTENT ACROSS THE HIGHER TERRAIN. CHANCES FOR
PRECIP SOUTH OF I-80 QUICKLY TREND LOWER DURING THIS TIMEFRAME, AND
REMAIN LARGELY CONFINED TO THE TERRAIN. INITIALLY SNOW LEVELS WILL
REMAIN AT VALLEY FLOORS THURSDAY NIGHT/FRIDAY MORNING, BUT WITH THIS
PERSISTENT WARM ADVECTION REGIME SNOW LEVELS WILL RISE ABOVE 5000
FEET BY LATE FRIDAY.
A SHORTWAVE TROUGH EMBEDDED WITHIN THIS BELT OF WESTERLIES WILL
BRUSH BY NORTHERN UTAH FRIDAY NIGHT THROUGH SATURDAY, ENHANCING
PRECIPITATION NORTH OF I-80 AND INCREASING THE PROBABILITY FOR
MEASURABLE PRECIP ACROSS THE REMAINDER OF NORTHERN UTAH. WITH A MORE
MILD WESTERLY FLOW IN PLACE SNOW LEVELS SATURDAY WILL REMAIN ABOVE
5000 FEET RESULTING IN VALLEY RAIN/MOUNTAIN SNOW ACROSS NORTHERN
UTAH. AS THIS WAVE MOVES AWAY FROM THE AREA PRECIP CHANCES WILL
TREND LOWER SATURDAY NIGHT. WITH THE JET AXIS REMAINING FURTHER
NORTH, MOST OF CENTRAL AND SOUTHERN UTAH WILL REMAIN DRY THROUGH
MOST IF NOT ALL OF THIS EVENT.
CONFIDENCE DECREASES SOMEWHAT IN THE FORECAST BEGINNING SUNDAY AND
CONTINUING THROUGH EARLY NEXT WEEK, OWING TO SPREAD WITHIN THE
ENSEMBLE FORECAST SYSTEMS CENTERED AROUND WHETHER THE MID LEVEL
RIDGE BEGINS TO AMPLIFY AGAIN PUSHING THE BELT OF WESTERLIES FURTHER
NORTH AND AWAY FROM THE FORECAST AREA, OR WHETHER A LOWER AMPLITUDE
RIDGE ALLOWS A MORE PREDOMINANT WESTERLY FLOW INTO THE INTERIOR
PACIFIC NORTHWEST AND FAR NORTHERN GREAT BASIN. THE FORMER, DRIER
SOLUTION IS FAVORED BY A LITTLE MORE THAN 60% OF ENSEMBLE MEMBERS AT
THIS POINT, WHICH WOULD YIELD GENERALLY MILD AND DRY CONDITIONS, BUT
INCREASE THE CHANCE FOR VALLEY STAGNATION HEADING INTO EARLY NEXT
WEEK.
AVIATION...KSLC
GRADUAL CIG REDUCTION IS EXPECTED THROUGH THE
DAY, DROPPING BELOW 6000 FEET THIS AFTERNOON AS A COLD STORM BRINGS
SNOW SHOWERS TO THE TERMINAL. REDUCTIONS TO MVFR AND BRIEF IFR
CONDITIONS ARE POSSIBLE IN THE EVENING AND OVERNIGHT AS A PERIOD OF
HEAVIER PRECIPITATION IS EXPECTED TO ACCOMPANY A FRONTAL PASSAGE.
WINDS REMAIN OVERALL LIGHT THROUGH THE TAF PERIOD, PREVAILING FROM
THE SOUTH FOR MOST OF THE DAY BEFORE SWITCHING NORTHERLY BEHIND THE
FRONTAL PASSAGE OVERNIGHT.
REST OF UTAH AND SOUTHWEST WYOMING
A GRADUAL DECREASE IN CIGS IS
EXPECTED FOR NORTHERN UTAH TERMINALS THIS MORNING AS A COLD STORM
MOVES IN FROM THE NORTH. SNOW SHOWERS ASSOCIATED WITH THIS STORM ARE
EXPECTED TO MOVE INTO NORTHERN UTAH AND SOUTHWEST WYOMING AROUND 21Z
THIS AFTERNOON, GRADUALLY MOVING SOUTHWARD THROUGH THE REMAINDER OF
THE DAY. THESE SHOWERS MAY BRING PERIODIC MVFR/IFR CONDITIONS TO
NORTHERN UTAH TERMINALS THROUGH EARLY WEDNESDAY MORNING. WINDS
REMAIN GENERALLY LIGHT AND TERRAIN DRIVEN ACROSS THE AIRSPACE THIS
MORNING, REMAINING LIGHT THROUGH THE DAY UNTIL A COLD FRONT MOVING
THROUGH THE REGION THIS EVENING AND OVERNIGHT BRINGS INCREASED
NORTHERLY WINDS INTO WEDNESDAY.
SLC WATCHES/WARNINGS/ADVISORIES
UT...NONE.
WY...NONE.
SHORT TERM/AVIATION...WHITLAM
LONG TERM...SEAMAN
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