427
FXUS65 KSLC 112159
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
259 PM MST SAT JAN 11 2025
SYNOPSIS
A COLD AIRMASS WILL REMAIN IN PLACE ACROSS THE REGION
THROUGH AT LEAST MIDWEEK.
SHORT TERM (THROUGH 12Z MONDAY)
WITH COLD TEMPERATURES ALOFT
AND RELATIVELY STEEP LAPSE RATES, SNOW SHOWERS HAVE CONTINUED TO
IMPACT PORTIONS OF SALT LAKE COUNTY AND NORTHERN UTAH COUNTY
THROUGH MID-AFTERNOON. LOOKING AT TRENDS, FLOW APPEARS TO BE
SHIFTING TO A MORE NORTHERLY DIRECTION, SHIFTING PRECIPITATION
TOWARD THE WESTERN SIDE OF THE SALT LAKE VALLEY AND INTO THE
TOOELE VALLEY.
CAMS HAVE STARTED TO VEER, SOME KEEPING PRECIPITATION ACROSS SLCO
THROUGH EVENING, SOME REDEVELOPING PRECIPITATION ACROSS SLCO
NEAR MORNING. THIS WIDE SPREAD IN REPRESENTATION OF PRECIPITATION
WOULD SUGGEST CAMS AND MODELS IN GENERAL ARE HAVING A DIFFICULT
TIME RESOLVING TRENDS OVER THE NEXT 12 HOURS.
EXPECT ACCUMULATING SNOW TO SLOWLY WIND DOWN OVER THE COTTONWOOD
CANYONS, AND THE POTENTIAL FOR ACCUMULATIONS TO INCREASE A BIT
AFTER SUNSET ACROSS WESTERN SALT LAKE AND EASTERN TOOELE COUNTY.
SNOW MAY CONTINUE, ESPECIALLY FOR THE TOOELE VALLEY AND SKULL
VALLEY INTO THE OVERNIGHT HOURS. WHILE THE MOST LIKELY SCENARIO
IS THAT ACCUMULATIONS WILL REMAIN LESS THAN 2 INCHES, IF SNOW
SHOWERS BECOME PARTICULARLY STRONG OVER A SPECIFIC AREA FOR A FEW
HOURS, HIGHER ACCUMULATIONS WILL BE REALIZED. EVENING SHIFT WILL
MONITOR CONDITIONS, BUT FOR NOW, CONFIDENCE ISN'T SUFFICIENT TO
ADD ANY WINTER WEATHER ADVISORIES TO THE VALLEYS.
WINTER WEATHER ADVISORIES CONTINUE FOR THE MOUNTAINS AND NO
CHANGES WERE NEEDED.
SNOW SHOWERS WILL AGAIN OCCUR ACROSS THE REGION, ESPECIALLY THE
NORTHERN MOUNTAINS, UNDER A COLD, UNSTABLE AIRMASS SUNDAY
AFTERNOON AND EVENING.
LONG TERM (AFTER 12Z MONDAY)
A COLD AND DRY AIRMASS WILL BE IN
PLACE TO START THE PERIOD AS NORTHERLY FLOW REMAINS IN PLACE.
TEMPERATURES WILL BOTTOM OUT ~5 DEGREES BELOW NORMAL MONDAY AND
TUESDAY BEFORE A GRADUAL WARM UP AS FLOW BECOMES LIGHTER AND
SWITCHES MORE OUT OF THE WEST THANKS TO A PNW RIDGE. THIS RIDGE
WILL BE ORIENTED NORTH OF A CUTOFF LOW OFF THE COAST OF CALIFORNIA
CREATING A REX BLOCK PATTERN. GUIDANCE IS IN AGREEMENT THAT THIS
PATTERN STAYS IN PLACE THROUGH THE END OF THE WEEK. THIS PATTERN
WILL BLOCK ANY TROUGH FROM MOVING THROUGH THE AREA AND ALLOW FOR A
GRADUAL WARM UP CLOSER TO NORMAL TEMPERATURES FOR THIS TIME OF
YEAR BY THE END OF THE WEEK. EVEN THOUGH WEAKER FLOW ALOFT DOES
DEVELOP NEXT WEEK, THE SHORT RESIDENCE TIME OF VALLEY INVERSIONS
WILL HELP TO PREVENT HAZE FROM BUILDING TOO MUCH BEFORE THE NEXT
TROUGH MOVES IN BY NEXT WEEKEND.
THE WEEKEND TROUGH IS STARTING TO LOOK MORE AND MORE LIKELY WITH
ALL ENSEMBLE MEMBERS ON BOARD WITH A TROUGH AT SOME POINT NEXT
WEEKEND. THE TIMING AND MAGNITUDE OF THE TROUGH ARE A BIT
UNCERTAIN, BUT THE TROUGH'S ORIGINS WILL BE CONTINENTAL IN NATURE.
THIS WOULD REDUCE THE AMOUNT OF QPF ASSOCIATED WITH THE STORM. AS
OF NOW, THE MEDIAN QPF AMONGST THE ENSEMBLE MEMBERS IS ONLY
0.03". HOWEVER, THE 700MB TEMPERATURES ARE LOOKING LIKE THE
COLDEST OF THE SEASON. THE MEDIAN TEMPERATURES ARE -19C WITH THE
25TH PERCENTILE STILL VERY COLD AT - 15C. SO THERE WILL BE LITTLE
CONCERN OVER PRECIPITATION TYPE, AS IT SHOULD BE COLD ENOUGH FOR
ALL SNOW. THE ISSUE WILL BE WITH THE LACK OF MOISTURE ASSOCIATED
WITH THE FRONTAL PASSAGE.
AVIATION...KSLC
LIGHT SNOW SHOWERS PRODUCING MOSTLY VFR
CONDITIONS ARE LIKELY TO CONTINUE ANOTHER FEW HOURS UNTIL AROUND
00- 02Z, THOUGH THERE IS A SMALL CHANCE THAT THESE SHOWERS LAST
EVEN LATER INTO THE EVENING GIVEN UNCERTAINTIES WITH LAKE-EFFECT
SNOW. PERIODS OF MVFR VIS/CIGS ARE POSSIBLE WITHIN HEAVIER SHOWERS
(20% CHANCE). NORTHERLY WINDS WILL CONTINUE, BUT MAY BECOME LIGHT
AND VARIABLE AT TIMES OVERNIGHT. HIGH-END MVFR CIGS COULD RETURN
OVERNIGHT, MOST LIKELY BETWEEN 08-13Z (40% CHANCE).
REST OF UTAH AND SOUTHWEST WYOMING
LIGHT SNOW SHOWERS AND EVER
SO GRADUALLY DECREASING IN COVERAGE ACROSS NORTHERN UTAH, LIKELY
BECOMING CONFINED TO HIGHER TERRAIN AND OVER THE TOOELE VALLEY
AFTER 01Z. GIVEN THE NATURE OF LAKE-EFFECT SNOW, THE DURATION OF
SNOWFALL OVER THE TOOELE VALLEY IS UNCERTAIN, BUT COULD LAST
THROUGH THE NIGHT (40% CHANCE). VFR-MVFR CONDITIONS ARE EXPECTED
OVERNIGHT ACROSS NORTHERN AND CENTRAL UT/SOUTHWEST WY, WITH CIGS
LOWERING TO MVFR IN MANY LOCATIONS OVERNIGHT BETWEEN 07-14Z.
SOUTHERN UT WILL REMAIN LARGELY DRY. NORTHERLY WINDS WILL LIKELY
PERSIST, WITH GUSTS OUT OF THE NORTH TO NORTHEAST POSSIBLE EARLIER
IN THE NIGHT AT KCDC, KSGU, AND KBCE.
SLC WATCHES/WARNINGS/ADVISORIES
UT...WINTER WEATHER ADVISORY UNTIL 8 PM MST THIS EVENING FOR
UTZ110>113.
WINTER WEATHER ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR UTZ117.
WY...NONE.
KRUSE/MAHAN/CUNNINGHAM
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY
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