821
FXUS65 KSLC 101100
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
500 AM MDT SAT MAY 10 2025
SYNOPSIS
HIGH PRESSURE WILL GRADUALLY SHIFT EASTWARD THROUGH THE
REGION THROUGH THIS WEEKEND, BRINGING MILD CONDITIONS. AS THIS
SHIFTS EAST AND A NEW STORM SYSTEM APPROACHES, WIND GUSTS WILL
INCREASE DAY TO DAY. SYSTEM WILL PUSH THROUGH BY TUESDAY, BRINGING
COOLER AND MORE UNSETTLED CONDITIONS THROUGH AT LEAST MIDWEEK.
SHORT TERM (THROUGH 12Z/6AM MONDAY)
AN EXPANSIVE AND FAIRLY
STRONG RIDGE OF HIGH PRESSURE WILL BECOME BETTER CENTERED ATOP
UTAH MOVING INTO SATURDAY. ALREADY MILD TEMPERATURES WILL WARM
FURTHER THROUGH THE DAY AS H7 TEMPERATURES INCREASE INTO THE +9C
TO +12C RANGE OR SO. PER SPC UPPER AIR CLIMATOLOGY AT KSLC
SPECIFICALLY, THIS WOULD FALL BETWEEN THE 90TH PERCENTILE TO THE
DAILY MAX. IN TURN AFTERNOON HIGHS WILL BE QUITE MILD, AROUND 10F
TO 20F ABOVE CLIMATOLOGICAL NORMAL FOR THIS TIME OF YEAR. THIS
TRANSLATES TO MID 70S ACROSS SOUTHWEST WYOMING, GENERALLY MID TO
UPPER 80S ACROSS MUCH OF THE WASATCH FRONT, AND MID 90S THROUGH
LOWER WASHINGTON COUNTY. WHILE A STRAY SHOWER ALONG THE HIGH
TERRAIN CANNOT BE ENTIRELY RULED OUT, DRY AIR AND SUBSIDENT EFFECT
OF THE RIDGE SHOULD PRECLUDE ANYTHING MUCH FROM GETTING GOING.
WITH THE MID LEVEL RIDGE AXIS JUST SLIGHTLY STARTING TO SHIFT A
BIT EAST, WILL SEE SOME MODEST INCREASE IN SOUTHWESTERLY FLOW AND
A CORRESPONDING INCREASE TO WIND GUSTS ACROSS WESTERN UTAH.
MOVING INTO SUNDAY A POTENT TROUGH WILL START DIGGING INTO THE
PACNW, HELPING TO START FLATTENING AND NUDGING THE RIDGE FURTHER
OUT OF THE AREA. THIS WILL ALSO RESULT IN A TIGHTENING OF THE
GRADIENT, AND IN TURN A FURTHER INCREASE TO SOUTHWESTERLY DEEP
LAYER FLOW. A CORRIDOR OF ENHANCED H7 WINDS ROUGHLY IN THE 30-40
KT RANGE WILL DEVELOP THROUGHOUT MUCH OF WESTERN TO NORTHERN UTAH,
FURTHER INCREASING THE CORRESPONDING SURFACE GUSTS IN THE FACE OF
GOOD MIXING THROUGH THE DIURNAL PEAK OF THE AFTERNOON. IN
GENERAL, THE WEST DESERT AND MANY WESTERN VALLEYS CAN EXPECT GUSTS
IN THE 30-40 MPH RANGE, WITH A FEW LOCALIZED SPOTS (ESPECIALLY IN
THE WEST DESERT) GUSTING CLOSER TO 45 MPH OR SO. ELSEWHERE EAST
OF THE HIGH TERRAIN, STILL WILL PROBABLY SEE BREEZY CONDITIONS
WITH GUSTS IN THE 20-35 MPH RANGE. GIVEN THAT MODEL GUIDANCE IF
ANYTHING TRENDED VERY SLIGHTLY DOWNWARD AND MAGNITUDES ARE A BIT
MARGINAL, HELD OFF ON ANY TARGETED WIND ADVISORY ISSUANCE FOR AT
LEAST ONE MORE SET OF MODEL RUNS TO COME IN. DESPITE THE RIDGE
STARTING TO SHIFT, H7 TEMPERATURES WILL BE SIMILAR TO THAT OF
SATURDAY, AND AS SUCH FORECAST HIGHS WILL ALSO BE SIMILARLY MILD.
ONE DIFFERENCE THOUGH IS THE FLOW IN COMBINATION WITH AT LEAST
SOME PHASING OF THE SOUTHERN STREAM WILL INCREASE MOISTURE AND
FORCING, YIELDING ISOLATED TO SCATTERED DIURNAL SHOWERS AND
THUNDERSTORMS. ACTIVITY WILL BE MOST FAVORED ALONG/NORTH OF THE
I-80 CORRIDOR, AND ALONG/EAST OF THE HIGH NORTHERN TERRAIN NORTH
OF THE I-70 CORRIDOR. PRECIPITATION COVERAGE WILL QUICKLY DIMINISH
MOVING INTO THE OVERNIGHT HOURS. WIND GUSTS ON A BROADER SCALE
WILL ALSO TREND DOWNWARD GIVEN DECREASED MIXING.
LONG TERM (AFTER 12Z/6AM MONDAY)
THE LONGWAVE TROUGH THAT WILL
BRING SEVERAL CONSECUTIVE WINDY DAYS THROUGHOUT SOUTHWEST WYOMING
AND UTAH WILL TRACK INTO THE WESTERN U.S. MONDAY. A LACK OF
SHORTWAVE ENERGY ROTATING IN WITH THE SOUTHWEST FLOW WILL BRING
DRIER CONDITIONS AFTER SHOWERS FOR THE END OF THE WEEKEND. THE
INCOMING LONGWAVE TROUGH WILL RESULT IN STRONGER WINDS AS A
STRENGTHENING PRESSURE GRADIENT WILL BE IN PLACE FOR MUCH OF THE
SOUTHWEST U.S. MODELS ARE IN GOOD AGREEMENT ON 700 MB WINDS OF 40-50
KNOTS. WITH DRY CONDITIONS AND EFFICIENT MIXING, GUSTS AT THE
SURFACE WILL BE SIMILAR.
THE BAROCLINIC ZONE ASSOCIATED WITH THE LONGWAVE TROUGH WILL BE TO
THE WEST THROUGH AT LEAST MOST OF MONDAY. THERE IS UNCERTAINTY ON
TIMING FOR WHEN THAT WILL REACH UTAH, WITH A MOST LIKELY RANGE FROM
MONDAY EVENING THROUGH TUESDAY MORNING. ALTHOUGH THERE IS
UNCERTAINTY WITH TIMING, THERE IS GOOD AGREEMENT WITH ENSEMBLE
MEMBERS ON THE AMPLITUDE OF THE SYSTEM, WITH MOST PRECIPITATION IN
SOUTHWEST WYOMING AND NORTHERN UTAH. VALLEY RAINFALL FOR THESE
LOCATIONS WILL GENERALLY RANGE FROM 0.25-0.75". SNOW LEVELS WILL BE
AROUND 6500 FEET AFTER THE FRONT TRACKS THROUGH. MOUNTAIN SNOW
ACCUMULATION WILL GENERALLY RANGE FROM 3-6" WITH LOCALLY HIGHER
TOTALS.
THE STORM SYSTEM WILL BRING STRONG COLD AIR ADVECTION. VALLEY
TEMPERATURES MONDAY WILL BE IN THE MID 80S FOR MUCH OF UTAH, AROUND
15F WARMER THAN NORMAL. IN THE POST-FRONTAL ENVIRONMENT BY
WEDNESDAY, VALLEY TEMPERATURES WILL GET TO AROUND 60F, AROUND 10F
COOLER THAN NORMAL.
THERE IS MORE UNCERTAINTY AFTER THE TROUGH AXIS SLIDES EAST, WITH
MOST ENSEMBLE MEMBERS BUILDING A RIDGE TO OFF THE WEST COAST. PRIOR
TO THAT SLIDING INLAND, SOME MEMBERS BRING SHORTWAVE ENERGY FROM THE
NORTHWEST, WHICH WOULD ALLOW FOR MORE PRECIPITATION.
AVIATION...KSLC
MOSTLY CLEAR CONDITIONS WITH LIGHT SOUTHEAST
WINDS WILL LAST THROUGH THE MORNING. SOUTHEAST WINDS WILL INCREASE
FOR THE AFTERNOON, WITH GUSTS AROUND 20 KNOTS. THERE IS ROUGHLY A 20-
30% CHANCE THAT WINDS TRANSITION TO NORTHWEST BETWEEN 21-00Z, IN
WHICH WIND SPEEDS WOULD BE LIGHTER. SOUTHEAST WINDS WILL STAY
ENHANCED INTO THE EVENING WITH INCREASING CLOUDS.
REST OF UTAH AND SOUTHWEST WYOMING...MOSTLY CLEAR CONDITIONS WITH
LIGHT WINDS WILL LAST THROUGH THE MORNING. WINDS RANGING FROM
SOUTHEAST TO SOUTHWEST WILL INCREASE BY LATE MORNING, WITH GUSTS
AROUND 20 KNOTS FOR SOUTHWEST WYOMING AND MOST OF UTAH. WINDS WILL
LIGHTEN, BUT STAY ENHANCED, INTO THE EVENING WITH INCREASING CLOUDS.
FIRE WEATHER
HIGH PRESSURE WILL REMAIN THE DOMINANT WEATHER
FEATURE OVER UTAH INTO THE WEEKEND. THIS WILL BRING CONTINUED
DRYING AND WARMING, WITH TEMPERATURES SATURDAY INTO SUNDAY
APPROACHING DAILY RECORD HIGHS. WITH THE STRONG HEATING, THERE
WILL BE SOME INSTABILITY, RESULTING IN VERY ISOLATED SHOWERS AND
THUNDERSTORMS EACH AFTERNOON OVER THE HIGHEST TERRAIN. THE RIDGE
WILL MOVE EAST SUNDAY AS A PACIFIC STORM SYSTEM MOVES ONSHORE,
RESULTING IN A SIGNIFICANT INCREASE IN SOUTHERLY FLOW. THERE IS A
MEDIUM CHANCE OF WIND GUSTS IN EXCESS OF 40 MPH AS EARLY AS SUNDAY
OVER WESTERN UTAH. THE CHANCE OF STRONG GUSTS BECOMES GREATER ON
MONDAY, WITH THE THREAT SPREADING ACROSS MUCH OF CENTRAL AND
SOUTHERN UTAH. THE THREAT FOR STRONG WINDS WILL PERSIST OVER
SOUTHEAST UTAH FOR TUESDAY. IN ADDITION TO THE WINDS, THE FRONT
WILL BRING MUCH COOLER TEMPERATURES BEGINNING TUESDAY, BRINGING
HIGHS BACK TO OR BELOW SEASONAL NORMALS, AND INCREASING RELATIVE
HUMIDITIES, WITH AREAS OF SHOWERS TUESDAY INTO WEDNESDAY,
PRIMARILY FOR NORTHERN AND CENTRAL UTAH.
FIRE WEATHER
HIGH PRESSURE INITIALLY SETTLED DIRECTLY ATOP
THE REGION SATURDAY MORNING WILL GRADUALLY START SHIFTING
EASTWARD. WHILE THE HIGH PRESSURE WILL MAINTAIN MILD AND GENERALLY
DRIER CONDITIONS, INCREASING SOUTH TO SOUTHWESTERLY DEEP LAYER
FLOW WILL IN TURN RESULT IN AN INCREASE IN DAILY WINDS. WIDESPREAD
WIND GUSTS IN THE 30-40 MPH RANGE ARE EXPECTED ACROSS MUCH OF
WESTERN UTAH SUNDAY AFTERNOON, INCREASING INTO THE 40-50 MPH RANGE
FOR MONDAY AS A STORM SYSTEM APPROACHES. A WEAKER EMBEDDED SYSTEM
WILL ALSO BRING SOME ISOLATED TO SCATTERED SHOWERS SUNDAY
AFTERNOON, PRIMARILY IN NORTHERN UTAH AND ALONG/EAST OF UTAH'S
HIGH TERRAIN. PRECIPITATION CHANCES INCREASE MORE MARKEDLY THROUGH
TUESDAY AS AFOREMENTIONED SYSTEM AND AN ASSOCIATED COLD FRONT
PUSH THROUGH. PRECIPITATION AND WETTING RAIN CHANCES WILL BE
HIGHEST ACROSS THE NORTHERN 2/3 OF UTAH, GENERALLY NORTH OF THE
I-70 CORRIDOR. OTHER THAN PRECIP, THIS WILL ALSO RESULT IN AN
ABRUPT WIND SHIFT AND ONSET OF COOLING TEMPERATURES. COOLER
UNSETTLED CONDITIONS WILL THEN LINGER ON THROUGH AT LEAST
THURSDAY, WITH UNCERTAINTY IN THE FORECAST EVOLUTION NOTED
THEREAFTER.
SLC WATCHES/WARNINGS/ADVISORIES
UT...NONE.
WY...NONE.
SHORT TERM...WARTHEN
LONG TERM...WILSON
AVIATION...WILSON
FIRE WEATHER...WARTHEN
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY
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