861
FXUS65 KSLC 222120
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
320 PM MDT WED OCT 22 2025
SYNOPSIS
A LOW PRESSURE SYSTEM WILL CROSS THE DESERT SOUTHWEST
THROUGH EARLY FRIDAY, BRINGING UNSETTLED CONDITIONS, PARTICULARLY
FOR SOUTHERN UTAH. HIGH PRESSURE WILL RETURN FOR FRIDAY INTO
SATURDAY BEFORE A COLDER SYSTEM IMPACTS THE AREA SUNDAY INTO
MONDAY.
SHORT TERM (THROUGH 12Z/6AM FRIDAY)
A BROAD LOW PRESSURE HAS
MOVED OVER SOUTHERN CALIFORNIA THIS AFTERNOON, WITH THE FRONT END
OF THE SYSTEM APPROACHING SOUTHWEST UTAH. SEEING SOME LIGHT
SHOWERS CONTINUING OVER SOUTHERN PORTIONS OF UTAH, PARTICULARLY
THE SOUTHWEST, WITH COVERAGE EXPECTED TO INCREASE AND SPREAD
NORTHWARD AS THE LOW CONTINUES EASTWARD INTO THE DESERT SOUTHWEST.
TEMPERATURES THIS AFTERNOON ARE SIMILAR TO YESTERDAY, WITH MAXES
NEAR TO JUST BELOW SEASONAL NORMALS.
THE LOW IS ON TRACK TO CROSS ARIZONA TOMORROW BEFORE MOVING INTO
NEW MEXICO AND COLORADO ON FRIDAY. THE PRESENCE OF THE LOW WILL
KEEP CONDITIONS UNSETTLED OVER SOUTHERN UTAH, WITH THE FOCUS OF
ASSOCIATED SHOWER ACTIVITY MOVING EASTWARD WITH THE TRACK OF THE
LOW. WITH THE PERSISTENT CLOUD COVER, SOUTHERN UTAH TEMPERATURES
WILL DROP BELOW SEASONAL NORMALS WITH LITTLE DIFFERENCE IN
NORTHERN UTAH TEMPERATURES.
LONG TERM (AFTER 12Z/6AM FRIDAY)
FORECAST UNCERTAINTY CONTINUES
TO BE FAIRLY HIGH REGARDING THE WEEKEND STORM, WITH STILL HIGHER
THAN AVERAGE SPREAD IN QPF AND MOUNTAIN SNOW ACROSS NORTHERN UTAH
AND SOUTHWEST WYOMING.
AT THE START OF THE LONG-TERM, HOWEVER, EXPECT LARGELY QUIESCENT
CONDITIONS WITH HIGH PRESSURE RESIDING OVER THE REGION ON FRIDAY AND
INTO SATURDAY. HIGH TEMPERATURES WILL INCREASE FRIDAY INTO SATURDAY
AHEAD OF THE NEXT STORM SYSTEM, REACHING AROUND 5-10 DEGREES ABOVE
NORMAL STATEWIDE.
BY SATURDAY EVENING, HOWEVER, MOISTURE WILL BEGIN TO FILTER INTO THE
STATE FROM THE NORTHWEST AS A BROAD LONGWAVE TROUGH PUSHES THROUGH
THE NORTHWESTERN US. POPS WILL INCREASE FROM WEST TO EAST,
OVERSPREADING THE NORTHERN HALF OF UTAH BY SUNDAY MORNING. DESPITE
EXCELLENT SYNOPTIC SUPPORT, THERE IS STILL A HIGHER DEGREE OF
UNCERTAINTY WITH THE AMOUNT OF MOISTURE THAT MAKES IT THIS FAR
INLAND, AS THE SIERRA NEVADA WILL LIKELY BLOCK A LOT OF THAT
MOISTURE GIVEN THE PLUME'S TRAJECTORY. TO QUANTIFY THIS UNCERTAINTY,
THE NBM 25TH-75TH QPF SPREAD IN THE COTTONWOODS RANGES FROM 0.15-
1.00" OF LIQUID EQUIVALENT...STILL LOWER OVERALL THAN PRIOR
FORECASTS. THIS COULD BE THE DIFFERENCE BETWEEN A 2-4" SNOWSTORM AND
AN 10-14" STORM. A SIMILAR DEGREE OF UNCERTAINTY CAN BE FOUND IN
NORTHERN VALLEYS, TOO, THOUGH IT'S WORTH NOTING THAT UNCERTAINTY
DECREASES FURTHER NORTH AND THAT THE VALLEY SNOW POTENTIAL HAS
DECREASED.
ANOTHER AREA OF UNCERTAINTY INITIALLY IS HOW FAR SOUTH THE TROUGH'S
ASSOCIATED COLD FRONT WILL REACH, WHICH COULD DICTATE SNOW LEVELS AS
WELL AS THE LAKE-EFFECT POTENTIAL EARLY NEXT WEEK. AS THIS FRONT
PUSHES THROUGH AT LEAST NORTHERN UTAH BY SUNDAY AFTERNOON, 700-MB
TEMPERATURES WILL DROP INITIALLY DOWN TO -5C TO +1C (ANOTHER 25TH-
75TH PERCENTILE THAT HAS A WIDE SPREAD), WITH SNOW LEVELS AROUND
6000-8000FT.
AS FLOW TURNS MORE ZONAL HEADING INTO MONDAY, WE COULD SEE A
SECONDARY PUSH OF MOISTURE ALONG A WEAK WAVE COMING FROM N-CA/S-OR,
RESULTING IN MORE PRECIPITATION AND A SECONDARY DECREASE IN
TEMPERATURES ALONG THIS MOIST WESTERLY TO WEST-NORTHWESTERLY FLOW.
ENSEMBLE GUIDANCE SUGGESTS STILL A WIDE RANGE IN H7 TEMPERATURES
ACROSS NORTHERN UTAH AROUND -9C TO -2C. IF THE COOLER SOLUTIONS PAN
OUT, WE COULD SEE MUCH LOWER SNOW LEVELS AS WELL AS HIGHER CHANCES
FOR LAKE-EFFECT PRECIPITATION OR AT LEAST LAKE-ENHANCEMENT,
PARTICULARLY FOR AREAS ALONG THE NORTHERN WASATCH.
AFTER TUESDAY, FORECAST CONFIDENCE INCREASES IN HIGH PRESSURE
BUILDING ACROSS THE WESTERN US, LIKELY BRINGING WARMER AND DRIER
CONDITIONS TO THE FORECAST AREA.
AVIATION...KSLC
LIGHT NORTHWEST WINDS WILL TRANSITION TO LIGHT
SOUTHEAST WINDS AROUND 03Z. BROKEN CLOUDS IN VFR RANGE WILL PREVAIL.
ISOLATED RAIN SHOWERS WILL BE CAPABLE OF ALTERING WIND DIRECTION
FROM 03-12Z.
REST OF UTAH AND SOUTHWEST WYOMING
RELATIVELY LIGHT WINDS WITH
ISOLATED TO SCATTERED RAIN SHOWERS MOSTLY SOUTH OF KSLC WILL LAST
THROUGH 12Z. SHOWERS WILL BE CAPABLE OF OUTFLOW WINDS THAT ALTER
WIND DIRECTION. CLOUDS AND PRECIPITATION WILL DIMINISH FROM
NORTHWEST TO SOUTHEAST THROUGH THE DAY.
SLC WATCHES/WARNINGS/ADVISORIES
UT...NONE.
WY...NONE.
SHORT TERM...TRAPHAGAN
LONG TERM...CUNNINGHAM
AVIATION...WILSON
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY
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