363
FXUS65 KSLC 132206
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
406 PM MDT TUE MAY 13 2025
SYNOPSIS
AS A LARGE PACIFIC TROUGH MOVES ACROSS THE AREA
THROUGH MIDWEEK, COOL AND UNSETTLED CONDITIONS WILL CONTINUE.
ANOTHER TROUGH WILL IMPACT THE AREA OVER THE WEEKEND.
SHORT TERM (THROUGH 12Z/6AM THURSDAY)
A COLD FRONT IS
POSITIONED NEAR A KMLF-KPUC LINE THIS AFTERNOON, THE LEADING EDGE
OF A BROAD PACIFIC TROUGH. LOCATIONS ALONG AND BEHIND THE
BOUNDARY ARE SEEING NOTICEABLY COOLER CONDITIONS, IN SOME SPOTS
30F OR MORE COOLER THAN VALUES OBSERVED YESTERDAY, WITH SCATTERED
SHOWERS. UNSEASONABLY WARM, DRY, AND VERY WINDY CONDITIONS HAVE
BEEN OBSERVED IN AREAS AHEAD OF THE FRONT, WITH SOME GUSTS IN
EXCESS OF 40 MPH. A WIND ADVISORY REMAINS IN EFFECT FOR THOSE AREA
INTO THE EVENING.
THE COOL AND UNSETTLED WEATHER WILL TONIGHT INTO WEDNESDAY AS THE
FRONT AND ASSOCIATED TROUGH CONTINUE EAST. MOISTURE WILL REMAIN
THE LIMITING FACTOR WITH ASSOCIATED SHOWER ACTIVITY, BUT SHOULD
CONTINUE TO SEE GOOD COVERAGE OF SHOWERS ACROSS NORTHERN AND
CENTRAL UTAH, PARTICULARLY DURING THE DAY WEDNESDAY. MAXES WILL
AVERAGE 10F BELOW SEASONAL NORMALS ACROSS THE AREA.
LONG TERM (AFTER 12Z/6AM THURSDAY)
AS ONE COLD, LATE SEASON
TROUGH DEPARTS THE REGION TOWARD THE END OF THE WEEK, ANOTHER ONE
WILL BE IN THE QUEUE AND IS ANTICIPATED TO PROGRESS THROUGH THE
REGION OVER THE WEEKEND. AS A RESULT, THE BIG PICTURE TRENDS IN THE
WEATHER LATE IN THE WEEK THROUGH EARLY NEXT WEEK WILL BE
CHARACTERIZED BY COOLER AND WETTER CONDITIONS ACROSS MUCH OF THE
FORECAST AREA.
ON THURSDAY, A TRAILING SHORTWAVE TROUGH WILL ACCOMPANY THE BACK END
OF THE DEPARTING LONGWAVE TROUGH THAT HAS BROUGHT US MUCH COOLER AND
WETTER CONDITIONS ON TUESDAY AND WEDNESDAY. THE RESULTING INCREASE
IN MID-LEVEL INSTABILITY WILL HELP TO DRIVE AFTERNOON SHOWERS AND
THUNDERSTORMS ACROSS THE NORTHERN HALF OF UTAH WHILE MAINTAINING
COOLER SURFACE TEMPERATURES. TEMPERATURES WILL REBOUND BY UPWARDS OF
5-7 DEGREES ACROSS UTAH AND SOUTHWEST WYOMING, HOWEVER, DAYTIME
HIGHS WILL STILL FALL SHORT OF CLIMATOLOGICAL NORMALS FOR THIS TIME
OF YEAR (ANYWHERE FROM 2 TO 10 DEGREES BELOW NORMAL), PARTICULARLY
ACROSS NORTHERN UTAH AND SOUTHWEST WYOMING. SLOW WARMING CONTINUES
ACROSS THE REGION THROUGH FRIDAY AS THE AFOREMENTIONED SHORTWAVE
DEPARTS AND LOW LEVEL TEMPERATURES INCREASE... BUT AGAIN,
TEMPERATURES WILL FALL SHORT OF NORMAL. ISOLATED SHOWERS AND
THUNDERSTORMS MAY STILL BE PRESENT OVER THE HIGH TERRAIN IN THE
NORTHERN AREA BY FRIDAY AFTERNOON, BUT THIS TIME WITH FAR LESS
COVERAGE AS COMPARED TO THURSDAY.
SHORTLY THEREAFTER, AN UPSTREAM LONGWAVE TROUGH WILL BEGIN
ENCROACHING ON THE WEST COAST LATE FRIDAY NIGHT THROUGH EARLY
SATURDAY. THE LEADING SHORTWAVE AND ITS ASSOCIATED COLD FRONTAL
BOUNDARY ARE EXPECTED TO ARRIVE OVER THE EASTERN GREAT BASIN REGION
BY SATURDAY AFTERNOON, BRINGING AN INCREASE IN COVERAGE OF SHOWERS
AND THUNDERSTORMS ACROSS UTAH AND SOUTHWEST WYOMING, PARTICULARLY
TOWARD THE EVENING HOURS. DYNAMICS ASSOCIATED WITH THIS TROUGH
APPEAR TO BE MAXIMIZED THROUGH THE OVERNIGHT HOURS (BASED ON
ENSEMBLE GUIDANCE) FROM SATURDAY INTO SUNDAY. AS SUCH, WOULD
ANTICIPATE THIS PERIOD TO FEATURE SOME OF THE HEAVIEST PRECIPITATION
ACROSS THE REGION. THE COLD CORE OF THIS FEATURE WILL LINGER OVER
THE FORECAST AREA THROUGH SUNDAY, THEN BEGIN TO DEPART THE REGION
THROUGH MONDAY. WHILE THE COLD CORE LINGERS, EXPECT SHOWERS TO EXIST
ACROSS THE FORECAST AREA, WITH THE AFTERNOON HOURS FAVORING THE
HEAVIEST PRECIPITATION POTENTIAL DUE TO ENHANCED CONVECTION.
CURRENT PRECIPITATION AMOUNTS RANGE FROM 0.1-0.25IN ACROSS THE
NORTHERN TWO-THIRDS OF THE AREA (10TH PERCENTILE) TO A WIDESPREAD
0.7-1.2IN WITH UPWARDS OF 2-2.5IN IN THE HIGHEST TERRAIN ACROSS
UTAH. THE SPREAD IS QUITE LARGE AT THIS POINT IN TIME, HOWEVER, THE
AREA MOST LIKELY TO EXPERIENCE HIGHER PRECIPITATION AMOUNTS WILL BE
ACROSS NORTHERN UTAH, WITH SOUTHERN UTAH ACTUALLY SEEING ABOUT A 10-
15% CHANCE OF NOT SEEING ANY PRECIPITATION AT ALL. GIVEN THE COLD
TEMPERATURES ASSOCIATED WITH THE TROUGH, SNOW LEVELS ARE ANTICIPATED
TO DROP BELOW 8,000FT BY SUNDAY EVENING. HIGHER ELEVATION VALLEY
AREAS MAY BEGIN TO SEE SNOW MIX IN WITH RAIN DURING THIS PERIOD,
HOWEVER, SIGNIFICANT ACCUMULATIONS ARE NOT EXPECTED AT THIS TIME.
THE MOST SIGNIFICANT ACCUMULATIONS OF SNOWFALL ARE EXPECTED AT THE
HIGHEST ELEVATIONS ACROSS UTAH AT THIS TIME (WESTERN UINTAS, HIGH
SUMMITS OF THE CENTRAL WASATCH, TUSHAR MOUNTAINS, ETC.). WILL NEED
TO MONITOR THE TRENDS IN HOW COLD THIS SYSTEM GETS AND WHETHER OR
NOT PEAK DYNAMIC FORCING AND MOISTURE ACCOMPANY THE COLD. CURRENT
MODELED 48-HOUR SNOWFALL SUPPORTS UPWARDS OF 20 INCHES IN THE UPPER
COTTONWOODS AT THE 90TH PERCENTILE... SIGNIFICANT IMPACTS WILL
MATERIALIZE IF THIS SCENARIO BECOMES MORE LIKELY.
AVIATION...KSLC
SHOWERS WILL CONTINUE, WITH A BRIEF LULL POSSIBLE
BETWEEN ~23-01Z. ANOTHER TRAILING ROUND OF SHOWERS WILL IMPACT THE
TERMINAL AROUND 01-04Z, WITH WINDS TRANSITIONING TO SOUTHEASTERLY
THEREAFTER. THESE SHOWERS MAY BE SLIGHTLY MORE CONVECTIVE IN NATURE,
WITH A 10% CHANCE OF THUNDERSTORMS ON STATION. A FEW SHOWERS MIGHT
DEVELOP TO THE NORTH OVER ~KOGD BETWEEN 05-10Z, BUT SHOULD REMAIN
FAR ENOUGH NORTH TO AVOID ANY IMPACTS AT KSLC. MOUNTAIN OBSCURATION
AND VFR CONDITIONS ARE LIKELY TO CONTINUE.
REST OF UTAH AND SOUTHWEST WYOMING
GUSTY SOUTHWESTERLY WINDS
CONTINUE AHEAD OF THE COLD FRONT, WHICH IS CURRENTLY SITUATED OVER
ROUGHLY KMLF-KPUC-KU69 (AS OF 3PM). THIS FRONT WILL CONTINUE TO
SHIFT EASTWARD THROUGH THE EVENING, WITH A TRANSITION TO GUSTY
NORTHWESTERLY WINDS AFTER THE FRONTAL PASSAGE. WINDS WILL LARGELY
DIMINISH AFTER 03-05Z. SHOWERS CURRENTLY LOCATED WEST OF I-15 AND/OR
NORTH OF I-70 WILL GRADUALLY DECREASE IN COVERAGE THROUGH THE
EVENING, WITH A FEW LINGERING SHOWERS POSSIBLE OVERNIGHT NEAR
KMLF/KCDC AND KOGD IN PARTICULAR. MOST AREAS WILL CONTINUE TO SEE
VFR CONDITIONS, THOUGH ISOLATED MVFR CIGS CANNOT BE RULED OUT.
FIRE WEATHER
A STRONG TROUGH AND ASSOCIATED COLD FRONTAL
BOUNDARY WILL CONTINUE TO GRADUALLY WORK SOUTHEAST THROUGH UTAH
TUESDAY. AHEAD OF THE FRONT, PRIMARILY EAST OF UTAH'S HIGH
TERRAIN, STRONG GUSTY SOUTH TO SOUTHWEST WINDS WILL REDEVELOP AND
AFTERNOON HUMIDITY VALUES WILL REMAIN IN THE HIGH SINGLE DIGITS TO
MID TEENS. WINDS WILL TREND WEST TO NORTHWESTERLY BEHIND THE
FRONT AND REMAIN MORE MODESTLY GUSTY FOR A PERIOD OF TIME. SHOWERS
AND A FEW THUNDERSTORMS WILL ACCOMPANY THE FRONT, WITH FORCING
AND MOISTURE SUFFICIENT TO THEN MAINTAIN SHOWER CHANCES BEHIND THE
FRONT INTO MIDWEEK AS THE BROADER/DEEPER SYSTEM SHIFTS THROUGH
OVERHEAD. SOME LIGHT SNOW ACCUMULATION WILL BE POSSIBLE AT HIGH
ELEVATION LOCATIONS GENERALLY ABOVE 9000 FEET. A SERIES OF WEAKER
REINFORCING WAVES WILL HELP KEEP AN UNSETTLED PATTERN CONTINUE
THROUGH THE REMAINDER OF THE WORK WEEK, ESPECIALLY FOR NORTHERN
UTAH. ANOTHER FAIRLY DEEP AND MOIST SYSTEM THEN REMAINS FAVORED TO
IMPACT UTAH THROUGH THE WEEKEND.
SLC WATCHES/WARNINGS/ADVISORIES
UT...WIND ADVISORY UNTIL 9 PM MDT THIS EVENING FOR UTZ120-121-126>131.
WY...NONE.
SHORT TERM/FIRE WEATHER...TRAPHAGAN
LONG TERM...WEBBER
AVIATION...CUNNINGHAM
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY
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