620
FXUS65 KSLC 201855
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1255 PM MDT SUN SEP 20 2026
KEY MESSAGES, ISSUED 1001 PM MDT SAT SEP 19 2026
- HIGH PRESSURE WILL BRING DRY CONDITIONS THROUGH MONDAY WITH
TEMPERATURES NEAR OR JUST BELOW SEASONAL NORMALS.
- MOISTURE AND INSTABILITY WILL RETURN TO THE AREA BEGINNING LATE
MONDAY, BRINGING AN INCREASING POTENTIAL OF SHOWERS AND
THUNDERSTORMS. THE UNSETTLED PATTERN IS MOST LIKELY TO CONTINUE
FOR MUCH OF THE REMAINDER OF THE UPCOMING WEEK.
DISCUSSION, ISSUED 1001 PM MDT SAT SEP 19 2026
THE PACIFIC NORTHWEST LOW THAT HAS BEEN MOVING
ACROSS NORTHERN UTAH IS NOW CENTERED OVER CENTRAL WYOMING THIS
EVENING. ISOLATED SHOWERS AND THUNDERSTORMS CONTINUED INTO THE
EARLY EVENING FOR NORTHEASTERN PORTIONS OF THE FORECAST AREA, BUT
GIVEN THE LOSS OF DAYTIME HEATING AND THE EASTWARD MOVEMENT OF THE
LOW, SHOWERS HAVE DISSIPATED AND SKIES ARE MOSTLY CLEAR FOR THE
VAST MAJORITY OF THE AREA. NORTHERN UTAH AND SOUTHWEST WYOMING
LOCATIONS SAW MUCH COOLER TEMPERATURES TODAY, WITH MAXES AVERAGING
10F BELOW SEASONAL NORMALS. OVER SOUTHERN UTAH, THERE WAS MUCH
LESS COOLING, KEEPING TEMPERATURES NEAR NORMAL FOR THIS TIME OF
YEAR.
HIGH PRESSURE IS EXPECTED TO MOVE OVERHEAD TOMORROW AFTERNOON,
WITH UTAH AND SOUTHWEST WYOMING SANDWICHED IN BETWEEN THE EXITING
LOW AND ANOTHER ONE APPROACHING THE CALIFORNIA COAST. AS THE RIDGE
BUILDS, MAXES FOR NORTHERN PORTIONS OF THE AREA WILL INCREASE BY A
FEW DEGREES, RUNNING 5-7F ABOVE SEASONAL NORMALS, WITH LITTLE
CHANGE OVER SOUTHERN UTAH. BY MONDAY AFTERNOON, THE RIDGE AXIS IS
ON TRACK TO MOVE INTO COLORADO, WITH THE RESULTANT SOUTHERLY FLOW
BRINGING TEMPERATURES BACK TO NEAR NORMALS ACROSS THE ENTIRE AREA.
SOUTHERLY FLOW OVER THE AREA IS EXPECTED TO INCREASE BY MONDAY
NIGHT AS THE CALIFORNIA LOW MAKES ITS WAY INTO THE GREAT BASIN. IN
THIS FLOW, MONSOONAL MOISTURE IS EXPECTED TO ADVECT BACK NORTHWARD
INTO THE AREA, WITH PWS EXPECTED TO BE IN THE 0.6 TO 0.8 INCH
RANGE ACROSS MUCH OF THE AREA BY EARLY TUESDAY. THOUGH CONFIDENCE
IS HIGH THAT THERE WILL BE LESS MOISTURE COMING UP WITH THIS PUSH
THAN WHAT WAS SEEN LAST WEEK, IT WILL STILL INCREASE THE POTENTIAL
OF SHOWERS AND THUNDERSTORMS ACROSS THE AREA. THERE REMAINS SOME
SPREAD IN THE GUIDANCE WITH REGARD TO THE SYSTEM'S TRACK AFTER IT
MOVES INTO THE GREAT BASIN AND HOW MUCH IT WEAKENS WHILE ONSHORE.
HOWEVER, THE MAJORITY OF GUIDANCE IS NOW INDICATING IT WILL TAKE A
TURN INTO SOUTHERN UTAH MONDAY NIGHT, MOVING ACROSS THE REMAINDER
OF THE AREA IN A WEAKENED STATE DURING THE DAY TUESDAY. WITH THIS
EXTRA INSTABILITY, THE FORECAST FOR COVERAGE OF CONVECTION ON
TUESDAY IS DEFINITELY TRENDING UPWARD.
ENSEMBLE SPREAD INCREASES FURTHER FOR THE LATTER PART OF THE
UPCOMING WEEK. GUIDANCE IS GENERALLY FAVORING A CONTINUED
UNSETTLED PATTERN FOR MUCH OF THE REMAINDER OF THE WEEK, KEEPING
TEMPERATURES NEAR NORMAL WITH OCCASIONAL CHANCES OF SHOWERS AND
THUNDERSTORMS. IT SHOULD BE NOTED THAT A MINORITY OF GUIDANCE,
INCLUDING THE LATEST DETERMINISTIC EC, SHOW STRONG HIGH PRESSURE
RETURNING BY LATE IN THE UPCOMING WEEK, BRINGING A WARMING AND
DRYING TREND.
AVIATION, ISSUED 509 AM MDT SUN SEP 20 2026
KSLC...VFR CONDITIONS WILL PERSIST ACROSS THE KSLC AIRSPACE THROUGH
THE TAF PERIOD WITH DIURNAL WIND SHIFTS. THE NEXT WIND SHIFT TO
NORTHWESTERLY CAN BE EXPECTED AROUND 18Z.
REST OF UTAH AND SOUTHWEST WYOMING...VFR CONDITIONS ARE EXPECTED TO
PERSIST ACROSS ALL TERMINALS THROUGH THE TAF PERIOD WITH DIURNAL
WIND SHIFTS. LOW CLOUDS ARE EXPECTED THROUGH THE MORNING AT KEVW
WITH BRIEF INSTANCES OF IFR CIGS POSSIBLE, THOUGH LENGTH REMAINS
UNCERTAIN ENOUGH TO LEAVE OUT OF THE TAF AT THIS TIME.
FIRE WEATHER
COOL, DRY, AND STABLE CONDITIONS WILL CONTINUE AREAWIDE UNTIL MONDAY
EVENING WHEN SHOWERS AND STORMS MOVE INTO SOUTHERN UTAH THANKS TO
AN AREA OF LOW PRESSURE MOVING INTO THE GREAT BASIN. THESE STORMS
WILL BE MOVING FROM SOUTH TO NORTH, ARRIVING IN NORTHERN UTAH ON
TUESDAY. THESE STORMS WILL BE FAST MOVING, BUT RAINFALL RATES WILL
BE HIGH ENOUGH TO QUICKLY PRODUCE WETTING RAINS. SOME STRONG
STORMS WILL BE EMBEDDED WITHIN THE COMPLEX WHICH WILL BE CAPABLE
OF STRONG AND ERRATIC WINDS, FREQUENT LIGHTNING, AND SOME HAIL.
CONDITIONS BECOME MOSTLY DRY AND STABLE BY WEDNESDAY, EXCEPT FOR
AREAS OF EASTERN UTAH THAT HOLD ON TO MOISTURE, WITH NEAR NORMAL
CONDITIONS PERSISTING THROUGH THE REMAINDER OF THE WEEK.
SLC WATCHES/WARNINGS/ADVISORIES
UT...NONE.
WY...NONE.
PUBLIC...TRAPHAGAN
AVIATION...WORSTER
FIRE WEATHER...MAHAN
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY
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