969
FXUS65 KSLC 211945
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
145 PM MDT FRI AUG 21 2026
KEY MESSAGES, ISSUED 1018 PM MDT THU AUG 20 2026
- HOT TEMPERATURES WILL PERSIST OVER THE VALLEYS OF NORTHERN UTAH
FRIDAY, WITH LOW TEMPERATURES IN THE MID TO UPPER 70S PROVIDING
LITTLE OVERNIGHT RECOVERY.
- MONSOONAL MOISTURE WILL SURGE INTO UTAH AND SOUTHWEST WYOMING
FRIDAY AND SATURDAY, BRINGING AN INCREASED THREAT OF
THUNDERSTORMS PRODUCING HEAVY RAINFALL AND FLASH FLOODING.
- MOISTURE IS EXPECTED TO DECREASE FROM SUNDAY THROUGH TUESDAY,
BRINGING LESS COVERAGE OF SHOWERS AND THUNDERSTORMS AND LOWER
POTENTIAL FOR HEAVY RAINFALL EARLY NEXT WEEK AND BEYOND.
DISCUSSION
LATE MORNING AND AFTERNOON SATELLITE IMAGERY REVEALS
A BROAD VEIL OF CLOUD COVER MOVING ACROSS CENTRAL AND NORTHERN
UTAH WITH FAR SOUTHERN AND EASTERN UTAH REMAINING LARGELY CLOUD
FREE. WITHIN THIS AREA OF ENHANCED CLOUD COVER, ISOLATED
THUNDERSTORMS ARE DEVELOPING, OWING TO THE INCREASED ATMOSPHERIC
MOISTURE AND INSTABILITY BUILDING INTO THE REGION. FOR THE
NORTHERN AND CENTRAL PORTIONS OF THE FORECAST AREA, SHOWER AND
THUNDERSTORM COVERAGE IS EXPECTED TO INCREASE THROUGH THE
AFTERNOON AS THE SHORTWAVE LEADING THE INFLUX OF MOISTURE
CONTINUES NORTH. THE SUBSIDENT WAKE OF THIS WAVE, HOWEVER, IS
LIKELY TO LIMIT THE AMOUNT OF CONVECTION AND STORM DEVELOPMENT
THAT WE SEE ACROSS THE SOUTHERN AREA. THIS IS THE BIGGEST CHANGE
WITH THE FORECAST TODAY. AS SUCH, WHILE THUNDERSTORMS PRODUCING
HEAVY RAINFALL AND INCREASED FLASH FLOOD POTENTIAL ARE STILL
EXPECTED IN SOUTHERN UTAH, THE COVERAGE OF SUCH WILL BE MUCH LESS
THAN PREVIOUSLY FORECAST. THIS THREAT IS NOW TRANSITIONING INTO
CENTRAL UTAH, AS WELL AS A PORTION OF NORTHERN UTAH. IN NORTHWEST
UTAH WHERE SUFFICIENT SURFACE MOISTURE IS LACKING, ANY STORMS
DEVELOPING WILL CARRY POTENTIAL FOR STRONG OUTFLOW WINDS IN EXCESS
OF 40 MPH.
THIS WAVE OF ENERGY WILL EXIT THE REGION THROUGH SATURDAY, PLACING
MUCH OF THE FORECAST AREA UNDER A SUBSIDENT WAKE. WHILE
ATMOSPHERIC MOISTURE WILL BE ELEVATED, THE AREAWIDE SUBSIDENCE
WILL HELP TO INHIBIT WIDESPREAD SHOWER AND THUNDERSTORM COVERAGE.
AGAIN, WHILE COVERAGE IS NOT EXPECTED TO BE AS WIDESPREAD AS
PREVIOUSLY THOUGHT, ANY STORMS THAT DO DEVELOP WILL CARRY HIGHER
THAN NORMAL POTENTIAL OF HEAVY RAINFALL. IF THESE STORMS END UP
OVER A PARTICULARLY SENSITIVE AREA (SLOT CANYONS, RECENT BURN
SCARS, URBANIZED AREAS, ETC.) THEN THE THREAT OF FLASH FLOODING
WILL BE ELEVATED.
THE INCREASE IN AREAWIDE MOISTURE WILL HELP TO MODERATE
TEMPERATURES AS WE HEAD THROUGH THE WEEKEND, WITH MOST AREAS
OUTSIDE OF LOWER WASHINGTON COUNTY EXPECTED TO FALL BELOW TRIPLE
DIGIT TERRITORY. MODELS HAVE BEEN CONSISTENT WITH THE SUPPORT OF A
DRYING ATMOSPHERE FROM SUNDAY FORWARD, WHICH WILL ALLOW FOR LOWER
COVERAGE OF SHOWERS AND THUNDERSTORMS ACROSS UTAH AND SOUTHWEST
WYOMING, AS WELL AS A DECREASING RISK OF FLASH FLOODING INTO EARLY
NEXT WEEK. DRY CONDITIONS LOOK TO BE MAINTAINED FROM ROUGHLY
WEDNESDAY FORWARD AS MOISTURE VACATES THE REGION AND HIGH PRESSURE
REMAINS IN PLACE.
AVIATION...KSLC
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING
SOUTH AND EAST OF THE TERMINAL EARLY THIS AFTERNOON WILL BRING A
CHANCE OF LIGHTNING AND STRONG OUTFLOW WINDS IN EXCESS OF 40 KTS
DURING THE 23-02Z TIMEFRAME. AWAY FROM THUNDERSTORMS, VFR CONDITIONS
WITH SOUTHERLY WINDS WILL PREVAIL THROUGH THE AFTERNOON AND EVENING.
REST OF UTAH AND SOUTHWEST WYOMING...SCATTERED SHOWERS AND
THUNDERSTORMS WILL BRING A CHANCE FOR LIGHTNING AND STRONG OUTFLOW
WINDS IN EXCESS OF 40 KTS TO NORTHERN TERMINALS THROUGH 03Z THIS
EVENING. ISOLATED SHOWERS AND THUNDERSTORMS ARE POSSIBLE FURTHER
SOUTH NEAR KCDC AND KSGU. AWAY FROM ANY THUNDERSTORMS, VFR
CONDITIONS CAN BE EXPECTED THROUGH THE TAF PERIOD WITH SOUTHERLY
WINDS THIS AFTERNOON BECOMING TERRAIN DRIVEN THIS EVENING.
FIRE WEATHER
HOT TEMPERATURES REMAIN IN PLACE ACROSS THE AREA TODAY, WITH
DRY CONDITIONS EXPECTED IN NORTHWEST AND EASTERN UTAH WHILE
SOUTHWEST UTAH SEES AN INCREASE IN MOISTURE. WITH THE INCREASE IN
MOISTURE ACROSS THE SOUTHERN HALF OF UTAH, AFTERNOON SHOWER AND
THUNDERSTORM DEVELOPMENT IS EXPECTED THROUGH THE REMAINDER OF
TODAY WITH STORMS BRINGING POTENTIAL FOR WETTING RAINS. COVERAGE
OF SHOWERS AND THUNDERSTORMS WILL BE GREATEST ACROSS CENTRAL AND
NORTHERN UTAH, HOWEVER, WETTING RAIN POTENTIAL WILL DECREASE NORTH
OF THE US-50/ I-70 CORRIDOR. THE BIGGER THREAT FOR CENTRAL AND
NORTHERN UTAH WILL BE ISOLATED DRY LIGHTNING AND GUSTY OUTFLOW
WINDS IN EXCESS OF 35-40 MPH. THESE STRONG WINDS AND DRY SURFACE
CONDITIONS MAY BRING SHORT-LIVED CRITICAL FIRE WEATHER CONDITIONS.
MOISTURE WILL CONTINUE TO PUSH NORTHWARD ON SATURDAY, BRINGING
IMPROVEMENT TO AFTERNOON HUMIDITY ACROSS THE NORTHERN AND CENTRAL
AREA WHILE THE SOUTHERN AREA WILL SEE THE BEGINNING OF A SLOW
DRYING TREND. THAT SAID, SHOWER AND THUNDERSTORM POTENTIAL WILL
STILL BE ELEVATED OVER THE HIGH TERRAIN FEATURES THROUGHOUT UTAH
OVER THE WEEKEND, HOWEVER, THE CHANCES FOR WETTING RAINS WILL
SHARPLY DECREASE. MOISTURE WILL GRADUALLY DECREASE AREAWIDE EACH
DAY FROM SUNDAY THROUGH TUESDAY NEXT WEEK, WITH DECREASING
COVERAGE OF PRECIPITATION EXPECTED ALONGSIDE A DRYING SURFACE
HUMIDITY TREND. BY WEDNESDAY, WIDESPREAD HUMIDITY AT, OR BELOW, 15
PERCENT IS ANTICIPATED TO BE MAINTAINED THROUGH THE REMAINDER OF
THE WEEK.
SLC WATCHES/WARNINGS/ADVISORIES
UT...HEAT ADVISORY UNTIL 7 AM MDT SATURDAY FOR UTZ101>106.
WY...NONE.
PUBLIC...WEBBER
AVIATION...SEAMAN
FIRE WEATHER...WEBBER
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY
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