134  
FXUS65 KSLC 210842  
AFDSLC  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SALT LAKE CITY UT  
242 AM 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, PERSISTING THROUGH AT LEAST EARLY NEXT  
WEEK. THIS WILL BRING AN INCREASED THREAT OF SHOWERS AND  
THUNDERSTORMS CAPABLE OF PRODUCING HEAVY RAIN THAT COULD LEAD TO  
FLASH FLOODING.  
 

 
   
DISCUSSION, ISSUED 1018 PM MDT THU AUG 20 2026
 
 
HIGH PRESSURE IS CENTERING ITSELF OVER THE FOUR  
CORNERS REGION THIS EVENING, WITH A SOUTHERLY FLOW DEVELOPING OVER  
UTAH AND SOUTHWEST WYOMING. DESPITE SOME DRYING OVER THE PAST  
COUPLE OF DAYS, SATELLITE DERIVED PW VALUES ARE STILL  
PREDOMINATELY IN THE 0.7 TO 0.8 INCH RANGE, MORE THAN ENOUGH FOR  
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS OVER THE HIGHER TERRAIN  
THIS AFTERNOON, WITH CONVECTIVE ACTIVITY CONTINUING OVER SOUTHERN  
UTAH, INCLUDING A FEW STRONG THUNDERSTORMS SHORT RANGE GUIDANCE IS  
INDICATING THAT SHORTWAVE ENERGY MOVING IN FROM ARIZONA SHOULD  
KEEP SOME SHOWERS AND THUNDERSTORMS GOING THROUGH THE FIRST PART  
OF THE OVERNIGHT HOURS, WITH COVERAGE DIMINISHING AS SUNRISE  
APPROACHES.  
 
TEMPERATURES WERE QUITE HOT ACROSS THE VALLEYS OF NORTHERN UTAH  
THIS AFTERNOON, WITH MOST VALLEYS SEEING TEMPERATURES AROUND 100F.  
LOWS IN THE LOWER TO MID 70S WILL NOT PROVIDE MUCH IN THE WAY OF  
RELIEF, WITH HIGHS IN THIS AREA TOMORROW EXPECTED TO BE SIMILAR TO  
TODAY. GOING HEAT ADVISORY COVERS THIS THREAT WELL.  
 
THE SOUTHERLY FLOW THAT IS DEVELOPING WILL ALLOW MONSOON MOISTURE  
TO SPREAD INTO CENTRAL AND SOUTHERN UTAH DURING THE DAY FRIDAY AND  
INTO NORTHERN PORTIONS OF THE AREA FRIDAY EVENING INTO SATURDAY  
MORNING. AS A RESULT, COVERAGE OF CONVECTION WILL BE MORE  
WIDESPREAD TOMORROW AFTERNOON, BUT GIVEN THE LACK OF ADDITIONAL  
FORCING MECHANISMS INITIALLY, SHOULD BE FOCUSED OVER THE HIGHER  
TERRAIN AT FIRST. SEEING EVIDENCE THAT SOME MORE SHORTWAVE ENERGY  
FROM ARIZONA WILL EJECT NORTHWARD DURING THE LATE AFTERNOON,  
IMPACTING NORTHERN UTAH DURING THE EVENING, POTENTIALLY BRINGING  
ADDITIONAL CONVECTION TO THE VALLEYS OF NORTHERN UTAH.  
 
ONCE THE MOISTURE IS IN PLACE, THERE IS LITTLE CHANGE IN THE  
PATTERN EXPECTED THROUGH EARLY NEXT WEEK AS CONFIDENCE IS HIGH  
THAT THE RIDGE WILL CONTINUE TO PARK ITSELF OVER THE FOUR CORNERS.  
THIS WILL BRING HIGH TEMPERATURES NEAR SEASONAL NORMALS BY THE  
START OF THE UPCOMING WEEK, WITH A DAILY THREAT OF SHOWERS AND  
THUNDERSTORMS THAT COULD PRODUCE HEAVY RAIN CAPABLE OF FLASH  
FLOODING, PARTICULARLY DURING THE AFTERNOON AND EARLY EVENING. AS  
THE MIDDLE OF NEXT WEEK APPROACHES, CONFIDENCE IN THE PATTERN  
DECREASES NOTICEABLY, WITH A GOOD PORTION OF GUIDANCE SHOWING A  
DRYING TREND FROM THE WEST AS THE RIDGE RETROGRADES OVER ARIZONA.  
 

 
   
AVIATION, ISSUED 1018 PM MDT THU AUG 20 2026
 
 
KSLC, ISSUED 1018 PM MDT THU AUG 20 2026...  
THE SLC TERMINAL WILL SEE VFR CONDITIONS  
THROUGH THE OVERNIGHT HOURS WITH SOME SCATTERED CLOUDS. SOUTHERLY  
WINDS WILL CONTINUE OVERNIGHT BEFORE SHIFTING TO THE NORTH BETWEEN  
19Z AND 21Z. WITH INCREASING MOISTURE, THERE IS A 30 PERCENT  
CHANCE OF THE TERMINAL SEEING A PERIOD OF GUSTY AND ERRATIC  
THUNDERSTORM WINDS FRIDAY, WITH THE MOST LIKELY TIME DURING THE  
LATE AFTERNOON AND EARLY EVENING.  
 
REST OF UTAH AND SOUTHWEST WYOMING...VFR CONDITIONS WILL PREVAIL  
ACROSS THE AIRSPACE THROUGH THE OVERNIGHT HOURS. SCATTERED SHOWERS  
AND THUNDERSTORMS OVER SOUTHERN UTAH ARE EXPECTED TO PERSIST INTO  
THE OVERNIGHT HOURS BEFORE DIMINISHING AS SUNRISE APPROACHES. ANY  
STORMS THAT DEVELOP WILL HAVE THE POTENTIAL TO PRODUCE GUSTY AND  
ERRATIC WINDS, LIGHTNING, AND BRIEF MOUNTAIN OBSCURATIONS. WITH  
MOISTURE INCREASING TOMORROW, COVERAGE OF SHOWERS AND  
THUNDERSTORMS WILL BECOME A BIT MORE WIDESPREAD TOMORROW  
AFTERNOON, WITH SIMILAR POTENTIAL AVIATION IMPACTS AS TODAY. AWAY  
FROM THUNDERSTORMS, GENERALLY LIGHT AND TERRAIN DRIVEN WINDS WILL  
PREVAIL.  
 

 
   
FIRE WEATHER
 
HIGH PRESSURE CENTERED OVER THE FOUR CORNERS WILL PEAK  
TEMPERATURES TODAY WITH A GRADUAL COOLING TREND THROUGH THE  
WEEKEND. IT IS ALSO DRAWING UP MOISTURE INTO THE AREA THAT WILL  
REMAIN IN PLACE THROUGH EARLY NEXT WEEK. SOME DYING SHOWERS REMAIN  
ACROSS SOUTHWESTERN UTAH THIS MORNING. THIS WILL REMAIN THE  
PATTERN THROUGH THE WEEKEND: SHOWERS AND STORMS DEVELOPING DURING  
THE DAY WITH SOME STORMS LINGERING INTO THE OVERNIGHT. WHERE  
EXACTLY THESE STORMS LINGER WILL BE DETERMINED BY WHERE THE  
HEAVIER PRECIPITATION DEVELOPS DURING THE DAY.  
 
THE HIGHEST CHANCE OF PRECIPITATION WILL BE IN THE MOUNTAINS WITH  
SIGNIFICANTLY LOWER PRECIPITATION, PARTICULARLY WETTING RAIN,  
CHANCES ACROSS THE LOWER TERRAIN WHERE MIN RH WILL STILL BE LOW IN  
THE UPPER TEENS TO LOW 20S. STORMS REMAIN THROUGH EARLY NEXT WEEK  
ALONG WITH INCREASING SOUTHWESTERLY WINDS AS LOW PRESSURE GRAZES  
THE AREA TO THE NORTH.  
 

 
   
SLC WATCHES/WARNINGS/ADVISORIES
 
 
UT...HEAT ADVISORY UNTIL 7 AM MDT SATURDAY FOR UTZ101>106.  
 
HEAT ADVISORY UNTIL 7 AM MDT THIS MORNING FOR UTZ115-116.  
 
WY...NONE.  

 
 

 
 
PUBLIC...TRAPHAGAN  
AVIATION...TRAPHAGAN  
FIRE WEATHER...MAHAN  
 
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...  
HTTP://WEATHER.GOV/SALTLAKECITY  
 
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