674  
FXUS65 KSLC 182155  
AFDSLC  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SALT LAKE CITY UT  
355 PM MDT TUE AUG 18 2026  
   
KEY MESSAGES, ISSUED 928 AM MDT TUE AUG 18 2026
 
 
- BUILDING HIGH PRESSURE WILL BRING A STEADY WARMING TREND IN  
TEMPERATURES AS CONDITIONS DRY, BRINGING A THREAT OF ISOLATED  
CRITICAL FIRE WEATHER CONDITIONS.  
 
- MONSOON MOISTURE WILL MOVE BACK INTO UTAH AND SOUTHWEST WYOMING  
LATE IN THE WEEK, PERSISTING THROUGH AT LEAST EARLY NEXT WEEK.  
THIS WILL BRING AN INCREASED THREAT OF SHOWERS AND THUNDERSTORMS  
CAPABLE OF PRODUCING FLASH FLOODING.  
 

 
   
DISCUSSION, ISSUED 928 AM MDT TUE AUG 18 2026
 
 
HIGH PRESSURE IS CENTERED NEAR THE UTAH/NEVADA  
BORDER THIS MORNING WITH SOME SHORTWAVE ENERGY RIPPLING OVER THE  
TOP OF IT. THUS, SEEING CLEAR SKIES EXCEPT FOR SOUTHWEST WYOMING  
AND AREAS NEAR THE UTAH/IDAHO BORDER. SATELLITE DERIVED PWS  
INDICATE VALUES PRIMARILY IN THE 0.7 TO 1.0 INCH RANGE, ENOUGH  
MOISTURE FOR SOME AFTERNOON CONVECTIVE DEVELOPMENT. COVERAGE  
SHOULD BE GENERALLY ISOLATED IN NATURE, WITH THE BEST COVERAGE  
OVER NORTHEASTERN PORTIONS OF THE AREA, CLOSER TO THE UPPER JET  
ASSOCIATED WITH THE PASSING SHORTWAVE ENERGY.  
 
UNDER THE INFLUENCE OF THE RIDGE, HIGH TEMPERATURES TODAY WILL BE  
SIMILAR TO YESTERDAY WITH MAXES NEAR SEASONAL NORMALS. WITH THE  
RIDGE EXPECTED TO AMPLIFY AND MOVE OVERHEAD WEDNESDAY INTO  
THURSDAY, TEMPERATURES WILL STEADILY WARM, WITH MAXES AVERAGING UP  
TO 10F ABOVE SEASONAL NORMALS BY THURSDAY, WITH THE GREATEST  
DEPARTURE FROM NORMAL OVER NORTHERN PORTIONS OF THE AREA. THE  
AIRMASS WILL DRY OUT DURING THIS TIME, WITH RELATIVE HUMIDITIES  
APPROACHING CRITICAL VALUES FOR PORTIONS OF WESTERN UTAH. LOCALLY  
BREEZY CONDITIONS COULD BRING A FEW POCKETS OF CRITICAL FIRE  
WEATHER CONDITIONS, BUT OVERALL THE THREAT IS QUITE ISOLATED.  
HEATRISK VALUES ARE FORECAST TO MOVE INTO THE RED (MAJOR) RANGE  
FOR SOME NORTHERN UTAH VALLEYS ON THURSDAY, INCLUDING THE WEST  
DESERT AND PARTS OF THE WASATCH FRONT. OVERALL, THOUGH, THE  
INCREASED THREAT OF HEAT RELATED ILLNESS WILL BE MITIGATED DUE TO  
OVERALL ACCLIMATION DURING THE SEASON.  
 
BY FRIDAY, THERE IS HIGH CONFIDENCE THAT THE RIDGE WILL MOVE ITS  
AXIS TO THE MONSOON FAVORED POSITION OVER THE FOUR CORNERS,  
DRAWING DEEP MOISTURE BACK NORTHWARD AND INCREASING THE POTENTIAL  
OF SHOWERS AND THUNDERSTORMS CAPABLE OF PRODUCING FLASH FLOODING.  
THIS WILL ALSO REMOVE THE THREAT OF CRITICAL FIRE WEATHER  
CONDITIONS AND BRING TEMPERATURES BACK TO NEAR NORMAL FOR THIS  
TIME OF YEAR. THE MONSOON MOISTURE IS EXPECTED TO REMAIN IN PLACE  
THROUGH AT LEAST EARLY NEXT WEEK.  
 

 
   
AVIATION, ISSUED 1130 AM MDT TUE AUG 18 2026
 
 
 
 
KSLC...WNW TO NW WINDS UP TO AROUND 10 KTS EXPECTED TO HOLD THROUGH  
AROUND 04Z WEDNESDAY, SHIFTING SE THEREAFTER THROUGH THE NIGHT. VFR  
CONDITIONS TO PREVAIL WITH SCT TO BKN CLOUDS LARGELY ABOVE 10 KFT.  
 
REST OF UTAH AND SOUTHWEST WYOMING...IN SW WY AND FAR NE UT, SOME  
ISOLATED SHOWERS AND THUNDERSTORMS WILL DEVELOP THROUGH TUESDAY  
AFTERNOON. AT OTHER AREA TERMINALS, ANTICIPATE DIURNALLY NORMAL WIND  
SHIFTS WITH LIGHT MAGNITUDES GENERALLY LESS THAN 10 KTS, AND A MIX  
OF CLOUD COVER LARGELY ABOVE 10 KFT.  
 

 
   
FIRE WEATHER
 
HIGH PRESSURE TO THE WEST OF UTAH WILL BRINGING A  
WARMING AND DRYING TREND THROUGH THURSDAY, BRINGING TEMPERATURES  
UP TO 10F ABOVE SEASONAL NORMALS BY THURSDAY AFTERNOON. RELATIVE  
HUMIDITIES WILL DROP, WITH POCKETS OF CRITICALLY LOW RH VALUES  
DEVELOPING BY THURSDAY. WINDS COULD BE ENOUGH TO BRING ISOLATED  
POCKETS OF CRITICAL FIRE WEATHER CONDITIONS THURSDAY AFTERNOON,  
BUT COVERAGE IS LOOKING INCREASINGLY LIMITED. AS THE RIDGE MOVES  
EASTWARD FRIDAY, MONSOON MOISTURE WILL MOVE INTO THE AREA FROM THE  
SOUTH, REMAINING IN PLACE THROUGH EARLY NEXT WEEK. THIS WILL  
BRING INCREASED POTENTIAL FOR WETTING RAINFALL, IMPROVED RH  
VALUES, BUT ALSO THE POTENTIAL OF STORMS THAT COULD PRODUCE HEAVY  
RAIN THAT COULD LEAD TO FLASH FLOODING.  
 

 
   
SLC WATCHES/WARNINGS/ADVISORIES
 
 
UT...NONE.  
WY...NONE.  

 
 

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