013  
FXUS65 KSLC 091507  
AFDSLC  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SALT LAKE CITY UT  
907 AM MDT WED JUL 9 2025  
   
UPDATE  
UPDATED FOR AVIATION DISCUSSION.  
 
 
   
SYNOPSIS  
HOT AND MOSTLY DRY CONDITIONS WILL PERSIST OVER UTAH  
AND SOUTHWEST WYOMING TODAY, WITH A FEW HIGH BASED SHOWERS  
DEVELOPING OVER THE HIGHER TERRAIN THIS AFTERNOON. A WEAKENING  
STORM SYSTEM WILL CROSS NORTHERN UTAH AND SOUTHWEST WYOMING  
TONIGHT INTO EARLY THURSDAY, BRINGING TEMPERATURES BACK CLOSER TO  
SEASONAL NORMALS. HIGH PRESSURE WILL REBUILD BY THE WEEKEND,  
BRINGING ANOTHER WARMING TREND.  
 
 
   
SHORT TERM (THROUGH 12Z/6AM FRIDAY)  
HIGH PRESSURE REMAINS  
PARKED OVER THE DESERT SOUTHWEST THIS MORNING AS THE LOW THAT HAS  
BEEN HOVERING OFF THE PACIFIC COAST OVER THE LAST FEW DAYS MOVES  
ONSHORE OVER NORTHERN CALIFORNIA. UTAH AND SOUTHWEST WYOMING  
REMAIN UNDER A WARM SOUTHWEST FLOW ALOFT, WITH HIGH TEMPERATURES  
AGAIN EXPECTED TO AVERAGE AROUND 10F ABOVE SEASONAL NORMALS THIS  
AFTERNOON.  
 
THE TROUGH IS ON TRACK TO MOVE INTO THE GREAT BASIN THIS AFTERNOON  
AS IT WEAKENS. THE TRAJECTORY OF THE SYSTEM WILL MOVE THE  
PERSISTENT DRY SLOT AWAY FROM THE AREA, ALLOWING SOME MID AND HIGH  
LEVEL MOISTURE TO START TO ADVECT IN, ENOUGH FOR A FEW HIGH BASED  
SHOWERS TO DEVELOP OVER THE HIGHER TERRAIN THIS AFTERNOON AND INTO  
THE EARLY EVENING. AS THE LOW MOVES CLOSER, THE FLOW ALOFT WILL  
ALSO INCREASE, RESULTING IN SOME BREEZY CONDITIONS, PARTICULARLY  
OVER WESTERN UTAH. THIS WILL COMBINE WITH THE HOT AND DRY AIRMASS  
TO PRODUCE AREAS OF CRITICAL FIRE WEATHER CONDITIONS OVER PORTIONS  
OF SOUTHERN AND WESTERN UTAH, WHERE A RED FLAG WARNING IS IN  
EFFECT. SEE THE FIRE WEATHER SECTION OF THE AFD FOR MORE DETAILS.  
 
GUIDANCE IS IN GOOD AGREEMENT THAT THE WEAKENING TROUGH WILL TRACK  
ACROSS NORTHERN UTAH AND SOUTHWEST WYOMING TONIGHT INTO EARLY  
TOMORROW. GIVEN THE WEAKENED STATE OF THE SYSTEM AND OVERALL LACK  
OF MOISTURE AND DYNAMICS, ASSOCIATED SHOWER ACTIVITY WILL BE  
MINIMAL AT BEST. THE SYSTEM WILL, HOWEVER, BRING A COLD FRONT  
THROUGH, BRINGING A NOTICEABLE CHANGE IN TEMPERATURES FOR  
THURSDAY, PARTICULARLY FOR NORTHERN PORTIONS OF THE FORECAST AREA.  
THOSE AREAS WILL SEE AROUND 10F OF COOLING, BRINGING MAXES BACK  
AROUND TO NEAR SEASONAL NORMALS. COOLING OVER SOUTHERN UTAH WILL  
BE MORE LIMITED, A FEW DEGREES AT BEST.  
   
LONG TERM (AFTER 12Z/6AM FRIDAY)  
THE PERIOD STARTS WITH DRY  
WESTERLY/NORTHWESTERLY FLOW ALOFT AND SURFACE TEMPERATURES A FEW  
DEGREES BELOW NORMAL ACROSS NORTHERN UTAH/SW WYOMING. HOWEVER,  
ACROSS SOUTHERN UTAH TEMPERATURES WILL BE A FEW DEGREES ABOVE NORMAL  
GIVEN THE PROXIMITY TO A RIDGE CENTERED OVER SOUTHERN CALIFORNIA.  
HIGH PRESSURE WILL REMAIN CENTERED OVER CALIFORNIA THROUGH THE  
WEEKEND AND INTO EARLY NEXT WEEK. THIS WILL KEEP CONDITIONS DRY WITH  
GRADUALLY WARMING TEMPERATURES ACROSS NORTHERN UTAH WHILE SOUTHERN  
UTAH KEEPS TEMPERATURES BETWEEN 105-108F.  
 
GUIDANCE IS STARTING TO HINT AT A BREAKDOWN IN THE RIDGE AND  
POTENTIALLY RE-ORIENTING FURTHER TO THE EAST TO ALLOW FOR A RETURN  
OF SOME MOISTURE BY THE MIDDLE TO THE END OF NEXT WEEK. THE SIGNAL  
IS STILL PRETTY WEAK WHICH WOULD LIKELY LIMIT THE MAGNITUDE AND  
EXTENT OF THE MOISTURE TO THE TERRAIN OF SOUTHERN AND CENTRAL UTAH.  
HOWEVER, THE LATEST CPC FORECAST DOES HAVE A BETTER MONSOON SIGNAL  
IN THE JULY 16-22 TIME PERIOD ACROSS ARIZONA AND SOUTHERN UTAH WITH  
LOWER PROBABILITIES (BUT STILL FAVORING WETTER) THE FURTHER NORTH  
YOU GO.  
 
 
   
AVIATION...KSLC  
PREDOMINANTLY VFR CONDITIONS WILL CONTINUE  
TODAY/TONIGHT, THOUGH WITH A COMPLICATED AND LOWER-CONFIDENCE WIND  
FORECAST. SOUTHERLY WIND GUSTS WILL INCREASE THIS MORNING, WITH A  
LOW CHANCE (10-40%) OF A LAKE BREEZE SNEAKING IN BETWEEN 19 AND 23Z  
WHICH WOULD TURN WINDS NORTHWESTERLY. BETWEEN 22Z-01Z, EXPECTING  
DEEPER CUMULUS AND VICINITY SHOWERS TO FORM WITH A THREAT OF OUTFLOW  
WINDS AND A LIKELY SWITCH TO NORTHWEST WINDS. THERE IS A VERY LOW  
CHANCE (<20%) OF CONTINUED SOUTHERLY WINDS INTO THE EVENING. A COLD  
FRONT WILL PUSH THROUGH BETWEEN 3 AND 6Z TURNING WINDS TO CONSISTENT  
NORTHWESTERLY AND CLEARING SKIES FOR THE REST OF THE NIGHT.  
 
   
REST OF UTAH AND SOUTHWEST WYOMING  
VFR CONDITIONS WILL PERSIST  
FOR THE ENTIRE AIRSPACE THROUGHOUT THE PERIOD. SOUTHERLY WINDS WILL  
BE GUSTY FOR MOST LOCATIONS DURING THE DAY AHEAD OF A MOSTLY DRY  
FRONT. THIS FRONT WILL PUSH THROUGH THE NORTHERN AIRSPACE DURING THE  
AFTERNOON/EVENING WITH ISOLATED (~20% CHANCE) HIGH-BASED CONVECTION  
ACROSS THE NORTH AND EAST PORTIONS OF THE AREA. THE PRIMARY IMPACT  
FROM THESE WILL BE GUSTY OUTFLOW WINDS WITH VERY LITTLE RAIN  
POSSIBLE.  
 
 
   
FIRE WEATHER  
HIGH PRESSURE CENTERED OVER THE DESERT SOUTHWEST  
WILL MAINTAIN A HOT AND DRY AIRMASS OVER UTAH TODAY. AS A PACIFIC  
STORM SYSTEM MOVES INTO THE GREAT BASIN DURING THE DAY, SOUTHWEST  
WINDS WILL INCREASE, PRODUCING AREAS OF CRITICAL FIRE WEATHER  
CONDITIONS DURING THE AFTERNOON AND EVENING ACROSS SOUTHERN AND  
WESTERN UTAH. WITH A SMALL INCREASE IN MID-LEVEL MOISTURE WITH AND  
AHEAD OF THE TROUGH, ANTICIPATING A FEW HIGH BASED STORMS FOCUSED  
OVER THE HIGHER TERRAIN THIS AFTERNOON AND EVENING, WITH GUSTY  
WINDS AND ISOLATED DRY LIGHTNING THE MAIN THREATS WITH ANY STORMS  
THAT DEVELOP. THE TROUGH WILL PASS ACROSS NORTHERN UTAH IN A  
WEAKENED STATE LATE WEDNESDAY INTO EARLY THURSDAY, BRINGING MORE  
SEASONABLE TEMPERATURES BEHIND IT BUT LITTLE IN THE WAY OF  
PRECIPITATION. HIGH PRESSURE WILL THEN REBUILD FOR THE UPCOMING  
WEEKEND, BRINGING CONTINUED DRY CONDITIONS AND ANOTHER WARMING  
TREND.  
 
 
   
SLC WATCHES/WARNINGS/ADVISORIES  
 
UT...RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR UTZ492-493-  
495>498.  
 
WY...NONE.  
 
 
 
 
SHORT TERM...TRAPHAGAN  
LONG TERM...MAHAN  
AVIATION...VAN CLEAVE  
FIRE WEATHER...TRAPHAGAN  
 
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