391  
FXUS65 KSLC 230954  
AFDSLC  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SALT LAKE CITY UT  
354 AM MDT TUE APR 23 2024  
   
SYNOPSIS
 
ABOVE AVERAGE TEMPERATURES REMAIN IN PLACE THROUGH  
MID-WEEK AS HIGH PRESSURE DOMINATES. A CLOSED LOW SYSTEM WILL  
PROGRESS INLAND THROUGH THE SECOND HALF OF THE WEEK, BRINGING  
COOLER AND WETTER WEATHER INTO THE WEEKEND.  
 

 
   
SHORT TERM (THROUGH 12Z/6AM THURSDAY)
 
A WEAK BOUNDARY CONTINUES  
TO LIFT OUT OF THE REGION TODAY, ALLOWING FOR SLOWLY WARMING  
TEMPERATURES ACROSS THE NORTHERN THIRD OF THE FORECAST AREA. A  
MID-LEVEL MOISTURE AXIS WILL REMAIN DRAPED ACROSS THE NORTHERN  
THIRD OF THE AREA AS WELL, BRINGING INCREASED CLOUD COVER AND A  
FEW LIGHT MOUNTAIN SHOWERS. IT IS UNLIKELY THAT PRECIPITATION WILL  
REACH THE GROUND GIVEN HOW DRY THE NEAR SURFACE ENVIRONMENT IS,  
HOWEVER, IF ANYTHING DOES REACH THE SURFACE IT SHOULD BE QUITE  
NEGLIGIBLE (I.E. TRACE AMOUNTS). WITH A TOUCH OF MID-LEVEL  
INSTABILITY AND AFTERNOON SOLAR INSOLATION, CAN'T RULE OUT AN  
ISOLATED, SHORT-LIVED THUNDERSTORM.  
 
PUSHING INTO WEDNESDAY THE PATTERN BEGINS TO CHANGE AS A MID-LEVEL  
RIDGE AXIS BEGINS SHIFTING DOWNSTREAM OF THE AREA, OPENING THE  
DOOR TO A CLOSED LOW SYSTEM. AS THIS RIDGE AXIS SHIFTS DOWNSTREAM,  
INCREASING MOISTURE WILL BE INTRODUCED TO THE REGION WHICH WILL  
ALLOW FOR INCREASED CHANCE OF SEEING MEASURABLE PRECIPITATION,  
MAINLY ACROSS THE NORTHERN REACHES OF THE FORECAST AREA. FURTHER  
WARMING OF THE AIRMASS IS EXPECTED ACROSS THE NORTHERN HALF OF  
UTAH AND SOUTHWEST WYOMING, HOWEVER, A SLIGHT COOLING TREND WILL  
BE NOTED ACROSS THE SOUTHERN HALF OF UTAH AS THE INFLUENCE OF THE  
CLOSED LOW BEGINS TO SPREAD INTO THE SOUTHWEST.  
   
LONG TERM (AFTER 12Z/6AM THURSDAY)
 
THE LONG TERM PORTION OF THE  
FORECAST PERIOD BEGINS ON THURSDAY WITH THE CLOSED LOW OVER SOCAL  
OPENING UP AND EJECTING ACROSS NORTHERN AZ/SOUTHERN UT.  
DETERMINISTIC MODELS AND ASSOCIATED ENSEMBLE MEMBERS ARE NOW IN  
FAIRLY GOOD AGREEMENT REGARDING THIS EVOLUTION. SOME SHOWER ACTIVITY  
LOOKS POSSIBLE IN THE WARM SECTOR AHEAD OF THE TROUGH AXIS, FIRING  
UP ALONG THE SPINE OF THE CENTRAL MOUNTAINS THROUGH THE WESTERN  
UINTAS. BEHIND THE ASSOCIATED COLD FRONT, ADDITIONAL SHOWERS ARE  
PROGGED TO SPREAD IN FROM THE NORTHWEST THROUGH THE DAY. WHILE  
TEMPERATURES COOL, THE AIRMASS WILL REMAIN MILD ENOUGH TO MAINTAIN  
RELATIVELY HIGH SNOW LEVELS THROUGH THE DAY, AROUND 8.5-9KFT.  
 
ADDITIONAL TRAILING FEATURES WILL QUICKLY FOLLOW THE INITIAL TROUGH,  
LEADING TO THE DEVELOPMENT OF A MEAN LONGWAVE TROUGH OVER THE  
WESTERN CONUS WHICH WILL CONTINUE TO BRING UNSETTLED WEATHER INTO  
THE WEEKEND. WITHIN THIS WAVE TRAIN, THE NEXT TROUGH, A MORE SUBTLE  
SHORTWAVE DISTURBANCE, IS EXPECTED TO CROSS THE AREA FRIDAY  
MORNING/AFTERNOON, FOLLOWED BY A DEEPER TROUGH FRIDAY EVENING/  
SATURDAY MORNING. CLUSTER ANALYSIS OF ENSEMBLE MEMBERS SHOW MAINLY  
SMALL DIFFERENCES IN TIMING AND AMPLITUDE OF THE TROUGH PATTERN. AS  
SUCH, CONFIDENCE IS HIGH IN THE OVERALL PATTERN AND EVOLUTION, WITH  
SOME UNCERTAINTY WITH THE DETAILS. FRIDAY LOOKS TO BE THE WETTEST  
DAY OF THIS STRETCH OF WET WEATHER. PWAT ANOMALIES IN THE 97TH  
PERCENTILE OF CLIMATOLOGY ARE NOTED ACROSS PORTIONS OF UTAH ON  
FRIDAY, AND ECMWF-BASED EXTREME FORECAST INDEX SHOWS A SIGNAL FOR  
ABNORMALLY HIGH QPF AS WELL. CURRENT FORECAST IS CARRYING A 2.5-DAY  
TOTAL (THURS MORNING THROUGH SATURDAY AFTERNOON) OF OVER 1.5 INCHES  
OF QPF OVER THE RIDGELINES, AND AROUND 1 INCH OR MORE IN THE  
ADJACENT VALLEYS.  
 
COLDER TEMPERATURES WILL BE ASSOCIATED WITH THE FRIDAY AND SATURDAY  
SYSTEMS. WIDESPREAD BELOW NORMAL AFTERNOON MAX TEMPERATURES ARE  
EXPECTED BOTH DAYS, AND SNOW LEVELS ARE EXPECTED TO FALL TO BETWEEN  
7-8KFT. AS SUCH, EXPECT MOUNTAIN SNOW ACCUMULATIONS, POTENTIALLY  
SIGNIFICANT ABOVE 8KFT. STILL QUESTIONABLE AT THIS TIME WHETHER THIS  
WILL RESULT IN ANY SIGNFICIANT IMPACTS OWING TO SUN ANGLES AND ROAD  
TEMPERATURES.  
 
THERE REMAINS SOME UNCERTAINTY AS TO HOW QUICKLY THE STORM  
SYSTEMS EXIT THE AREA. DETERMINISTICS HAVE PRECIPITATION LARGELY  
WINDING DOWN BY SATURDAY EVENING, ALTHOUGH CLUSTER ANALYSIS  
INDICATES A BIT MORE SPREAD. HOWEVER, BY SUNDAY AFTERNOON, ALL  
CLUSTERS SHOW THE TROUGH ALREADY EAST OF UTAH. UNCERTAINTY INCREASES  
AGAIN AFTER THAT, BUT EXPECT A GENERAL WARMING AND DRYING TREND  
THROUGH THE EARLY PART OF NEXT WEEK.  
 

 
   
AVIATION...KSLC
 
VFR CONDITIONS WILL BE MAINTAINED OVER THE KSLC  
TERMINAL THROUGH THE VALID TAF PERIOD. MID-LEVEL CLOUD COVER WILL  
REMAIN IN PLACE THROUGH MUCH OF THE DAY, ONLY DISSIPATING FOR A  
BRIEF PERIOD MID-MORNING. LIGHT AND VARIABLE FLOW EARLY THIS  
MORNING WILL RETURN TO A NORTHERLY FLOW AROUND 16-17Z.  
   
REST OF UTAH AND SOUTHWEST WYOMING
 
VFR CONDITIONS WILL REMAIN  
IN PLACE THROUGH THE VALID TAF PERIOD ACROSS UTAH AND SOUTHWEST  
WYOMING. MID-LEVEL CLOUD COVER, WITH ELEVATED SHOWERS, WILL  
PREVAIL ACROSS THE NORTHERN HALF OF THE AREA. WINDS ACROSS THE  
NORTHERN THIRD OF THE AREA WILL REMAIN OUT OF THE NORTH. FOR THE  
SOUTHERN TWO-THIRDS, EXPECT PREDOMINANTLY SOUTHWESTERLY WINDS WITH  
AFTERNOON GUSTS TO AROUND 25-30 MPH.  
 

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

 
 

 
 
SHORT TERM...WEBBER  
LONG TERM...CHENG  
AVIATION...WEBBER  
 
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...  
HTTP://WEATHER.GOV/SALTLAKECITY  
 
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