312  
FXUS65 KSLC 261454  
AFDSLC  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SALT LAKE CITY UT  
854 AM MDT SUN MAR 26 2023  
   
UPDATE
 
IMPRESSIVE AREA OF SNOWFALL CONTINUES TO MOVE EASTWARD  
FROM THE SOUTH END OF THE CACHE VALLEY TO THE NORTH END OF THE  
TOOELE AND SALT LAKE VALLEYS AS OF 845AM MDT. THIS BAND HAS  
PRODUCED WIDESPREAD SNOWFALL RATES OF 1 TO 3 INCHES PER HOUR, WITH  
REPORTS OF 4 INCHES OF SNOWFALL IN THE OGDEN METRO AREA. SLRS ARE  
IN THE 20-30:1 RANGE, WITH EXTREMELY EFFICIENT ACCUMULATION OF  
DENDRITES. THIS IS THE FIRST TIME IN MY CAREER I'VE SEEN SNOWFALL  
THIS WIDESPREAD AND HEAVY, AND TO SEE IT SO POORLY REPRESENTED ON  
AVAILABLE MODEL GUIDANCE. THE BAND APPEARS TO BE ASSOCIATED WITH  
A SHORTWAVE AND LOW LEVEL FRONTOGENESIS AXIS TIED TO A SURFACE  
FRONT EXTENDING SOUTHWARD FROM THE SOUTHEAST IDAHO SURFACE LOW.  
GIVEN THE POOR MODEL REPRESENTATION, CONFIDENCE IS LOW ON HOW THIS  
BAND WILL PROGRESS. MAJORITY OF GUIDANCE WEAKENS THE  
FRONTOGENESIS AXIS BY 18Z, AND THEREFORE THE BAND SHOULD WEAKEN AT  
THE SAME TIME. WILL CONTINUE TO NOWCAST AND UPDATE AS NEEDED.  
 

 
   
SYNOPSIS
 
LOW PRESSURE OVER THE AREA WILL MAINTAIN COOL AND  
UNSETTLED CONDITIONS TODAY WITH SCATTERED SNOW SHOWERS ACROSS THE  
AREA TODAY INTO TONIGHT. A BRIEF BREAK IN THE WEATHER IS EXPECTED BY  
LATE MONDAY AND CONTINUING INTO TUESDAY BEFORE INCREASING SOUTHWEST  
FLOW BRINGS ANOTHER MOIST STORM SYSTEM INTO THE AREA FOR THE MIDDLE  
TO LATTER PORTION OF THE WEEK  
 

 
   
SHORT TERM (THROUGH 12Z TUESDAY)
 
A LONGWAVE TROUGH REMAINS IN  
PLACE ACROSS THE WESTERN CONUS THIS MORNING, WITH A CLOSED LOW OVER  
SOUTHEAST IDAHO. THIS LONGWAVE TROUGH WILL MAINTAIN AN UNSEASONABLY  
COLD AIRMASS OVER THE AREA TODAY AND TOMORROW. A SHORTWAVE  
DISTURBANCE EMBEDDED WITHIN THE LONGWAVE TROUGH AND WHICH IS  
CURRENTLY DIVING IN ACROSS THE PACNW STATES AND NORCAL WILL ARRIVE  
INTO UTAH LATE THIS AFTERNOON. AHEAD OF THIS FEATURE, A REINFORCING  
COLD FRONT WILL PUSH INTO UTAH, RELATIVELY WEAK ACROSS THE NORTH BUT  
STRENGTHENING AS IT REACHES SOUTHERN UTAH THIS AFTERNOON. ALREADY  
SEEING AN AREA OF SHOWERS MOVING ACROSS NORTHERN UTAH NEAR THIS  
BOUNDARY. THE SNOW SHOWERS WILL EXPAND IN COVERAGE ACROSS THE  
FORECAST AREA THROUGH THE DAY OWING TO THE BOUNDARY AND INCREASED  
INSTABILITY ASSOCIATED WITH DAYTIME HEATING.  
 
THE SNOW SHOWERS WILL DECREASE OVERNIGHT AS THE TROUGH EXITS THE  
AREA. HOWEVER, LINGERING MOISTURE AND COLD AIR ALOFT MAY SET OFF  
LAKE-EFFECT SNOW ACROSS THE GSL LATE TONIGHT INTO TOMORROW MORNING.  
LOCAL EXPERIMENTAL GUIDANCE BASED ON THE 00Z GFS INDICATE A 50-65%  
CHANCE OF LAKE-EFFECT SNOW DURING THIS TIMEFRAME. EARLIER RUNS OF HI-  
RES MODELS WERE ALSO PRODUCING A SOLID LAKE BAND. HOWEVER, SOME OF  
THEM HAVE NOW PULLED BACK WITH THE LATEST RUNS, WHICH SUGGESTS THAT  
THE PROBABILITY COULD BE LOWER THAN THE AFOREMENTIONED EXPERIMENTAL  
GUIDANCE. HOWEVER, IF THE LAKE EFFECT OCCURS, THE MOST LIKELY AREA  
OF IMPACT WILL BE THE SL VALLEY INTO THE COTTONWOOD CANYONS,  
ALTHOUGH SOUTHERN DAVIS COUNTY AND THE EASTERN TOOELE VALLEY AND  
OQUIRRHS COULD BE IMPACTED AT TIMES AS WELL. AT THIS TIME, SNOW  
SHOWERS TODAY AND TONIGHT ARE EXPECTED TO BE BELOW ADVISORY  
CRITERIA, WITH MINOR VALLEY ACCUMULATIONS AND 2-6 INCHES IN THE  
MOUNTAINS. HOWEVER, IF LAKE-EFFECT SNOW DOES OCCUR, AREAS UNDERNEATH  
SAID LAKE EFFECT COULD SEE LOCALIZED HEAVIER SNOW WHICH COULD  
WARRANT A WINTER WEATHER HIGHLIGHT AND BRING IMPACTS TO THE MORNING  
COMMUTE. GIVEN TYPICAL UNCERTAINTY REGARDING LAKE EFFECT EVENTS,  
WILL ALLOW FUTURE SHIFTS TO EVALUATE THE FORECAST FURTHER AND TO  
ALLOW COORDINATION WITH CORE PARTNERS.  
 
MUCH QUIETER WEATHER IS EXPECTED TOMORROW AFTERNOON THROUGH TOMORROW  
NIGHT AS A SHORTWAVE RIDGE BUILDS INTO THE AREA. TEMPERATURES ARE  
FORECAST TO WARM A FEW DEGREES FOR TOMORROW, BUT REMAIN 15-25F BELOW  
CLIMATOLOGICAL NORMALS. STILL, AT LEAST IT IS STARTING TO TREND IN  
THE RIGHT DIRECTION. BUT IS IT FINALLY THE END OF THE ACTIVE WEATHER  
PATTERN OF LATE? NOPE.  
 
   
LONG TERM (AFTER 12Z TUESDAY)
 
ACTIVE PATTERN CONTINUES THROUGH  
THE FORESEEABLE FUTURE, WITH ONLY BRIEF TRANSITORY RIDGING  
INTERRUPTING OTHERWISE PERSISTENT LONGWAVE TROUGHS PARKED OVER THE  
GREAT BASIN THROUGH DAY 7 AND BEYOND. COOLER AND WETTER THAN AVERAGE  
CONDITIONS WILL PERSIST FOR NORTHERN AND CENTRAL UTAH, WHILE  
SOUTHERN UTAH MAY EXPERIENCE SLIGHTLY MORE EFFECTIVE WARMING WITH  
BETTER EXPOSURE TO WARM ADVECTION IN BRIEF RIDGING AND BETTER  
CHANCES FOR CLEARING SKIES BETWEEN STORMS.  
 
FORECAST REMAINS LARGELY UNCHANGED FROM PRIOR FORECAST CYCLES WITH  
ONLY MINOR CHANGES TO TIMING AS ENSEMBLE MEAN SLOWS THE PROGRESSION  
OF THE TROUGH THROUGH THE REGION. ONSET TIMING REMAINS MID-MORNING  
WEDNESDAY AS MOISTURE PUSHES IN FROM THE SOUTHWEST ALONG THE LEADING  
EDGE OF THE POSITIVELY TILTED TROUGH, WITH BROAD SYNOPTIC LIFT UNDER  
A FAVORABLY LOCATED JET MAX KICKING OFF PRECIPITATION FROM  
SOUTHWESTERN UTAH TO SOUTHWESTERN WYOMING NEARLY SIMULTANEOUSLY.  
CONTINUED PRECIPITATION IS FORECAST THROUGH THURSDAY, THOUGH WILL  
BECOME MORE SHOWERY AS TIME GOES ON AND EVENTUALLY CURTAILED TO  
NORTHERN UTAH BY THURSDAY EVENING/FRIDAY MORNING WHERE A MIX OF  
OROGRAPHICALLY FORCED PRECIPITATION AND AN EMBEDDED SHORTWAVE  
PROVIDE ADDITIONAL FORCING.  
 
WINDS WORTH KEEPING AN EYE ON FOR WESTERN UTAH ON WEDNESDAY,  
SOUTHEASTERN UTAH ON THURSDAY, THOUGH REMAIN BELOW IMPACT THRESHOLDS  
AT THIS TIME. UNIMPRESSIVE UPPER LEVEL FLOW MAXING OUT NEAR 40KT AT  
700MB SHOULD LIMIT WHAT MOMENTUM CAN AND DOES MIX TO THE SURFACE.  
 
INTO THE WEEKEND, THE AFOREMENTIONED TRANSITORY RIDING REMAINS THE  
MOST LIKELY SOLUTION, HOWEVER MORE ZONAL PRESENTATIONS AMONG  
ENSEMBLE FORECASTS WOULD LEAD TO CONTINUED UNSETTLED BUT UNIMPACTFUL  
WEATHER. THE NEXT SYSTEM COULD ARRIVE AS EARLY AS SUNDAY NIGHT.  
 

 
   
AVIATION...KSLC
 
BAND OF SNOW MOVING THROUGH THE SLC METRO THIS  
MORNING IS PRODUCING LIFR CONDITIONS, AND 1 TO 3 INCH PER HOUR  
SNOWFALL RATES. THIS IS EXPECTED TO PERSIST THROUGH 16Z.  
UNSETTLED WEATHER THROUGHOUT THE DAY HAS THE POTENTIAL TO LEAD TO  
SOMETIMES BRIEF CHAOTIC WIND SHIFTS AND BRIEF PERIODS OF SNOW IN  
THE AFTERNOON. AS SCATTERED SHOWERS CLEAR OUT SUNDAY EVENING, A  
LAKE EFFECT SNOW BAND MAY DEVELOP. HOWEVER, SHOULD THIS BAND SHIFT  
OVERHEAD, IT HAS THE POTENTIAL TO PRODUCE MODERATE SNOWFALL  
BETWEEN 3-7AM LOCAL TIME MONDAY MORNING.  
   
REST OF UTAH AND SOUTHWEST WYOMING
 
UNSETTLED WEATHER AREA-WIDE  
TODAY WILL PRODUCE VARIABLE WINDS WITH LARGELY MVFR CONDITIONS  
ACROSS THE NORTH AND VFR CONDITIONS ACROSS CENTRAL AND SOUTHERN  
TERMINALS. SCATTERED SHOWERS MAY PRODUCE MODERATE SNOWFALL AND  
PERIODS OF IFR WHEN OVERHEAD, ESPECIALLY FOR NORTHERN UTAH AND  
SOUTHWEST WYOMING. SHOWERS WILL TAPER OFF THROUGH THE EARLY EVENING  
EXCEPT ACROSS FAR NORTHERN UTAH AND SOUTHWEST WYOMING WHERE ACTIVITY  
IS LIKELY TO CONTINUE WELL INTO SUNDAY NIGHT.  
 

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

 
 

 
 
ADESMET/CHENG/WESSLER  
 
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...  
HTTP://WEATHER.GOV/SALTLAKECITY  
 
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