275  
FXUS65 KSLC 270307  
AFDSLC  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SALT LAKE CITY UT  
907 PM MDT THU APR 26 2018  
   
SYNOPSIS
 
HIGH PRESSURE WILL BRING VERY WARM TEMPERATURES TO THE  
AREA THROUGH FRIDAY. A LOW PRESSURE SYSTEM OVER THE EASTERN  
PACIFIC WILL MOVE EAST INTO THE GREAT BASIN SUNDAY, THEN TRACK  
SLOWLY THROUGH THE REGION EARLY NEXT WEEK.  
 

 
   
DISCUSSION
 
EVENING WATER VAPOR AND H5 ANALYSIS INDICATE  
AMPLIFIED UPPER RIDGING ACROSS THE INTERMOUNTAIN WEST, WITH A  
THERMAL RIDGE NOTED FROM EXTREME SW UTAH NW ACROSS NEVADA. WITHIN  
THIS THERMAL RIDGE MODEST MID/HIGH LEVEL MOISTURE EXISTS, AND WILL  
GRADUALLY SHIFT DOWNSTREAM OVER THE AREA DURING THE NEXT 24 HOURS  
AS A CUT OFF LOW CURRENTLY OFF THE NORCAL COAST GRADUALLY SPINS ON  
SHORE.  
 
BUFR SOUNDINGS DEPICT LITTLE IF ANY THREAT OF PRECIP EXISTS FROM  
ANY CONVECTIVE DEVELOPMENT THAT MAY OCCUR OVER THE MTN SPINES  
TOMORROW, BUT DO SEE POTENTIAL FOR VIRGA AND SOME ISOLATED GUSTY  
WINDS OVER THE MTNS DUE TO THE DRY SUB-CLOUD LAYER IN PLACE. BULK  
OF MARGINAL PWAT WILL REMAIN ABOVE H6 OWING TO THIS THINKING.  
 
OF MORE IMPORTANCE WILL BE THE TEMPS, LIKELY RUNNING SOME 15-20  
DEGREES ABOVE CLIMO AS THE THERMAL RIDGE ORIENTS OVERHEAD. COULD  
FLIRT WITH SOME RECORDS IN CENTRAL/NORTHERN UTAH, BUT OVERALL IT  
LOOKS BORDERLINE AND JUST OVERLY MILD AS A WHOLE.  
 
PREVIOUS FORECAST REMAINS WELL ON TRACK, AND HAVE MADE NO CHANGES  
THIS EVENING. PREVIOUS DISCUSSION FOLLOWS.  
 
PREVIOUS DISCUSSION...TEMPERATURES IN GENERAL WILL BE 15-20 DEGREES  
ABOVE NORMAL FRIDAY AND SATURDAY WHICH MEANS THESE TEMPS WILL BE  
RECORD CHALLENGING. TEMPERATURES WILL COOL BACK TO NEAR NORMAL  
ACROSS THE WESTERN VALLEYS AND NORTHERN UTAH AND SOUTHWEST WYOMING  
BY SUNDAY. HOWEVER, THE SOUTHEASTERN PORTIONS OF THE CWA WILL  
CONTINUE TO HAVE TEMPERATURES SEVERAL DEGREES ABOVE NORMAL ON  
SUNDAY.  
 
THE COLD POCKET ALOFT WILL BRUSH BY NORTHERN PORTIONS OF THE CWA  
SUNDAY BRINGING A THREAT OF SHOWERS AND ISOLATED THUNDERSTORMS  
WHILE THE SOUTHERN TWO-THIRDS OF THE FORECAST AREA SHOULD REMAIN  
DRY.  
 
THE LARGE PACIFIC LOW CONTINUES TO ENCROACH ON UTAH AND SOUTHWEST  
WYOMING SUNDAY NIGHT, WITH ANOTHER ROUND OF LOW LEVEL COLD  
ADVECTION PUSHING INTO THE NORTHERN HALF OF THE CWA THROUGH THE  
NIGHT AND INTO MONDAY MORNING. THIS LOW LEVEL FORCING, COMBINED  
WITH ANOTHER MID-LEVEL VORT LOBE SWINGING OVER THE AREA, SHOULD  
COMBINE TO INCREASE THE COVERAGE OF PRECIPITATION ACROSS THE AREA  
THROUGH THE DAY MONDAY. HAVE GENERALLY INCREASED POPS AND  
DECREASED TEMPERATURES THROUGH THIS PERIOD OF TIME, AND THIS FIRST  
GOOD INITIAL PUSH COULD BE THE BEST PERIOD OF PRECIPITATION FOR  
NORTHERN UTAH ASSOCIATED WITH THE LONGWAVE TROUGH OVER THE WEST.  
 
ONCE THIS INITIAL WAVE EXITS TO THE EAST MONDAY NIGHT, THE NEXT  
ROUND OF DECENT, WELL-ORGANIZED FORCING LOOKS TO COME WITH A  
SHORTWAVE DROPPING DOWN THE WEST COAST MONDAY NIGHT, THEN SWINGING  
ACROSS THE DESERT SOUTHWEST TUESDAY INTO WEDNESDAY. THIS COULD FOCUS  
THE BEST PRECIPITATION ACROSS THE SOUTHERN HALF OF UTAH, BUT IN  
GENERAL CAN'T RULE OUT SHOWERS ANYWHERE IN THE CWA THROUGH THE FIRST  
HALF OF THE WEEK, AS ENOUGH MOISTURE AND INSTABILITY LOOKS TO LINGER  
FOR STRAY SHOWERS HERE AND THERE.  
 
THE WEATHER PATTERN BECOMES CONSIDERABLY DRIER AND MORE STABLE BY  
THE END OF THE WORK WEEK, AS THE LONGWAVE TROUGH SHIFTS TO THE EAST  
AND A RIDGE BUILDS OVER THE WEST. THERE IS STILL SOME DISCREPANCY  
ABOUT WHETHER THIS STARTS THURSDAY OR FRIDAY, BUT EITHER WAY A  
WARMING TREND LOOKS LIKELY HEADING INTO NEXT WEEKEND.  
 

 
   
AVIATION
 
OPERATIONAL WEATHER CONCERNS WILL REMAIN MINIMAL AT  
THE KSLC TERMINAL THROUGH THE VALID TAF PERIOD. LIGHT AND VARIABLE  
SURFACE WINDS CURRENTLY IN PLACE WILL RETURN TO THE SOUTHEAST BY  
04Z PER NORM.  
 

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

 
 

 
 
DISCUSSION/AVIATION...MERRILL  
PREVIOUS DISCUSSION...STRUTHWOLF/SCHOENING  
 
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...  
HTTP://WEATHER.GOV/SALTLAKECITY  
 
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION  
VISIT...  
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP  
 
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