355  
FXUS65 KSLC 202230  
AFDSLC  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SALT LAKE CITY UT  
330 PM MST MON NOV 20 2017  
   
SYNOPSIS
 
A WEATHER SYSTEM WILL BRUSH BY NORTHERN UTAH AND  
SOUTHWEST WYOMING THIS EVENING. STRONG HIGH PRESSURE ALOFT WILL  
FOLLOW FOR THE MIDDLE AND LATTER PORTIONS OF THE WEEK.  
 

 
   
SHORT TERM (THROUGH 00Z FRIDAY)
 
DEEP LAYER MOISTURE CONTINUES  
TO STREAM ACROSS NORTHERN UTAH IN ADVANCE OF A WEAK SHORT WAVE  
TROUGH POISED TO TRANSLATE ACROSS IDAHO/WYOMING OVER THE NEXT 12  
HOURS. WAA AND WEAK UPGLIDE HAS BEEN SUFFICIENT FOR PERIODIC LIGHT  
SNOW SHOWERS OVER THE HIGHEST TERRAIN IN THE NORTH, BUT IN LARGE  
PRECIP HAS REMAINED VIRGA DUE TO DRY LOW LEVELS IN PLACE. HAVE  
NOTED A GRADUAL MOISTENING FROM THE TOP DOWN OVER THE LAST FEW  
HOURS, SO ANTICIPATING THE POTENTIAL OF SOME RAIN SHOWERS TO  
INCREASE ALONG THE UT/ID BORDER REGION THIS EVE. THIS SAID,  
ANYTHING THAT REACHES THE SURFACE WILL REMAIN VERY LIGHT DUE TO  
INCREASINGLY STABLE VERTICAL PROFILES.  
 
LOW AMPLITUDE RIDGING IN PLACE WILL BEGIN TO AMPLIFY OVER THE  
EASTERN GREAT BASIN BEGINNING TUESDAY. DO ANTICIPATE MAINTENANCE  
OF A FAIR BIT OF MID LEVEL CLOUD COVER OVER THE FAR NORTH TUESDAY DUE  
TO THE RIDGE AXIS REMAINING WEST FOR THE TIME BEING, BUT A  
CONTINUATION OF WARM ADVECTION WILL ALLOW FOR A MARKED WARMING  
TREND TO ENSUE. LATE WEEK TEMPS LOOK POISED TO RUN SOME +10-15  
DEGREES ABOVE CLIMO FOR MOST LOCALES AS SAID AXIS SHIFTS EAST AND  
OVERHEAD.  
   
LONG TERM (AFTER 00Z FRIDAY)
 
A LARGE RIDGE OVER THE DESERT  
SOUTHWEST WILL CONTINUE TO BE THE DOMINANT FEATURE THROUGH THE  
EXTENDED FORECAST. ON THE NORTH END OF THIS RIDGE, A SHORTWAVE  
TROUGH IS EXPECTED TO SLIDE THROUGH PRIMARILY IDAHO AND MONTANA ON  
THURSDAY NIGHT AND FRIDAY, WHICH SHOULD INCREASE CLOUD COVER ACROSS  
NORTHERN UTAH, AND POTENTIALLY BRING SOME LIGHT PRECIPITATION TO FAR  
NORTHERN UTAH.  
 
THE RIDGE AMPLIFIES FURTHER ON SATURDAY AND SUNDAY. ADDITIONAL WEAK  
WAVES COULD BRUSH ACROSS FAR NORTHERN UTAH, BUT IN GENERAL THE  
WEEKEND SHOULD BE WARM AND DRY ACROSS THE FORECAST AREA.  
 
FOR NOW, GLOBAL MODELS LIKE THE IDEA OF A TROUGH PUSHING INTO THE  
WEST COAST SUNDAY NIGHT AND MONDAY, WITH INCREASING SOUTHWESTERLY  
FLOW ACROSS THE GREAT BASIN. THERE IS THEN CONSIDERABLE DISAGREEMENT  
ABOUT HOW FAR SOUTH THE TROUGH DIGS AS IT TRAVELS EASTWARD ON  
TUESDAY. DETAILS REMAIN LOW CONFIDENCE, BUT MODELS HOLDING ONTO THIS  
TROUGH FOR A COUPLE RUNS AT LEAST BUILDS HOPE THAT THERE WILL BE  
SOMETHING OTHER THAN A RIDGE TO LOOK AT BY THE END OF NOVEMBER.  
 

 
   
AVIATION
 
THE SLC TERMINAL WILL SEE VFR CONDITIONS THROUGH THE  
EVENING WITH MOSTLY CLOUDY SKIES. THERE IS A 20 PERCENT CHANCE OF  
CIGS BRIEFLY DROPPING TO OR BELOW 6000 FEET AGL THROUGH THE EARLY  
EVENING WITH PRECIPITATION IN THE VICINITY OF THE TERMINAL.  
SOUTHERLY WINDS ARE EXPECTED TO PREVAIL THROUGH THE EVENING, BUT  
THERE IS A 30 PERCENT CHANCE OF WINDS RETURNING TO THE NORTHWEST FOR  
A TIME BEFORE ABOUT 00Z.  
 

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

 
 

 
 
MERRILL/SCHOENING/TRAPHAGAN  
 
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  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab UT Page
The Nexlab ID Page
The Nexlab WY Page Main Text Page