506  
FXUS65 KRIW 210908  
AFDRIW  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE RIVERTON WY  
208 AM MST SAT DEC 21 2024  
   
KEY MESSAGES
 
 
- NEAR RECORD HIGH TEMPERATURES FOR PARTS OF CENTRAL WYOMING  
AGAIN TODAY.  
 
- DUAL SHORTWAVE TROUGHS BRING MORE SNOWFALL TO THE WESTERN  
MOUNTAINS THIS WEEKEND INTO EARLY NEXT WEEK.  
 
- I'M DREAMING OF A TAN CHRISTMAS. SAID NO ONE EVER.  
 

 
   
DISCUSSION
 
 
ISSUED AT 140 AM MST SAT DEC 21 2024  
 
NOT MUCH CHANGE IN THE ONGOING FORECAST THROUGH THE NEXT WEEK,  
WITH MODELS AGREEING ON QUICKLY MOVING ZONAL FLOW BRINGING BRIEF  
WAVES THROUGH THE AREA EVERY COUPLE DAYS, WHILE HOLDING BACK THE  
COLD TEMPERATURES FOR THE FORESEEABLE FUTURE...  
 
RIDING CONTINUES TO BRING WESTERLY FLOW TO THE REGION, CAUSING  
DOWNSLOPING WARMING TO AREAS EAST OF THE DIVIDE. THIS WILL BRING  
NEAR RECORD TEMPERATURES TO AREAS ALONG THE I-25 CORRIDOR AND  
THE BIGHORN BASIN, WITH HIGHS IN THE 50S TO NEAR 60! ON THE  
SHORTEST DAY OF THE YEAR. IN WYOMING. AREAS WEST OF THE DIVIDE  
WILL STILL REACH INTO THE 30S, BUT THE SNOW PACK IN THOSE AREAS  
WILL KEEP TEMPS IN CHECK FOR THE WEEKEND.  
 
THE NEXT TWO SHORTWAVES SWEEP ACROSS NORTHERN WYOMING SATURDAY  
NIGHT AND AGAIN SUNDAY NIGHT, BRINGING A BRIEF PUSH OF  
PRECIPITATION INTO THE WESTERN MOUNTAINS. THE WESTERLY FLOW AND  
BRIEF MOISTURE TAP FROM THE PACIFIC WILL CAUSE OROGRAPHIC LIFT  
FOR SNOWFALL. BEST PEAK SNOWFALL RATES WILL BE WHEN THE WAVES  
PASS BY SATURDAY NIGHT AND SUNDAY NIGHT, BUT OVERALL WEAKNESS OF  
THESE SYSTEM WILL KEEP SNOW RATES LOW THROUGH THE PERIOD.  
CURRENT FORECAST SNOWFALL ACCUMULATIONS WILL GENERALLY REACH 6  
TO 8 INCHES FOR THE TETONS AND 3 TO 6 INCHES FOR THE SALTS AND  
WYOMINGS BY MONDAY EVENING. THE FIRST TROUGH SATURDAY NIGHT  
STILL LOOKS TO HAVE A HIGH WIND COMPONENT WITH AN ADJACENT JET  
STREAK MOVING THROUGH. MODELS HAVE BACKED OFF A BIT ON THE  
STRENGTH OF THE WINDS, BUT THE MAIN FOCUS OF THE GUSTY WINDS  
WILL BE ACROSS CENTRAL WY FROM SOUTH PASS TOWARD CASPER.  
 
ANOTHER BRIEF LULL COMES THROUGH TUESDAY BEFORE THE NEXT TROUGH  
MOVES ACROSS THE CENTRAL ROCKIES CHRISTMAS MORNING. THE MAIN  
CORE OF THIS SYSTEM GOES SOUTH INTO COLORADO, SO SNOWFALL WILL  
BE LIMITED TO ANY MOISTURE THAT CAN BE SQUEEZED OUT BY  
OROGRAPHIC LIFT, LIMITING NEW SNOW TO THE HIGHER ELEVATIONS,  
WITH TOTAL ACCUMULATIONS STAYING UNDER 2 INCHES. IN ESSENCE, IF  
YOU CURRENTLY HAVE SNOW ON THE GROUND NOW, CONGRATULATIONS, YOU  
SHOULD WAKE UP TO A WHITE CHRISTMAS. IF YOU DON'T HAVE SNOW  
CURRENTLY, YOU WON'T HAVE WHITE ON THE GROUND FOR CHRISTMAS  
MORNING.  
 

 
   
AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
 
 
ISSUED AT 945 PM MST FRI DEC 20 2024  
 
VFR CONDITIONS WILL CONTINUE AT ALL TERMINALS THROUGH THE TAF  
PERIOD. WINDS WILL REMAIN LIGHT FOR MOST TERMINALS AS WELL,  
EXCEPT KCPR. WIND GUSTS WILL INCREASE 25 TO 30 KT AROUND 17Z AND  
CONTINUE THROUGH THE REST OF THE PERIOD. OTHERWISE, MID TO HIGH  
CLOUDS (SOME DUE TO LEE ENHANCEMENT OFF THE ABSAROKA AND WIND  
RIVER MOUNTAINS) WILL CONTINUE TO STREAM OVER THE FORECAST AREA.  
 

 
   
RIW WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  
 

 
 

 
 
DISCUSSION...STRAUB  
AVIATION...LAVOIE/MYERS  
 
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