098
FXUS65 KRIW 211021
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
321 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 /12Z TAFS THROUGH 12Z SUNDAY/
ISSUED AT 318 AM MST SAT DEC 21 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.
CEILINGS WILL LOWER IN VICINITY OF KJAC AFTER 06Z SUNDAY BUT ANY
PRECIPITATION SHOULD HOLD OFF UNTIL AFTER 12Z SUNDAY.
RIW WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...STRAUB
AVIATION...HATTINGS
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