812
FXUS65 KRIW 281712
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1012 AM MST SUN DEC 28 2025
KEY MESSAGES
- A MAINLY DRY BUT COLD DAY TODAY AND COLD NIGHT TODAY BEHIND A
COLD FRONT.
- A NEW WARMING TREND BEGINS MONDAY AND ESPECIALLY FROM TUESDAY
AND THROUGH NEW YEARS DAY.
- LITTLE OR NO RAIN OR SNOW IS EXPECTED AT LEAST THROUGH
WEDNESDAY AND POSSIBLY THROUGH NEW YEARS DAY.
DISCUSSION
ISSUED AT 1238 AM MST SUN DEC 28 2025
IT LOOKS LIKE OLD MAN WINTER HAS FINALLY AWAKENED FROM HIS LONG
SLUMBER AND HAS BROUGHT WYOMING BACK TO REALITY. A COLD FRONT
HAS DROPPED ACROSS THE AREA AND USHERED IN MUCH COLDER
TEMPERATURES, BUFFALO IS DOWN TO 4 DEGREES AS I WRITE THIS, IT
WAS 61 ON CHRISTMAS DAY AND ALMOST 70 ON CHRISTMAS EVE. AS I
WRITE THIS AFTER MIDNIGHT, THERE ARE STILL SOME SNOW SHOWERS
ONGOING, BUT THE OVERALL TREND IS DOWNWARD. ALL SHOWERS SHOULD
BE OVER SUNRISE.
ALL IN ALL, WE ARE ENTERING A QUIETER PERIOD OF WEATHER AS HIGH
PRESSURE WILL BUILD OVER THE STATE. IT LOOKS FAIRLY TRANQUIL
FOR AT LEAST THE NEXT FOUR AND POSSIBLY THE NEXT FIVE DAYS WILL
BE DRY ACROSS ALMOST THE ENTIRE AREA. THE MAIN CONCERN WILL BE
TEMPERATURES. IT WILL BE MUCH COLDER TODAY, BUT FOR MOST OF THE
AREA, IT WILL ONLY BE BACK TO WHAT IS EXPECTED FOR LATE
DECEMBER. NORTHERN WYOMING WILL BE BELOW NORMAL, ESPECIALLY
AREAS LIKE CODY AND BUFFALO THAT SAW SOME ACCUMULATING SNOW
YESTERDAY. SUNDAY NIGHT ALSO LOOKS LIKE A RATHER COLD NIGHT, BUT
NOTHING UNUSUAL.
HOWEVER, THE COLD WON'T LAST. FLOW WILL TURN MORE ZONAL AS WE GO
THROUGH THE WEEK AND TEMPERATURES WILL ONCE AGAIN BEGIN AN UPWARD
TREND, SURGING ABOVE NORMAL AGAIN BY THE END OF THE YEAR. IT
WILL LIKELY NOT BE AS WARM AS AROUND CHRISTMAS, BUT
TEMPERATURES 10 TO POSSIBLY AS MUCH AS 20 DEGREES FAHRENHEIT
ABOVE NORMAL LOOK VERY LIKELY (AT LEAST A 4 OUT 5 CHANCE) FROM
TUESDAY AND ESPECIALLY WEDNESDAY THROUGH THE END OF THE WEEK.
THE WARM TEMPERATURES MAY ALSO LEAD TO SOME GUSTY WIND IN THE
FAVORED LOCATIONS, BUT HIGH WIND IS NOT EXPECTED AT THIS TIME.
THE NEXT CHANCE OF PRECIPITATION WOULD ARRIVE ON THURSDAY NIGHT AT
THE EARLIEST, BUT MORE LIKELY FRIDAY OR NEXT WEEKEND IN THE
FORM OF A PACIFIC TROUGH. IS IS FAR FROM CERTAIN THOUGH AS THE
MODELS HAVE BEEN FLIP-FLOPPING FOR THE PAST FEW DAYS. OBVIOUSLY,
DETAILS ARE IMPOSSIBLE TO DETERMINE THIS FAR OUT. SO, IT LOOKS
LIKE THE WEATHER AS WE CLOSE OUT 2025 AND START 2026 IS LOOKING
RELATIVELY QUIET.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1012 AM MST SUN DEC 28 2025
WEST OF THE CONTINENTAL DIVIDE...KJAC/KRKS/KPNA/KBPI TERMINALS
ALL TERMINALS TO BE VFR THROUGH THE FORECAST PERIOD. THE ONE CAVEAT
WILL BE WARM AIR ADVECTION OVERNIGHT, WHICH WILL SET-UP VALLEY/BASIN
INVERSIONS. HIGH-RESOLUTION ENSEMBLES AND INDIVIDUAL DETERMINISTIC
GUIDANCE GIVES LITTLE TO NO HINT AT LOW CLOUDS OR FOG. HOWEVER,
GIVEN THE WARM AIR ADVECTION ALONG WITH A FRESH SNOWPACK AND
ONLY HIGH CLOUDS, HAVE CONTINUED WITH FEW005 AT KJAC LATE
TONIGHT AND MONDAY MORNING TO GIVE SOME HINT AT THIS POSSIBILITY
(LESS THAN 20 PERCENT). OTHERWISE, INCREASING MID/HIGH CLOUDS
ARRIVE LATE TONIGHT AND DRIFT SOUTH ACROSS THE REGION MONDAY.
GUSTY WEST-NORTHWEST WIND SUNDAY AFTERNOON DIMINISHES AT
SOUTHWEST TERMINALS WITH THE SETTING SUN.
EAST OF THE CONTINENTAL DIVIDE...KCPR/KCOD/KRIW/KLND/KWRL TERMINALS
ALL TERMINALS TO BE VFR THROUGH 18Z/MONDAY AS WEAKLY CYCLONIC
NORTHERLY FLOW ALOFT PREVAILS. KCPR SEES GUSTY WESTERLY WIND 14-
28KTS SUNDAY AFTERNOON BEFORE TAILING OFF TO 10-13KTS AT SUNSET
THROUGH THE OVERNIGHT HOURS. SOUTHWEST WIND PICKS UP BETWEEN 14Z-
16Z/MONDAY AT KCPR, WHILE OTHER TERMINALS REMAIN LESS THAN 10KTS AND
ARE MAINLY DIURNALLY-DRIVEN. OTHERWISE, MID/HIGH CLOUDS
INCREASE LATE TONIGHT AND TRACK SOUTH ACROSS THE STATE MONDAY.
PLEASE SEE THE AVIATION WEATHER CENTER AND/OR CWSU ZLC AND ZDV FOR
THE LATEST INFORMATION ON ICING AND TURBULENCE FORECASTS.
RIW WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...HATTINGS
AVIATION...CNJ
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