132
FXUS65 KRIW 282235
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
335 PM MST SUN DEC 28 2025
KEY MESSAGES
- A CHILLY BUT QUIET SUNDAY ACROSS THE COWBOY STATE WITH COLD
TEMPERATURES PERSISTING INTO MONDAY MORNING.
- A WARMING TREND BEGINS MONDAY WITH TEMPERATURES GRADUALLY
RETURNING TO SLIGHTLY ABOVE NORMAL THROUGH NEW YEARS DAY.
- LITTLE TO NO CHANCES FOR PRECIPITATION THROUGH THE FIRST HALF
OF THE WEEK WITH SOME CHANCES DEVELOPING BY THE END OF THE
WEEK.
UPDATE
ISSUED AT 1146 AM MST SUN DEC 28 2025
NOT MUCH TO UPDATE AS A QUIET WEATHER PATTERN LOOKS TO SETTLE
IN ACROSS THE REGION THROUGH THE END OF THE YEAR. COLD
TEMPERATURES PERSIST THROUGH MONDAY MORNING BEFORE A WARMING
TREND BEGINS. TEMPERATURES LOOK TO GRADUALLY WARM THROUGH THE
WEEK WITH HIGHS GETTING BACK INTO THE MID TO UPPER 40S EAST OF
THE DIVIDE AND MID TO UPPER 30S WEST OF THE DIVIDE BY NEW YEARS
EVE. ABOVE NORMAL TEMPERATURES LOOK TO PERSIST INTO THE SECOND
HALF OF THE WEEK. LONG RANGE MODELS CONTINUE TO INDICATE THE
POSSIBILITY FOR A DISTURBANCE BRINGING PRECIPITATION CHANCES
BACK TO THE STATE BY THE END OF THE WEEK. HOWEVER, CONFIDENCE
STILL REMAINS LOW AT THIS TIME WITH A BETTER IDEA OF WHAT TO
EXPECT LIKELY TO COME INTO FOCUS OVER THE NEXT FEW DAYS.
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 /00Z TAFS THROUGH 00Z TUESDAY/
ISSUED AT 335 PM MST SUN DEC 28 2025
WEST OF THE CONTINENTAL DIVIDE...KJAC/KRKS/KPNA/KBPI TERMINALS
VFR PREVAILS AT ALL TERMINALS THROUGH 00Z/TUESDAY. MID-LEVEL WARM
AIR ADVECTION WILL ALLOW FOR VALLEY/BASIN INVERSIONS TO SET-UP
OVERNIGHT. MIDDAY SUNDAY HIGH-RESOLUTION ENSEMBLES AND DETERMINISTIC
GUIDANCE GIVES NO HINT AT THE DEVELOPMENT OF LOW CLOUDS OR FOG AT
KJAC. THESE INVERSIONS COMBINED WITH RECENT SNOW AND ONLY HIGH
CLOUDS OVERNIGHT, THERE COULD STILL BE A VERY LOW CHANCE (10 PERCENT
OR LESS) FOR LOW CLOUDS AT KJAC LATE TONIGHT AND MONDAY MORNING.
NORTHERLY FLOW ALOFT ALLOWS FOR A BATCH OF MID/HIGH CLOUD COVER TO
TRANSIT THE REGION LATE TONIGHT AND MONDAY. GUSTY WEST-NORTHWEST
WIND SUNDAY AFTERNOON DIMINISHES AT SOUTHWEST TERMINALS WITH THE
SETTING SUN. KRKS SEES WEST-SOUTHWEST 10-20KT SURFACE WIND RETURN
AROUND MIDDAY MONDAY.
EAST OF THE CONTINENTAL DIVIDE...KCPR/KCOD/KRIW/KLND/KWRL TERMINALS
TERMINALS REMAIN VFR THROUGH 00Z/TUESDAY AS NORTHERLY FLOW CONTINUES
ACROSS THE FORECAST AREA. GUSTY WESTERLY WIND 14-22KTS SUNDAY
AFTERNOON AT KCPR SLOWS TO AROUND 10KTS EARLY IN THE PERIOD BEFORE
SOUTHWEST WIND INCREASES TO 14-28KTS BETWEEN 14Z-16Z/MONDAY.
REMAINING TERMINALS STAY LESS THAN 10KTS AS DIURNALLY-DRIVEN WIND
DIRECTIONS PERSIST. MID/HIGH CLOUDS INCREASE LATE TONIGHT AND
TRANSIT THE REGION 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.
UPDATE...DZIEWALTOWSKI
DISCUSSION...HATTINGS
AVIATION...LOWE
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page