715
FXUS65 KRIW 222245
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
345 PM MST THU JAN 22 2026
KEY MESSAGES
- A COLD FRONT MOVES IN TONIGHT, BRINGING COLD TEMPERATURES TO
THE AREA FOR FRIDAY. COLDEST TEMPERATURES OCCUR SATURDAY
MORNING, WITH LOWS AROUND AND BELOW 0 DEGREES.
- LIGHT SNOW IS POSSIBLE, MAINLY EAST OF THE DIVIDE FRIDAY INTO
SATURDAY. UP TO 2 INCHES IS POSSIBLE FOR PORTIONS OF THE
BIGHORN BASIN, JOHNSON COUNTY, AND NATORNA COUNTY, WITH LESSER
CHANCES ELSEWHERE.
UPDATE
ISSUED AT 1127 AM MST THU JAN 22 2026
NO CHANGES TO THE OVERALL MESSAGE FOR THE NEXT FEW DAYS. A COLD
FRONT MOVES IN TONIGHT, USHERING IN COLDER TEMPERATURES FOR THE END
OF THE WEEK. WINDS DO NOT LOOK TO BE A MAJOR CONCERN, WITH GUSTS
MAYBE TOPPING AROUND 30 MPH WITH FRONTAL PASSAGE FOR FAVORED AREAS
LIKE THE BIGHORN BASIN AND NATORNA COUNTY, MAINLY THE WESTERN
COUNTY. BREEZY WINDS 15 TO 20 MPH BECOME MORE WIDESPREAD FOR FRIDAY
AFTERNOON.
FOR TEMPERATURES, THE COLDEST PERIOD WILL LIKELY BE SATURDAY MORNING
LOWS (THOUGH FRIDAY IS ALSO NOTABLY COLDER). THERE IS A WIDESPREAD
60 TO 100 PERCENT CHANCE FOR SATURDAY MORNING LOWS TO BE 0 DEGREES
OR LESS, WITH THE WARMEST TEMPERATURES ACROSS SOUTHERN SWEETWATER
COUNTY. FOR THE COLDEST AREAS, THERE IS A 20 TO 40 PERCENT CHANCE
FOR BELOW NEGATIVE 10 DEGREES IN THE BIGHORN BASIN AND A 40 TO 60
PERCENT CHANCE FOR JOHNSON AND NATRONA COUNTIES. LOCALIZED COLD
PRONE LOCATIONS (LIKE NEAR RIVERS AND IN LOW SPOTS) COULD BE IN THE
NEGATIVE TEENS FOR THESE LOCATIONS. CLOUD COVER AND SNOW POTENTIAL
WILL BE THE GREATEST INFLUENCE IN THESE TEMPERATURES, ADDING SOME
UNCERTAINTY WITH THE CURRENT TEMPERATURE FORECAST. WIND IS NOT A
GREAT FACTOR SATURDAY MORNING, BUT A LIGHT BREEZE AROUND 10 MPH IN
JOHNSON AND NATRONA COUNTY COULD HAVE FEEL-LIKE TEMPERATURES IN THE
NEGATIVE TEENS.
FOR SNOW, GREATEST ACCUMULATIONS ARE EAST OF THE DIVIDE, MAINLY THE
EASTERN BIGHORN BASIN AND JOHNSON/NATRONA COUNTIES. LATEST GUIDANCE
WOULD SUGGEST 40 TO 60 PERCENT CHANCE FOR AT LEAST HALF AN INCH IN
THE BIGHORN BASIN AND 60 TO 70 PERCENT CHANCE FOR THE LOWER
ELEVATIONS OF JOHNSON AND NATRONA COUNTIES. HIGHER-END AMOUNTS OF 2
INCHES OR MORE IS POSSIBLE FOR BUFFALO (20 PERCENT CHANCE) AND
CASPER (40 PERCENT CHANCE). WITH THE EXPECTED NORTH-NORTHWEST FLOW,
SOUTHERN CASPER WILL LIKELY SEE MORE SNOW THAN NORTHERN PARTS.
DISCUSSION
ISSUED AT 237 AM MST THU JAN 22 2026
FOR THE MOST PART THINGS ARE QUIET AT THE HUMBLE RIVERTON
WEATHER ABODE AS HIGH PRESSURE IS BRINGING DRY, QUIET AND FOR
THE MOST PART SEASONABLY COLD WEATHER TONIGHT. WE HAVE TWO
QUESTIONS TONIGHT THAT WE ARE PONDERING TONIGHT FOR THE FORECAST
AS WE LISTEN TO CLASSIC ROCK TONIGHT (TWO GEN XERS WORKING
TONIGHT). THE FIRST IS HOW MUCH SNOW WE WILL GET OVER THE NEXT
THREE DAYS, AND THE SECOND, MORE IMPORTANT QUESTION, IS HOW COLD
WILL IT GET AS WE HAVE THE COLDEST AIR OF THE SEASON MOVING IN
FOR THE WEEKEND AND WILL PEOPLE BE STONE COLD, COLD AS ICE OR SO
COLD (I THREW IN BREAKING BENJAMIN FOR THE MILLENNIALS). WE
WILL DO SOMETHING DIFFERENT AND ADDRESS THESE INDIVIDUALLY.
WE WILL START WITH SNOW. DRY CONDITIONS ARE EXPECTED TODAY, BUT THE
NEXT COLD FRONT (THE THIRD WE HAVE SEEN THIS WEEK) WILL CROSS
THE AREA TONIGHT AND INTO FRIDAY. AND, I'M GOING TO SOUND LIKE A
BROKEN RECORD, WITH THE ARCTIC ORIGINS OF THE AIR, IT HAS
LITTLE MOISTURE TO WORK WITH. AS A RESULT, SNOWFALL AMOUNTS ARE
EXPECTED TO BE LIGHT. IN THE DETERMINISTIC MODEL REALM, THE
EUROPEAN BRINGS A FAIRLY BROAD AREA OF LIGHT QPF (LESS THAN A
TENTH OF AN INCH) ACROSS MOST AREAS EAST OF THE DIVIDE. THE GFS
IS MUCH DRIER WITH ONLY SOME LIGHT SNOW SHOWERS ACROSS AREAS
EAST OF THE DIVIDE. THEN WE TRANSITION INTO THE PROBABILISTIC
REALM OF ENSEMBLE GUIDANCE. THE SNOW IS STILL EXPECTED TO BE OF
THE ANAFRONTAL VARIETY, FALLING BEHIND THE FRONT. AND WITH THE
NORTHERLY FLOW BEHIND THE FRONT, THE HEAVIEST SNOW (A RELATIVE
TERM WITH THIS SYSTEM) WOULD FALL IN THE FAVORED NORTHERLY
UPSLOPE LOCATIONS. THIS LOOKS TO BE FURTHER EAST AS WELL,
GENERALLY AROUND CASPER AND FROM THERMOPOLIS AND EASTWARD INTO
THE SOUTHEASTERN BIGHORN BASIN. EVEN HERE, THE CHANCE OF OVER AN
INCH OF SNOW IN THE LOWER ELEVATIONS IS ONLY 1 OUT OF 2. WHEN
WE BUMP THE TOTALS TO ADVISORY LEVEL (3 INCHES), THE ONLY
POSSIBLE AREA IS AROUND CASPER, WHERE THERE WILL BE A BIT OF
RIGHT REAR QUADRANT JET ENERGY TO ENHANCE LIFT A BIT. EVEN HERE,
THE CHANCE IS ONLY 1 OUT OF 5 AT THE MOST. THIS, PLUS THE FACT
THE COLD AIR WILL OOZE IN RATHER THEN MOVE IN QUICKLY, WIND
SHOULD NOT BE TOO STRONG. SO, NO ADVISORIES HERE. ELSEWHERE, THE
CHANCE OF AN INCH OF SNOW IS LESS THAN 1 OUT OF 10. THIS ROUND
OF SNOW SHOULD END FRIDAY NIGHT. AFTER A DRY SATURDAY, THE
FOURTH AND LAST FRONT WILL MOVE INTO THE AREA SATURDAY NIGHT.
THIS SYSTEM IS EVEN DRIER AND WILL BRING EVEN LESS SNOW, WITH
ONLY SOME SHOWERS EXPECTED AND ANY ACCUMULATION EXPECTED TO BE
LIGHT.
THE MAIN STORY LOOKS TO BE THE COLD AIR, THE COLDEST OF THE SEASON.
ONE DISCLAIMER HERE, THIS WILL NOT BE A RECORD BREAKING COLD
OUTBREAK. TEMPERATURES WILL GENERALLY BE 10 TO 15 DEGREES BELOW
NORMAL AS THE CORE OF THE COLD AIR WILL REMAIN WELL TO THE
EAST, OVER THE NORTHERN PLAINS AND GREAT LAKES, WITH WYOMING
SEEING MORE OF A GLANCING BLOW. THE 700 MILLIBAR TEMPERATURES
WILL BE GENERALLY DOWN TO AROUND MINUS 21, AS OPPOSED THE MINUS
30S FURTHER EAST. FRIDAY WILL BE THE COLDEST DAY IN A LONG TIME
FOR AREAS EAST OF THE DIVIDE, WITH HIGHS REMAINING IN THE TEENS
AND SINGLE DIGITS. AS OF NOW, IT IS LOOKING MORE LIKELY THAT
MANY AREAS WILL SEE LOWS IN BELOW ZERO EAST OF THE DIVIDE, WITH
MOST AREAS HAVING AT LEAST 4 OUT OF 5 CHANCE. THERE ARE STILL A
COUPLE OF WILD CARDS THOUGH. ONE IS IF THE CLOUDS DON'T CLEAR
QUICKLY ENOUGH, KEEPING TEMPERATURES UP JUST A BIT. THE OTHER IS
SNOW COVER. AREAS FURTHER WEST MAY NOT HAVE ANY SNOW COVER,
KEEPING TEMPERATURES A BIT WARMER. THE COLDEST TEMPERATURES MAY
END UP BEING IN NATRONA COUNTY, WHERE SNOW COVER SHOULD BE THE
DEEPEST, AIDING IN COOLING. HERE, THERE IS A 2 OUT OF 5 CHANCE
OF LOWS LOWER THAN MINUS 10. AS FOR COLD HIGHLIGHTS, DON'T THINK
THEY ARE NEEDED NOW SINCE MINUS 20 IS NOT EXPECTED AND THE WIND
SHOULD BE FAIRLY CALM. SATURDAY LOOKS COLD AS WELL.
THE COLD SHOULD NOT LAST THOUGH, AS THE COLD AIR MOVES TO THE EAST
AS FLOW TURNS MORE NORTHWESTERLY AND WESTERLY. A SLOW MODERATION
BEGINS ON SUNDAY, BUT SHOULD REALLY BE FELT ON MONDAY AS A WEAK
SHORTWAVE APPROACHES AND MIXES OUT THE ATMOSPHERE. TEMPERATURES
SHOULD RETURN TO ABOVE NORMAL LEVELS AGAIN ON MONDAY. THE FORECAST
GETS MORE MUDDY AFTER THAT, BUT NO ARCTIC AIR IS EXPECTED AS WE HAD
TOWARD THE END OF JANUARY.
AVIATION /00Z TAFS THROUGH 00Z SATURDAY/
ISSUED AT 345 PM MST THU JAN 22 2026
VFR CONDITIONS EXPECTED THROUGHOUT THE PERIOD AT ALL LOCATIONS.
LIGHT WINDS 10KTS OR LESS EXPECTED UNDER A WEAK GRADIENT WITH
INCREASING UPPER LEVEL CLOUDS THROUGH THE EVENING LOWERING TO
THE MID LEVELS BY 12Z FRIDAY MORNING. BEST CHANCE FOR SNOW ON
STATION WILL BE AT CPR AFTER 12Z WITH PROB30 GROUPS, AND LESS
THAN 10% FOR COD/WRL CARRYING ONLY VCSH AFTER 18Z. OTHERWISE,
LOW BUT VFR CEILINGS EXPECTED ACROSS THE ENTIRE CWA WITH THE
APPROACHING DISTURBANCE BUT MOST WILL REMAIN DRY.
PLEASE SEE THE AVIATION WEATHER CENTER AND/OR CWSU ZDV AND ZLC FOR
THE LATEST INFORMATION ON ICING AND TURBULENCE FORECASTS.
RIW WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...WITTMANN
DISCUSSION...HATTINGS
AVIATION...LOWE
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