976
FXUS65 KRIW 300411
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
911 PM MST MON DEC 29 2025
KEY MESSAGES
- ANOTHER NIGHT OF CHILLY TEMPERATURES FOR WESTERN VALLEYS WITH
MOSTLY CLEAR SKIES.
- TEMPERATURES CONTINUE THEIR GRADUAL WARMING TREND THROUGH MID-
WEEK, BECOMING ABOVE NORMAL BY NEW YEARS EVE DAY (WEDNESDAY).
- DRY CONDITIONS PREVAIL FOR THE REST OF THE YEAR ACROSS THE
STATE. THE NEXT SYSTEM MOVES IN THURSDAY, AND WESTERN WYOMING
HAS A 60 TO 80% CHANCE FOR PRECIPITATION BY THE AFTERNOON
HOURS, WITH RAIN FOR VALLEY BOTTOMS AND SNOW ABOVE 7000 FT.
UPDATE
ISSUED AT 1212 PM MST MON DEC 29 2025
NOTHING TO UPDATE REGARDING THE PREVIOUS DISCUSSION AS THE
OVERALL PATTERN REMAINS QUIET AND MILD THROUGH THE NEXT FEW
DAYS. CHILLY TEMPERATURES ARE FORECAST ACROSS THE STATE TODAY
WITH HIGHS IN THE 30S EAST OF THE DIVIDE AND 20S TO LOW 30S WEST
OF THE DIVIDE. COLDER AIR IS PERSISTING IN SOME WESTERN VALLEYS
WHERE RECENT SNOWFALL OCCURRED SUCH AS STAR VALLEY, WHERE HIGHS
MAY STRUGGLE TO GET INTO THE 20S TODAY. OTHERWISE, NOT MUCH
MORE TO ADD IN TERMS OF THE SHORT TERM FORECAST. THE NEXT CHANCE
FOR PRECIPITATION LOOKS TO POSSIBLY ARRIVE BY THE SECOND HALF
OF THE WEEK WITH CHANCES FAVORING WESTERN WY. MODELS ARE NOT
SHOWING ALL THE IMPRESSIVE OF A SYSTEM SO IMPACTS AT THIS TIME
ARE LOOKING MINIMAL.
DISCUSSION
ISSUED AT 132 AM MST MON DEC 29 2025
HIGH PRESSURE WILL BE HOLDING CONTROL ALONG THE NORTHERN ROCKIES
DURING THE NEXT SEVERAL DAYS, DEFLECTING THE STORM TRACK BACK
INTO CANADA AND KEEPING MILD TEMPERATURES GOING FOR WYOMING.
LOWS THIS MORNING HAVE BEEN COLD, WITH TEMPS WELL BELOW ZERO FOR
THE WESTERN VALLEYS, AND IN THE SINGLE DIGITS ABOVE ZERO EAST OF
THE DIVIDE. SOUTHWEST FLOW RETURNS TODAY, HELPING TO CARVE OUT
SOME OF THE COLD POOL THAT HAS SETTLED IN THE REGION. WITH THE
COLD POOL NOT OVERLY STRONG AND NOT REINFORCED BY ANY SNOWPACK,
EXPECT A GOOD RECOVERY OF TEMPERATURES INTO THE 30S THIS
AFTERNOON. WESTERN VALLEYS THAT DO HAVE SNOWPACK AND ARE
STARTING A LOWER TEMPERATURES WILL HAVE MORE TROUBLE GETTING
OUT OF THE TEENS THIS AFTERNOON. THIS PATTERN WILL CONTINUE
THROUGH THE REMAINDER OF THE WEEK, AS THE RIDGE HOLDS IN PLACE,
PUSHING SYSTEMS OFF TO THE NORTH AND CONTINUING TO CARVE UP ANY
REMAINING COLD POOL. MOST AREAS WILL BE BACK IN THE 40S BY
WEDNESDAY, WITH JACKSON HOLE AND STAR VALLEY HOLDING BACK A BIT
DEPENDING ON HOW FAST SURFACE SNOW THINS OUT.
THE RIDGE TRIES TO SHIFT MORE EAST LATE IN THE WEEK, OPENING THE
DOOR FOR SOME MOISTURE TO GET BACK INTO THE WESTERN MOUNTAINS,
BUT A LACK OF SIGNIFICANT SUPPORTING STORM SYSTEMS WILL KEEP ANY
SNOWFALL ON THE LIGHTER SIDE FOR THE TIME BEING.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 906 PM MST MON DEC 29 2025
VFR CONDITIONS PREVAIL ACROSS THE REGION OVER THE NEXT 24 HOURS
WITH MINIMAL AVIATION WEATHER IMPACTS EXPECTED. HIGH CLOUDS
INCREASE DURING THE MORNING HOURS TUESDAY, AND COULD OBSCURE THE
HIGHEST PEAKS OF THE ABSAROKA AND BIGHORN RANGES. GENERALLY
LIGHT WINDS ARE FORECAST FOR ALL AREAS, WITH TYPICAL WINDY SPOTS
LIKE KCPR SEEING GUSTS TO AROUND 20 KT DURING THE AFTERNOON
HOURS TUESDAY. NO PRECIPITATION IS IN THE FORECAST.
RIW WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...DZIEWALTOWSKI
DISCUSSION...STRAUB
AVIATION...VANDENBOOGART
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