228
FXUS65 KRIW 180442
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
942 PM MST SAT JAN 17 2026
KEY MESSAGES
- A WEAK DISTURBANCE WILL BRING INCREASED WINDS (GUSTS OF 40 TO
50 MPH) AND LIGHT SNOW CHANCES (LESS THAN AN INCH) TO LOWER
ELEVATIONS OF NORTHERN JOHNSON COUNTY TONIGHT THROUGH SUNDAY.
- MILD AND MOSTLY DRY ELSEWHERE THROUGH THE WEEKEND.
- ABOVE AVERAGE TEMPERATURES, BREEZY WINDS, AND MOSTLY DRY
CONDITIONS WILL PERSIST THROUGH MUCH OF THE UPCOMING WEEK.
UPDATE
ISSUED AT 114 PM MST SAT JAN 17 2026
NOT MUCH CHANGE IN THE FORECAST TODAY, WITH A MILD AND MOSTLY
DRY WEEKEND NOW IN PLACE ACROSS THE STATE. AS NOTED BELOW, AN
INCOMING DISTURBANCE WILL ELEVATE WIND AGAIN ACROSS THE BIGHORNS
AND JOHNSON COUNTY TONIGHT. THIS WILL ALSO BRING THE WEEKEND'S
ONLY SHOT AT A LITTLE MOISTURE, WITH LOW SNOW CHANCES (20-30%)
ACROSS THE SAME WIND IMPACTED AREAS THROUGH THE DAYLIGHT HOURS
SUNDAY. THE OWL CREEK/BRIDGER RANGE, EASTERN ABSAROKAS, AND
CASPER MOUNTAIN WILL SEE SIMILAR CHANCES DURING THIS TIME. THE
BEST CHANCE FOR LIGHT SNOW ACCUMULATIONS ACROSS LOWER ELEVATIONS
WILL BE ALONG THE I-90 CORRIDOR, INCLUDING THE BUFFALO AREA
WHICH MAY SEE A HALF INCH SUNDAY (ONLY 10% CHANCE OF EXCEEDING
AN INCH).
DISCUSSION
ISSUED AT 145 AM MST SAT JAN 17 2026
THIS WINTER'S DOMINANT H5 RIDGE REMAINS STEADY ALONG THE WEST
COAST, WHICH WILL CONTINUE TO PROVIDE THE UNUSUALLY WARM WINTER
ACROSS THE STATE. NOT MUCH TO KNOCK THIS AREA OUT OF PLACE, SO
THE TRANQUIL WINTER CONTINUES FOR THE UPCOMING WEEK. FOR TODAY,
A RETURN OF WESTERLY WINDS ACROSS THE STATE, WITH GUSTY WINDS
EXPECTED IN THE USUAL LOCATIONS ACROSS NATRONA COUNTY AND ACROSS
SOUTH PASS. FOR THE MOST PART, GUSTS WILL BE LIMITED TODAY, WITH
PEAK GUSTS AROUND 30 KNOTS THIS AFTERNOON. THE WESTERLY FLOW
WILL AGAIN BRING BACK SOME WARMING TO THE STATE, WITH HIGHS
RECOVERING INTO THE 30S AND 40S THIS AFTERNOON. THE DIFFICULT
PIECE IN THIS FORECAST WILL BE ACROSS JOHNSON COUNTY. MODELS ARE
NOT PICKING UP ON ANY DOWNSLOPING WESTERLY FLOW THERE TODAY, SO
TEMPERATURES ARE HOLDING BACK IN THE LOWER 30S. IF ANY
DOWNSLOPING DOES FORM UP, THIS COULD EASILY PUSH THEIR
TEMPERATURES WELL INTO THE 40S. FOR WESTERN VALLEYS, SHALLOW
COLD POOLS WILL BE SHELTERED FROM WEST WINDS FOR TODAY, SO HIGHS
WILL MAX OUT AROUND 30.
OVERNIGHT TONIGHT, ANOTHER WEAK CLIPPER-STYLE WAVE WILL SWEEP
ACROSS THE NORTHERN PLAINS, WITH THE TAIL EDGE BRUSHING AGAINST
CENTRAL WY. THIS WILL BRING REINFORCING COLD AIR BACK TO MAINLY
ALONG THE I-25 CORRIDOR, ALONG WITH A RUSH OF COLD NORTHWEST
WINDS. WINDS COULD AGAIN GUST 45 TO 50 MPH ACROSS JOHNSON COUNTY
ON SUNDAY. WHILE A FEW LIGHT SNOW SHOWERS ARE POSSIBLE AS THE
SYSTEM PASSES THROUGH, WINDS GENERALLY AREN'T IN A FAVORABLE
DIRECTION FOR ANY SIGNIFICANT ACCUMULATIONS IN THE BIGHORNS.
WESTERN VALLEYS WILL NOT BE GENERALLY IMPACTED BY THIS SYSTEM,
SO THE STATUS QUO WITH THE SHALLOW COLD AIR KEEPING TEMPS AROUND
30 AGAIN FOR SUNDAY.
AND SO THIS PATTERN CONTINUES THE UPCOMING WEEK, WITH QUICK-
MOVING SYSTEMS EXPECTED TUESDAY NIGHT AND FRIDAY, BRINGING
REINFORCING COLD AIR EACH TIME, ALONG WITH SOME GUSTY WINDS TO
CENTRAL WY. WIND RETURN FLOW ON TUESDAY AHEAD OF THAT SYSTEM
LOOKS TO BE A BIT STRONGER, BRINGING TEMPERATURES EAST OF THE
DIVIDE BACK INTO THE 40S FOR THE DAY. WESTERN VALLEYS HOLD
STEADY IN THE 30S CLOSER UNDER THE WESTERN RIDGE. THE SYSTEM
LATE THIS WEEK LOOKS TO BE BETTER PLACED TO BRING BACK SOME
MODEST SNOWFALL TO THE WESTERN MOUNTAINS.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 935 PM MST SAT JAN 17 2026
WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS TERMINALS.
HIGH PRESSURE KEEPS A MAINLY CLEAR SKY AND RELATIVELY LIGHT WINDS
THROUGH MUCH OF THE PERIOD. HIGH CLOUDS WILL BEGIN TO MOVE OVER
THE AREA FROM THE NORTH AFTER 00Z. WINDS WILL BE DIURNALLY
DRIVEN SUNDAY, WITH SLIGHT INCREASES IN THE AFTERNOON.
EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL TERMINALS.
A COLD FRONT WILL MOVE IN FROM THE NORTH SUNDAY, BRINGING A
NORTHERLY WIND SHIFT AND BRIEF GUSTY WINDS WITH ITS PASSAGE AND
FOR A FEW HOURS AFTER. PRECIPITATION CHANCES WITH THIS FRONT ARE
VERY LIMITED, WITH 20 PERCENT CHANCES FOR FAVORED TERRAIN
LOCATIONS LIKE KCOD, KCPR, AND KLND. THE BEST CHANCES FOR SNOW
WILL BE OVER THE NORTH END OF THE BIGHORN MOUNTAINS INTO
NORTHERN JOHNSON COUNTY BETWEEN 12Z AND 18Z. CLOUDS DO INCREASE
AS THE FRONT PROGRESSES SOUTHWARD, WITH THE LATEST MODEL RUNS
INDICATING LOW- END VFR TO MVFR CEILINGS, WHICH MAY BE TOO
PESSIMISTIC. THESE LOWER CEILINGS WILL LIKELY OCCUR AFTER 03Z.
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...MYERS
DISCUSSION...STRAUB
AVIATION...LAVOIE/WITTMANN
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