276
FXUS65 KRIW 201736
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1036 AM MST TUE JAN 20 2026
KEY MESSAGES
- A COLD FRONT WILL BRING STRONG WIND TO MUCH OF THE AREA THIS
AFTERNOON, WITH SOME LIGHT SNOW POSSIBLE EAST OF THE DIVIDE.
- TWO MORE FRONTS BRING MORE SHOTS OF COLD AIR WEDNESDAY AND
FRIDAY ALONG WITH GUSTY WIND, BUT LITTLE CHANCE OF MEANINGFUL
SNOW.
- ABOVE NORMAL TEMPERATURES SHOULD RETURN SUNDAY INTO THE FIRST
PART OF NEXT WEEK.
DISCUSSION
ISSUED AT 228 AM MST TUE JAN 20 2026
THERE ARE CERTAIN MILESTONES I WATCH THROUGH THE FIRST PART OF
THE YEAR. NOT BEING A WINTER LOVER, THESE ARE MARKERS I USE TO
SEE WHEN WINTER WILL END (ALTHOUGH I WOULD TAKE THIS ONE
EVERY TIME). TODAY IS THAT WE ARE A MONTH PAST THE SOLSTICE.
HOWEVER, WE STILL HAVE A LONG WAY TO GO, AND TODAY WILL BE A
REMINDER OF THAT IN PORTIONS OF THE AREA.
THE FIRST WILL TODAY, AS A COLD FRONT DROPS SOUTHWARD ACROSS THE
AREA. THE AIR BEHIND IT IS NOT ALL THAT COLD THOUGH. IT ALSO HAS
LITTLE MOISTURE TO WORK WITH. HOWEVER, THERE WILL BE IMPACTS,
ESPECIALLY TO ONE PORTION OF THE AREA. AND THIS IS JOHNSON
COUNTY. IT WILL NOT BE A LONG IMPACT THOUGH, THE ONLY LASTING
AROUND 6 HOURS, GENERALLY FROM AROUND 10 AM TO 4 PM. FIRST THE
SNOWY PART. THIS LOOKS TO BE THE LEAST IMPACTFUL, ALMOST ALL OF
THE LOWER ELEVATION LOCATIONS HAVE LESS THAN A 1 IN 5 CHANCE OF
AN INCH OR MORE OF SNOW, WITH ONLY A SMALL PORTION OF THE
BIGHORNS HAVING AT LEAST A 1 IN 2 CHANCE OF 2 INCHES OR MORE.
THE MAIN IMPACT LOOKS TO BE THE WIND. THIS WILL BE ESPECIALLY
SO IN THE FAVORED NORTHWEST FLOW / COLD ADVECTION LOCATIONS.
AND THIS INCLUDES, OBVIOUSLY, JOHNSON COUNTY. PROBABILISTIC
GUIDANCE GIVES AT LEAST A 2 OUT OF 3 CHANCE OF WIND GUSTS PAST
50 MPH THERE, AS WELL AS IN SOME OF THE WINDIER LOCATIONS WEST
OF CODY AND HIGHWAY 120. WE DID GIVE THOUGHT TO A HIGH WIND
WARNING. HOWEVER, THE 700 MILLIBAR WINDS ONLY TOP OUT AT AROUND
45 KNOTS. IN ADDITION, THIS WOULD BE A BRIEF TIME, MAINLY POST
FRONTAL BETWEEN AROUND 12 AND 3 PM. WE WILL ISSUE A SPECIAL
WEATHER STATEMENT TO COVER FOR THIS ALONG WITH REDUCED
VISIBILITY FROM POSSIBLE BLOWING AND DRIFTING SNOW WITH THE
FRONTAL PASSAGE. ALL SNOW SHOULD END SHORTLY AFTER SUNSET, WITH
A CLEARING SKY AND CHILLY TEMPERATURES OVERNIGHT.
ANOTHER COLD FRONT WILL THEN APPROACH AND MOVE THROUGH THE AREA
ON WEDNESDAY. THIS ONE HAS EVEN LESS MOISTURE TO WORK WITH AND
WOULD ONLY PRODUCE SOME SNOW SHOWERS OVER THE WESTERN BIGHORNS.
THE MAIN CONCERN WILL AGAIN BE STRONG WIND. MOST MOS GUIDANCE
KEEPS WIND BELOW HIGH WIND CRITERIA, BUT IT WILL BE BLUSTERY IN
THE SAME LOCATIONS MUCH OF WEDNESDAY, WITH AROUND A 1 IN 2
CHANCE OF WIND GUSTS PAST 45 MPH IN SIMILAR AREAS AS THIS
AFTERNOON. THIS SYSTEM WILL ALSO USHER IN A COLDER AIR MASS,
ALTHOUGH THE CORE OF THE COLD AIR WILL REMAIN EAST OF THE
FORECAST AREA. THE COLDEST AREAS WILL BE JOHNSON AND NATRONA
COUNTIES, WHERE HIGHS ON THURSDAY COULD BE 20 DEGREES COLDER
THAN TODAY, ALTHOUGH THERE IS A SPREAD IN THE MODEL GUIDANCE. A
THIRD FRONT THEN MOVES THROUGH ON FRIDAY, THIS ONE AGAIN DRY
ALTHOUGH IT WILL BRING ANOTHER SHOT OF COOLER AIR. HOWEVER,
TEMPERATURES SHOULD ONLY AVERAGE 5 TO 10 DEGREES BELOW NORMAL,
NOTHING OUT OF THE ORDINARY. SOME GUIDANCE DOES SHOW A BIT OF
MOISTURE OVERRUNNING THE COLD DOME FRIDAY NIGHT AND SATURDAY,
POSSIBLY BRINGING SOME LIGHT SNOW TO SOUTHERN WYOMING, BUT THIS
IS FAR FROM CERTAIN. THEN STARTING LATER THIS WEEKEND AND INTO
EARLY NEXT WEEK, RIDGING LOOKS TO BUILD ACROSS THE AREA AND
BRING A RETURN TO NEAR TO ABOVE NORMAL TEMPERATURES.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1035 AM MST TUE JAN 20 2026
MODERATE NORTHWEST MID-LEVEL FLOW WITH HIGH CLOUDS THIS MORNING
IS GIVING WAY TO A SHORTWAVE TROUGH FROM THE NORTH. VFR
CONDITIONS AT ALL TAF SITES LATE THIS MORNING WILL CONTINUE
THROUGH THE FORECAST PERIOD, WITH A SLIGHT CHANCE OF MVFR
CONDITIONS AT KCOD, KWRL, AND KCPR DUE TO SNOW SHOWERS WITH THE
COLD FRONT THIS AFTERNOON. KBYG (NOT A TAF SITE) IS THE MOST
LIKELY TO SEE MVFR CONDITIONS WITH SNOW SHOWERS AND STRONG
NORTHWEST WIND AND WIND GUSTS OVER 45 KTS. WITH THE
STRENGTHENING SURFACE PRESSURE GRADIENT, WINDS HAVE INCREASED AT
SEVERAL TAF SITES ALREADY WITH GUSTS OVER 30 KTS, AND GUSTY NW-
N-NE WINDS ARE EXPECTED AT SITES EAST OF THE CONTINENTAL DIVIDE
AS THE COLD FRONT MOVES SOUTH. SW WY SITES WILL SEE GUSTY NW
WINDS, AND KJAC WILL SEE A SHIFT TO NORTH WINDS EARLIER THAN
TYPICAL LATE THIS AFTERNOON AS A RESULT. THE HIGHER TERRAIN
ALONG AND EAST OF THE DIVIDE WILL BE PARTIALLY OBSCURED THROUGH
21/03Z.
MID- AND HIGH-LEVEL CLOUDS WILL MOVE SOUTH OUT OF THE FORECAST
AREA BY 21/03Z WITH LINGERING LOW CLOUDS AROUND THE MOUNTAINS
AND ACROSS JOHNSON/NATRONA COUNTIES. SKIES WILL BE MOSTLY CLEAR
TO PARTLY CLOUDY FOR THE REST OF THE AREA THROUGH ABOUT 21/09Z
WHEN HIGH CLOUDS RETURN TO NORTHERN WY AS WELL AS SW WY. ANOTHER
SHORTWAVE TROUGH OVER THE NORTHERN PLAINS WILL BRING NNE WINDS
BACK TO SITES EAST OF THE DIVIDE BEFORE 21/18Z, WITH FEWER
CLOUDS EXPECTED WITH THE DRIER BOUNDARY. OTHERWISE, BREEZY AND
GUSTY WNW WINDS RETURN TO SW WY SITES WED AFTERNOON.
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.
DISCUSSION...HATTINGS
AVIATION...MCDONALD
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