627
FXUS65 KRIW 241450
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
850 AM MDT SAT OCT 24 2026
KEY MESSAGES
- DRY AND COOL TODAY BEHIND YESTERDAY'S COLD FRONT. CLOUD COVER
DECREASES THROUGH THE AFTERNOON.
- A WEAK WEATHER SYSTEM BRINGS A FEW SHOWERS LATE TONIGHT INTO
SUNDAY, BUT RAIN AND SNOWFALL AMOUNTS WILL REMAIN ON THE LIGHT
SIDE.
- A MORE POTENT SYSTEM ARRIVES MONDAY NIGHT AND TUESDAY,
BRINGING RAIN AND SNOW SHOWERS TO NORTHERN AND WESTERN WYOMING
AND GUSTY WINDS TO CENTRAL AND SOUTHERN WYOMING.
DISCUSSION
ISSUED AT 228 AM MDT SAT OCT 24 2026
WE ARE CURRENTLY EXPERIENCING SOME RATTLING AT THE RIVERTON WEATHER
ABODE. THIS IS COMING COMPLIMENTS OF OUR GOOD FRIEND COLD ADVECTION,
FOLLOWING THE PASSAGE OF A COLD FRONT. SOME OF THE MORE PRONE AREAS,
LIKE NEAR BUFFALO, HAVE SEEN WIND GUSTS AROUND 50 MPH TONIGHT. THESE
EVENTS ARE USUALLY SHORT LIVED THOUGH, AND MOST OF THE WIND SHOULD
BE OVER BY SUNRISE.
WE ARE CURRENTLY IN A FAST MOVING PATTERN, WHICH WILL BRING A FEW
CHANCES OF PRECIPITATION TO THE AREA. THE AREA WILL BE IN BETWEEN
SYSTEMS TODAY, WHICH SHOULD BRING A DRY BUT COOL START TO THE FOURTH
WEEKEND OF THE MONTH, WITH TEMPERATURES AVERAGING AROUND 5 DEGREES
BELOW NORMAL. THE NEXT CHANCE OF SHOWERS ARRIVES TONIGHT AS THE
UPPER LEVEL LOW NOW LOCATED OVER ARIZONA THAT HAS BEEN BRINGING ALL
THE SEVERE WEATHER TO THE DESERT SOUTHWEST MOVES TO THE NORTHEAST.
THANKFULLY, IT WILL BE SIGNIFICANTLY WEAKER WHEN IT ARRIVES HERE
TONIGHT AND SUNDAY. RECENT MODEL TRENDS KEEP THE LOW FURTHER EAST,
TAKING IT OVER SOUTHEASTERN WYOMING, AND ALSO KEEPING A BULK OF THE
MOISTURE EAST OF THE AREA. AS A RESULT, PRECIPITATION AMOUNTS SHOULD
REMAIN ON THE LIGHT SIDE, WITH ALL LOCATIONS EXCEPT THE WIND RIVER
RANGE HAVING A LESS THAN 1 IN 2 CHANCE OF A TENTH OF AN INCH OR MORE
OF PRECIPITATION. OTHERWISE, EXPECT A MOSTLY CLOUDY AND SEASONABLE
DAY.
WE SHOULD THEN HAVE A PERIOD OF QUIET WEATHER ON MONDAY AS THERE
WILL BE ANOTHER GAP IN AREAS OF LOW PRESSURE. THEN THE SECOND SYSTEM
ARRIVES MONDAY NIGHT INTO TUESDAY. THIS SYSTEM IS OF PACIFIC ORIGIN
AND WILL HAVE A BIT MOISTURE AND JET ENERGY TO WORK WITH SO IMPACTS
WILL BE GREATER. HOWEVER, WITH THE FLOW ZONAL AND RATHER FAST, THE
LOW SHOULD BE A FAST MOVER TO LIMIT THE DURATION OF THOSE IMPACTS.
AS FOR THE PRECIPITATION, MOST GUIDANCE SHOWS THE HIGHEST AMOUNTS
ACROSS NORTHERN WYOMING, ESPECIALLY IN THE WESTERN MOUNTAINS WITH A
PERIOD OF OROGRAPHIC ENHANCEMENT. MOST AREAS IN THE NORTHWEST HAVE
AT LEAST A 3 OUT OF 4 CHANCE OF A TENTH OF AN INCH OR MORE OF QPF,
WITH A 1 IN 2 CHANCE OF A QUARTER OF AN INCH OR MORE. DUE TO THE
FAST MOVEMENT OF THE SYSTEM, CHANCES OF A HALF AN INCH OR MORE ARE
GENERALLY LESS THAN 2 OUT OF 5. THE NEXT QUESTION IS HOW MUCH WILL
BE SNOW. SOME GUIDANCE SHOWS 700 MILLIBAR TEMPERATURES FALLING AS
LOW AS MINUS 6, WHICH WOULD LOWER SNOW LEVELS TO VALLEY FLOORS. THE
QUESTION IS HOW MUCH MOISTURE WILL BE LEFT OVER WHEN THE COLD AIR
ARRIVES. IN THE PROBABILISTIC REALM OF THE ENSEMBLES, MOST OF
THE MOUNTAINS, AS WELL AS THE JACKSON VALLEY, HAVE AT LEAST A 1
IN 2 CHANCE OF AN INCH OR SNOW OR MORE, WITH A SIMILAR CHANCE OF
OVER 3 INCHES ABOVE 8500 FEET. HOWEVER, DUE TO THE FAST
MOVEMENT OF THE SYSTEM, THE CHANCE OF 6 INCHES IS LESS THAN 1
OUT OF 5, SO ADVISORIES LOOK UNLIKELY AT THIS TIME. TRAVEL COULD
BE DIFFICULT FOR A TIME, SINCE THERE WILL BE AN 100 KNOT JET
OVER THE AREA AT THE TIME, AND THERE COULD BE SOME BLOWING SNOW
OVER THE PASSES THAT COULD REDUCE VISIBILITY.
AND THE STRENGTH OF THE JET, ALONG WITH SOME STRONG SOUTHWEST FLOW
ON THE SOUTH SIDE OF THE LOW, WILL BRING STRONG WIND TO CENTRAL AND
SOUTHERN PORTIONS OF THE AREA ON TUESDAY. THE NBM ENSEMBLE SHOWS AT
LEAST A 1 IN 2 CHANCE OF WIND GUSTS PAST 40 MPH ON TUESDAY
AFTERNOON, WITH THE AREA FROM MUDDY CAP THROUGH CASPER HAVING AT
LEAST 1 IN 2 CHANCE OF GUSTS OVER 50 MPH. THE CHANCE OF GUSTS OVER
60 MPH IS UNDER 1 IN 4 FOR THE MAJOR TRAVEL CORRIDORS THOUGH, SO
WIND HIGHLIGHTS LOOK UNLIKELY AT THIS POINT, BUT WE WILL HAVE TO
WATCH IT CLOSELY.
QUIETER CONDITIONS SHOULD THEN MOVE IN FOR MOST OF THE REMAINDER OF
THE WORKWEEK WITH RIDGING BUILDING OVER THE AREA, BRING MAINLY DRY
CONDITIONS AND ABOVE NORMAL TEMPERATURES. A FEW OROGRAPHIC SHOWERS
MAY OCCUR ACROSS WESTERN WYOMING BUT IT SHOULD BE DRY MOST OF THE
TIME. A STRONGER SYSTEM MAY APPROACH FOR NEXT WEEKEND, BUT GUIDANCE
DIVERGES SUBSTANTIALLY THIS FAR OUT SO DETAILS ARE VERY DIFFICULT TO
NAIL DOWN THIS FAR OUT.
AVIATION /12Z TAFS THROUGH 12Z SUNDAY/
ISSUED AT 502 AM MDT SAT OCT 24 2026
THE FRONT HAS NOW REACHED THE CONTINENTAL DIVIDE. WIND HAS BEGUN
TO DECREASE ACROSS MOST OF THE TERMINALS AS COLD ADVECTION
DECREASES. WIND SHOULD REMAIN 11 KNOTS OR LESS AT MOST TERMINALS
THROUGH 12Z SUNDAY WITH THE EXCEPTION OF KCPR AND KRKS WHERE
GUSTS TO 20 TO 25 KNOTS ARE POSSIBLE AFTER 18Z UNTIL SUNSET.
MVFR CONDITIONS WILL PERSIST AT SOME TERMINALS BEFORE CEILINGS
LIFT AND THE SKY GRADUALLY CLEARS THROUGH THE MORNING HOURS. A
FEW SHOWERS MAY MOVE IN VICINITY OF KRKS AFTER 08Z SUNDAY BUT
NOT ENOUGH CONFIDENCE TO INCLUDE IN THE TAFS AT THIS TIME.
RIW WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...HATTINGS
AVIATION...HATTINGS
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page