789
FXUS65 KRIW 250428
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1028 PM MDT SAT OCT 24 2026
KEY MESSAGES
- REMAINING COOL BEHIND LAST NIGHT'S COLD FRONT. LOW CLOUDS
PERSIST ACROSS THE WIND RIVER BASIN AND NORTHWESTERN PORTIONS
OF THE AREA.
- 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.
- IT WILL REMAIN COOL WITH TEMPERATURES TRENDING WARMER LATE IN
THE UPCOMING WEEK.
UPDATE
ISSUED AT 1235 PM MDT SAT OCT 24 2026
NO MAJOR CHANGES WITH THIS UPDATE, WITH DRY AND COOL WEATHER TODAY.
CLOUDS SLOWLY ERODE THROUGH THE AFTERNOON, EVIDENT BY CURRENT
SATELLITE IMAGERY. A WEATHER SYSTEM LATE TONIGHT AND THROUGH
SUNDAY BRINGS PRECIPITATION CHANCES (15-30%) TO THE AREA, MOSTLY
FOR THE SOUTHWEST PORTION OF THE STATE. ANY TOTALS ARE LIGHT,
WITH MAYBE AROUND 0.1" FOR A HEAVIER SHOWER.
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 WIND 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 OF MOISTURE AND JET ENERGY TO WORK WITH SO
IMPACTS WILL BE GREATER. HOWEVER, WITH THE FLOW BEING 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 OF THIS
PRECIPITATION WILL BE SNOW. SOME GUIDANCE SHOWS 700 MILLIBAR
TEMPERATURES FALLING AS LOW AS MINUS 6C, 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, 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 WORK WEEK WITH RIDGING BUILDING OVER THE AREA, BRINGING
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.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 1021 PM MDT SAT OCT 24 2026
LOW CLOUD COVER HAS FINALLY THINNED OUT LATE THIS AFTERNOON,
WITH MAINLY MIDLEVEL CLOUDS ACROSS CENTRAL WY TONIGHT. THICKER
MIDLEVEL CLOUDS WILL DRIFT NORTHWEST FROM KRKS INTO KBPI/PNA
AROUND 18Z, BUT ARE CURRENTLY EXPECTED TO STAY AT OR ABOVE 5000
FEET. REMAINING AREAS SEE ONLY SCATTERED CLOUDS THROUGH THE
REST OF THE DAY INTO THE EARLY EVENING SUNDAY. MORE DENSE LOW
CLOUDS ARE EXPECTED TO MOVE INTO KCPR AROUND 06Z/26, WITH MVFR
TO IFR CONDITIONS THERE AFTER THAT TIME.
RIW WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...WITTMANN
DISCUSSION...HATTINGS
AVIATION...STRAUB
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