502
FXUS65 KRIW 180445
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1045 PM MDT FRI OCT 17 2025
KEY MESSAGES
- GUSTY WEST WINDS CONTINUE OVERNIGHT, LESSENING SOME SATURDAY
MORNING AND AFTERNOON.
- SHOWERS WILL RETURN TO NORTHERN WYOMING TONIGHT AS THE NEXT
SYSTEM ARRIVES. THIS BRINGS LIGHT RAIN AND MOUNTAIN SNOW
SHOWERS TO AREAS ALONG AND EAST OF THE CONTINENTAL DIVIDE
THROUGH SATURDAY MORNING.
- UNSETTLED CONDITIONS CONTINUE ON SUNDAY AS ANOTHER SYSTEM
ARRIVES. WIDESPREAD GUSTY TO STRONG WINDS ARE POSSIBLE
THROUGH THE DAY, WITH RAIN AND MOUNTAIN SNOW SHOWERS EXPECTED
SUNDAY AFTERNOON THROUGH MONDAY MORNING.
UPDATE
ISSUED AT 106 PM MDT FRI OCT 17 2025
HIGH CLOUDS CONTINUE TO SWEEP ACROSS CENTRAL WY THIS AFTERNOON
AHEAD OF THE NEXT WEATHER SYSTEM. WITH THE GRADIENT TIGHTENING
WITH THE APPROACHING STORM, SOUTHWEST WINDS ARE RAMPING UP
ACROSS CENTRAL AND SOUTHERN WY. FREQUENT GUSTS OF 25 TO 30 MPH
WILL CONTINUE, WITH A FEW GUSTS APPROACHING 40MPH AROUND GREATER
CASPER.
THIS NEXT SYSTEM IS POISED TO RACE THROUGH OVERNIGHT
TONIGHT,BRINGING SOME LIGHT PRECIPITATION MAINLY FOR THE
ABSAROKAS, THE BIGHORN BASIN, AND INTO THE I-25 CORRIDOR. PRECIP
AMOUNTS WILL BE LIMITED, DUE TO BOTH THE QUICK SPEED OF THE
SYSTEM AND THE MINIMAL AMOUNT OF MOISTURE AVAILABLE. THE SYSTEM
WILL BE THROUGH THE AREA BY AROUND NOON SATURDAY, WITH THE LOWER
ELEVATIONS OF THE BIGHORN BASIN AND JOHNSON COUNTY ONLY
RECEIVING A FEW HUNDREDTHS OF RAINFALL, WHILE THE ABSAROKAS AND
BIGHORN RANGE GENERALLY 2 TO 4 INCHES OF SNOWFALL.
ONCE THE SYSTEM DEPARTS SATURDAY, EXPECT MOSTLY CLEAR SKIES AND
COLDER TEMPERATURES ONLY PEAKING IN THE UPPER 40S TO MID 50S.
DISCUSSION
ISSUED AT 354 AM MDT FRI OCT 17 2025
WITH THE PREVIOUS SYSTEM NOW WELL OFF TO OUR NORTHEAST, FRIDAY WILL
BE DRY AND MILD AS TEMPERATURES RETURN TO SEASONABLE NORMS. HOWEVER,
IT WON'T BE A CALM DAY FOR MOST AS WESTERLY WINDS INCREASE THIS
MORNING DUE TO A BUILDING SURFACE PRESSURE AND THERMAL GRADIENT. THE
STRONGEST WINDS WILL LIKELY BE SEEN ALONG THE CODY FOOTHILLS AND IN
THE UPPER WIND RIVER BASIN AS A DOWNSLOPING FLOW IS ESTABLISHED OUT
OF THE ABSAROKAS AND WINDS. GUSTS OF 35 TO 45 MPH CAN BE EXPECTED
HERE THROUGH THE DAY WITH GENERALLY LESSER MAGNITUDES ELSEWHERE.
THE MOSTLY CLEAR SKIES EXPECTED THIS AFTERNOON WON'T LAST LONG AS
THE NEXT SYSTEM DROPS SOUTH INTO THE AREA THIS EVENING. THIS
TROUGH AND ASSOCIATED UPPER LEVEL 120 KNOT JET WILL BRING A
QUICK SHOT OF MOISTURE AND COLDER AIR ALONG AND EAST OF THE
CONTINENTAL DIVIDE THIS EVENING THROUGH SATURDAY MORNING. GIVEN
THE SPEED OF THIS SYSTEM AND A LACK OF DEEPER MOISTURE, QPF
AMOUNTS ARE GENERALLY UNDER A TENTH OF AN INCH ACROSS LOWER
ELEVATIONS, FOCUSED MOSTLY IN THE BIGHORN BASIN AND JOHNSON AND
NATRONA COUNTIES. THE ABSAROKAS AND BIGHORNS SHOULD PICK UP A
QUICK FEW INCHES OF SNOW OVERNIGHT WITH MINIMAL TRAVEL IMPACTS
EXPECTED. THIS TROUGH WILL ALREADY BE ON ITS WAY OUT BY MID-
SATURDAY MORNING, AND ANY LINGERING SHOWERS SHOULD QUICKLY GIVE
WAY TO WIDESPREAD SUNNY SKIES AROUND NOON AS DRIER AIR MOVES IN
BEHIND IT.
RIDGING BUILDS IN SATURDAY NIGHT, KEEPING DRY AND CLEAR CONDITIONS
THROUGH SUNDAY MORNING. HOWEVER, THE UNSETTLED PATTERN WILL CONTINUE
AS THE NEXT SYSTEM APPROACHES SUNDAY AFTERNOON. THIS IS NOW LOOKING
MORE SIMILAR TO TONIGHT'S SYSTEM, WITH THE MAJORITY OF PRECIPITATION
EXPECTED ALONG AND EAST OF THE DIVIDE AS AN OPEN TROUGH SLIDES
ACROSS THE NORTHERN ROCKIES THROUGH MONDAY MORNING. THIS ONE SHOULD
DROP A LITTLE FARTHER SOUTH, HOWEVER, WITH PRECIPITATION ALSO
EXTENDING TO WESTERN WYOMING. AMOUNTS ARE LOOKING FAIRLY SIMILAR AS
WELL, WITH THE MOUNTAINS AGAIN PICKING UP SOME LIGHT SNOW
ACCUMULATION. THIS SYSTEM MAY ALSO BRING WIDESPREAD STRONG
WINDS ON SUNDAY AHEAD OF A COLD FRONT THAT WILL PUSH IN SUNDAY
EVENING. THIS WARRANTS WATCHING FOR POTENTIAL WIND HIGHLIGHTS,
BUT CURRENTLY GUIDANCE KEEPS GUSTS BELOW CRITERIA.
GENERALLY DRY CONDITIONS AND SEASONABLE TO SLIGHTLY ABOVE NORMAL
TEMPERATURES ARE THEN EXPECTED MONDAY THROUGH AT LEAST THE MIDDLE OF
NEXT WEEK AS UPPER FLOW BECOMES MORE ZONAL. FURTHER OUT, ENSEMBLE
CLUSTER ANALYSIS CURRENTLY FAVORS ABOVE AVERAGE 500 MB HEIGHTS
THROUGH THE END OF THE WEEK, KEEPING MILD AND DRIER CONDITIONS
ACROSS THE AREA INTO NEXT WEEKEND.
AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
ISSUED AT 1045 PM MDT FRI OCT 17 2025
A WEAK WEATHER SYSTEM WILL SLIDE THROUGH THE AREA FROM THE NORTH
TONIGHT INTO SATURDAY MORNING. THIS WILL KEEP WIND ELEVATED AT MOST
TERMINALS OVERNIGHT AS A COLD FRONT PUSHES IN FROM THE NORTH. AHEAD
OF THE FRONT WIND WILL REMAIN SOUTHWESTERLY AND BEHIND THE FRONT
WIND WILL BECOME NORTHWESTERLY TO NORTHEASTERLY. WIND SHEAR WILL
ALSO BE AN ISSUE AHEAD OF THE FRONT TONIGHT AS STRONG WIND OCCURS IN
THE LOWEST FEW THOUSAND FEET.
THERE IS NOT MUCH MOISTURE ASSOCIATED WITH THIS WEATHER SYSTEM, SO
RAIN CHANCES WILL BE LOW (<15%) FOR MOST TERMINALS. THE BEST CHANCE
IS AT KWRL WITH PREVAILING MVFR CONDITIONS FROM 07Z-11Z SATURDAY
MORNING. THERE IS ALSO A PROB30 AT KCOD FROM 06Z-10Z, WITH MVFR
CONDITIONS. AT ALL OTHER TERMINALS CONDITIONS WILL REMAIN VFR, BUT
SOME BRIEF SCT020-030 CLOUDS MAY DEVELOP AT KRIW AND KLND AS THE
FRONT PUSHES THROUGH. WIND WILL GENERALLY BE WEAKER BEHIND THE
FRONT, SO EXPECT A WEAKENING TREND IN WIND HEADING INTO SATURDAY
MORNING FOR THE NORTHERN HALF OF THE AREA. WIND WILL REMAIN STRONG
FOR THE SOUTHERN HALF OF THE AREA SATURDAY MORNING AS THE FRONT
APPROACHES AND ULTIMATELY FAILS TO MAKE IT WEST OF THE CONTINENTAL
DIVIDE. WIND WILL THEN GRADUALLY DIMINISH LATE SATURDAY
AFTERNOON INTO SATURDAY EVENING AS THE SYSTEM DEPARTS.
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...STRAUB
DISCUSSION...MYERS
AVIATION...ROWE
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