296
FXUS65 KRIW 161038
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
438 AM MDT THU OCT 16 2025
KEY MESSAGES
- A SYSTEM WILL BRING WIDESPREAD PRECIPITATION TO THE AREA
THROUGH THIS EVENING ALONG WITH COLDER TEMPERATURES.
- SNOW WILL MAINLY BE LIMITED TO THE MOUNTAINS, THOUGH A
CHANGEOVER TO SNOW IS POSSIBLE AT ELEVATIONS DOWN TO AROUND
6,500 FT THROUGH THE MORNING HOURS. WINTER TRAVEL CONDITIONS
ARE EXPECTED OVER MOUNTAIN PASSES.
- WARMER AND DRIER CONDITIONS ARE EXPECTED ON FRIDAY.
- SATURDAY THROUGH EARLY NEXT WEEK WILL REMAIN UNSETTLED WITH AN
ADDITIONAL SYSTEM OR TWO BRINGING PRECIPITATION CHANCES TO THE
AREA.
DISCUSSION
ISSUED AT 434 AM MDT THU OCT 16 2025
THE FORECAST IN THE SHORT TERM WILL CONTINUE TO BE DOMINATED BY A
HIGHLY AMPLIFIED TROUGH AND ASSOCIATED UPPER LOW THAT IS NOW MOVING
INTO SOUTHERN WYOMING. ONGOING JET-INDUCED SHOWERS AND THUNDERSTORMS
WILL BE BOLSTERED BY SUNRISE AS THE LOW MOVES FARTHER NORTHEASTWARD
INTO CENTRAL WYOMING. COLDER AIR IS CONCURRENTLY MOVING EAST ACROSS
THE STATE THIS MORNING. PRECIPITATION IS EXPECTED TO BECOME FAIRLY
WIDESPREAD BY MID-MORNING, WRAPPING CYCLONICALLY AROUND THE LOW AND
STEADIEST ACROSS CENTRAL WYOMING AND OVER ANY MOUNTAINS.
SNOW LEVELS WILL DROP TO AROUND OR JUST UNDER 7,000 FT THIS MORNING,
WHICH COULD AT LEAST BRIEFLY BRING LIGHT ACCUMULATIONS TO ELEVATED
SURFACES ACROSS WESTERN WYOMING AND THE GREEN RIVER BASIN. WINTER
WEATHER ADVISORIES REMAIN IN EFFECT FOR MOST OF THE MOUNTAINS
THROUGH THIS EVENING. THE BIGHORNS CONTINUE TO BE THE EXCEPTION,
WITH MOST OF THE ACCUMULATION THERE EXPECTED TO BE ALONG THE HIGHER
PEAKS OF THE CLOUD PEAK WILDERNESS. TRAVEL IMPACTS DUE TO SNOW
SHOULD REMAIN LIMITED TO THE MOUNTAIN PASSES ACROSS THE AREA.
PRECIPITATION WILL BEGIN TO WANE BY SUNSET TODAY AS THE LOW MOVES
INTO NORTHEASTERN WYOMING AND DRIER AIR PUSHES IN BEHIND IT. JOHNSON
COUNTY AND THE EASTERN BIGHORN BASIN WILL LIKELY HOLD ON TO
PRECIPITATION THE LATEST BEFORE MOST OF THIS ACTIVITY COMES TO AN
END BY MIDNIGHT. LIGHT SNOW MAY CONTINUE OVERNIGHT ACROSS THE
MOUNTAINS OF NORTHWESTERN WYOMING THOUGH WITH LITTLE TO NO
ADDITIONAL ACCUMULATION. TOTAL LIQUID PRECIPITATION AMOUNTS THROUGH
THE REST OF THIS SYSTEM WILL BE HIGHEST ALONG THE TRACK OF THE
LOW FROM NORTHERN SWEETWATER COUNTY THROUGH JOHNSON COUNTY.
THESE AREAS WILL GENERALLY HAVE AROUND A 50 TO 70 PERCENT CHANCE
OF AT LEAST A QUARTER OF AN INCH AND A 30 TO 50 PERCENT CHANCE
OF AT LEAST A HALF INCH.
WESTERLY WIND WILL INCREASE FRIDAY MORNING IN THE WAKE OF THE SYSTEM
AS SURFACE PRESSURE DECREASES TO OUR EAST. TEMPERATURES WILL
MODERATE FRIDAY AFTERNOON AND NO PRECIPITATION IS EXPECTED. GUIDANCE
IS THEN KEYING IN ON A GLANCING BLOW FROM A TROUGH TO OUR NORTH
ARRIVING FRIDAY NIGHT. THIS SHOULD BRING A COLD FRONT AND A QUICK
SHOT OF MOISTURE THROUGH SATURDAY MORNING ALONG AND EAST OF THE
CONTINENTAL DIVIDE. BY SATURDAY AFTERNOON THIS FEATURE SHOULD
ALREADY BE EAST OF THE AREA, WITH RIDGING SETTLING IN BEHIND IT.
ACCORDINGLY, SUNDAY IS FAVORED TO BE WARMER AND DRIER. HOWEVER,
GUIDANCE IS SHOWING YET ANOTHER SYSTEM ARRIVING SUNDAY EVENING. THIS
ONE APPEARS A LITTLE MORE SUBSTANTIAL AND MAY RETURN MORE WIDESPREAD
PRECIPITATION CHANCES TO THE AREA EARLY NEXT WEEK, INCLUDING
MOUNTAIN SNOW.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1031 PM MDT WED OCT 15 2025
300MB 100KT JET AND DIFFLUENCE ALOFT HAS BEEN DRIVING ONGOING
CONVECTION WEDNESDAY EVENING AHEAD OF A TIGHTLY WOUND UPPER LOW OVER
UTAH. THUNDERSTORMS THROUGH THE EARLY MORNING HOURS THURSDAY WILL
GENERALLY BE CONFINED TO NATRONA AND JOHNSON COUNTIES. OTHERWISE,
SCATTERED WEAKER CONVECTION SPREADS SOUTH-TO-NORTH ACROSS THE
FORECAST AREA OVERNIGHT. IFR/MVFR CEILINGS REMAIN ACROSS THE BIGHORN
BASIN AND FROM KCPR TO KBYG.
IFR/MVFR CONDITIONS BECOME MORE WIDESPREAD EARLY THURSDAY MORNING AS
THE CLOSED LOW MOVES NORTHEAST AND BEGINS TO CROSS THE REGION. THE
BEST CHANCE OF PRECIPITATION IS STILL BETWEEN 10Z-18Z/THURSDAY.
EXPECT THE IFR/MVFR CEILINGS TO INFILTRATE KRIW AND KLND BETWEEN 08Z-
12Z/THURSDAY BEHIND NORTHERLY SURFACE FLOW. AT KRKS, ADDITIONAL LIFT
PROVIDED BY THE CLOSED LOW SHOULD PROVIDE A PERIOD OF MORE INTENSE
PRECIPITATION, LIKELY IN THE FORM OF SNOW, THURSDAY MORNING LEADING
TO IFR/MVFR CONDITIONS. GUSTY WEST TO NORTHWEST SURFACE WIND 15-
30KTS ARRIVES IN SOUTHWEST WYOMING AROUND MIDDAY THURSDAY ALLOWING
FOR CONDITIONS TO DRY OUT AND IMPROVE, ESPECIALLY AT KRKS.
SIMILARLY, WEST-SOUTHWEST SURFACE WIND PUSHES INTO KCPR AND ERODES
THE LOWER CEILINGS AS VFR RETURNS AROUND 18Z-20Z/THURSDAY. HOWEVER,
THERE IS THE POTENTIAL (30 PERCENT) THAT THE WIND DOES NOT
MATERIALIZE AS EARLY AND PESKY LOWER CEILINGS PERSIST. THE GENERAL
TREND BETWEEN 23Z/THURSDAY AND 03Z/FRIDAY WILL BE TOWARD DRIER AND
DEVELOPING VFR FROM WEST-TO-EAST. MOUNTAIN TOPS OBSCURED ACROSS THE
BIGHORN BASIN THROUGHOUT THE FORECAST PERIOD, WHILE MOUNTAIN TOPS
ARE OBSCURED ACROSS THE REMAINDER OF THE AREA.
RIW WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY UNTIL 11 PM MDT THIS EVENING FOR
WYZ002-012-014-015-024.
DISCUSSION...MYERS
AVIATION...CNJ
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