573
FXUS65 KRIW 141113
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
413 AM MST THU NOV 14 2024
KEY MESSAGES
- A FEW WESTERN MOUNTAIN SNOW SHOWERS EXPECTED TODAY WITH ONLY
LIGHT ACCUMULATION. GUSTY SOUTHWEST WINDS WILL CONTINUE
ACROSS THE MOUNTAINS AND WIND PRONE LOCATIONS.
- A WEATHER SYSTEM APPROACHES FRIDAY, BRINGING INCREASED SNOW CHANCES
TO THE WEST THROUGH EARLY SATURDAY MORNING. LIGHT SNOW IS
LIKELY TO SPILL INTO THE LOWER ELEVATIONS AS WELL. WINTER
TRAVEL CONDITIONS LIKELY ACROSS WESTERN MOUNTAINS PASSES.
- ANOTHER SYSTEM POSSIBLE SUNDAY NIGHT INTO EARLY NEXT WEEK,
THOUGH DETAILS REMAIN UNCERTAIN ON IMPACT POTENTIAL.
DISCUSSION
ISSUED AT 325 AM MST THU NOV 14 2024
A LITTLE WARMER FOR MOST LOCATIONS TODAY AS WEAK RIDGING PERSISTS
ACROSS THE AREA. WITH INCREASED SOUTHWEST FLOW STACKED THROUGH THE
ATMOSPHERE, IT WILL CONTINUE TO BE WINDY ACROSS THE MOUNTAINS AND
WIND CORRIDOR. THERE IS A WEAK SHORTWAVE EVIDENT ON IR IMAGERY THAT
WILL APPROACH OVER THE NEXT FEW HOURS. THIS WILL BRING ISOLATED
SNOW SHOWERS TO THE NORTHWESTERN MOUNTAINS THROUGH THE MORNING.
ANY ACCUMULATION WILL BE LIGHT (AN INCH OR TWO), MOSTLY LIMITED
TO THE SOUTHWESTERN PLATEAUS OF YELLOWSTONE AND THE WESTERN
SLOPES OF THE TETONS AND SOUTHERN ABSAROKAS.
A DEEPENING LONGWAVE TROUGH ACROSS THE WESTERN US WILL APPROACH
WYOMING ON FRIDAY. THIS WILL LEAD TO STRONG SOUTHERLY FLOW AHEAD OF
IT, AND A WINDY AFTERNOON ACROSS SOUTHERN WYOMING AS A RELATIVE
SURFACE LOW CONTRIBUTES TO A PRESSURE GRADIENT THERE. WESTERN AREAS
WILL BEGIN TO SEE PRECIPITATION MOVE IN DURING THE AFTERNOON, THOUGH
MOST OF THIS WILL HOLD OFF UNTIL FRIDAY EVENING. A COLD FRONT WILL
SWEEP FROM WEST TO EAST THROUGH SATURDAY MORNING, WITH SNOW PICKING
UP OVERNIGHT AS THE TROUGH AXIS PUSHES THROUGH THE STATE.
MOISTURE IS NOT VERY IMPRESSIVE WITH THIS SYSTEM, WITH PWATS
GENERALLY UNDER A QUARTER INCH. REGARDLESS, THIS SHOULD BE GOOD
ENOUGH FOR NEAR ADVISORY (AT LEAST 6 INCHES) AMOUNTS OF SNOW FOR
THE WESTERN MOUNTAINS, AND AN INCH OR TWO ACROSS THE WESTERN
VALLEYS. MOST OF THIS WILL FALL BEFORE SUNRISE, THEN SPREAD
FARTHER EAST THROUGH THE REST OF SATURDAY MORNING. WITH THE
COLDER AIR, PRECIPITATION SHOULD FALL AS SNOW EVERYWHERE.
ACCUMULATIONS WILL BE LIGHTER EAST OF THE DIVIDE AND ACROSS
SOUTHERN AREAS, WITH SNOW TOTALS RANGING FROM NOTHING TO AN INCH
OR SO ON THE HIGH SIDE. PRECIPITATION CHANCES DECREASE THROUGH
THE AFTERNOON AS THE SYSTEM MOVES EAST, WITH ONLY LINGERING
SHOWERS ACROSS THE WESTERN MOUNTAINS BY SATURDAY EVENING.
OTHERWISE, IT WILL BE COLDER SATURDAY, WITH A BREEZY WEST WIND
FOR MOST.
SUNDAY WILL LIKELY BE A TRANSITION DAY BETWEEN TWO SYSTEMS, WITH
DRIER BUT GUSTY CONDITIONS. GUIDANCE IS STILL HINTING AT THE NEXT
TROUGH DROPPING OUT OF THE NORTHWESTERN US SUNDAY NIGHT THROUGH
MONDAY, THOUGH UNCERTAINTY REMAINS HIGH ON THE STRENGTH AND POSITION
OF THIS AS IT PROGRESSES TOWARD WYOMING. REGARDLESS, THE CURRENT
FORECAST REFLECTS A CONTINUED ACTIVE PATTERN, WITH AT LEAST LIGHT
PRECIPITATION CHANCES RAMPING BACK UP FOR MONDAY, FOLLOWED BY COLDER
AND DRIER CONDITIONS THROUGH THE MIDDLE OF NEXT WEEK.
AVIATION /12Z TAFS THROUGH 12Z FRIDAY/
ISSUED AT 411 AM MST THU NOV 14 2024
MID-TO-HIGH LEVEL CLOUDS ARE AROUND TODAY, BUT NO PRECIPITATION IS
EXPECTED THROUGH THE TAF PERIOD. THERE IS ABOUT A 20% CHANCE OF
PRECIPITATION AT KJAC FROM 12Z TO 18Z THIS MORNING. LATEST MODELS
ARE KEEPING REFLECTIVITY CONFINED TO THE MOUNTAINS, SO HAVE LEFT
MENTION OUT OF THE TAF. LOW VFR, TO MAYBE (10% CHANCE) BRIEF MVFR,
CEILINGS OCCUR.
A LITTLE FOG IS POSSIBLE THIS MORNING NEAR KBPI. CONFIDENCE REMAINS
LOW, BUT HAVE INDICATED THE POTENTIAL WITH A FEW030 GROUP.
SOUTHWEST FLOW ALOFT AHEAD OF AN INCOMING TROUGH KEEPS BREEZY TO
WINDY CONDITIONS FOR A FEW SITES, NAMELY KCOD AND KCPR, WHERE GUSTS
UP TO AROUND 30 KNOTS ARE POSSIBLE. MODEL SOUNDING DATA SUGGESTS THE
POTENTIAL FOR WIND SHEAR AT KCOD THIS MORNING AND AFTERNOON, WHERE
40 KNOT WINDS OCCUR ABOVE THE SURFACE. THERE IS THE POSSIBILITY
THESE WINDS MIX DOWN TO THE SURFACE. ELSEWHERE, WINDS SHOULD
GENERALLY REMAIN 10 KNOTS OR LESS, WITH PERHAPS A FEW PERIODS OF UP
TO 15 KNOT WINDS THIS AFTERNOON. WINDS EVERYWHERE DECREASE THIS
EVENING, LEAVING RELATIVELY LIGHT WINDS TONIGHT.
HIGH CLOUDS INCREASE LATE IN THE PERIOD AS A WEATHER SYSTEM
APPROACHES. PRECIPITATION CHANCES DON'T BEGIN TO INCREASE UNTIL
AFTER THE TAF PERIOD, HOWEVER.
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...MYERS
AVIATION...WITTMANN
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