676
FXUS65 KCYS 292308
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
408 PM MST SAT NOV 29 2025
KEY MESSAGES
- A WINTER WEATHER ADVISORY WILL GO INTO EFFECT FOR THE SIERRA
MADRE AND SNOWY MOUNTAINS SUNDAY MORNING FOR SNOW
ACCUMULATIONS UP TO 10 INCHES.
- VERY ACTIVE LONG TERM FORECAST EXPECTED WITH MULTIPLE TROUGHS
MOVING THROUGH AND PROMOTING SNOW CHANCES, AS WELL AS A HIGH
WIND EVENT POSSIBLE TUESDAY.
- TEMPERATURES WILL REMAIN VERY COLD THROUGH MID-WEEK, BEFORE A
WEAK WARMING TREND ARRIVES WEDNESDAY ONWARDS.
SHORT TERM /THROUGH MONDAY/
ISSUED AT 321 PM MST SAT NOV 29 2025
A SHORT LIVED RIDGE MOVES OVER THE INTERMOUNTAIN WEST FOR A
QUICK BREAK BETWEEN SYSTEMS. WHILE IT WILL BE COLD TODAY THE
SKIES WILL STAY RELATIVELY CLEAR AND WINDS RATHER LIGHT FOR THE
REGION THIS AFTERNOON AND EVENING. 700MB TEMPERATURES LOOK TO
REMAIN BETWEEN -10 TO -15C ALLOWING FOR ANOTHER NIGHT OF
TEMPERATURES IN THE SINGLE DIGITS ACROSS SOUTHEAST WYOMING AND
THE NEBRASKA PANHANDLE. MID LEVEL WATER VAPOR ALREADY SHOWS THE
NEXT SYSTEM PUSHING INTO THE PACIFIC NORTHWEST. THIS SYSTEM IS
EXPECTED TO TRACK THROUGH THE SOUTHERN PORTION OF IDAHO AND INTO
THE NORTHERN PORTION OF UTAH AND INTO COLORADO. THERE IS STILL
A LITTLE DISCREPANCY IN THE EXACT TRACK OF THIS SYSTEM BUT
OVERALL CONSENSUS HAS THE SYSTEM TRACKING THROUGH THE MIDDLE OF
COLORADO CONFINING MOST OF OUR PRECIPITATION TO THE HIGHER
ELEVATIONS IN OUR SOUTHERN COUNTIES. SOME HIGH-RES GUIDANCE DOES
TAKE THE STORM A LITTLE FURTHER SOUTH CAUSING SOME LIGHTER SNOW
ACCUMULATIONS BUT USING THE AVERAGE KUCHERA AND 10:1 RATIO FOR
SNOW ACCUMULATIONS A RANGE PUT BETWEEN 6-10 INCHES FOR THE
SIERRA MADRE AND SNOWY MOUNTAINS. THE ADJACENT AREAS COULD SEE
BETWEEN 2-4 INCHES FROM 11AM SUNDAY THROUGH 5AM MONDAY. THE
GLOBAL MODELS DEPICT A BAND OF FRONTOGENESIS AND STREAM OF
VORTICITY SETTING UP OVER CARBON AND ALBANY COUNTY INCREASING
THE SNOWFALL RATES AND OVERALL ACCUMULATIONS. THE NAM NEST HAS A
SLIGHTLY MORE NORTHERN TRACK AND CHOSE VIOLENCE WITH TOTAL SNOW
ACCUMULATIONS UP TO 18 INCHES FOR THE 12Z RUN USING THE KUCHERA
RATIO. WHILE AN OUTLIER DIVERTING FROM THE MODEL CONSENSUS IT
CAN'T NECESSARILY BE RULED OUT IF THE SYSTEM WERE TO WOBBLE
SLIGHTLY NORTH. THE HREF PAINTS A NEIGHBORHOOD PROBABILITY OF 70
TO 90 PERCENT OF SEEING GREATER THAN 5.0 INCHES OF SNOW OVER
THE SIERRA MADRE MOUNTAINS AND A 20 PERCENT CHANCE OF OVER 5
INCHES FOR THE SNOWY MOUNTAIN FROM SUNDAY NIGHT THROUGH 5 AM
MONDAY MORNING. THE PROBABILITIES DROP TO 20 PERCENT FOR GREATER
THAN 10 INCHES FOR THE SIERRA MADRE RANGE AND 0 PERCENT FOR THE
SNOWY RANGE. THIS INCREASES THE CONFIDENCE OF SNOW
ACCUMULATIONS BETWEEN 6 TO 10 INCHES PROMPTING A WINTER WEATHER
ADVISORY FOR THE MOUNTAINS.
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/
ISSUED AT 321 PM MST SAT NOV 29 2025
LONG TERM REMAINS ACTIVE AS WE SEE A SYSTEM BRING GUSTY WINDS
AND PRECIPITATION CHANCES TO START THE PERIOD, FOLLOWED BY A
BRIEF DRY PERIOD ALONGSIDE SOME WARMING TO BRING US BACK TO NEAR
NORMAL TEMPERATURES, BUT ANOTHER APPROACHING SYSTEM AT THE END
OF THE PERIOD WILL CAUSE ANOTHER POTENTIAL HIGH WIND EVENT
ALONGSIDE INCREASING PRECIPITATION CHANCES ONCE AGAIN.
THE PERIOD BEGINS MONDAY AS WE SEE HIGH WINDS RETURNING TO THE
CWA THANKS TO AN APPROACHING TROUGH AND STRONG JET. WINDS AT
700MB LATE MONDAY THROUGH TUESDAY SHOULD INCREASE INTO THE 50-60
KNOT RANGE AND, WHILE NOT THE STRONGEST, DOWNWARD OMEGA VALUES
SHOULD BE CONDUCIVE ENOUGH TO MIX THESE WINDS TO THE SURFACE
PRIMARILY AT OUR WINDIEST SPOTS OF BOTH ARLINGTON AND BORDEAUX.
IN HOUSE GUIDANCE PAINTS AN 80-90% PROBABILITY FOR ARLINGTON,
WHILE BORDEAUX SITS A LITTLE LOWER IN THE 50-60% RANGE, BUT
STILL LIKELY. WITH SUCH CONSISTENCY, THE EXPECTATION IS LIKELY
WE'LL SEE HIGH WIND WARNINGS WITH THIS SYSTEM. MEANWHILE PRIOR
TO THE ARRIVAL OF THIS, TEMPERATURES WILL REMAIN SEVERAL DEGREES
COOLER COMPARED TO NORMAL ON MONDAY, FOLLOWED BY A SLIGHT
WARMUP THAT SHOULD PLACE US AROUND AVERAGE ON TUESDAY. THEN INTO
TUESDAY AS THE TROUGH STARTS TO MOVE INTO THE REGION,
PRECIPITATION OVERSPREADS WITH TEMPERATURES ALSO COOLING THANKS
TO THE PASSING COLD FRONT. EXPECT AS PRECIPITATION MOVES IN
LATER TUESDAY THROUGH WEDNESDAY, WE SHOULD BE COLD ENOUGH AT ALL
LEVELS TO PROMOTE SNOWFALL, BUT WITHOUT A STRONG AMOUNT OF QPF,
OVERALL ACCUMULATIONS SHOULD BE FAIRLY LIGHT - A FEW INCHES FOR
THE MOUNTAINS, AND AROUND AN INCH OR LESS FOR LOWER ELEVATION
LOCATIONS, WITH SOME LOCALLY HEAVIER AMOUNTS NOT OUT OF THE
QUESTION AND WINDY CONDITIONS PROMOTING BLOWING SNOW AND SOME
LOCALLY HIGH DRIFTS.
TEMPERATURES ON WEDNESDAY REMAIN WIDESPREAD AT OUR BELOW
FREEZING FOR HIGHS, BUT EXPECT A GENTLE WARMING TREND THEREAFTER
WITH HIGHS WARMING INTO THE 30'S TO 40'S BY FRIDAY. THE REGION
WILL DRY OUT ON WEDNESDAY, BUT THURSDAY INTO FRIDAY WE SHOULD
SEE A RETURN OF LIGHT TO OCCASIONALLY MODERATE MOUNTAIN SNOW
THANKS TO UPSLOPE FLOW. AND ON THE NOTE OF OUR FLOW PATTERN,
MODELS CONTINUE TO INDICATE WE'LL BE SEEING OUR NEXT HIGH WIND
EVENT FRIDAY INTO SATURDAY WITH THE APPROACH OF OUR NEXT TROUGH,
WITH IN HOUSE GUIDANCE ALREADY PEAKING INTO THE 60-80%
PROBABILITY RANGE FOR OUR WIND PRONE LOCATIONS. WHILE OVERALL
ACTIVE, OVERALL CURRENT FORECASTS SUGGEST OUR MOST IMPACTFUL
CONDITIONS WILL REMAIN THE REGION'S USUAL HIGH WINDS AS WE MOVE
INTO THE START OF DECEMBER.
AVIATION /00Z TAFS THROUGH 00Z SUNDAY/
ISSUED AT 405 PM MST SAT NOV 29 2025
FAIRLY BENIGN TO START THE 00Z TAF PERIOD WITH MOSTLY CLEAR
SKIES, DECREASING WINDS, AND NO VISIBILITY REDUCTIONS. UPPER-
LEVEL CLOUDS MOVE IN AFTER SUNSET WITH WINDS BECOMING LIGHT AND
VARIABLE. PRIMARY AVIATION CONCERN FOR THE 00Z TAF PERIOD WILL
BE THE INCOMING SNOW SHOWERS LATE IN THE PERIOD WITH INCREASING
WINDS IN THE MORNING AND DECREASING CEILINGS AHEAD OF THE SNOW.
VFR EXPECTED TO PREVAIL THROUGH THE PERIOD AT ALL SITES EXCEPT
FOR KRWL, KCDR, AND KAIA. KCDR AND KAIA MAY SEE LOW-LEVEL
CEILINGS EARLY THIS MORNING, THOUGH CONFIDENCE IS LOW AT THIS
TIME.
CYS WATCHES/WARNINGS/ADVISORIES
WY...WINTER WEATHER ADVISORY FROM 11 AM SUNDAY TO 5 AM MST MONDAY
FOR WYZ112-114.
NE...NONE.
SHORT TERM...MM
LONG TERM...CG
AVIATION...AM
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