177
FXUS65 KCYS 220953
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
253 AM MST FRI NOV 22 2024
KEY MESSAGES
- ABOVE AVERAGE TEMPERATURES FORECAST OVER SOUTHEAST WYOMING
AND WESTERN NEBRASKA TODAY AND TOMORROW.
- ELEVATED FIRE WEATHER CONCERNS EXISTS TODAY AND TOMORROW
AFTERNOON FOR PORTIONS OF SOUTHEAST WYOMING, ESPECIALLY FOR
SATURDAY AFTERNOON.
- NEAR TO BELOW NORMAL TEMPERATURES WILL PREVAIL FOR SUNDAY
THROUGH THANKSGIVING. CHANCES FOR SNOW WILL BE GREATEST ON
SUNDAY AND WEDNESDAY, WITH DRIER CONDITIONS FOR MONDAY,
TUESDAY AND THANKSGIVING.
SHORT TERM /THROUGH SUNDAY/
ISSUED AT 250 AM MST FRI NOV 22 2024
QUIET WEATHER RULES THE DAY FOR OUR AREA THIS MORNING. THIS IS
NOT EXPECTED TO CHANGES AS VERY LITTLE FORECAST UPDATES SHOW ANY
DEVIATIONS TO THE INHERITED FORECAST PACKAGE. THE UPPER LEVEL
RIDGE AXIS WILL PROPAGATE OVERHEAD LATER TODAY, BRINGING A SURGE
OF WARMER AREA FROM THE MEXICAN PLATEAU AND FOUR CORNERS REGION
OF THE DESERT SOUTHWEST. DAYTIME HIGHS WILL BE A COUPLE DEGREES
WARMER THAN YESTERDAY, WITH MANY AREAS ALONG AND EAST OF THE
I-25 CORRIDOR HITTING THE 60 DEGREE MARK OR HIGHER TODAY. A FEW
PATCHY AREAS IN THE LOWER ELEVATIONS OF FAR SOUTHEAST WYOMING
WILL SEE ELEVATED FIRE WEATHER CONCERNS TODAY, BUT THE WIND
GUSTS SHOULD STAY BELOW CRITICAL THRESHOLDS FOR ANY HEADLINES.
LATE FRIDAY NIGHT INTO SATURDAY MORNING WILL BRING ANOTHER
PERIOD OF POOR TO FAIR OVERNIGHT HUMIDITY RECOVERY ALONG THE
LARAMIE RANGE, AND OTHER REGIONS THAT CONTINUE TO STAY IN THE
NIGHTTIME INVERSION/THERMAL BELT. MAXIMUM HUMIDITY RECOVERY
BETWEEN 20-30 PERCENT WILL KEEP THE FUELS ON THE DRY SIDE. AS WE
BEGIN TO SEE MORNING SUNSHINE, TEMPERATURES WILL QUICKLY WARM
UP. THE DRY AIR WILL STICK AROUND FOR MOST OF THE DAY,
ESPECIALLY EAST OF THE LARAMIE RANGE. MINIMUM HUMIDITY VALUES
BY EARLY SATURDAY AFTERNOON WILL CAUSE ANOTHER DAY OF ELEVATED
TO NEAR- CRITICAL FIRE WEATHER CONCERNS, ESPECIALLY IN CONVERSE
AND NIOBRARA COUNTY. WIND GUSTS WILL PICK UP BY THE AFTERNOON
HOURS, BUT THE LOWEST RH VALUES WILL NOT BE CO-LOCATED WHERE THE
STRONGER WIND GUSTS ALONG AND WEST OF THE LARAMIE RANGE ARE
FAVORED.
A STRONG COLD FRONT IS PROGGED TO SWEEP THROUGH THE AREA FROM
NORTHWEST TO SOUTHEAST EARLY SUNDAY MORNING. THE FROPA WILL
ULTIMATELY SLIDE DOWN TOWARDS NORTHEAST CO BY 21Z SUNDAY - 0Z
MONDAY. THERE IS NOT A STRONG SIGNAL FOR FRONTOGENETICAL FORCING
OF WIDESPREAD SNOW SHOWERS ACROSS THE CWA THROUGH SUNDAY
AFTERNOON. HOWEVER, EXPECT A GRADUAL INCREASE IN SNOW SHOWER
ACTIVITY FROM NORTHWEST TO SOUTHEAST AS THE DAY PRESSES ONWARD.
THE WARMEST DAYTIME HIGHS ALONG THE NE PANHANDLE/I-80 CORRIDOR
SHOULD RESULT IN A RAIN TO RAIN/SNOW MIX NEAR 0Z MONDAY. HIGHEST
CONFIDENCE IN ACCUMULATING SNOWFALL AT THIS TIME OF INSPECTION
LOOKS TO BE LOCALIZED TO THE SNOWY AND SIERRA MADRE MTN RANGES.
THE COLD TEMPERATURES WILL MAKE IT FEEL LIKE WINTER FOR THE
BEGINNING OF THE NEXT HOLIDAY WEEK, AFTER A PLEASANT START TO
THE WEEKEND.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/
ISSUED AT 250 AM MST FRI NOV 22 2024
COLD FRONT FORECAST TO LAY ALONG A LINE FROM NORTHEAST COLORADO
TO RAWLINS TO RIVERTON SUNDAY EVENING. GFS/ECMWF/SREF ALL
SHOWING GOOD AGREEMENT ON OUR WESTERN MOUNTAINS GETTING SNOW AT
00Z MONDAY...BUT THEN BEGIN TO STRAY AFTERWARDS. GFS KEEPS
PRECIPITATION GOING ACROSS MUCH OF THE CWA. THE ECMWF SOLUTION
ON THE OTHER HAND...HAS BEGUN TO SHOW PRECIPITATION DROPPING
SOUTH INTO COLORADO. DID CUT POPS BY 10 PERCENT OR SO TO REFLECT
THE ECMWF SOLUTION.
DRIER FOR MONDAY AS SHORTWAVE RIDGING MOVES OVER THE AREA. LOOKS
LIKE THE SURFACE FRONT WILL BE WELL SOUTH ACROSS SOUTHWESTERN
COLORADO THROUGH THE DAY MONDAY.
STILL SOME UNCERTAINTY ON TUESDAY AND WEDNESDAY. ECMWF BRINGS A
UPPER SHORTWAVE INTO THE AREA FROM THE WEST THAT LIFTS THE
SURFACE FRONT NORTH ONCE AGAIN TO THE WYOMING/COLORADO
STATELINE TUESDAY NIGHT INTO WEDNESDAY. GFS FURTHER SOUTH ACROSS
COLORADO/NEW MEXICO. SO WE ARE GOING TO NEED TO KEEP AN EYE ON
WHERE THIS SYSTEM ACTUALLY TRACKS. FOR NOW...WILL CONTINUE WITH
THE ECMWF SOLUTION FOR HIGHER POPS. MAY NEED TO SIGNIFICANTLY
LOWER POPS THIS TIMEFRAME IF IT BEGINS TO SHOW A MORE SOUTHERLY
TRACK.
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
ISSUED AT 1029 PM MST THU NOV 21 2024
NO AVIATION CONCERNS FOR THE TAF PERIOD. A RIDGE OF HIGH
PRESSURE OVER THE ROCKIES WILL KEEP ANY WEATHER AT BAY. SOME
HIGH LEVEL CLOUDS WILL FLOAT OVERHEAD OVERNIGHT WITH BOTH MID
AND HIGH LEVEL CLOUDS INCREASING DURING THE DAY TOMORROW. WINDS
WILL REMAIN LIGHT AND VARIABLE OVERNIGHT AT MOST TERMINALS, WITH
LIGHT WINDS CONTINUING INTO THE DAY TOMORROW.
CYS WATCHES/WARNINGS/ADVISORIES
WY...NONE.
NE...NONE.
SHORT TERM...BW
LONG TERM...GCC
AVIATION...SF
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