686
FXUS65 KCYS 182122
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
222 PM MST THU DEC 18 2025
KEY MESSAGES
- A LACK OF SIGNIFICANT MOISTURE COMBINED WITH STRONG WINDS AND
NEAR CRITICAL RH VALUES HAS PROMPTED A RED FLAG WARNING
ISSUANCE FOR THIS AFTERNOON AND AGAIN ON FRIDAY.
- ANOTHER HIGH WIND EVENT IS EXPECTED TONIGHT INTO FRIDAY,
POSSIBLY LINGERING INTO EARLY SATURDAY. EXPECT WIDESPREAD
GUSTS 60 TO 80 MPH WITH WIND GUSTS POSSIBLY EXCEEDING 90 MPH
ALONG PORTIONS OF I-25 AND I-80.
- BREEZY CONDITIONS ARE EXPECTED BEYOND SATURDAY ACROSS THE CWA,
BUT NOT AS SIGNIFICANT AS DAYS PRIOR.
SHORT TERM /THROUGH FRIDAY NIGHT/
ISSUED AT 222 PM MST THU DEC 18 2025
LETS START OFF THIS SHORT TERM DISCUSSION WITH WHAT IS GOING ON
TODAY. AS YOU GO OUTSIDE YOU'LL NOTICE ONE THING RIGHT AWAY, THE
WINDS HAVE WEAKENED, SOMEWHAT, ENJOY THIS WHILE IT LASTS
BECAUSE IT WILL BE SHORT-LIVED. HOWEVER, CONDITIONS ARE RIPE FOR
ANOTHER AFTERNOON OF FIRE WEATHER CONCERNS FROM CHEYENNE TO
SYDNEY AND POINTS SOUTH. MUCH LIKE YESTERDAY, WE ARE NOT SEEING
OUR TYPICAL RED FLAG CRITERIA THAT WE LOOK FOR, BUT WITH BREEZY
CONDITIONS COUPLED WITH A VAST AREA OF DRY GRASSES, CONDITIONS
ARE RIPE FOR FIRE WEATHER. THEREFORE, RED FLAG WARNINGS HAVE
BEEN ISSUED FOR THE AFOREMENTIONED AREA FROM THIS AFTERNOON
INTO THE EVENING HOURS. OKAY, AFTER THIS SHORT-LIVED LULL IN
WINDS, CHANGES ARE IN STORE BY THIS EVENING. EXPECT WINDS TO
REALLY RAMP UP, FIRST, ACROSS OUR WESTERN FORECAST ZONES THEN
OVERTAKING THE ENTIRE CWA BY TONIGHT. THIS INCREASE IN WINDS
WILL ONCE AGAIN BRING ANOTHER DAY OF FIRE WEATHER CONCERNS FOR
FRIDAY. BUT THIS TIME THINGS ARE A LITTLE DIFFERENT, VAST AREAS
OF DRY GRASSES COUPLED WITH WIDESPREAD STRONG WINDS WILL CREATE
A LARGER AREA OF CONCERN. SO, WITH THAT BEING SAID, RED FLAG
WARNINGS HAVE BEEN ISSUED FOR ALL OUR FIRE WEATHER ZONES FROM
I-25 AND POINTS EAST, INCLUDING THE NEBRASKA PANHANDLE, FRIDAY
AFTERNOON INTO THE OVERNIGHT HOURS.
WITH ALL THE FIRE WEATHER TALK OUT OF THE WAY, LETS TALK ABOUT
WINDS. THIS AFTERNOON/EVENING WILL BEGIN THE NEXT ROUND OF POWERFUL
WINDS ACROSS THE CWA THAT WILL CONTINUE THROUGH FRIDAY. WHY, WELL,
IN THE MID-LEVELS WE WILL SEE A STOUT 700MB JET STRENGTHEN OVER
OUR CWA, BRINGING WINDS UPWARDS OF 100 KNOTS. IN ADDITION,
NEGATIVE OMEGA (GFS) WILL HELP MIX THESE WINDS DOWN TO THE
SURFACE. ALL THIS ALONG COMBINED WITH A TIGHT PRESSURE GRADIENT
AT THE SURFACE ARE THE PERFECT INGREDIENTS FOR ANOTHER HIGH WIND
EVENT OVER MUCH OF OUR CWA. SO, FOR OUR KNOWN STRONGEST WIND
PRONE AREAS, IT IS NOT OUT OF THE REALM OF POSSIBILITY TO SEE
GUSTS TOPPING OUT NEAR 100 MPH. WHILE, MANY OTHER LOCATIONS
WILL SEE WINDS GUSTING IN THE 60 TO 80 MPH RANGE. THEREFORE,
HIGH WIND WARNINGS HAVE BEEN ISSUED STARTING THIS AFTERNOON FOR
SEVERAL OF OUR WESTERN FORECAST ZONES AND SPREADING EAST INTO
THE NEBRASKA PANHANDLE BY FRIDAY AFTERNOON. MANY LOCATIONS WILL
SEE WINDS DIMINISH TO LESS THEN THE HIGH WIND CRITERIA THROUGH
FRIDAY NIGHT INTO EARLY SATURDAY MORNING.
IN OTHER NEWS, TEMPERATURES WILL CLIMB INTO THE 30S AND 40S TODAY,
DIPPING INTO THE 20S TO LOW 30S TONIGHT. EXPECT WARMER TEMPERATURES
FRIDAY WITH HIGHS SOARING BACK INTO THE 50S AND 60S WHILES LOWS FALL
TO NEAR 30 FOR MANY LOCATIONS. WHERE IS OUR SNOW, WELL, YOU'LL HAVE
TO GO HIGH INTO THE MOUNTAINS WEST OF I-25 TO SEE ANY OF THAT AS
THEY WILL HAVE THE GREATEST CHANCES OF SEEING THE WHITE STUFF. EAST
OF I-25, EVEN WITH A FRONT DIVING SOUTH ACROSS OUR CWA LATE FRIDAY
INTO SATURDAY, MANY LOCATIONS WILL SEE LITTLE IF ANY PRECIPITATION.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
ISSUED AT 222 PM MST THU DEC 18 2025
WESTERN RIDGING REMAINS SUPPRESSED WITH ALASKAN TROUGHING ATTEMPTING
TO KINK THE FLOW AND FORCE SOME RIDING BACK INTO THE WESTERN CONUS
BY SUNDAY. REGARDLESS FLOW REMAINS PRIMARILY ZONAL THROUGH EARLY
NEXT WEEK BEFORE IT BECOMES MORE SW ALOFT. BY TUESDAY PACIFIC
TROUGHING BECOMES SO PRONOUNCED THAT THE RIDGE AXIS SHIFTS ALL THE
WAY EAST OF THE ROCKIES AND ORIENTED FROM EASTERN TEXAS NORTHWARDS
TO MONTANA/THE DAKOTAS. CURRENT CLUSTER ANALYSIS DOES SHOW A NUMBER
OF WAVES AMID THE SW FLOW BETWEEN SUNDAY AND NEXT THURSDAY BUT FOR
ONE REASON OR ANOTHER THE ASSOCIATED MOISTURE LOOKS TO REMAIN WELL
WEST OF US UNTIL THURSDAY, MEANING NO WHITE CHRISTMAS FOR MOST
UNLESS YOU LIVE ABOVE 8,000FT WHERE THERE IS CURRENTLY SNOWPACK.
TEMPERATURES ALSO WILL NOT FEEL VERY WINTER/CHRISTMAS LIKE WITH
DAILY HIGHS RANGING FROM THE 40S AND 50S ON SUNDAY TO 50S AND 60S
FOR THE WORK(HOLIDAY) WEEK.
NOW THE QUESTION ON EVERYONE'S MIND... WILL WE GET AN EARLY
CHRISTMAS PRESENT FROM MOTHER NATURE AND SEE THE WIND MACHINE TURN
OFF? SOMEWHAT SURPRISINGLY ACTUALLY YES. WHILE SUNDAY INTO MONDAY
LOOKS TO HAVE AT LEAST A CHANCE IN THE WIND PRONES ANYTHING BLEEDING
INTO THE ADJACENT AREAS AND ESPECIALLY HIGH PLAINS ALONG AND EAST OF
I25 LOOKS MUCH LESS OF A SLAM DUNK. ENSEMBLES DO SHOW MEMBERS WITH
700MB WINDS INTO THE 50-60KT RANGE BUT HIGHER THAN 60KTS SEEMS TIED
TO MOUNTAIN WAVE ACTIVITY ALONG THE NORTHERN LARAMIE RANGE UP NEAR
DOUGLAS AND CHUGWATER. OVERALL THE FACT THAT THIS WILL BE SW FLOW
ALOFT AND NOT WESTERLY WILL LIKELY LIMIT THE AREAS THE SEE HIGH
WINDS AND SHOULD FAVOR THOSE NORTHERN AREAS MORE FOR THIS EVENT (AND
OF COURSE THE WIND PRONE AREA OF ARLINGTON.) AS WE GET CLOSER TO THE
EVENT THINGS SHOULD BECOME CLEARER THAN THE MUD THEY CURRENTLY ARE.
BEYOND THIS WEEKEND/EARLY WEEK WIND HOWEVER THINGS LOOK MUCH MORE
PLEASANT WITH DAILY PEAK GUSTS IN THE WIND PRONES LIKELY IN THE 40-
50MPH RANGE AND ADJACENT AREAS SEEING GUSTS ONLY UP TO 30MPH.
AVIATION /12Z TAFS THROUGH 12Z FRIDAY/
ISSUED AT 445 AM MST THU DEC 18 2025
VFR CONDITIONS EXPECTED OVER THE NEXT 24 HOURS. WINDS REMAIN THE
PRIMARY HAZARD AS WIDESPREAD GUSTS OF 30-50 KNOTS PERSIST INTO
THIS EVENING FOR WY TERMINALS, WHILE NE TERMINALS SHOULD SEE A
BREAK FROM WINDS DURING THE AFTERNOON AND EVENING AS WINDS CALM
DOWN TO AROUND 12-15 KNOTS OR LESS. WINDS RESUME GUSTING FOR
ALL TERMINALS BY TOMORROW MORNING THOUGH, WITH GUSTS 25-50 KNOTS
BY THE END OF THE TAF PERIOD, ALONGSIDE LOW LEVEL WIND SHEAR.
CIGS EXPECTED TO BE AROUND MID TO HIGH LEVELS AT FEW TO SCT.
CYS WATCHES/WARNINGS/ADVISORIES
WY...RED FLAG WARNING FROM 10 AM TO 11 PM MST FRIDAY FOR WYZ417-418-
430>433.
RED FLAG WARNING UNTIL 5 PM MST THIS AFTERNOON FOR WYZ430-431.
HIGH WIND WARNING FROM 11 PM THIS EVENING TO 5 AM MST SATURDAY
FOR WYZ101-107-118.
HIGH WIND WARNING FROM 5 AM TO 11 PM MST FRIDAY FOR WYZ102-108-
119.
HIGH WIND WARNING FROM 8 PM THIS EVENING TO 5 AM MST SATURDAY
FOR WYZ103-105-106-109-113-115-117.
HIGH WIND WARNING FROM 5 PM THIS AFTERNOON TO 11 AM MST
SATURDAY FOR WYZ104-110-116.
NE...RED FLAG WARNING FROM 10 AM TO 11 PM MST FRIDAY FOR NEZ434>437.
HIGH WIND WARNING FROM 11 AM TO 11 PM MST FRIDAY FOR NEZ019-
020-054-095-096.
RED FLAG WARNING UNTIL 5 PM MST THIS AFTERNOON FOR NEZ437.
SHORT TERM...RZ
LONG TERM...WFOCYS
AVIATION...MAC
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