607
FXUS65 KCYS 132157
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
357 PM MDT FRI MAR 13 2026
KEY MESSAGES
- THE LONG DURATION HIGH WIND EVENT WILL TAKE A SHORT BREAK
OVERNIGHT INTO EARLY SATURDAY MORNING BEFORE WIDESPREAD
STRONG WINDS AND HIGH FIRE DANGER RETURN TO THE AREA SATURDAY.
- EXPECT WIDESPREAD WIND GUSTS OF 50 TO 70 MPH WITH LOCALIZED
GUSTS UP TO 85 MPH ON SATURDAY.
- A STRONG COLD FRONT SATURDAY EVENING WILL BRING MUCH COLDER
TEMPERATURES AND A QUICK ROUND OF LOCALLY HEAVY SNOW SHOWERS,
WITH POTENTIAL FOR WIDESPREAD LIGHT ACCUMULATIONS.
- STRONG NORTHWEST TO NORTH WINDS WILL CONTINUE OVER THE HIGH
PLAINS INTO SUNDAY, PRODUCING SUB-ZERO WIND CHILL
TEMPERATURES.
- RECORD WARM TEMPERATURES MAY BE IN STORE FOR THE REGION BY
MID-WEEK, BUT UNCERTAINTY IS HIGHER AT THIS TIME.
SHORT TERM /THROUGH SUNDAY NIGHT/
ISSUED AT 400 PM MDT FRI MAR 13 2026
HIGH WINDS CONTINUE ACROSS THE AREA, BUT FORTUNATELY, THE HAZARD IS
MORE LIMITED THAN WHAT WE SAW YESTERDAY. WHILE A STRONG 700-MB JET
REMAINS PARKED OVERHEAD TODAY, THE LACK OF A MOUNTAIN TOP INVERSION
AND WINDS CONTINUING TO INCREASE ABOVE 500-MB HAS PROMOTED MORE OF A
SHORT AMPLITUDE STANDING MOUNTAIN WAVE SETUP TODAY AS OPPOSED TO THE
SIGNIFICANT MOUNTAIN WAVE BREAKING OBSERVED YESTERDAY. DUE TO THE
SHORT AMPLITUDE OF TODAY'S WAVE, MOST OF THE STRONGER WIND GUSTS
HAVE RETREATED CLOSER TO THE TERRAIN BARRIERS, BUT WIDESPREAD WIND
GUSTS BETWEEN 65 AND 85 MPH ARE ONGOING IN THE ARLINGTON/ELK
MOUNTAIN AREAS AND ALONG THE CREST OF THE LARAMIE RANGE. ELSEWHERE
IN SOUTHEAST WYOMING, WE ARE GENERALLY SEEING WIND GUSTS IN THE 50
TO 65 MPH RANGE, WHICH IS EXPECTED TO CONTINUE INTO THE EARLY
EVENING HOURS. THE COOLER, MORE MOIST AIRMASS IS PARKED ALONG A
LINE FROM ROUGHLY LUSK TO BRIDGEPORT, KEEPING THE DRY WESTERLY
WINDS AT BAY FOR NOW. THIS FEATURE WILL ADVANCE WESTWARD
OVERNIGHT, AND THE HIGH WINDS ARE EXPECTED TO RETREAT BACK INTO
THE WIND PRONE AREAS (IF NOT HAVE A BRIEF LULL ENTIRELY ACROSS
THE AREA) FOR THE OVERNIGHT INTO SATURDAY MORNING.
THE BREAK IN THE WINDS WILL BE SHORT-LIVED. A POWERFUL PACIFIC
TROUGH WILL BEGIN TO RAMP UP PRESSURE AND HEIGHT GRADIENTS ACROSS
THE AREA BY THE MORNING HOURS. SATURDAY'S WIND WILL BE MORE
WIDESPREAD THAN TODAY, BUT AGAIN NOT TO THE MAGNITUDE OF WHAT WAS
OBSERVED YESTERDAY. WIND GUSTS EXCEEDING 60 MPH WILL ALSO SPREAD
EASTWARD INTO AT LEAST THE EASTERN ROW OF ZONES IN WYOMING (WHICH
WERE ADDED BACK TO THE HIGH WIND WARNING STARTING MID MORNING
SATURDAY), AND POSSIBLY INTO THE NEBRASKA PANHANDLE. EXPECT FAIRLY
WIDESPREAD GUSTS OF 50 TO 70 MPH THROUGH THE DAY WITH LOCALIZED
GUSTS UP TO AROUND 85 MPH STILL POSSIBLE IN THE WIND PRONE AREAS.
FORECAST SOUNDINGS FOR SATURDAY SUGGEST A LOWER CEILING BUT
WIDESPREAD EVENT. WE DO NOT HAVE MUCH OF AN INVERSION TO SPEAK OF,
WHICH WILL LIMIT THE POTENTIAL FOR MOUNTAIN WAVE BREAKING AND
DOWNSLOPE ACCELERATION. HOWEVER, DEEP, WELL-MIXED BOUNDARY LAYERS
SUGGEST THAT WE SHOULD HAVE LITTLE TROUBLE MIXING THE 45 TO 65 KNOT
700-MB WINDS DOWN TO THE SURFACE. VERY WARM TEMPERATURES AND DEEP
MIXING WILL ALSO DRY OUT THE SURFACE, LEADING TO VERY LOW
HUMIDITIES. THIS WILL LEAD TO CRITICAL FIRE DANGER ACROSS MUCH OF
THE AREA ONCE AGAIN. THE RED FLAG WARNING WAS EXPANDED TO INCLUDE
THE DOUGLAS TO ALLIANCE CORRIDOR. LATER SHIFTS WILL NEED TO CONSIDER
ANOTHER SHIFT NORTHWARD INTO THE LUSK TO CHADRON / PINE RIDGE
CORRIDOR, BUT RH VALUES WERE NOT QUITE TO CRITERIA AS OF THIS
WRITING. EXPECT GUSTY WINDS TO CONTINUE INTERMITTENTLY INTO THE
EVENING HOURS, BUT RAPID CHANGES WILL BE ON THE WAY WITH THE
ARRIVAL OF A POWERFUL COLD FRONT SATURDAY EVENING. THIS WILL
HAVE TWO PRIMARY IMPACTS: SNOW AND MORE WIND. WE WILL BREAK DOWN
THE TWO IMPACTS BELOW.
MORE WIND: AS THE PACIFIC TROUGH MOVES OVERHEAD, A VERY STRONG COLD
FRONT WILL PUSH THROUGH THE AREA. EXPECT THIS TO ARRIVE IN THE
NORTHERN/WESTERN ZONES AROUND 7-9PM. THE FRONT WILL BE ACCOMPANIED
BY A WIND SHIFT TO THE NORTH OR NORTHWEST, BUT THE VERY RAPID
PRESSURE RISES ALONG THE BOUNDARY MAY LEAD TO ANOTHER ROUND OF WIND
GUSTS TO 60 OR 70 MPH AND BLOWING DUST. THIS WILL RACE THROUGH THE
AREA, REACHING SIDNEY BY 11PM TO MIDNIGHT. A VERY STRONG SURFACE
PRESSURE GRADIENT WILL REMAIN OVER THE AREA THROUGH SUNDAY MORNING
AS WE WILL BE SANDWICHED BETWEEN A STRONG SURFACE CYCLONE
STRENGTHENING OVER THE CENTRAL PLAINS AND AN ARCTIC HIGH PRESSURE
SETTING IN OVER THE NORTHERN ROCKIES AND NORTHERN PLAINS. FOR THE I-
25 CORRIDOR AND THE I-80 SUMMIT ZONES, HIGH WIND WARNINGS WERE
EXTENDED UNTIL NOON SUNDAY TO ACCOUNT FOR THIS ADDITIONAL ROUND OF
STRONG WINDS. THE NEWLY ISSUED EXPANDED WARNING FOR NIOBRARA,
GOSHEN, AND EASTERN LARAMIE COUNTIES ALSO RUNS THROUGH NOON SUNDAY
TO ACCOUNT FOR THIS ADDITIONAL WIND HAZARD. LASTLY, A HIGH WIND
WATCH WAS ISSUED FOR THE NEBRASKA PANHANDLE BEGINNING MIDNIGHT
SATURDAY NIGHT (TO COVER THE FRONTAL PASSAGE) AND CONTINUING THROUGH
MID AFTERNOON SUNDAY. THE STRONG PRESSURE GRADIENT WILL SCOOT OUT
FROM WEST TO EAST ON SUNDAY, LEADING TO A GRADUAL DECREASE IN WINDS
DURING THE AFTERNOON HOURS. WE WILL FINALLY GET A BREAK FROM THE
WINDS BY SUNDAY AFTERNOON INTO MONDAY MORNING, BUT THE THREAT FOR
HIGH WINDS WILL RETURN TO THE ARLINGTON/ELK MOUNTAIN AREA AS EARLY
AS MONDAY MORNING.
SNOW: THE PASSING COLD FRONT WILL ALSO COME WITH A BOOST IN MID-
LEVEL MOISTURE. WHILE ORGANIZED LIFT IS NOT VERY IMPRESSIVE WITH
THIS SYSTEM, WE HAVE A PERIOD OF VERY STRONG FRONTOGENESIS AND GOOD
VORTICITY ADVECTION ALOFT MOVING THROUGH THE AREA. THIS SHOULD BE
ENOUGH TO KICK OFF SNOW SHOWERS DESPITE THE LACK OF ISENTROPIC LIFT
OR ANY WRAP-AROUND BEHIND THE DEPARTING SYSTEM. IN ADDITION, THERE
WILL BE VERY STRONG MECHANICAL LOW-LEVEL FORCING AS INDICATED BY
SURFACE PRESSURE RISES AT A RATE OF 2-4MB PER HOUR FOR THE FIRST
SEVERAL HOURS BEHIND THE COLD FRONT. WITH MODESTLY STEEP LAPSE RATES
IN PLACE, WE MAY BE ABLE TO GET SOME LOCALLY HEAVY SNOW SHOWERS,
POSSIBLY UP TO SNOW SQUALL CRITERIA IN SOME AREAS. THE WINDOW FOR
PRECIPITATION IS VERY SHORT, BUT HEAVIER RATES COULD STILL LEAD TO
SOME SNOW IMPACTS. MOST OF THE HEAVIER SNOW SHOWER ACTIVITY IS
EXPECTED GENERALLY BETWEEN 8PM AND 2AM, WITH LIGHTER SNOW SHOWERS
CONTINUING THROUGH MID MORNING. FOR ACCUMULATIONS, WE ARE GENERALLY
EXPECTING A WIDESPREAD DUSTING TO AN INCH OF SNOW (WITH A LOT OF
WIND MAKING IT DIFFICULT TO MEASURE). HIGHER TOTALS IN THE 1-4"
RANGE CAN BE EXPECTED IN LOCALIZED REGIONS FAVORED BY NORTHWEST TO
NORTHERLY FLOW, INCLUDING THE I-80 CORRIDOR BETWEEN ELK MOUNTAIN AND
CHEYENNE, AND THE PINE RIDGE CORRIDOR FROM DOUGLAS TO CHADRON.
CONFIDENCE IS TOO LOW TO ISSUE ANY WINTER WEATHER ADVISORIES TODAY,
BUT LATER SHIFTS WILL NEED TO TAKE ANOTHER LOOK AT THIS.
ANYWHERE
LONG TERM /MONDAY THROUGH THURSDAY/
ISSUED AT 400 PM MDT FRI MAR 13 2026
WE WAVE GOOD-BYE TO OUR UPPER-LEVEL TROUGH AS IT MOVES EAST, DEALING
WITH THE COOLER TEMPERATURES AND DRIER CONDITIONS IN ITS WAKE
MONDAY. TEMPERATURES REACH THE UPPER 40S IN MOST SPOTS EXCEPT IN THE
NEBRASKA PANHANDLE WHERE TEMPERATURES WILL BE IN THE LOWER 40S AND
ELEVATIONS ABOVE ABOUT NINE THOUSAND FEET REMAINING BELOW FREEZING
THROUGHOUT THE DAY. PRECIPITATION IS EXPECTED TO BE ABSENT, EXCEPT
PERHAPS FOR THE SNOWY AND SIERRA MADRE RANGES WHERE LINGERING SNOW
SHOWERS MAY PERSIST ESPECIALLY ON THE WEST FACING SLOPES.
WE SHIFT GEARS TO A PATTERN TYPICAL OF SUMMER WITH THE INTRODUCTION
OF AN UPPER-LEVEL RIDGE PARKED OVER THE SOUTHWESTERN CONUS. 500 MB
TEMPERATURES ARE CURRENTLY PROGGED TO BE MAXED OUT PER THE NAEFS
MEAN TEMPERATURES CLIMATOLOGY. THIS SIGNAL IS THERE THROUGH THE END
OF THE FORECAST PERIOD. DAILY MAXIMUM TEMPERATURES ARE LIKELY TO
CLIMB BEGINNING TUESDAY REACHING LOW TO MID 70S WEST OF I-25 AND THE
NORTHERN LARAMIE RANGE, WHILE HIGHER ELEVATIONS IN THE INTERIOR
REACH THE LOW 60S. WEDNESDAY SOME PLACES MAY REACH THE 80S,
PARTICULARLY IN RIVER VALLEYS OF EAST WYOMING AND THE NEBRASKA
PANHANDLE. THIS TREND CONTINUES THURSDAY WITH MORE WIDESPREAD UPPER
70 AND LOWER 80 HIGH TEMPERATURES. WE UNFORTUNATELY WILL NOT SEE
MUCH IN THE WAY OF PRECIPITATION. THIS RIDGE WILL SHUNT AWAY THE JET
STREAM TO OUR NORTH AND EAST, AND NO EMBEDDED WAVE PACKETS ARE
EVIDENT IN MODEL ENSEMBLES TO HELP SPUR LIFTING NEEDED FOR
PRECIPITATION UNTIL PERHAPS PAST THIS FORECAST PERIOD.
ONE OF THE ONLY BENEFITS OF THIS RIDGING PATTERN ARE THE REDUCTION
OF STRONG WINDS. WINDS MAY STAY STRONG MONDAY THROUGH THURSDAY,
THANKS TO THE TIGHT 500 MB PRESSURE GRADIENTS BETWEEN THE RIDGE AND
LOW PRESSURE TO OUR NORTH AND EAST. HOWEVER, AS THE RIDGE SHIFTS
EAST AND GROWS, THESE GRADIENTS RELAX ALLOWING FOR WEAKER FLOW OUT
OF THE WEST/SOUTHWEST. GUSTY CONDITIONS ARE STILL POSSIBLE IN OUR
WIND PRONE AREAS, BUT NOTHING LIKE WHAT WE EXPERIENCED YESTERDAY.
WORSENING RELATIVE HUMIDITY VALUES ARE ALSO IN PLAY. WIDESPREAD
MINIMUM DAYTIME VALUES IN THE 20S ON TUESDAY AND IN THE TEENS FROM
WEDNESDAY THROUGH FRIDAY. POOR NIGHTTIME RECOVERIES ARE LIKELY.
WHILE WINDS ARE NOT AS STRONG, WITH THE LACKLUSTER PRECIPITATION
RECENTLY, LOW RH VALUES, AND PREDICTED RECORD WARMTH MAY LEAD TO
FIRE WEATHER CONDITIONS WITH OUR DRIED FUELS. STAY TUNED FOR UPDATES
REGARDING THIS UPCOMING CONCERN.
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
ISSUED AT 1148 AM MDT FRI MAR 13 2026
HIGH BASED CLOUDS WILL BE MOVING THROUGH THE AREA INTO THE
OVERNIGHT PERIOD AND POSSIBLY A CLEARING TOMORROW IF THOSE
CLOUDS STAY ANCHORED TO THE MOUNTAINS OVER NORTHWEST WYOMING
AREA. A BIT OF LULL IN THE WINDS ARE LIKELY TO HAPPEN OVERNIGHT
WITH THE WINDS RAMPING TOMORROW. LOW LEVEL WINDSHEAR IS A
POSSIBLE CONCERN OVERNIGHT AS THE STANDING MOUNTAIN WAVE MAY
STILL BE ACTIVE AT 50 KNOTS AT 2,000FT. LOW LEVEL WINDSHEAR WILL
BE ADDED TO THE 00Z TAFS FOR WIND DIRECTION CERTAINTY.
CYS WATCHES/WARNINGS/ADVISORIES
WY...RED FLAG WARNING FROM 10 AM TO 8 PM MDT SATURDAY FOR WYZ418.
RED FLAG WARNING UNTIL 8 PM MDT SATURDAY FOR WYZ430>433.
HIGH WIND WARNING UNTIL 8 PM MDT THIS EVENING FOR WYZ108-119.
HIGH WIND WARNING UNTIL NOON MDT SUNDAY FOR WYZ101-106-107-
116>118.
HIGH WIND WARNING FROM 10 AM SATURDAY TO NOON MDT SUNDAY FOR
WYZ102-108-119.
HIGH WIND WARNING UNTIL MIDNIGHT MDT SATURDAY NIGHT FOR
WYZ103>105-109-113.
HIGH WIND WARNING UNTIL 3 AM MDT SUNDAY FOR WYZ110-115.
HIGH WIND WARNING UNTIL 6 AM MDT SATURDAY FOR WYZ114.
NE...RED FLAG WARNING FROM 10 AM TO 8 PM MDT SATURDAY FOR NEZ435.
HIGH WIND WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY
AFTERNOON FOR NEZ002-003-019>021-054-055-095-096.
RED FLAG WARNING UNTIL 8 PM MDT SATURDAY FOR NEZ436-437.
HIGH WIND WARNING UNTIL 8 PM MDT THIS EVENING FOR NEZ020-054.
SHORT TERM...MN
LONG TERM...RV
AVIATION...MM
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