431
FXUS65 KCYS 142325
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
525 PM MDT WED OCT 14 2026
KEY MESSAGES
- ANOTHER ROUND OF RAIN AND HIGH ELEVATION SNOW IS EXPECTED LATE
WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING.
- ACCUMULATING SNOW IS EXPECTED ABOVE 7000 FT THIS EVENING
THROUGH THURSDAY MORNING. SNOW LEVELS MAY LOWER DOWN TO 5500
TO 6000 FEET BRIEFLY BEFORE PRECIPITATION ENDS LATER THURSDAY
MORNING.
- A GROWING-SEASON-ENDING FREEZE IS EXPECTED THURSDAY NIGHT
INTO FRIDAY MORNING ACROSS THE ENTIRE AREA.
- DRIER AND MILDER WEATHER EXPECTED THIS WEEKEND INTO EARLY NEXT
WEEK.
SHORT TERM /THROUGH THURSDAY NIGHT/
ISSUED AT 400 PM MDT WED OCT 14 2026
MOST OF OUR AREA IS IN THE MIDST OF ANOTHER LULL IN THE ACTION AS
THE SLOW MOVING, POWERFUL UPPER LEVEL LOW ROTATES TO OUR SOUTH. DRY
AIR IN THE MIDDLE TO UPPER ATMOSPHERE IS APPARENT ON GOES WATER
VAPOR IMAGERY MOVING OVER MOST OF THE AREA AS A DRY SLOT ON THE
EASTERN FLANK OF THE STORM SYSTEM. THIS IS NOT OBVIOUS LOOKING
UP FROM THE SURFACE THOUGH, AS PERSISTENT EASTERLY UPSLOPE FLOW
IS KEEPING LOW CLOUDS FIRMLY LOCKED IN PLACE EVERYWHERE ALONG
AND EAST OF THE LARAMIE RANGE. LOW CLOUDS ARE CLEARLY APPARENT
ON GOES VISIBLE SATELLITE IMAGERY WITH THE MID TO UPPER LEVEL
CLOUD COVER GONE. PRECIPITATION RATES HAVE GONE DOWN TO NEAR
ZERO WITHOUT THE MOISTURE ALOFT, BUT PORTIONS OF THE AREA ARE
STILL OBSERVING MIST. THE CLOUD COVER IS HOLDING TEMPERATURES
DOWN FOR THE ENTIRE AREA. ONLY AROUND CHADRON ARE TEMPERATURES
EXCEEDING 50 DEGREES, WHILE EVERYWHERE ELSE REMAINS STUCK IN
THE 40S.
A DYNAMIC PERIOD OF WEATHER IS ANTICIPATED OVER THE NEXT 18 HOURS AS
THE LAST PHASE OF THIS STORM SYSTEM GETS UNDERWAY. THE CENTER OF THE
UPPER LEVEL LOW IS CURRENTLY LOCATED NEAR THE FOUR CORNERS, BUT THE
PRIMARY BAND OF PRECIPITATION IS DEVELOPING ACROSS CENTRAL WYOMING.
THIS FEATURE IS FORCED BY POSITIVE THETA-E ADVECTION AND ISENTROPIC
LIFT, WHICH SHOULD EVENTUALLY TRANSITION INTO THE TROWAL. MODEL
GUIDANCE IS FINALLY CONVERGING ON A SOLUTION WITH THIS SYSTEM, BUT
THERE HAVE BEEN A FEW RECENT CHANGES IN THE OVERALL EVOLUTION. WHILE
THIS HAS REMOVED SEVERAL OF THE OUTLIER MODELS FROM PREVIOUS RUNS
AND INCREASED CONFIDENCE, THE OFFICIAL FORECAST HAS NOT CHANGED
SIGNIFICANTLY. THE LATEST RAP GUIDANCE SHOWS THE UPPER LEVEL LOW
STRUGGLING TO FULLY SEPARATE FROM THE NORTHERN BRANCH TROUGH THIS
EVENING. THIS IS EXPECTED TO LIMIT ISENTROPIC LIFT ON THE ENTIRE
NORTHEAST FLANK OF THE SYSTEM, WHICH REDUCES THE WINDOW FOR
PRECIPITATION TO JUST THE NARROW TROWAL ON THE BACK EDGE.
SHOWER ACTIVITY IS STILL EXPECTED TO INCREASE THIS EVENING, BUT
QPF EXPECTATIONS ARE MORE MODEST UNTIL THE PRIMARY BAND OF
PRECIPITATION DEVELOPS AND MOVES THROUGH THE AREA FROM NORTHWEST
TO SOUTHEAST THURSDAY MORNING. WHILE PRECIPITATION RATES ARE
STILL EXPECTED TO BE HEALTHY UNDERNEATH THIS BAND, IT WILL BE
NARROW AND MOVING FAIRLY RAPIDLY, REDUCING OVERALL QPF COMPARED
TO SOME OF THE MORE AGGRESSIVE MODEL SOLUTIONS YESTERDAY.
CURRENT EXPECTATIONS ARE FOR 0.5 TO 0.75" LIQUID PRECIPITATION
IN THE CORE OF THE BAND FROM AROUND ARLINGTON TOWARDS TORRINGTON
AND POSSIBLY ALLIANCE. 0.25 TO 0.5" OF QPF ARE NOW THE MOST
LIKELY SCENARIO ALONG THE DOUGLAS TO CHADRON CORRIDOR AND ALONG
I-80 EAST OF CHEYENNE, THOUGH LOCALIZED EMBEDDED CONVECTIVE
CORES WILL LIKELY LEAD TO LOCALLY HIGHER AMOUNTS IN A FEW AREAS.
PRECIPITATION WILL COME TO AN ABRUPT END THURSDAY MORNING,
AROUND DAYBREAK ALONG A RAWLINS TO CHADRON LINE, AND THEN CLOSER
TO NOON AROUND SIDNEY AS A VERY DRY AIRMASS PUSHES IN BEHIND
THE NORTHERN BRANCH SHORTWAVE SWEEPING THROUGH.
THE COLD AIR EXPECTATIONS FOR THIS SYSTEM REMAIN ON TRACK WITH
PREVIOUS FORECASTS. SNOW LEVELS WILL PLUMMET OVERNIGHT TONIGHT AS
THE COLDEST AIR MOVES IN BETWEEN ABOUT 3AM AND 9AM. THIS IS STILL
EXPECTED TO ALIGN WITH THE TIMING OF THE HEAVIEST PRECIPITATION
RATES MOVING ACROSS THE AREA. CONFIDENCE REMAINS HIGH IN
ACCUMULATING SNOW ABOUT 7000 FT IN ELEVATION, INCLUDING THE CITY OF
LARAMIE. THE WINTER WEATHER ADVISORY HAS BEEN EXPANDED TO INCLUDE
THE LARAMIE VALLEY WITH BETWEEN 2 AND 4 INCHES OF SNOW AS THE MOST
LIKELY SCENARIO AT THIS TIME. WHILE THIS IS SOMEWHAT ON THE LOW END
FOR AN ADVISORY, IT WILL BE THE FIRST EVENT OF THE SEASON AND LIKELY
COME WITH A BRIEF WINDOW OF HEAVY SNOWFALL RATES ALIGNED WITH THE
THURSDAY MORNING COMMUTE. THE REMAINING WINTER WEATHER ADVISORIES
REMAIN ON TRACK. BETWEEN 6000 FT AND 7000 FT, SNOW IS EXPECTED TO
MIX IN WITH RAIN IN THE NARROW COLDEST WINDOW THURSDAY MORNING.
BETWEEN A DUSTING AND AN INCH OF SNOW CAN BE EXPECTED IN THIS
ELEVATION WINDOW, WHICH INCLUDES CHEYENNE. TEMPERATURES WILL BE
HIGHLY MARGINAL, AND MAY NOT QUITE REACH FREEZING EVEN IF AREAS
RECEIVE SOME SNOW.
EXPECT A COLD AND BLUSTERY DAY ACROSS THE AREA THURSDAY. WHILE SKIES
WILL CLEAR, EXPECT GUSTY NORTH TO NORTHWEST WINDS UP TO AROUND 30 TO
40 MPH OVER MUCH OF THE AREA WITH HIGHS STUCK IN THE 40S TO LOW 50S.
THIS WILL SET UP THURSDAY NIGHT FOR THE COLDEST TEMPERATURES OF THE
SEASON. RECENT MODEL GUIDANCE HAS TRENDED SLOWER IN THE END OF THE
GUSTY WINDS, MEANING WE MAY STILL BE QUITE BREEZY INTO THE OVERNIGHT
HOURS, ESPECIALLY EARLY. THIS HAS MODERATED TEMPERATURE EXPECTATIONS
SLIGHTLY, BUT THE AIRMASS SHOULD STILL BE SUFFICIENTLY COLD TO
PRODUCE A WIDESPREAD FREEZE, EVEN IF A SHALLOW SURFACE INVERSION
NEVER MANAGES TO DEVELOP. A FREEZE WATCH HAS BEEN ISSUED FOR THE
ENTIRE AREA EXCLUDING THE MOUNTAINS FROM MIDNIGHT UNTIL 9AM
FRIDAY.
LONG TERM /FRIDAY THROUGH WEDNESDAY/
ISSUED AT 400 PM MDT WED OCT 14 2026
AFTER COMING OFF A HARD FREEZE THURSDAY NIGHT, TEMPERATURES WILL
GRADUALLY WARM UP FRIDAY AFTER MELTING OFF FROST AND POTENTIALLY
SNOW FOR SOME AREAS. AS THE PACIFIC STORM EXISTS TOWARDS THE
GREAT LAKES REGION, UPPER-LEVEL RIDGING WILL BEGIN TO BUILD IN
BEHIND IT. THE RIDGE WILL RAPIDLY USHER IN WARM AIR ALOFT, WITH
700 MB TEMPERATURES RISING INTO THE UPPER SINGLE DIGITS. DESPITE
THE WARM TEMPERATURES ALOFT, SURFACE TEMPERATURES WILL TAKE
LONGER TO REBOUND. HIGHS ON FRIDAY WILL BE ABOUT 10 DEGREES
BELOW AVERAGE, WITH TEMPERATURES GENERALLY IN THE 50S ACROSS THE
FORECAST AREA. AREAS WITH SNOW COVER COULD BE COOLER, NAMELY
THE LARAMIE VALLEY, WITH HIGHS IN THE 40S. EVEN THOUGH
TEMPERATURES WILL BE ON THE SEASONABLY COOL SIDE, AMPLE SUNSHINE
THROUGHOUT THE DAY WILL HELP CUT THROUGH SOME OF THE CHILL.
AS THE UPPER-LEVEL RIDGE SHIFTS EASTWARD OVERNIGHT ON FRIDAY, MID-
LEVEL WINDS WILL BECOME MORE WESTERLY. THE WESTERLY WINDS WILL POSE
A POSSIBLE CONCERN FOR HIGH WINDS IN THE TYPICAL SOUTHEAST WYOMING
WIND PRONES OF ARLINGTON AND BORDEAUX DURING THE DAY SATURDAY. MSLP
GRADIENTS WILL STEEPEN ALONG AND WEST OF THE LARAMIE RANGE. CAG TO
CPR 850 MB GRADIENTS ALSO REACH THE 50 METER RANGE, SIGNALING
THE POTENTIAL FOR GRADIENT DRIVEN MARGINAL HIGH WINDS IN THE
WIND PRONES. 700 MB WINDS WILL REACH ABOUT 40 KTS, BUT
SUBSIDENCE IS RATHER WEAK AND WILL LIKELY NOT PLAY A HUGE ROLE
IN THE WINDS SATURDAY INTO SUNDAY MORNING. WIND GUSTS OF AT
LEAST 40 TO 50 MPH WILL BE LIKELY DURING THE DAY SATURDAY AND
INTO THE OVERNIGHT HOURS. WESTERLY WINDS WILL HELP PLAY A ROLE
IN THE WARM, ABOVE AVERAGE TEMPERATURES ON SATURDAY. DOWNSLOPING
WINDS WILL AID 90TH PERCENTILE 700 MB TEMPERATURES IN ACHIEVING
DAYTIME HIGHS IN THE 70S FOR AREAS EAST OF THE LARAMIE RANGE.
TO THE WEST, HIGHS AROUND 60 DEGREES CAN BE EXPECTED. AMPLE
SUNSHINE IS ONCE AGAIN EXPECTED FOR SATURDAY.
ABOVE AVERAGE TEMPERATURES WILL CONTINUE INTO THE START OF NEXT WEEK
WITH HIGHS IN THE 60S AND 70S EXPECTED SUNDAY THROUGH TUESDAY.
CONDITIONS DURING THIS TIME ARE ALSO EXPECTED TO REMAIN DRY, WITH
MOSTLY SUNNY SKIES EXPECTED EACH DAY. CANNOT RULE OUT A LOW-END
CHANCE OF PRECIPITATION DURING THE EVENING ON TUESDAY AS A SHORTWAVE
GLANCES THE CWA, HOWEVER, MODELS SEEM TO HAVE TRENDED THIS
DRIER.
AVIATION /00Z TAFS THROUGH 00Z FRIDAY/
ISSUED AT 525 PM MDT WED OCT 14 2026
A STORM SYSTEM WILL MOVE THROUGH THE REGION, THIS WILL BRING A
PLETHORA OF AVIATION IMPACTS TO ALL TERMINALS IN OUR CWA. ONE OF
WHICH ARE LOW CIGS, EXPECT A CONTINUATION OF MVFR TO IFR CIGS,
POSSIBLY DOWN TO LIFR AT TIMES, FOR ALL THE SITES. ANOTHER IS
PRECIPITATION MOVING IN THIS AFTERNOON/EVENING FOR THE
SOUTHEAST WYOMING TERMINALS AND THEN INTO THE NEBRASKA
PANHANDLE. THIS PRECIPITATION WILL MAINLY START OUT AS RAIN, BUT
WITH A SURGE OF COLDER AIR AS WINDS BECOME NORTHERLY, THIS RAIN
WILL TRANSITION TO SNOW PRIMARILY FOR THE SOUTHEAST WYOMING
TERMINALS. THIS SNOW MAY REDUCE VIS SIGNIFICANTLY, POSSIBLY DOWN
TO IFR VIS. HOWEVER, RAIN IS NOT EXPECTED TO TRANSITION TO SNOW
ACROSS THE NEBRASKA PANHANDLE WHILE THIS PRECIPITATION IS
EXPECTED TO LINGER THROUGHOUT MOST OF THE NIGHT. AS MENTIONED
PREVIOUSLY, WINDS WILL BECOME NORTHERLY AS THE STORM BEGINS TO
MOVE OFF TO THE EAST, AS IT DOES, LOOK FOR WINDS TO RAMP UP WITH
GUSTS 20 TO AS HIGH AS 35 KNOTS.
CYS WATCHES/WARNINGS/ADVISORIES
WY...FREEZE WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY MORNING
FOR WYZ101-102-104>111-113-115>119.
WINTER WEATHER ADVISORY UNTIL NOON MDT THURSDAY FOR WYZ110-112-
116.
WINTER WEATHER ADVISORY UNTIL NOON MDT THURSDAY FOR WYZ114.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO NOON MDT
THURSDAY FOR WYZ115.
DENSE FOG ADVISORY UNTIL 6 PM MDT THIS EVENING FOR WYZ116.
NE...FREEZE WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY MORNING
FOR NEZ002-003-019>021-054-055-095-096.
SHORT TERM...MN
LONG TERM...SF
AVIATION...RZ
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