509
FXUS65 KCYS 260454
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1055 PM MDT SAT APR 25 2026
KEY MESSAGES
- A MESSY PATTERN IS ANTICIPATED TODAY THROUGH MUCH OF THE
UPCOMING WEEK, ALLOWING FOR ONGOING PRECIPITATION CHANCES
ACROSS THE ENTIRE CWA. THE BEST CHANCE FOR PRECIPITATION WILL
BE SUNDAY, WITH WIDESPREAD SHOWERS AND THUNDER.
- A WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR THE SIERRA MADRE
AND SNOWY RANGES FROM 6PM SATURDAY THROUGH 6AM MONDAY.
SHORT TERM /THROUGH SUNDAY NIGHT/
ISSUED AT 346 PM MDT SAT APR 25 2026
RADAR IS PICKING UP ON LIGHT SHOWERS IN THE WESTERN PORTION OF THE
CWA WHERE CLEAR SKIES HAVE LEAD TO WARMING AND THE DEVELOPMENT OF A
CUMULUS FIELD. SHOWERS ARE ORIGINATING OUT OF THIS CUMULUS
FIELD, HOWEVER IT DOES NOT APPEAR THAT MUCH, IF ANY
PRECIPITATION IS REACHING THE GROUND DUE TO THE DRY LOW-LEVELS.
THIS SHOWER ACTIVITY WILL CONTINUE THROUGH THE EVENING HOURS PER
HI-RES GUIDANCE AND SHOULD MAINLY STAY ALONG AND WEST OF THE
INTERSTATE 25 CORRIDOR WHERE THERE IS CLEANING. THE NEBRASKA
PANHANDLE REMAINS RATHER STABLE THIS AFTERNOON WITH COOLER
TEMPERATURES DUE TO A PERSISTENT LOW STRATUS DECK. AS A RESULT,
WENT AHEAD AND NUDGED HIGH TEMPERATURES DOWN INTO THE 40S FOR
THE NEBRASKA PANHANDLE FOR THE REMAINDER OF THE AFTERNOON.
CANNOT RULE OUT A STRAY SHOWER OVERNIGHT AS SUFFICIENT LOW-LEVEL
MOISTURE MOVES INTO THE AREA, HOWEVER, INSTABILITY AND FORCING
WILL LIKELY LIMIT THEIR DEVELOPMENT.
PRECIPITATION WILL BECOME MORE WIDESPREAD SUNDAY MORNING AS THE NEXT
SHORTWAVE MOVES INTO WYOMING. PRECIPITATION DURING THE MORNING HOURS
WILL BE MORE STRATIFORM IN NATURE GIVEN THE STABLE ENVIRONMENT.
AFTER SOME WARMING AND PARTIAL CLEARING, A SECONDARY ROUND OF
PRECIPITATION IS EXPECTED THAT WILL BE MORE CONVECTIVE. HI-RES
GUIDANCE SHOWS WIDESPREAD SHOWERS AND THUNDERSTORMS DEVELOPING OFF
THE HIGH TERRAIN AND PUSHING NORTHEAST THROUGH THE AFTERNOON. BOTH
PWATS AND IVT VALUES ARE IN THE 90TH PERCENTILE FOR NAEFS
CLIMATOLOGY SO A WET DAY WITH AMPLE MOISTURE IS EXPECTED. ALTHOUGH
SHOWERS WILL BE SCATTERED IN NATURE, IT IS LIKELY THAT ALL LOCATIONS
SEE SOME TYPE OF PRECIPITATION EITHER SUNDAY OR SUNDAY NIGHT.
THUNDER WILL ALSO BE POSSIBLE IN BOTH RAIN AND SNOW SHOWERS
THROUGHOUT THE DAY TOMORROW AS A FEW HUNDRED JOULES OF CAPE EXIST.
THERE IS NOT A STRONG SIGNAL FOR SEVERE STORMS, HOWEVER BECAUSE THIS
IS WYOMING AND THE HIGH PLAINS, CANNOT RULE OUT ROGUE GUSTS TO 60
MPH OR SMALL HAIL. SHOWERS WILL RETURN TO A MORE STRATIFORM STATE
ONCE AGAIN SUNDAY NIGHT. WITH THE SHORTWAVE MOVING OUT OF THE CWA,
COVERAGE OF PRECIPITATION WILL BE LOWER OVERNIGHT. RAIN WILL
TRANSITION TO SNOW AS TEMPERATURES COOL OFF THROUGH THE EVENING.
LOWER ELEVATION SNOW ACCUMULATIONS WILL BE POSSIBLE, BUT WILL
GENERALLY BE BELOW AN INCH WITH MOST PLACES EXPECTED TO SEE A
DUSTING. THE SNOWY AND SIERRA MADRE RANGES WILL BE THE EXCEPTION TO
THIS WITH WINTER WEATHER ADVISORIES IN PLACE FOR ACCUMULATIONS OF 6
TO 12 INCHES ABOVE 8500 FEET. SNOW WILL GRADUALLY TAPER OFF
THROUGH MONDAY MORNING AS THE SHORTWAVE MOVES OUT OF THE AREA.
LONG TERM /MONDAY THROUGH SATURDAY/
ISSUED AT 346 PM MDT SAT APR 25 2026
A DEPARTING UPPER LEVEL TROUGH WILL BE PUSHING INTO
THE NORTHERN PLAINS MONDAY MORNING. THERE MAY BE SOME LINGERING
SHOWERS IN THE PANHANDLE THAT WILL PUSHING EAST THROUGH THE MORNING.
A WEAK TRANSIENT RIDGE WILL PUSH THROUGH THE INTERMOUNTAIN WEST
GIVING US A TEMPORARY PAUSE IN THE SHOWERS MONDAY AFTERNOON. THIS
BREAK WILL BE SHORT-LIVED AS ANOTHER SHORTWAVE WILL BE MOVING INTO
THE INTERMOUNTAIN WEST BY MONDAY EVENING. THE GLOBAL MODELS ROUGHLY
AGREE ON THE TIMING WITH THIS SHORTWAVE AS WELL BUT START TO
DISAGREE ON THE STRENGTH OF SHORTWAVE. THE GFS WANTS TO START TO
CLOSE OFF THE SHORTWAVE INDICATING A STRONGER SYSTEM BUT THE
CANADIAN AND EURO MAINTAIN IT AS AN OPEN WAVE TO SUGGEST A
POTENTIALLY WEAKER SYSTEM MIGRATING THROUGH THE ROCKIES. THERE LOOKS
TO BE SUFFICIENT MOISTURE AS OUR COOLER TEMPERATURES WILL HELP
MAINTAIN A BORDERLINE SATURATED ENVIRONMENT DURING THE WORK WEEK.
THIS UPCOMING WEEK WILL REMAIN PRETTY ACTIVE WITH MULTIPLE
SHORTWAVES THROUGHOUT THE WEEK. EACH WAVE OR SYSTEM LOOKS TO HAVE
VORTMAXES ACCOMPANYING THEM TO ADD IN THE SYNOPTIC LIFT AND GIVE THE
REGION SOME MUCH NEEDED RAIN CHANCES. 700MB TEMPERATURES RANGE FROM -
3C TO +1C KEEPING TEMPERATURES AROUND 40 TO 50 DEGREES DURING THE
DAY AND DROPPING INTO THE 30'S AT NIGHT BRING FOR A SLIGHT CHANCE
FOR SOME RAIN TRANSITIONING TO SNOW DURING THE OVERNIGHT HOURS INTO
THE FOLLOWING EARLY MORNING. OUTSIDE THE SIERRA MADRE, SNOWY, AND
NORTHERN LARAMIE RANGES, TOTAL SNOW ACCUMULATIONS LOOK TO BE LESS
THAN AN INCH WITH MEASURABLE ACCUMULATIONS ON THE MOUNTAIN PEAKS AND
POSSIBLY SOME LIGHT ACCUMULATION IN THE FOOTHILLS BETWEEN LARAMIE IN
CHEYENNE AS THE MODELS DO HINT TO SOME POSSIBLY ENHANCED SNOWFALL
DUE TO MESOSCALE FORCING IN THAT AREA. THE VAST MAJORITY OF THE
COUNTIES ALONG AND EAST OF THE I-25 SHOULD EXPECT MOST OF THE
PRECIPITATION TO COME DOWN AS RAIN WITH NON ACCUMULATING (TRACE)
AMOUNTS OF SNOWFALL IF SHOWERS OCCUR OVERNIGHT.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 1055 PM MDT SAT APR 25 2026
A STATIONARY FRONT WILL REMAIN NEAR THE COLORADO AND WYOMING BORDER
TONIGHT BEFORE SLOWLY LIFTING NORTHEAST SLOWLY AS A WARM FRONT AHEAD
OF THE NEXT PACIFIC UPPER LEVEL DISTURBANCE. WIDESPREAD LOW CIGS AND
IFR CONDITIONS, PERIODS OF RAIN AND SNOW, AND SOME FOG POSSIBLE IN
BETWEEN BANDS OF SHOWERS THROUGH SUNDAY AFTERNOON.
HAZARDS/WEATHER TRENDS: IFR CIGS ARE DEVELOPING ACROSS PORTIONS OF
THE WESTERN NEBRASKA PANHANDLE WITH EAST TO SOUTHEAST WINDS. EXPECT
THESE WINDS TO CONTINUE THROUGH MUCH OF SUNDAY, SO TRANSITIONED TO
PREVAILING IFR TO LIFR CIGS FOR ALL WESTERN NEBRASKA TERMINALS. KCDR
WILL BE THE LAST TO SEE IFR CONDITIONS...TOWARDS DAYBREAK SUNDAY.
PERIODS OF RAINFALL AND/OR SNOW/RAIN MIX WILL RESULT IN BRIEF MVFR
CONDITIONS AT TIMES.
LOWER CONFIDENCE FOR THE SOUTHEAST WYOMING TERMINALS WITH SOME DELAY
IN TIMING AND ANOTHER BAND OF SNOW LIFTING FROM SOUTH TO NORTH EARLY
SUNDAY MORNING. KLAR AND KRWL HAVE THE BEST CHANCE OF SEEING
ADDITIONAL SNOWFALL FROM THIS WARM FRONT AS IT SLOWLY LIFTS NORTH,
SO ADDED SOME MENTION OF SNOW AND IFR CONDITIONS. KCYS HAS THE BEST
CHANCE TO SEE LOCALLY DENSE FOG WITH MODELS BECOMING MORE AGGRESSIVE
WITH LOWERING VIS. ADDED VIS BETWEEN 1/2 TO 1 MILE THROUGH 13Z
SUNDAY.
CYS WATCHES/WARNINGS/ADVISORIES
WY...WINTER WEATHER ADVISORY UNTIL 6 AM MDT MONDAY FOR WYZ112-114.
NE...NONE.
SHORT TERM...SF
LONG TERM...MM
AVIATION...TJT
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