033
FXUS65 KCYS 140522
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1122 PM MDT WED MAY 13 2026
KEY MESSAGES
- NEAR TO RECORD WARMTH EXPECTED WEDNESDAY UNDER HIGH PRESSURE
ALOFT. GUSTY SHOWERS AND THUNDERSTORMS POSSIBLE THROUGH
WEDNESDAY EVENING.
- RED FLAG WARNINGS HAVE BEEN EXPANDED TO INCLUDE ALL OF WESTERN
NEBRASKA AND EXTENDED THROUGH FRIDAY EVENING.
- HIGH WIND WATCHES HAVE BEEN UPGRADED TO WARNINGS FOR THE
TYPICAL WIND PRONE REGIONS OF SOUTHEAST WYOMING FROM LATE
WEDNESDAY NIGHT THROUGH THURSDAY EVENING.
- NEXT CHANCE FOR PRECIPITATION RETURNS DURING THE WEEKEND
ALONGSIDE COOLER CONDITIONS.
SHORT TERM /THROUGH FRIDAY NIGHT/
ISSUED AT 245 PM MDT WED MAY 13 2026
SHOWERS ARE BEGINNING TO POP UP WEST OF THE LARAMIE RANGE EARLY THIS
AFTERNOON. SHOWERS WILL CONTINUE TO SPREAD EASTWARD THROUGHOUT THE
AFTERNOON INTO EASTERN WYOMING AND EVENTUALLY THE NEBRASKA
PANHANDLE BY THIS EVENING. MODEL SOUNDINGS SHOW A DECENT AMOUNT
OF CAPE, SO THESE SHOWERS HAVE THE POTENTIAL TO PRODUCE
LIGHTNING. SOUNDINGS ALSO SHOW A DEEPLY INVERTED-V PROFILE WITH
EXTREMELY DRY SURFACE AND LOW-LEVEL. DCAPE VALUES ACROSS THE CWA
ARE 1500 J/KG AND GREATER, LEADING TO THE THREAT OF DRY
MICROBURSTS. WIND GUSTS IN EXCESS OF 70 MPH CANNOT BE RULED OUT.
ALSO, LITTLE IF ANY PRECIPITATION WILL ACTUALLY MAKE IT TO THE
GROUND, LEADING TO DRY LIGHTNING CONCERNS. HI-RES GUIDANCE HAS A
FEW ISOLATED SHOWERS/STORMS CONTINUING OVERNIGHT AS AN UPPER-
LEVEL TROUGH BEGINS TO PASS NORTH OF THE CWA. SHOWERS WILL
LIKELY BE OUT OF THE AREA BY THURSDAY MORNING.
AS THE AFOREMENTIONED TROUGH SWINGS TO THE NORTH, MSLP GRADIENT
ALONG AND WEST OF THE LARAMIE RANGE WILL TIGHTEN EARLY THURSDAY
MORNING. 850 AND 700 MB CAG TO CPR HEIGHT GRADIENTS WILL ALSO
INCREASE WITH THE TROUGH TO THE NORTH, RAISING VALUES UP TO ALMOST
60 METERS. AS A RESULT, WINDS ALOFT WILL RESPOND, REACHING 55 TO 60
KTS OVER THE WIND PRONES. SUBSIDENCE WILL BE DECENT AND WILL
HELP WITH AIDING THESE WINDS DOWN TO THE SURFACE. UPGRADED THE
HIGH WIND WATCHES IN EFFECT FOR THE WIND PRONES TO WARNINGS WITH
THIS FORECAST PACKAGE. THE GFS HAS CONSISTENTLY BEEN SHOWING
THIS SIGNAL AND IN-HOUSE GUIDANCE SHOWS A 40 TO 60 PERCENT
CHANCE OF HIGH WINDS OCCURRING IN THE TYPICAL SOUTHEAST WYOMING
WIND PRONE AREAS. HIGH WINDS ARE MOST LIKELY TO OCCUR BETWEEN 6
AM AND 3 PM ON THURSDAY WITH WIND GUSTS BETWEEN 55 AND 65 MPH.
OUTSIDE OF THE WIND PRONES, THURSDAY IS STILL EXPECTED TO BE A VERY
WINDY DAY AS THE TROUGH PASSES TO THE NORTH. THE PREDOMINATELY
WESTERLY WINDS WILL ADD TO THE ALREADY DRY AIRMASS IN PLACE. WITH
DOWNSLOPE WINDS HELPING TO CONTRIBUTE TO WIDESPREAD RELATIVE
HUMIDITY VALUES IN THE SINGLE DIGITS. WIND GUSTS IN EXCESS OF 45 MPH
WILL LEAD TO WIDESPREAD CRITICAL FIRE WEATHER. A RED FLAG WARNING IS
IN EFFECT FOR THE NEBRASKA PANHANDLE THROUGH FRIDAY EVENING.
VEGETATION IN SOUTHEAST WYOMING IS IN GREEN UP WHICH LIMITS SOME OF
THE FIRE WEATHER CONCERNS, HOWEVER DID PUT OUT A SPECIAL WEATHER
STATEMENT FOR WYOMING THROUGH FRIDAY EVENING TO HIGHLIGHT THE
INCREASED FIRE DANGER AS CRITICAL CONDITIONS WILL BE PRESENT. FRIDAY
WILL BE ALMOST A REPEAT OF THURSDAY BUT WITH SLIGHTLY WEAKER
WINDS. WITH THE TROUGH OUT OF THE AREA ON FRIDAY, A ZONAL FLOW
PATTERN WILL BE IN PLACE WHICH STILL FAVORS WINDY CONDITIONS.
WIND GUSTS OVER 35 MPH WILL STILL BE POSSIBLE FOR MUCH OF THE
CWA ON FRIDAY WITH RELATIVE HUMIDITY VALUES STILL STUCK IN THE
SINGLE DIGITS FOR A LARGE PORTION OF THE AREA. AS SUCH, FIRE
WEATHER CONCERNS WILL CONTINUE THROUGH THE DAY FRIDAY.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
ISSUED AT 245 PM MDT WED MAY 13 2026
A WET AND UNSETTLED PATTERN IS TAKING SHAPE FOR THE THE LONG TERM
PERIOD FOR SOUTHEAST WYOMING AND WESTERN NEBRASKA. THIS PATTERN
WILL BE LARGELY DRIVEN BY AN APPROACHING TROUGH EMBEDDED IN
WESTERLY FLOW OVER THE NORTHWEST CONUS. THIS TROUGH WILL MOVE
INLAND ON SATURDAY AND PASS THROUGH THE REGION ON SUNDAY,
BRINGING LOWERING HEIGHTS AND A PLUME OF PACIFIC MOISTURE ALOFT
OVER THE HIGHER TERRAIN. AFTER A MILD DAY ON SATURDAY WITH A
HIGH LIKELIHOOD (OVER 75% CHANCE) OF ABOVE AVERAGE TEMPERATURES
THROUGHOUT THE HIGH PLAINS, A THE SURFACE FRONTAL BOUNDARY IS
EXPECTED TO DROP SOUTH THROUGH THE NORTHERN HIGH PLAINS. THIS
BOUNDARY WILL REACH EAST-CENTRAL WYOMING BY DAYBREAK ON SUNDAY
AND PUSH SOUTH THROUGHOUT THE DAY, BRINGING EASTERLY UPSLOPE
FLOW AND OVERCAST SKIES AS WELL AS A COOLDOWN IN TEMPERATURES.
WHILE ISOLATED SHOWERS WILL BE POSSIBLE ON SATURDAY AFTERNOON
AND EVENING IN A DEEPLY MIXED, PREFRONTAL AIRMASS, SUNDAY
APPEARS TO BRING HIGH CONFIDENCE OF AREA-WIDE LIGHT TO MODERATE
RAINFALL, ESPECIALLY IN THE FAVORED EASTERLY UPSLOPE REGIONS OF
THE CHEYENNE RIDGE AND LARAMIE RANGES. CURRENTLY, THE ECMWF
ENSEMBLE IS A BIT WETTER THAN MOST NAEFS MEMBERS, SUPPORTING
PERHAPS UP TO AN INCH OF RAIN IN THE SOUTH LARAMIE RANGE INTO
THE CHEYENNE RIDGE FROM SUNDAY THROUGH SUNDAY NIGHT. CONFIDENCE
REMAINS ONLY MODERATE FOR THESE HEAVIER RAINFALL AMOUNTS, AS
SUBTLE DIFFERENCES IN ENSEMBLE CLUSTERING SUGGEST SOME OF THE
DEEPER UPSLOPE MOISTURE MAY SNEAK A BIT TOO FAR SOUTH INTO THE
COLORADO FRONT RANGE AND LEAVE EASTERN WYOMING SLIGHTLY DRIER.
FROM MONDAY ONWARD, MODELS BEGIN TO DIVERGE AS GEFS MEMBERS
QUICKLY PUSH THIS SYSTEM EASTWARD TRANSITIONING US INTO A DRIER
PATTERN, WHEREAS ECMWF ENSEMBLE GUIDANCE GENERALLY SUPPORTS A
DEVELOPING MID-LEVEL LOW OVER WESTERN WYOMING AND CONTINUED
RAINFALL OVER MUCH OF THE STATE AS WELL AS WESTERN NEBRASKA ON
MONDAY. GIVEN THE POST-FRONTAL AIRMASS IN PLACE AND GENERALLY
SUPPRESSED JET PATTERN WE HAVE BEEN IN LATELY, THE INSTINCT
CURRENTLY IS TO FAVOR THE SLIGHTLY WETTER PATTERN FOR EARLY NEXT
WEEK. HIGHER CONFIDENCE EXISTS IN CONTINUED NEAR-AVERAGE
TEMPERATURES, WITH ANY DAYS OF PARTICULARLY HEAVY RAINFALL
LIKELY RESULTING IN LOWER THAN AVERAGE WEATHER. AS FAR AS SNOW
FOR OUR LATE-SEASON WINTER ENTHUSIASTS, CHANCES ARE LOOKING
INCREASINGLY LIKELY FOR A SNOWFALL REFRESH IN THE HIGHER
TERRAIN. MOST ENSEMBLE GUIDANCE KEEPS MID AND UPPER-LEVEL
TEMPERATURES COOLER THROUGH EARLY NEXT WEEK, RESULTING IN LOWER
SNOWFALL LEVELS IN THE SNOWY RANGE, SIERRA MADRES, AND EVEN
LARAMIE RANGE BY MON-TUES. UP TO A FOOT OR MORE OF LATE-SEASON
SNOWFALL IS BEING SUGGESTED BY AT LEAST 30% OF ENSEMBLE GUIDANCE
FROM THE SUNDAY-TUESDAY TIMEFRAME, ESPECIALLY AT ELEVATIONS
ABOVE 10KFT. WE WILL HAVE TO SEE IF THIS TREND CONTINUES IN
GUIDANCE BUT CONFIDENCE IS CERTAINLY GROWING IN ANOTHER LATE-
SEASON SNOWPACK BOOST.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1122 PM MDT WED MAY 13 2026
VFR CONDITIONS WILL CONTINUE ACROSS ALL TERMINALS FOR THE DURATION
OF THIS TAF PERIOD. BREEZY CONDITIONS FOR A MAJORITY OF THE SITES
WITH GUSTS UP TO 30 KNOTS THROUGH THE OVERNIGHT HOURS, WHILE KCYS
AND KCDR WILL SEE WINDS TAPER OFF TO GENERALLY LESS THAN 10 KNOTS. A
STRONG PRESSURE GRADIENT WILL TIGHTEN OVER THE REGION THURSDAY
MORNING, CAUSING WINDS TO RAMP UP ACROSS ALL TERMINALS BY 15Z WITH
WESTERLY GUSTS 25 TO 45 KNOTS. WIND SHEAR IS ALSO EXPECTED TO IMPACT
MOST OF THE NEBRASKA SITES DURING THE OVERNIGHT AND EARLY MORNING
HOURS BEFORE SURFACE WINDS INCREASE.
CYS WATCHES/WARNINGS/ADVISORIES
WY...HIGH WIND WARNING FROM 6 AM TO 6 PM MDT THURSDAY FOR WYZ106-
116.
HIGH WIND WARNING FROM 3 AM TO 6 PM MDT THURSDAY FOR WYZ110.
NE...RED FLAG WARNING UNTIL 7 PM MDT FRIDAY FOR NEZ434>437.
SHORT TERM...SF
LONG TERM...MAC
AVIATION...RZ
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