182
FXUS65 KCYS 041741
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1141 AM MDT SAT APR 4 2026
KEY MESSAGES
- A GORGEOUS WEEKEND IS IN STORE AS TEMPERATURES REBOUND INTO
THE 50S AND 60S WITH CLEARING SKIES AND MINIMAL PRECIPITATION
CHANCES.
- WARMER, DRIER WEATHER RETURNS FOR THE WEEK AHEAD, WITH FIRE
CONCERNS INCREASING AFTER MONDAY.
- MORE UNSETTLED WEATHER PATTERN MAY RETURN AS EARLY AS
WEDNESDAY AND CONTINUE INTO NEXT WEEKEND.
SHORT TERM /THROUGH SUNDAY NIGHT/
ISSUED AT 245 AM MDT SAT APR 4 2026
CURRENT IR SATELLITE LOOP EARLY THIS MORNING SHOWS THE DEPARTING
SNOW STORM MOVING EASTWARD ACROSS THE DAKOTAS AND EVENTUALLY
INTO THE GREAT LAKES REGION LATER TODAY. BEHIND IT, BRISK NORTHWEST
WINDS AND SOME LOWER CLOUDS REMAIN OVER SOUTHEAST WYOMING AND
WESTERN NEBRASKA. KCYS RADAR LOOP NOT SHOWING MUCH, SO SNOWFALL
IS UNLIKELY THIS MORNING OUTSIDE OF THE MOUNTAINS WITH A FEW
LIGHT RETURNS OVER THE SOUTHERN LARAMIE RANGE AND THE SNOWY RANGE.
GUSTY WINDS HAVE COME DOWN A BIT ACROSS THE SOUTHERN LARAMIE
RANGE WITH WEBCAMS SHOWING IMPROVING CONDITIONS AND LITTLE
SNOWFALL AND/OR DRIFTING SNOW. WILL ALLOW THE WINTER WEATHER
ADVISORY TO EXPIRE ON TIME EARLY THIS MORNING, AT 300 AM, WITH
ONLY SOME FLURRIES EXPECTED UNTIL SUNRISE. OTHERWISE, NOT MANY
CHANGES MADE TO TODAY'S FORECAST WITH SUNNY SKIES EXPECTED.
700MB TEMPERATURES WILL GRADUALLY INCREASE TOWARDS 0C ACROSS
SOUTHEAST WYOMING, BUT REMAIN BETWEEN -4C TO -8C ACROSS THE
EASTERN PLAINS. FORECAST HIGHS IN THE 50S TO MAYBE AROUND 60
BELOW 4500 FEET LOOKS REASONABLE THIS AFTERNOON WITH BREEZY
CONDITIONS CONTINUING BEHIND THE GREAT PLAINS STORM SYSTEM.
CLEAR SKIES SHOULD CONTINUE INTO TONIGHT WITH SOME HIGH CLOUDS
NORTH OF INTERSTATE 80, WHICH SHOULD RESULT IN DECENT
RADIATIONAL COOLING WITH LOWS DROPPING INTO THE 20S FOR MOST
LOCATIONS.
MODELS SHOW DRY WEATHER CONTINUING THROUGH SUNDAY AS ALL
GUIDANCE SHOWS A RIDGE OF HIGH PRESSURE TRANSLATING EASTWARD OUT
OF THE EASTERN PACIFIC. 700MB TEMPS WILL CLIMB ABOVE 0C THROUGH
THE DAY, WHICH SHOULD RESULT IN A PLEASANT EASTER WITH HIGHS IN
THE LOW TO UPPER 60S FOR MOST LOCATIONS ALONG AND EAST OF THE
I-25 CORRIDOR. ENSEMBLE GUIDANCE SHOWS TEMPERATURES SEVERAL
DEGREES LOWER COMPARED TO MOS GUIDANCE AND HIGH RES, LIKELY DUE
TO INCREASING SOUTHERLY WINDS...BUT THESE SHOULD START LATE
ENOUGH IN THE DAY TO NOT BE MUCH OF A CONCERN. KEPT HIGH
TEMPERATURES BETWEEN THE 75TH TO 90TH PERCENTILE DUE TO MOSTLY
SUNNY SKIES AND LIGHT WINDS. ALTHOUGH THE GFS AND NAM SHOW SOME
INSTABILITY NEAR AND ALONG THE LARAMIE RANGE SUNDAY AFTERNOON
WITH LIGHT TERRAIN-INDUCED CONVERGENCE, LIMITED TO MINIMAL
BOUNDARY LAYER MOISTURE SHOULD GREATLY LIMIT ANY POTENTIAL FOR
DAYTIME CONVECTION.
LONG TERM /MONDAY THROUGH FRIDAY/
ISSUED AT 127 AM MDT SAT APR 4 2026
THE WORK WEEK WILL BEGIN UNDERNEATH A MID-LEVEL RIDGE IN A WNW FLOW
PATTERN, RESULTING IN DRY AND MILD CONDITIONS WITH MUCH CALMER WINDS
(5-10 KNOTS) RELATIVE TO WHAT WE HAVE SEEN RECENTLY. HIGH
TEMPERATURES LOOK TO BE AT OR SLIGHTLY ABOVE CLIMATOLOGY IN THE MID
TO UPPER 50S BEFORE THE RIDGE BEGINS TO BREAK DOWN INTO TUESDAY AND
500 MB FLOW BECOMES MORE ZONAL. 700 MB FLOW RAMPS UP TO 45-50 KNOTS
THROUGHOUT THE DAY ON TUESDAY, WITH OMEGA FIELDS HINTING AT A
CLASSIC MOUNTAIN WAVE PATTERN, AND THEREFORE DOWNSLOPE FLOW
PARTICULARLY IN THE LEE OF THE LARAMIE RANGE. VERTICAL CROSS
SECTIONS INDICATE STRONG STATIC STABILITY AT MOUNTAIN TOP AS DENOTED
BY A TIGHT VERTICAL ISENTROPIC GRADIENT, WHICH IS ANOTHER FAVORABLE
SIGNATURE FOR DOWNSLOPING WINDS. DESPITE THE DAMPENING RIDGE, THIS
FLOW REGIME WILL RESULT IN HIGH TEMPERATURES BEING 10-15 DEGREES
WARMER THAN THE PREVIOUS DAY WITH ENSEMBLE GUIDANCE SHOWING 50TH
PERCENTILE MAXIMUM TEMPERATURES PUSHING 70 DEGREES EAST OF THE I-25
CORRIDOR. GIVEN THE UPTICK IN SURFACE WINDS ALONG WITH ENSEMBLE MEAN
RH VALUES AT OR BELOW 20%, TUESDAY WILL FEATURE FIRE CONCERNS
ESPECIALLY WITH PLENTY OF DRY FUELS WITH OUR EXTREME TO EXCEPTIONAL
DROUGHT STATUS. FIRE WEATHER HIGHLIGHTS AND RED FLAG CONDITIONS WILL
NEED TO BE MONITORED AS WE GET CLOSER TO THIS TIME FRAME.
MID-LEVEL FLOW WILL REMAIN ZONAL INTO WEDNESDAY, HOWEVER WITH A
DECREASE IN MOUNTAIN-TOP STABILITY AND OVERALL WEAKENING 700 MB
FLOW, SURFACE WINDS LOOK TO BE MORE RELAXED COMPARED TO THE PREVIOUS
DAY. WE ALSO INTRODUCE POPS TO THE FORECAST AT THIS TIME WITH WEAK
IMPULSES EMBEDDED IN THE ZONAL FLOW PROPAGATING ACROSS SOUTHERN
WYOMING. HOWEVER THE MAIN FORCING FOR ASCENT WILL BE WELL TO OUR
NORTH OVER MONTANA AND SOUTH DAKOTA, SO ANY PRECIPITATION WILL BE
LIGHT, WITH NBM PROBABILITIES OF SEEING QPF > 0.1" RUNNING AT 20-25%
EAST OF THE LARAMIE RANGE. THERE IS ALSO SOME WEAK INSTABILITY
PRESENT, HOWEVER WITH DRY LOW-LEVELS (SURFACE RH VALUES AROUND 25%),
ANY CONVECTION WILL LIKELY PRODUCE FAR MORE WIND THAN RAIN.
PRECIPITATION CHANCES WILL INCREASE TOWARDS THE END OF THE WORK WEEK
FOLLOWED BY A DECREASE IN TEMPERATURES AS SOUTHERN WYOMING AND
WESTERN NEBRASKA WILL BE LOCATED IN THE RIGHT-ENTRANCE REGION OF A
75-80 KNOT 250 MB JET, AS WELL AS DOWNSTREAM OF A SHORTWAVE TROUGH
OVER THE GREAT BASIN. UNDER SW FLOW ALOFT, SUBTROPICAL MOISTURE WILL
ADVECT INTO OUR AREA, WITH LREF PWAT VALUES EXCEEDING THE 90TH
PERCENTILE RELATIVE TO CLIMATOLOGY INTO THURSDAY THROUGH SATURDAY.
GIVEN THE SIGNAL FOR STRONG ISENTROPIC ASCENT ALONG WITH LOW-LEVEL
THETA-E ADVECTION, CONFIDENCE IS INCREASING THAT WE WILL FINALLY SEE
SOME BENEFICIAL MOISTURE FOR MUCH OF THE AREA. PROBABILITIES OF QPF
EXCEEDING 0.25" INTO SATURDAY RANGE FROM 60-70% EAST OF THE LARAMIE
RANGE, WITH THE HIGHEST PROBABILITIES OF EXCEEDING THIS THRESHOLD
OVER THE SNOWY AND SIERRA MADRE RANGES (AROUND 90%). EXPECT HIGH
TEMPERATURES TO BE SLIGHTLY COOLER THAN AVERAGE AT THIS TIME.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 1135 AM MDT SAT APR 4 2026
VFR IS EXPECTED TO PREVAIL TODAY, BUT MOST TERMINALS WILL SEE
SCATTERED CUMULUS CLOUD DEVELOPMENT IN THE 4K TO 8K FT RANGE
WITH THE DAY'S HEATING. NORTHWEST WINDS WILL ALSO CONTINUE
THROUGH SUNSET TODAY, WITH GUSTS GENERALLY 25 TO 35 KNOTS. A FEW
GUSTS TO AROUND 40 KNOTS WILL BE POSSIBLE. WINDS AND CLOUD COVER
WILL DECREASE AFTER SUNSET. THERE REMAINS A VERY SLIGHT CHANCE
FOR SOME SHALLOW FOG DEVELOPMENT TONIGHT INTO MONDAY MORNING,
BUT THE PROBABILITY IS TOO LOW (10%) TO ADD TO THE TAF AT THIS
TIME.
CYS WATCHES/WARNINGS/ADVISORIES
WY...NONE.
NE...NONE.
SHORT TERM...TJT
LONG TERM...NB
AVIATION...MN
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