140
FXUS65 KCYS 061735
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1135 AM MDT MON APR 6 2026
KEY MESSAGES
- ABOVE-AVERAGE TEMPERATURES AND LOW PRECIPITATION CHANCES REMAIN
IN PLACE ACROSS SOUTHEAST WYOMING AND WESTERN NEBRASKA ON MONDAY
INTO TUESDAY.
- WINDS WILL INCREASE ACROSS SOUTHEAST WYOMING TUESDAY INTO
WEDNESDAY, INCREASING FIRE CONCERNS.
- GREATER PRECIPITATION CHANCES RETURN TO SOUTHERN WYOMING AND
WESTERN NEBRASKA INTO THE WEEKEND, CONFIDENCE ON HOW MUCH
PRECIPITATION WE WILL SEE REMAINS LOW.
SHORT TERM /THROUGH TUESDAY/
ISSUED AT 225 AM MDT MON APR 6 2026
OVERNIGHT CONDITIONS REMAIN MILD AND TRANQUIL AS SOUTHERN WYOMING
AND WESTERN NEBRASKA REMAIN IN A NORTHWESTERLY FLOW REGIME
DOWNSTREAM OF A LONGWAVE RIDGE LOCATED OVER THE WESTERN THIRD OF THE
COUNTRY. AS WE ARE LOCATED AT THE INFLECTION POINT BETWEEN THE
AFOREMENTIONED RIDGE AND A LONGWAVE TROUGH OVER THE EASTERN THIRD OF
THE COUNTRY (A FAVORABLE LOCATION FOR AGEOSTROPHIC CONVERGENCE
ALOFT), WE REMAIN UNDER THE INFLUENCE OF A 1040 MB SURFACE HIGH
LOCATED OVER MONTANA AND NORTH DAKOTA RESULTING IN BROAD, 5-10 KNOT
E/ENE SURFACE WINDS.
LATER IN THE AFTERNOON/EARLY EVENING ON MONDAY, A WEAK BACKDOOR COLD
FRONT WILL MOVE IN FROM THE NORTHEAST, RESULTING IN ESE SURFACE FLOW
ALONG AND EAST OF THE LARAMIE RANGE, RESULTING IN AN INCREASE IN
CLOUD COVER POST FROPA. HOWEVER, GIVEN DRY LOW-LEVELS WITH 50TH
PERCENTILE RH VALUES AROUND 30%, NO PRECIPITATION IS EXPECTED AT
THIS TIME.
THE MID-LEVEL RIDGE WILL BEGIN TO DAMPEN AS WE HEAD INTO TUESDAY AND
FLOW WILL BECOME MORE ZONAL. DUE TO DOWNSLOPING, OUR WIND SPEEDS
WILL ALSO BEGIN TO RAMP UP ON TUESDAY AFTERNOON. WHILE RANDOM FOREST
GUIDANCE GENERALLY KEEPS WINDS BELOW HIGH-WIND CRITERIA, HIGH-
RESOLUTION ENSEMBLE GUIDANCE HAS MEAN GUSTS OF 15-20 MPH EAST OF THE
LARAMIE RANGE IN ADDITION TO RH VALUES < 25%, SO WILL MENTION FIRE
CONCERNS DURING THIS TIME ESPECIALLY WITH ABOVE-AVERAGE HIGH
TEMPERATURES IN THE 60S. SOME WEAK MID-LEVEL INSTABILITY IS ALSO
PROGGED (SBCAPE AROUND 100 J/KG) INTO TUESDAY AFTERNOON WITH
FORECAST SOUNDINGS SHOWING AN INVERTED-V PROFILE WITH SURFACE
DEWPOINT DEPRESSIONS OF 45-50 DEGREES, SO ANY CONVECTION WILL LIKELY
PRODUCE GUSTY WINDS RATHER THAN ANY BENEFICIAL PRECIPITATION. THIS
WILL EXACERBATE FIRE CONCERNS IN THE VICINITY OF ANY HIGH-BASED
CONVECTION.
LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/
ISSUED AT 250 AM MDT MON APR 6 2026
MODELS IN REASONABLE AGREEMENT THROUGH THE WEEKEND AND CONTINUE TO
SHOW A STRONG UPPER LEVEL LOW PASSING WELL NORTH OF WYOMING AND
WESTERN NEBRASKA TUESDAY NIGHT AND WEDNESDAY. OUTSIDE OF A FEW
SHOWERS ACROSS THE AREA, THE PRIMARY CONCERNS WILL BE STRONG GUSTY
WINDS WEDNESDAY AND FIRE WEATHER CONCERNS. 700MB WINDS WILL INCREASE
TO OVER 50 KNOTS BY MIDMORNING WEDNESDAY WITH EXCELLENT SUBSIDENCE
FOR A FEW OF THE WIND PRONE AREAS. WE'RE STARTING TO GET OUT OF "GAP
WIND SEASON", BUT THE ASSOCIATED COLD FRONT AND INCREASING 700MB
FLOW COULD RESULT IN SOME GUSTS OVER 58 MPH FOR ARLINGTON, ELK
MOUNTAIN, AND THE I-80 SUMMIT LATE TUESDAY NIGHT THROUGH MID
AFTERNOON ON WEDNESDAY. IN-HOUSE WIND GUIDANCE IS NOT COMPLETELY ON
BOARD AND SHOW MAINLY ELEVATED WIND GUSTS BETWEEN 45 TO 55 MPH,
LIKELY DUE TO THE POOR SURFACE PRESSURE GRADIENTS WITH THIS EVENT.
KEPT WIND GUSTS NEAR CRITERIA, ESPECIALLY AFTER MIDNIGHT EARLY
WEDNESDAY MORNING THROUGH NOON WEDNESDAY. OTHERWISE, THE BEST CHANCE
FOR PRECIPITATION DURING THIS SYSTEM MAY BE LATER ON INTO WEDNESDAY
EVENING ACROSS THE HIGH PLAINS, ONCE THE PRIMARY UPPER LEVEL LOW
MOVES EASTWARD INTO THE GREAT LAKES REGION.
AS WE HEAD INTO LATE WEEK, MODELS ARE STARTING TO SHOW A PATTERN
THAT'S MORE CONSISTENT WITH A TYPICAL SPRING TIME WEATHER PATTERN
ACROSS THE INTERMOUNTAIN WEST, WITH UPPER LEVEL TROUGHING DIGGING
FURTHER SOUTH ACROSS THE CALIFORNIA COASTLINE AND GREAT BASIN
REGION. SOUTHERN BRANCH OF THE POLAR JET LOOKS TO BECOME A LITTLE
MORE ACTIVE LATE IN THE WEEK AS SEVERAL DISTURBANCES LIFT NORTHEAST
ACROSS THE FRONT RANGE. ALTHOUGH NOT SYNOPTICALLY IMPRESSIVE,
SURFACE BASED CONVECTION WILL LIKELY BE MORE OF A FORECAST TOPIC IN
THE COMING DAYS. AGREE WITH THE PREVIOUS FORECASTS AND CURRENT
ENSEMBLE GUIDANCE WITH INCREASING POP WITH POSSIBLE THUNDERSTORMS BY
FRIDAY AND SATURDAY. IN ADDITION, NAEFS MEAN PWAT OVER THE FRONT
RANGE IS BETWEEN THE 90TH AND 95TH PERCENTILE (0.50 TO 0.75 INCHES)
FROM FRIDAY THROUGH SATURDAY. THIS IS LIKELY NOT ONLY DUE TO SURFACE
MOISTURE ADVECTION AS WINDS SHIFT INTO THE EAST, BUT ALSO MOISTURE
ADVECTION ALOFT AHEAD OF THE MAIN PACIFIC SYSTEM NEAR THE WEST
COAST. WIDESPREAD SHOWERS AND THUNDERSTORMS APPEAR UNLIKELY SINCE
THE BULK OF THE MID TO UPPER LEVEL ENERGY STAY TO OUR SOUTH.
REGARDLESS, WILL LIKELY SEE WIDELY SCATTERED TO SCATTERED CONVECTION
AT THE VERY LEAST IN THIS PATTERN. KEPT THUNDER OUT OF THE FORECAST
FOR NOW DUE TO UNKNOWN AMOUNT OF CLOUD COVER, WHICH MAY LIMIT DEEPER
CONVECTION. EVEN WITH BRIEF COOL DOWNS BEHIND EACH DISTURBANCE, VERY
LITTLE IMPACT ON HIGH TEMPERATURES EXPECTED WITH ABOVE AVERAGE
TEMPERATURES THROUGH THE END OF THE WEEK AND INTO THE
WEEKEND...GENERALLY IN THE 60S TO LOW 70S. SATURDAY LOOKS LIKE THE
WARMEST DAY BASED ON THE GRAND ENSEMBLE WITH HIGHS IN THE UPPER 60S
TO MID 70S.
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 1131 AM MDT MON APR 6 2026
NORTHWEST FLOW ALOFT WILL CONTINUE. SCATTERED TO BROKEN CLOUDS
NEAR 15000 FEET WILL PREVAIL, WITH CEILINGS NEAR 5000 FEET AT
SIDNEY AFTER 15Z TUESDAY. WINDS WILL GUST TO 29 KNOTS INTO
TONIGHT, THEN WILL GUST TO 30 KNOTS AFTER 13Z TUESDAY, EXCEPT AT
SCOTTSBLUFF.
CYS WATCHES/WARNINGS/ADVISORIES
WY...NONE.
NE...NONE.
SHORT TERM...NB
LONG TERM...TJT/MN
AVIATION...RUBIN
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