839
FXUS65 KCYS 300450
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1050 PM MDT WED APR 29 2026
KEY MESSAGES
- CHANCES FOR SCATTERED RAIN, WEAK THUNDERSTORMS, AND SNOW WILL
CONTINUE THROUGH THURSDAY NIGHT.
- WARMER AND DRIER CONDITIONS ARE EXPECTED TO RETURN FOR FRIDAY
INTO THE WEEKEND.
SHORT TERM /THROUGH FRIDAY NIGHT/
ISSUED AT 250 PM MDT WED APR 29 2026
ONGOING SCATTERED CONVECTION SEEN ACROSS THE REGION THIS
AFTERNOON AS A WEAK DISTURBANCE MOVES ACROSS THE AREA. WHILE
FORCING IS NOT STRONG, SOME MEAGER INSTABILITY IS PRESENT WITH
MUCAPE VALUES AROUND 250-400 J/KG, PROMOTING SPOTTY
THUNDERSTORMS WITH THIS ACTIVITY, BUT OUTSIDE OF THE LIGHTNING,
NOT EXPECTING ANYTHING STRONG, PARTICULARLY DUE TO A A STABLE
LAYER SITTING JUST ABOVE THE CLOUD TOPS AT AROUND 500MB. MOVING
AHEAD INTO THE NIGHTTIME HOURS, ANOTHER SHORTWAVE WILL DIVE
DOWN FROM THE NORTH AND BRING WITH IT A COLD FRONT. THIS SHOULD
SPUR THE NEXT ROUND OF PRECIPITATION FOR OUR AREA, WITH
WIDESPREAD RAIN AND SNOW, AND ONCE AGAIN A FEW THUNDERSTORMS
MIXED IN AS WELL. WITH THE COLD AIR, EXPECTING A SOLID PATCH OF
SNOW ACROSS OUR WESTERN ZONES IN AREAS AT OR ABOVE 5-6000 FT.
THIS MAY MIX DOWN A BIT LOWER AROUND SUNRISE AND JUST AFTER, AND
WE MAY SEE SOME RAIN MIXING WITH SNOW FOR LOCATIONS EAST OF THE
LARAMIE RANGE, BUT DON'T EXPECT A RETURN TO WINTER IF YOU'RE ON
THE EAST SIDE. MEANWHILE OVERALL QPF WILL REMAIN ON THE LOW
END, WITH AROUND 0.2-0.35 INCH FOR OUR HIGHEST PEAKS, WHICH
WILL TRANSLATE TO AROUND 3-5 INCHES OF SNOW, POSSIBLY UP TO 6 TO
7 AT MOST. THE NBM IS SUPPORTING THIS LOGIC WITH ONLY A 10-20%
PROBABILITY OF 6+ INCHES IN THE SNOWY RANGE, WHICH WILL KEEP US
JUST OUTSIDE OF ADVISORY LEVEL CRITERIA FOR THE MOUNTAINS.
MOVING INTO THURSDAY EVENING AND OVERNIGHT INTO FRIDAY, THE
AFOREMENTIONED TROUGH WILL CONTINUE TO DIVE INTO THE GREAT
PLAINS AND EXIT THE REGION, ALLOWING A RIDGE OF HIGH PRESSURE TO
BUILD INTO THE AREA THROUGH SATURDAY MORNING. SOME LINGERING
PRECIPITATION, MOSTLY FOR THE HIGH TERRAIN AND VERY LIGHT IN
NATURE, IS EXPECTED THROUGH FRIDAY MORNING, WITH SKIES CLEARING
AND TEMPERATURES WARMING AS WE ENTER A PERIOD OF WARMER AND
DRIER CONDITIONS. TEMPERATURES THURSDAY WILL BE IN THE 40'S TO
50'S BEHIND THE COLD FRONT, REBOUNDING INTO THE 50'S AND 60'S ON
FRIDAY WITH THE RIDGE. UNFORTUNATELY ALONGSIDE THIS WARMTH WE'LL
SEE MOISTURE DEPART AND RH VALUES DESCEND BACK INTO THE 20'S AND
TEENS ON FRIDAY. THANKFULLY UNDER A WEAK PRESSURE GRADIENT,
CRITICAL FIRE WEATHER CONDITIONS ARE UNLIKELY, BUT ELEVATED
CONCERNS FROM THE DRY WEATHER COULD BE POSSIBLE AS GREENUP EAST
OF THE I-25 CORRIDOR IS LIMITED AT BEST CURRENTLY.
LONG TERM /SATURDAY THROUGH TUESDAY/
ISSUED AT 250 PM MDT WED APR 29 2026
WITH UPPER-LEVEL RIDGING BUILDING INTO WYOMING ON SATURDAY, A
PLEASANT AND MILD WEEKEND IS IN STORE. 700 MB TEMPERATURES WILL
CLIMB ABOVE 0C, WITH TEMPERATURES AS HIGH AS +7C BY THE THE END OF
THE WEEKEND. TEMPERATURES ON BOTH SATURDAY AND SUNDAY WILL BE
VIRTUALLY THE SAME WITH HIGHS IN THE 60S AND 70S ACROSS SOUTHEAST
WYOMING AND WESTERN NEBRASKA. THESE HIGHS WILL BE ABOUT 10 DEGREES
ABOVE AVERAGE FOR EARLY MAY, MAKING IT A MILD WEEKEND. WITH THE WARM
TEMPERATURES WILL ALSO COME DRY CONDITIONS. THE RIDGE WILL USHER IN
A DRY AIRMASS WITH MOISTURE STARVED LOW AND MID-LEVELS. THIS WILL
LEAD TO ELEVATED FIRE CONDITIONS OVER THE WEEKEND. LUCKILY, THERE
WILL ALSO BE LITTLE WIND DURING THIS TIME FRAME WITH THE SURFACE
HIGH SITTING JUST TO THE SOUTH IN THE MOUNTAINS OF COLORADO.
THEREFORE, THIS WILL LIMIT ANY CRITICAL FIRE WEATHER CONDITIONS OVER
THE WEEKEND. THE HIGH PRESSURE AND SUBSIDENCE UNDER THE RIDGE WILL
ALSO ENSURE THAT PRECIPITATION CHANCES REMAIN MINIMAL WITH PARTLY TO
MOSTLY SUNNY SKIES.
UNSETTLED WEATHER IS EXPECTED TO RETURN FOR THE BEGINNING OF THE
WORK WEEK AS THE RIDGE WEAKENS FROM A STRONG TROUGH COMING ON SHORE
TO CALIFORNIA. ALTHOUGH CURRENT LONG RANGE GUIDANCE DOES NOT SHOW
ANY DIRECT IMPACTS FROM THE UPPER-LEVEL LOW AND ASSOCIATED TROUGH,
THE CWA WILL BE IN CLOSE ENOUGH PROXIMITY TO THE LOW AND TROUGH TO
SEE NEAR DAILY PRECIPITATION CHANCES THROUGH THE END OF THE WEEK.
TEMPERATURES, AT LEAST THROUGH MID-WEEK, LOOK TO HOLD STEADY IN THE
60S AND 70S. THIS COULD HELP SUPPORT CONVECTION, POTENTIALLY SEVERE,
ON BOTH MONDAY AND TUESDAY AS MODEL SOUNDINGS SHOW ALMOST 1000 J/KG
OF MUCAPE.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1050 PM MDT WED APR 29 2026
NORTHWEST FLOW WILL CONTINUE TONIGHT AS AN UPPER LEVEL TROUGH SLOWLY
MOVES SOUTH OUT OF CANADA. LOWERING CIGS WITH PERIODS OF LIGHT RAIN
AND SNOW POSSIBLE FOR SOUTHEAST WYOMING, WITH LITTLE TO NO
PRECIPITATION OVER WESTERN NEBRASKA.
HAZARDS/WEATHER TRENDS: EXPECT VFR CONDITIONS TO PREVAIL WITH
PERIODS OF LIGHT RAIN/SNOW OVER THE SOUTHEAST WYOMING TERMINALS
TONIGHT AND EARLY THURSDAY. PERIODS OF MVFR CIGS AND VIS ARE LOOKING
A LITTLE MORE LIKELY FOR KRWL, KLAR, AND MAYBE KCYS BETWEEN 06Z AND
15Z. CAN'T RULE OUT BRIEF IFR CONDITIONS, ESPECIALLY FOR KLAR, BUT
PROBABILITIES ARE LESS THAN 15% AT THIS TIME.
CYS WATCHES/WARNINGS/ADVISORIES
WY...NONE.
NE...NONE.
SHORT TERM...CG
LONG TERM...SF
AVIATION...TJT
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