512
FXUS65 KCYS 021748
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1148 AM MDT TUE JUN 2 2026
KEY MESSAGES
- THERE IS A SLIGHT RISK (LEVEL 2 OF 5) ACROSS THE EASTERN HIGH
PLAINS ON TODAY. LARGE HAIL, SEVERE WIND, AND AN ISOLATED
TORNADO WILL BE POSSIBLE ONCE AGAIN.
- THE POTENTIAL FOR A FEW AFTERNOON AND EVENING STRONG TO SEVERE
THUNDERSTORMS WILL CONTINUE THROUGH THE REMAINDER OF THE
WORK WEEK.
- TEMPERATURES WILL SLOWLY WARM TO WELL ABOVE SEASONAL AVERAGES
BY THE WEEKEND AS THUNDERSTORM CHANCES BECOME MORE ISOLATED.
SHORT TERM /THROUGH WEDNESDAY NIGHT/
ISSUED AT 315 AM MDT TUE JUN 2 2026
UNSETTLED WEATHER CONTINUES AS A UPPER-LEVEL TROUGH CONTINUES TO
SLOWLY SPIN OVER THE MONTANA/SASKATCHEWAN BORDER AND WILL SLOWLY
MOVE ALONG THE NORTHERN PLAINS/CANADIAN BORDER. AT THE SURFACE, A
FRONTAL BOUNDARY WILL MOVE ACROSS THE INTERMOUNTAIN WEST AND WILL
INTERACT WITH MOIST AND UNSTABLE AIR (DEW POINTS IN THE 50'S AND
LAPSE RATES BETWEEN 8.5-9.0), SUPPORTING MULTIPLE ROUNDS OF SHOWERS
AND THUNDERSTORMS. WITH LARGE SCALE FORCING AND SUFFICIENT AMOUNT OF
MOISTURE, CHANCES FOR CLUSTERING ALONG THE BOUNDARY AND HIGH RAIN
RATES WILL BE POSSIBLE. SPC HAS EXTENDED THEIR SLIGHT RISK AREA
FURTHER SOUTH TO INCLUDE THE NORTHERN HALF OF THE NEBRASKA. HI-RES
MODELS PUT THE 0-3KM SRH VALUES BETWEEN 200 AND 350 M2/S2 PRESENTING
THE SLIGHT CHANCE FOR LANDSPOUTS AND TORNADOS AS WELL THE POTENTIAL
FOR DECENT SIZED HAIL. HOWEVER, THERE WILL BE A SEMI-STRONG CAP OVER
THE NEBRASKA PANHANDLE THAT MAY LIMIT SEVERE THUNDERSTORMS FROM
PRODUCING AT ALL. MODEL SOUNDINGS PROG THE CONVECTION TEMPERATURE
FOR TODAY AS BEING BETWEEN 75 AND 81 DEGREES BY THIS AFTERNOON. WITH
THE FORECASTED HIGH TEMPS TO BE IN THE 70'S AND 80'S THERE'S A
CHANCE THE CIN ALONE MAY BE HIGH ENOUGH TO PREVENT ANY THUNDERSTORM
THAT FLOATS INTO THE PANHANDLE LOSES MOMENTUM AND NEVER AMOUNTS TO
ANYTHING MORE THAN A GARDEN VARIETY STORM. GOING OFF CONVECTIVE TEMP
ALONE SCOTTSBLUFF LOOKS TO BE THE BEST POTENTIAL AREA FOR STORMS TO
GO SEVERE AND TAKE ADVANTAGE OF THE POSSIBLE 1200 JOULES OF MLCAPE
DEPICTED BY THE RRFS. HOWEVER THE BETTER ENVIRONMENT LOOKS TO BE THE
WHERE THE ORIGINAL SLIGHT RISK WAS, FURTHER NORTH INTO SOUTH DAKOTA
NEAR RAPID CITY.
WEDNESDAY, A SHORTWAVE DISTURBANCE WILL DEVELOP ALONG THE NORTHWEST,
BRINGING SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE
INTERMOUNTAIN WEST. MODEL SOUNDINGS SHOW A CHANCE FOR OUR CONVECTIVE
PARTY TO CONTINUE WEDNESDAY AS WELL. THE SOUNDINGS SHOW THE CAP
ERODING BY THE AFTERNOON/EVENING TIME FRAME WITH STEEP LAPSE RATES.
DEWPOINTS MAY BE ONLY IN THE 40'S AND 50'S BUT THAT WILL BE
SUFFICIENT TO PRODUCE A SEVERE THUNDERSTORM. HOWEVER, THE
ENVIRONMENT TOMORROW WONT BE AS PRIMED AND EXPLOSIVE AS IT IS TODAY.
MODELS DEPICT MLCAPE BEING BETWEEN 100-300 JOULES WITH THE MUCAPE
MAXING OUT AROUND 800 JOULES. SRH(0-3KM) IS BARELY 100 M2/S2 AND THE
MODELS SHOW EVERY PARAMETER RAPIDLY DECREASING AFTER 00Z PUMPING THE
BRAKES ON OUR PARTY ONCE THE SUN STARTS TO SET SIGNIFYING AN
OVERWORKED ENVIRONMENT.
ON THE OTHER SIDE OF THINGS, CARBON COUNTY LOOKS TO CONTINUE TO GET
MISSED WITH ANY SUFFICIENT MOISTURE FOR TODAY AND TOMORROW. THE RH
VALUES FOR CARBON COUNTY LOOK TO BE BETWEEN 10 AND 15 PERCENT FOR
THE VAST MAJORITY OF THE COUNTY. IN MARCH, FUELS WERE REPORTED TO BE
IN GREEN UP BUT THIS STRETCH OF NO MOISTURE MAY EVENTUALLY START TO
CURE THE GRASSES AND OTHER FUELS SLOWLY INCREASING THEIR CHANCE FOR
COMBUSTIBILITY. SO WHILE A RED FLAG ISN'T GOING TO BE ISSUED, KEEP
AN EYE ON ANY FLAMES AND BURN RESPONSIBLY.
LONG TERM /THURSDAY THROUGH MONDAY/
ISSUED AT 900 PM MDT MON JUN 1 2026
LOOKING AHEAD TO THURSDAY, ANOTHER UPPER LEVEL SHORTWAVE TROUGH
RIGHT ON THE HEELS OF THE DEPARTING PRIMARY LOW WILL MOVE ACROSS THE
NORTHERN ROCKIES. THIS WILL PROVIDE SYNOPTIC FORCING FOR ADDITIONAL
ROUNDS OF AFTERNOON AND EVENING THUNDERSTORMS IN PLACE OF CONTINUING
LOW-LEVEL INSTABILITY AND MODEST WIND SHEAR OVER THE HIGH PLAINS. WE
ARE GETTING A LITTLE FAR OUT TO DISCUSS DETAILS OF THE POTENTIAL
CONVECTIVE THREAT, BUT PARAMETERS SUGGEST AT LEAST ISOLATED STRONG
TO SEVERE THUNDERSTORMS.
STORM CHANCES WILL DROP BACK SOMEWHAT FOR FRIDAY. A DEEP PACIFIC
TROUGH PUSHING INTO THE NORTHWEST CONUS WILL AMPLIFY THE DOWNSTREAM
RIDGE OVER THE ROCKIES AND PLAINS, PUSHING TEMPERATURES UPWARD INTO
THE WEEKEND. MOST AREAS WILL REACH THE 80S ON FRIDAY, WITH FAIRLY
WIDESPREAD 90S POSSIBLE SATURDAY AS THE RIDGE AXIS SHIFTS OVERHEAD.
700-MB TEMPERATURES PEAKING AROUND +12 TO +16C WILL BE AROUND THE
CLIMATOLOGICAL 90TH PERCENTILE. SUNDAY'S HIGHS MAY DROP SLIGHTLY FOR
OUR WESTERN ZONES, BUT SHOULD BE FAIRLY SIMILAR TO SATURDAY OVER THE
HIGH PLAINS, WITH WIDESPREAD MID 80S TO MID 90S. CURRENT FORECAST
REMAIN COMFORTABLY BELOW DAILY RECORD HIGHS, BUT IT WILL CERTAINLY
BE A WARM TO HOT FEW DAYS. ENSEMBLES HAVE DEVELOPED QUITE A BIT OF
SPREAD IN THE OUTLOOK FOR SURFACE MOISTURE DURING THIS PERIOD, WHICH
WILL FEED BACK INTO THE OUTLOOK FOR PRECIPITATION. THE MOST LIKELY
SCENARIO AT THIS TIME IS A DRIER LOWER ATMOSPHERE PROMOTING MORE
LIMITED THUNDERSTORM CHANCES ON FRIDAY AND SATURDAY, BUT MOISTURE
AND STORM CHANCES MAY BEGIN TO CREEP BACK UP ON SUNDAY AND INTO
EARLY NEXT WEEK.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1139 AM MDT TUE JUN 2 2026
THUNDERSTORMS REMAIN THE PRIMARY AVIATION CONCERN THIS AFTERNOON
AND EVENING. STRONG SOUTHERLY WINDS WILL CONTINUE INTO THE
AFTERNOON HOURS, BUT EXPECT GUSTS TO EASE GRADUALLY.
THUNDERSTORMS WILL DEVELOP IN THE NEXT FEW HOURS AND THEN MOVE
OFF TO THE NORTHEAST THROUGH THE EARLY EVENING HOURS. CONFIDENCE
IN DIRECT IMPACTS TO EACH TERMINAL IS NOT HIGH ENOUGH FOR
PREVAILING GROUPS YET, BUT BE READY FOR POSSIBLE AMDS AS STORMS
APPROACH A TERMINAL. THE PRIMARY HAZARDS WILL BE FREQUENT
LIGHTNING, GUSTY WINDS, BRIEF DOWNPOURS, AND ISOLATED LARGE
HAIL.
STORMS SHOULD DEPART THE AREA BY AROUND 03Z OR SO, THOUGH A FEW
SHOWERS MAY LINGER OVERNIGHT. LATE EVENING THUNDERSTORMS CANNOT
BE RULED OUT, BUT THE PROBABILITY IS FAIRLY LOW. SOUTHEAST WINDS
WILL KICK UP AGAIN OVERNIGHT OVER THE HIGH PLAINS, BUT EXPECT
THIS TO WEAKEN WEDNESDAY MORNING AND BEGIN TO SHIFT MORE
WESTERLY AT ALL TERMINALS EXCEPT SNY.
CYS WATCHES/WARNINGS/ADVISORIES
WY...NONE.
NE...NONE.
SHORT TERM...MM
LONG TERM...MN
AVIATION...MN
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