596
FXUS65 KCYS 220802
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
202 AM MDT MON JUN 22 2026
KEY MESSAGES
- A FEW ISOLATED SHOWERS AND STORMS ARE ANTICIPATED SUNDAY
AFTERNOON.
- WIDELY SCATTERED STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE
AGAIN ON MONDAY, WITH LARGE HAIL AND STRONG WINDS AS THE
PRIMARY HAZARD.
- DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS WILL CONTINUE
THROUGH MUCH OF THE WEEK AHEAD WITH TEMPERATURES NEAR AVERAGE
WEST OF I-25 AND COOLER THAN AVERAGE EAST OF I-25.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 202 AM MDT MON JUN 22 2026
ANOTHER DAY AND ANOTHER SHOT OF SEVERE WEATHER, MORE ON THAT IN A
BIT. WITH AN ABUNDANCE OF LOW-LEVEL MOISTURE IN PLACE, LOW CEILINGS
AND AREAS OF FOG ARE POSSIBLE FOR MANY LOCATION EAST OF THE I-25
CORRIDOR THROUGH THE EARLY MORNING HOURS, WITH MOST OF IT ERODING BY
NOON AS MODEL SOLUTIONS DEPICT. THEN, ATTENTION SHIFTS TO THE
POSSIBILITY OF SEVERE WEATHER ONCE AGAIN FOR THIS AFTERNOON
PRIMARILY EAST OF THE LARAMIE RANGE INTO THE NEBRASKA PANHANDLE.
THIS IS WHERE STORMS WILL INITIATE AND DRIFT OFF TO THE EAST,
SOMETIME BETWEEN 1-3PM. THE SEVERITY OF THE STORMS ARE ALWAYS ON OUR
MINDS AND WHAT ARE THE POSSIBILITIES OF TORNADOES. WELL, THERE WILL
BE AMPLE INSTABILITY IN PLACE ALONG WITH ENOUGH SHEAR, ENOUGH TO
PRODUCE STRONG WINDS AND LARGE HAIL, AT THE START. AS WE PROGRESS
THROUGH THE AFTERNOON HOURS, THE LOW-LEVEL JET SHOULD RAMP UP, THIS
WILL INCREASE VERTICAL SHEAR AND WITH AMPLE INSTABILITY IN PLACE,
THIS MAY SUPPER THE DEVELOPMENT OF SUPERCELLS. THESE SUPERCELLS WILL
HAVE THE CAPABILITY TO PRODUCE VERY LARGE HAIL AND PERHAPS A TORNADO
OR TWO INTO THE EVENING HOURS. ALL THIS IS SHOWN WITH IN-HOUSE HI-
RES GUIDANCE, THE DEVELOPMENT OF DISCRETE SUPERCELLS DEVELOPING
NEAR THE I-25 CORRIDOR AND TREKKING EAST INTO THE NEBRASKA PANHANDLE
DURING THE LATE AFTERNOON/EARLY EVENING HOURS. SOME OF THE
THUNDERSTORM ACTIVITY, MOST LIKELY LESS IN SEVERITY, MAY LAST INTO
THE OVERNIGHT HOURS AS AN UPPER LEVEL LOW TO OUR NORTH SUPPORTS
ADDITIONAL SYNOPTIC LIFT. WHEN ALL THE ACTIVITY ENDS LATE
TONIGHT, THE ADDED MOISTURE WILL ONCE AGAIN BRING ANOTHER ROUND
OF PATCHY FOG AND LOW CELINGS ACROSS THE HIGH PLAINS THROUGH
TUESDAY MORNING. ONE OTHER THING, HIGHS TODAY WILL TOP OUT INTO
THE LOW TO MID 80S WHILE LOWS TONIGHT (MONDAY NIGHT) DIP INTO
THE LOW TO MID 50S.
LONG TERM /TUESDAY THROUGH SUNDAY/
ISSUED AT 130 PM MDT SUN JUN 21 2026
THE LONG-TERM PERIOD WILL BEGIN UNDER ZONAL FLOW ALOFT UNDERNEATH A
FLAT LONGWAVE RIDGE WITH NUMEROUS EMBEDDED VORTICITY MAXIMA
PROPAGATING ACROSS SE WYOMING INTO WESTERN NEBRASKA. HIGH
TEMPERATURES ON TUESDAY WILL BE COOLER THAN THE PREVIOUS DAY THANKS
TO A COLD FRONTAL PASSAGE DURING THE MORNING HOURS WHICH WILL SHIFT
OUR SURFACE WINDS TO NNE. MOIST, POST-FRONTAL UPSLOPE FLOW WILL
INCREASE OUR SURFACE DEWPOINTS ACROSS SE WYOMING AND THE NEBRASKA
PANHANDLE INTO THE MID TO UPPER 50S COMBINED WITH 40-50 KNOT 500 MB
FLOW AND AN ASSOCIATED SHEAR-INDUCED VORTICITY MAXIMUM MOVING ACROSS
THE AREA WHICH WILL SET THE STAGE FOR CONVECTIVE INITIATION ON
TUESDAY AFTERNOON. FORECAST SOUNDINGS CONTINUE TO INDICATE EFFECTIVE
BULK SHEAR VALUES IN EXCESS OF 45 KNOTS, SO THERE WILL BE THE
POTENTIAL FOR A FEW SEVERE THUNDERSTORMS WITH THE ADDITION OF 500-
1000 J/KG OF MLCAPE CONFINED TO AREAS EAST OF THE I-25 CORRIDOR
WHERE THE GREATEST LOW-LEVEL MOISTURE WILL EXIST. THIS LINES UP WITH
THE DAY 3 SPC CONVECTIVE OUTLOOK WHICH PLACES CHEYENNE AND OTHER
LOCATIONS ALONG AND SOUTH OF THE I-80 CORRIDOR IN A MARGINAL RISK
FOR SEVERE WEATHER. DESPITE SUFFICIENT DEEP-LAYER SHEAR FOR
SUPERCELLS, LOW AND MID-LEVEL FLOW IS PROGGED TO BE QUITE WEAK,
LOWER THAN 10-15 KNOTS, YIELDING LITTLE TO NO LOW-LEVEL CURVATURE IN
THE HODOGRAPH. THIS SHOULD LIMIT THE OVERALL TORNADO THREAT WITH ANY
STORMS, LEAVING LARGE HAIL AND DAMAGING WINDS AS THE MAIN THREATS
WITH ANY SUPERCELLS. WITH THE COOLER POST-FRONTAL AIR MASS AND
LINGERING LOW-LEVEL MOISTURE, FORECAST HIGHS ON TUESDAY ARE EXPECTED
TO BE NEAR OR SLIGHTLY BELOW CLIMATOLOGY IN THE MID TO UPPER 70S
MAINLY EAST OF THE LARAMIE RANGE, WITH UPPER 70S TO LOW 80S TO THE
WEST.
THE PATTERN REMAINS ACTIVE INTO WEDNESDAY AS ANOTHER SHORTWAVE
TROUGH EMBEDDED IN THE ZONAL FLOW REGIME PROGRESSES ACROSS OUR AREA,
PROVIDING ANOTHER SOURCE FOR FORCING FOR ASCENT. SURFACE WINDS TURN
TO MORE SE, WHICH WILL ALLOW FOR ADDITIONAL THETA-E ADVECTION AND
LOW-LEVEL MOISTENING THROUGHOUT THE DAY. IT IS TOO FAR OUT TO GET
INTO SPECIFICS, BUT THE COMBINATION OF A LIFTING MECHANISM, PROGGED
DEWPOINTS IN THE MID 50S (RESULTING IN SURFACE-BASED INSTABILITY),
AND EFFECTIVE BULK SHEAR VALUES GREATER THAN 50 KNOTS, THERE WILL BE
A THREAT FOR SEVERE WEATHER ON WEDNESDAY AS WELL. SPC HAS PLACED
MUCH OF SE WYOMING AND THE PANHANDLE IN A DAY 4 RISK FOR SEVERE
WEATHER, SO FUTURE FORECASTS WILL HAVE TO BE MONITORED. HIGH
TEMPERATURES WILL AGAIN BE SLIGHTLY BELOW CLIMATOLOGY MAINLY IN THE
LOW TO MID 70S.
MUCH OF THE SAME FOR THURSDAY AS EMBEDDED DISTURBANCES CONTINUE TO
MOVE ACROSS OUR REGION AND CONSISTENT SIGNALS FROM ENSEMBLE GUIDANCE
THAT LOW-LEVEL MOISTURE WILL REMAIN IN PLACE EAST OF THE LARAMIE
RANGE. FORECAST SOUNDINGS AND MEDIUM-RANGE ENSEMBLES CONTINUE TO
SHOW SUFFICIENT DEEP-LAYER SHEAR AND FLOW ALOFT FOR ORGANIZED
CONVECTION, WITH PRIMARY HAZARDS TO BE IRONED OUT IN THE COMING
DAYS. AS WE FINISH OFF THE WORK WEEK AND HEAD INTO THE WEEKEND, THE
SYNOPTIC-SCALE FLOW PATTERN WILL BECOME SOUTHWESTERLY DOWNSTREAM OF
A RATHER HIGH-AMPLITUDE TROUGH CENTERED OVER BRITISH COLUMBIA AND
THE PACIFIC NORTHWEST. PWAT IS PROGGED TO BE AT OR ABOVE THE 80TH
PERCENTILE ON FRIDAY, SO THERE WILL BE THE POSSIBILITY FOR AN
ADDITIONAL ROUND OF LATE DAY AFTERNOON SHOWERS AND STORMS. SEVERE
POTENTIAL LOOKS LOW AT THIS TIME GIVEN THE LACK OF SHEAR. A WARMING
TREND WILL CONTINUE INTO THE WEEKEND WITH MOSTLY DRY CONDITIONS AND
TEMPERATURES NEAR OR SLIGHTLY ABOVE CLIMATOLOGY.
AVIATION /06Z TAFS THROUGH 06Z TUESDAY/
ISSUED AT 1145 PM MDT SUN JUN 21 2026
KAIA ASOS CAME BACK BUT THE CEILOMETER MAY STILL BE
MALFUNCTIONING BUT ALSO AMD NOT SKED WAS KEPT TO VERIFY THE ASOS
DATA FLOW IS SEMI STABLE FOR THE NEXT TAF PERIOD. ANYWAYS
THUNDERSTORMS ARE EXPECTED AROUND 21Z TOMORROW. MOSTLY ALL OF
GUIDANCE SUGGESTS THAT THESE STORMS WILL BE MORE OF A NEBRASKA
SHOW SO THE WYOMING WERE KEPT OUT OF ANY TSRA MENTION. FOG MAY
ALSO DEVELOP THROUGH THE NIGHT AS LOW CLOUDS START TO PUSH INTO
THE PINE RIDGE AREA. LARGE HAIL AND GUSTY WINDS LOOK TO BE THE
BIGGEST THREAT TO THE NEBRASKA TERMINALS TOMORROW AFTERNOON
THROUGH 04Z.
CYS WATCHES/WARNINGS/ADVISORIES
WY...NONE.
NE...NONE.
SHORT TERM...RZ
LONG TERM...NB
AVIATION...MM
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