981
FXUS65 KCYS 070521
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1121 PM MDT MON APR 6 2026
KEY MESSAGES
- ABOVE-AVERAGE TEMPERATURES AND LOW PRECIPITATION CHANCES REMAIN
IN PLACE ACROSS SOUTHEAST WYOMING AND WESTERN NEBRASKA
THROUGH TUESDAY.
- WINDS WILL INCREASE ACROSS SOUTHEAST WYOMING TUESDAY INTO
WEDNESDAY, INCREASING FIRE CONCERNS AND POTENTIAL FOR STRONG
WINDS IN THE WIND PRONE AREAS.
- GREATER PRECIPITATION CHANCES RETURN TO SOUTHERN WYOMING AND
WESTERN NEBRASKA INTO THE WEEKEND, CONFIDENCE IN PRECIPITATION
AMOUNTS REMAINS LOW.
SHORT TERM /THROUGH WEDNESDAY NIGHT/
ISSUED AT 333 PM MDT MON APR 6 2026
HINTS OF A MORE TYPICAL SPRINGTIME PATTERN ARE PRESENT IN THE SHORT-
TERM FORECAST AND CURRENT OBSERVATIONS THIS MONDAY AFTERNOON OVER
SOUTHEAST WYOMING AND WESTERN NEBRASKA. THE REGION REMAINS
SANDWICHED BETWEEN A FLAT RIDGE OVER THE WEST COAST, WITH A BROAD
TROUGH CENTERED OVER THE CANADIAN SHIELD, RESULTING IN NORTHWEST
FLOW ALOFT. A WEAK UPPER-LEVEL LOW IS POSITIONED OVER THE SOUTHERN
FOUR CORNERS REGION, RESULTING IN A SLIGHT INCREASE IN MID AND UPPER-
LEVEL MOISTURE OVER THE ROCKIES TODAY. AT THE SURFACE, STRONG APRIL
SUN-ANGLE AND SURFACE HEATING HAS SUPPORTED UPSLOPE EASTERLY FLOW IN
THE HIGH PLAINS.
WHILE SURFACE DEWPOINTS REMAIN QUITE LOW, GENERALLY IN THE LOW TO
MID 20S ACROSS NEBRASKA AND EASTERN WYOMING, STRONG SURFACE HEATING
AND A NORTH-SOUTH ORIENTED BOUNDARY OVER THE LARAMIE RANGE WILL
LIKELY BE ENOUGH TO TOUCH OFF AREAS OF CONVECTION THROUGH THE EARLY
EVENING HOURS. STRONG T/TD SPREADS WILL LIKELY LIMIT MOST OF THE
PRECIPITATION TO VIRGA OR A QUICK SHOWER AT MOST AS ANY ACTIVITY
MOVES EASTWARD THIS EVENING. AFTER A PARTLY CLOUDY OVERNIGHT, EXPECT
A VERY SIMILAR SETUP ON TUESDAY WITH EASTERLY UPSLOPE FLOW IN THE
HIGH PLAINS AND DRY WESTERLY FLOW OVER THE HIGHER TERRAIN OF
SOUTHERN WYOMING. WESTERLY FLOW WILL BE A BIT STRONGER ON TUESDAY,
LIKELY PUSHING THE INITIATION BOUNDARY FOR ISOLATED SHOWERS FARTHER
EAST, MORE OVER CHEYENNE AND LARAMIE COUNTY AS OPPOSED TO THE
LARAMIE RANGE TODAY. LOW-END POPS CONTINUE IN THE FORECAST TODAY,
GENERALLY REFLECTING MODEL BLENDS. ATTENTION WILL TURN TO A
STRENGTHENING MID-LEVEL JET AHEAD OF OUR NEXT FRONTAL SYSTEM, WHICH
WILL START TO RAMP WINDS UP ON TUESDAY EVENING THROUGH WEDNESDAY.
RIGHT NOW, IN-HOUSE FORECAST GUIDANCE SUGGESTS THE BEST POSSIBLE
WINDOW FOR EXCEEDING HIGH-WIND CRITERIA IN THE TYPICAL WYOMING WIND-
PRONE CORRIDORS ALONG I-80 AND I-25 WILL COME ON WEDNESDAY MORNING.
THIS IS WHEN THE BEST OVERLAP OF SUBSIDENCE AND HIGHEST PRESSURE
GRADIENTS OCCUR. HOWEVER, HIGH WIND WARNING EXCEEDANCE PROBABILITIES
ONLY SIT AT AROUND 35-40% - GENERALLY NOT ENOUGH CONFIDENCE FOR ANY
WIND HIGHLIGHTS AT THIS TIME. FINALLY, BY WEDNESDAY EVENING, MOST
ENSEMBLE GUIDANCE IS IN GOOD AGREEMENT PUSHING A COLD FRONT SOUTH
THROUGH THE HIGH PLAINS, ESPECIALLY IN EAST-CENTRAL WYOMING THROUGH
THE NE PANHANDLE. WHILE THERE IS A MINOR AMOUNT OF FRONTOGENETIC
FORCING FOR PRECIPITATION ON WEDNESDAY EVENING, CONTINUED DRY AIR IN
THE LOWER LEVELS WILL LIKELY EVAPORATE ANY PRECIPITATION THAT CAN
FORM AND ONLY VERY LOW-END POPS CONTINUE IN THE FORECAST FOR THIS
PERIOD. OVERALL, ONLY MINIMAL ADJUSTMENTS WERE MADE TO MODEL BLENDS
IN THIS FORECAST PACKAGE, GENERALLY FOCUSED ON WIND THREATS FOR
WEDNESDAY MORNING. FORECAST CONFIDENCE REMAINS HIGH WITH GOOD
AGREEMENT AMONG MODELS.
LONG TERM /THURSDAY THROUGH MONDAY/
ISSUED AT 333 PM MDT MON APR 6 2026
THE LONG TERM LOOKS MORE ACTIVE WITH A MORE TYPICAL SPRING TIME
PATTERN. AFTER A SERIES OF COLD FRONTS ON WEDNESDAY AND OVERNIGHT
THURSDAY, A RIDGE WILL MOVE EAST OF OUR AREA TO REINFORCE
SOUTHEASTERLY LOW LEVEL FLOW OVER THE PLAINS REGIONS OF WY AND
THE NE PANHANDLE. THIS FLOW WILL INCREASE DEWPOINTS INTO THE 40S
FOR THE NEXT COUPLE OF DAYS. THESE DEWS PAIRED WITH A RATHER
MOIST 700-500MB LEVEL LAYER ARE INCREASING PWAT VALUES DURING
THE FRIDAY AND SATURDAY TIMEFRAME. THE NAEFS MEAN PWAT OVER THE
FRONT RANGE IS BETWEEN THE 90TH AND 95TH PERCENTILE (0.50 TO
0.75 INCHES). THIS INCREASE IN MOISTURE IS LIKELY TO ELEVATE POP
VALUES. UNFORTUNATELY RAINFALL AMOUNTS ARE NOT IMPRESSIVE ON
GUIDANCE, GEFS HAS BETWEEN 25-40% CHANCES OF SEEING 0.1" OF
PRECIPITATION, CONFINED TO MOSTLY THE SOUTHERN AREAS OF WY AND
THE NE PANHANDLE. GIVEN THE LACK OF ANY SIGNIFICANT SOURCES OF
SYNOPTIC LIFT AND THE CONVECTIVE NATURE OF THE PRECIPITATION,
THE CONFIDENCE IN PRECIP AMOUNTS ARE LOW. THIS DOES NOT
COMPLETELY RULE OUT LOCALLY HEAVIER AMOUNTS, BUT THE GENERAL
PICTURE AT THIS TIME IS NOT OF WIDESPREAD RAIN OR SNOWFALL. A
FEW THUNDERSTORMS CANNOT BE RULED OUT EITHER AS MOST AI ENSEMBLE
MODELS SUPPORT IT AND DETERMINISTIC GFS DOES MANIFEST DAYTIME
VALUES OF ABOVE 100 J/KG MUCAPE THURSDAY AND FRIDAY, AND ABOVE
500 MUCAPE FOR THE NE PANHANDLE SATURDAY AFTERNOON. WIDESPREAD
CLOUD COVER MAY DAMPEN COVERAGE AND INTENSITY.
EVEN WITH BRIEF COOL DOWNS WITH THE LATE WEEK AND WEEKEND
DISTURBANCE PASSAGES, WE ARE LIKELY TO STAY 5-10 DEGREES ABOVE
AVERAGE. SATURDAY LOOKS TO BE THE WARMEST WITH GENERALLY MID 60S TO
MID 70S OVER THE REGION. AFTERWARDS A SLIGHT COOLING TREND WITH
CHANCES OF RAIN/SNOW SHOWERS GOING INTO MONDAY. MOST OF THE AREA HAS
A 40-50% CHANCE OF RAINFALL MONDAY, BUT CONFIDENCE IS LOW AT THIS
RANGE AND DEPENDS LARGELY ON THE POSITIONING OF SYNOPTIC
FEATURES.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 1119 PM MDT MON APR 6 2026
FAIR QUIET NIGHT ACROSS THE REGION WITH SOME HIGHER LEVEL CLOUDS
MOVING THROUGH THE AREA. KSNY, KAIA, KBFF, AND KCYS MAY SEE A
PERIOD OF MVFR CEILINGS IN THE EARLY MORNING HOURS, BUT SHOULD
SEE THE CLOUDS CLEARING OUT BY MID-DAY AS WINDS START TO PICK
UP. OTHER TERMINALS WILL REMAIN PARTLY CLOUDY OVERNIGHT WITH
HIGH LEVEL CLOUDS BEFORE WINDS START TO INCREASE AFTER DAYBREAK.
CYS WATCHES/WARNINGS/ADVISORIES
WY...NONE.
NE...NONE.
SHORT TERM...MAC
LONG TERM...RV
AVIATION...AM
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