306
FXUS65 KCYS 060545
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1145 PM MDT SUN APR 5 2026
KEY MESSAGES
- LOW END PRECIPITATION CHANCES WITH GUSTY SHOWERS POSSIBLE
MONDAY AND TUESDAY AFTERNOON/EVENING.
- HIGH WINDS ARE INCREASINGLY LIKELY TO RETURN TO THE WIND PRONE
AREAS OF SOUTHEAST WYOMING BY MID-WEEK.
- MORE UNSETTLED WEATHER IS EXPECTED TO RETURN LATE THIS WEEK
INTO THE WEEKEND, BUT THE DETAILS REMAIN UNCERTAIN AT THIS
TIME.
SHORT TERM /THROUGH TUESDAY/
ISSUED AT 215 PM MDT SUN APR 5 2026
THE SHORT TERM FORECAST REMAINS RELATIVELY BENIGN WITH MILD
TEMPERATURES EXPECTED THROUGH MID-WEEK COUPLED WITH LOW-END
PRECIPITATION CHANCES. THE REMAINDER OF EASTER SUNDAY WILL BE
PLEASANT WITH AFTERNOON HIGHS IN THE 50S AND 60S WITH MOSTLY SUNNY
SKIES AND LIGHT WINDS. TEMPERATURES OVERNIGHT WILL BE SEASONABLE
WITH NO PRECIPITATION CHANCES.
THE UPPER-LEVEL RIDGE OVER THE INTERMOUNTAIN WEST WILL WEAKEN AND
FLATTEN OUT DURING THE DAY TUESDAY AS A STRONG TROUGH SITS OVER THE
GREAT LAKES REGION. THE FLATTENING OF THE RIDGE WILL ALLOW A WEAK
BACKDOOR COOL FRONT TO SNEAK DOWN FROM THE NORTH AND BUT UP AGAINST
THE LEE SIDE OF THE LARAMIE RANGE. AS A RESULT, HIGH TEMPERATURES
EAST OF THE LARAMIE RANGE WILL BE ANYWHERE FROM 5 TO 15 DEGREES
COOLER COMPARED TO SUNDAY. INCREASED CLOUD COVER AND BREEZY
CONDITIONS WILL ADD TO THE COOLNESS. CONVERSELY, THOSE WEST OF THE
LARAMIE RANGE CAN EXPECT A WARMER DAY AS WARM AIR ALOFT IS ADVECTED
INTO CARBON AND ALBANY COUNTIES. HIGH TEMPERATURES WILL BE ABOUT 5
DEGREES WARMER THAN SUNDAY, WITH INCREASING CLOUDS DURING THE
AFTERNOON HOURS. CANNOT RULE OUT SOME HIGH TERRAIN CONVECTIVE
SHOWERS LATER IN THE AFTERNOON AS A CONVERGENCE ZONE SETS UP ALONG
THE LARAMIE RANGE. HOWEVER, THE LOW-LEVELS SEEM TOO DRY TO
SUPPORT ANY PRECIPITATION. THE SAME GOES FOR MONDAY NIGHT. SOME
HI-RES GUIDANCE SHOWS SHOWERS DEVELOPING OVERNIGHT IN THE
NEBRASKA PANHANDLE, BUT AGAIN THERE ARE LOW CHANCES OF THIS
OCCURRING, AND TRENDED POPS TOWARDS THE DRIER HRRR.
TUESDAY WILL SEE A REBOUND TO WARMER TEMPERATURES AS WINDS SWITCH
MORE WESTERLY UNDER THE FLATTENED RIDGE. DOWNSLOPING WINDS WILL HELP
WARM THE SURFACE, BUT MILD 700 MB TEMPERATURES WILL LIKELY BE THE
DRIVING FACTOR FOR ABOVE AVERAGE TEMPERATURES. HIGHS WILL BE IN
THE 60S AND 70S WITH MOSTLY SUNNY SKIES AND BREEZY CONDITIONS.
MODELS AGAIN SHOW POSSIBLE CHANCES FOR PRECIPITATION TUESDAY
AFTERNOON THROUGH TUESDAY NIGHT, SO ADDED LOW END POPS TO
SOUTHERN AREAS OF THE CWA TO ACCOUNT FOR ANY SHOWER DEVELOPMENT.
LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/
ISSUED AT 215 PM MDT SUN APR 5 2026
A STRONG UPPER LEVEL LOW IS EXPECTED TO PASS TO THE NORTH OF OUR
AREA TUESDAY NIGHT INTO WEDNESDAY. AS THIS APPROACHES, EXPECT TO SEE
AN INCREASE IN 700-MB WINDS AND LOW-LEVEL HEIGHT GRADIENTS. THE
THREAT FOR HIGH WINDS, PRIMARILY CONFINED TO THE WIND PRONE AREAS OF
SOUTHEAST WYOMING, WILL INCREASE DURING THIS PERIOD. THIS WILL BE A
MORE SYNOPTICALLY DRIVEN EVENT RATHER THAN A TRUE GAP WIND EVENT, SO
MANY TYPICAL PARAMETERS SUCH AS CROSS-BARRIER MSLP GRADIENTS ARE
FAIRLY UNIMPRESSIVE. HOWEVER, ENSEMBLES SHOW A GOOD SIGNAL FOR 700-
MB WINDS EXCEEDING 50 KNOTS OVER PORTIONS OF SOUTHEAST WYOMING.
NAEFS MEAN 700-MB WINDS ARE BETWEEN THE 90TH AND 97.5 PERCENTILE
TUESDAY NIGHT INTO WEDNESDAY MORNING. NBM PERFORMANCE, AND
PARTICULARLY ITS 24-HOUR MAXIMUM WIND PROBABILITY, IS TYPICALLY
BETTER WITH THESE TYPES OF EVENTS COMPARED TO THE GAP WIND EVENTS
MORE COMMON IN THE CORE WINTER MONTHS. THEREFORE, WE WILL RELY MORE
ON NBM PROBABILITIES SINCE THIS IS TYPICALLY THE TIME OF YEAR WHERE
TYPICAL HIGH WIND PARAMETERS START TO SEE DEGRADED PERFORMANCE IN
PREDICTING HIGH WINDS. NBM PROBABILITIES FOR WIND GUSTS EXCEEDING
HIGH WIND CRITERIA ARE AROUND 80% AT THIS TIME FOR THE ARLINGTON
AREA, 50% FOR THE I-80 SUMMIT, AND 20% FOR THE BORDEAUX AREA.
PROBABILITIES REMAIN AROUND 10% FOR MORE POPULATED AREAS OF
SOUTHEAST WYOMING ADJACENT TO THE WIND PRONE AREAS. IN ADDITION TO
THE WIND, FIRE WEATHER WILL ALSO BE A CONCERN. THIS WILL DEPEND HOW
FAR EAST OF I-25 THE DRY WESTERLY FLOW WILL BE ABLE TO REACH. MOST
MODEL GUIDANCE SHOWS AN INITIAL COLD FRONT PASSING THROUGH THE AREA
WEDNESDAY MORNING, RIDING ON THE LEADING EDGE OF A VERY SMALL
SURFACE HIGH PRESSURE SYSTEM. THE CORE OF THE HIGH MAY PASS THROUGH
THE AREA BY MIDDAY WEDNESDAY, ALLOWING FALLING PRESSURE TO SPREAD
TOWARDS THE WY/NE STATE LINE BY WEDNESDAY AFTERNOON. IF THIS OCCURS,
EXPECT TO SEE CRITICAL FIRE WEATHER CONDITIONS FOR SOUTHEAST WYOMING
ALONG AND EAST OF THE LARAMIE RANGE. IF THE HIGH PRESSURE REMAINS UP
AGAINST THE LARAMIE RANGE, THIS COULD MINIMIZE FIRE WEATHER
CONCERNS. SINCE WE ARE STILL A FEW DAYS OUT, THERE IS TOO MUCH
UNCERTAINTY TO SUGGEST WHICH OUTCOME WILL END UP FAVORED. RAIN AND
SNOW SHOWERS WILL BE POSSIBLE ALONG THE FRONT EARLY WEDNESDAY
MORNING, BUT PRECIPITATION AMOUNTS ARE EXPECTED TO REMAIN LIGHT.
HEADING LATER IN THE WEEK, ENSEMBLES CONTINUE TO SHOW PRECIPITABLE
WATER CREEPING ABOVE THE CLIMATOLOGICAL 90TH PERCENTILE ON THURSDAY
AND REMAINING THERE THROUGH THE WEEKEND. THIS WILL BE FORCED BY A
BROAD SOUTHWEST FLOW ALOFT REGIME AS A SLOW MOVING CLOSED LOW WORKS
INTO THE CALIFORNIA COAST LATE IN THE WEEK. FORCING, HOWEVER, LOOKS
FAIRLY LIMITED. THE GENERAL WEATHER PATTERN THURSDAY THROUGH SUNDAY
LOOKS LIKE A PATTERN OF DIURNAL CONVECTION, SUPPORTING ISOLATED TO
SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS EACH DAY.
THE DETAILS REMAIN UNCERTAIN, BUT IT WILL PROBABLY BE DIFFICULT TO
EXTRACT MUCH APPRECIABLE RAINFALL FROM THIS WEATHER PATTERN DUE TO
THE LACK OF ORGANIZED FORCING. LIMITED INSTABILITY WILL LIKELY BE
PRESENT, BUT CAPPING IS OFTEN AN ISSUE DURING THESE EARLY SEASON
CONVECTIVE EVENTS, AND STRONGER FORCING IS OFTEN NEEDED TO OVERCOME
THAT. FOR NOW, THE FORECAST CONTAINS 30 TO 60% CHANCES FOR
MEASURABLE PRECIPITATION EACH AFTERNOON AND EVENING ACROSS THE
AREA. THIS MAY BE A LITTLE ON THE HIGH SIDE, BUT CONFIDENCE IS LOWER
AT THIS LEAD TIME. THE PROBABILITY FOR MORE WIDESPREAD PRECIPITATION
WILL INCREASE LATE IN THE WEEKEND INTO EARLY NEXT WEEK AS ONE OR
MORE UPPER LEVEL LOWS MOVE ACROSS THE ROCKIES.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 1145 PM MDT SUN APR 5 2026
MIDLEVEL CLOUDINESS WILL BECOME MORE WIDESPREAD THIS MORNING AS A
SHALLOW COOL FRONT MOVES SOUTHWEST ACROSS THE HIGH PLAINS, SHIFTING
WINDS INTO THE EAST.
HAZARDS/WEATHER TRENDS: VFR CONDITIONS EXPECTED TO CONTINUE OVER THE
REGION FOR THE NEXT 24 HOURS. LIGHT AND VARIABLE WINDS WILL SHIFT
INTO THE EAST OR SOUTHEAST FOR THE HIGH PLAINS TERMINALS, AND REMAIN
OUT OF THE SOUTHEAST FOR KRWL AND KLAR. GUSTS UP TO 25 KNOTS ARE
POSSIBLE. PRECIPITATION LOOKS UNLIKELY AT THIS TIME (LESS THAN 10%
CHANCE).
CYS WATCHES/WARNINGS/ADVISORIES
WY...NONE.
NE...NONE.
SHORT TERM...SF
LONG TERM...MN
AVIATION...TJT
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page