707
FXUS65 KCYS 181741
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1141 AM MDT WED MAR 18 2026
KEY MESSAGES
- A RED FLAG WARNING IS IN EFFECT FOR ALL AREAS ALONG AND EAST
OF THE LARAMIE RANGE THROUGH SATURDAY EVENING. CRITICAL FIRE
DANGER IS EXPECTED.
- RECORD WARMTH WILL START AS EARLY AS THIS AFTERNOON, BUT MORE
LIKELY TO START ON THURSDAY AND CONTINUE THROUGH SATURDAY.
- COOLER, THOUGH STILL ABOVE AVERAGE, TEMPERATURES RETURN SUNDAY
BEHIND A COLD FRONT PUSHING THROUGH. ISOLATED TO SCATTERED
PRECIPITATION CHANCES EXPECTED WITH THIS FRONTAL PASSAGE.
SHORT TERM /THROUGH FRIDAY/
ISSUED AT 1219 AM MDT WED MAR 18 2026
STOUT, UPPER-LEVEL RIDGING REMAINS IN PLACE THROUGH MUCH OF THE
WEEK AS A CLOSED, UPPER-LEVEL HIGH OVER THE SOUTHWESTERN CONUS
BUILDS AND REMAINS NEARLY STATIONARY THROUGH THE END OF THE
WEEK. 500MB TEMPERATURES ARE EXPECTED TO SOAR TO ABOVE THE
99.5TH PERCENTILE THROUGH SUNDAY MORNING, PER NAEFS MEAN
TEMPERATURE CLIMATOLOGICAL PERCENTILES. 700MB TEMPERATURES WILL
SOAR INTO THE +8C TO +10C RANGE BY THIS AFTERNOON AND CONTINUING
THROUGH SATURDAY. THESE TEMPERATURES ARE ABOVE THE 99.5TH
PERCENTILE PER NAEFS MEAN TEMPERATURE CLIMATOLOGICAL
PERCENTILES, LEADING TO STRONG SUPPORT FOR WELL ABOVE AVERAGE TO
RECORD BREAKING HEAT STARTING AS EARLY AS THIS AFTERNOON, THOUGH
MORE LIKELY TO START THURSDAY AFTERNOON WHEN 700MB TEMPERATURES
SURPASS THE 99.5TH PERCENTILE. THE BIGGEST QUESTION WITH THIS
HEAT WILL BE EXACTLY HOW WARM IT GETS, AS WE STILL DO NOT HAVE
NEARLY AS MUCH DAYLIGHT HOURS AS THE SUMMER MONTHS.
ADDITIONALLY, SKIES WILL BE LARGELY CLEAR, BUT SOME CLOUDS MAKE
SNEAK INTO THE AREA AND POTENTIALLY DECREASE DAYTIME HIGH
TEMPERATURES. DECIDED TO BLEND THE NBM75TH WITH THE GFS TO GET
RECORD TEMPERATURES, BUT NOT IN THE REALM OF COMPLETELY
OBLITERATING THE RECORDS. THE FEWER NUMBER OF DAYTIME HOURS WILL
LIKELY PREVENT THE AREA FROM COMPLETELY OBLITERATING THE
RECORDS, BUT WITH SOME DOWNSLOPE EXPECTED ALONG AND EAST OF THE
LARAMIE RANGE, THIS CAN ALSO NOT BE COMPLETELY RULED OUT. STILL
KEPT TEMPERATURES IN THE 70S AND 80S FOR MOST DAYS, LEADING TO
RECORD TEMPERATURES FOR MUCH OF THE AREA. WEDNESDAY WILL BE THE
COOLEST DAY UNTIL SUNDAY WITH HIGHS CURRENTLY FORECAST TO BE IN
THE UPPER-60S WEST OF THE LARAMIE RANGE AND LOW- TO MID-70S
EAST, WITH A COUPLE SITES AROUND 80F.
UNFORTUNATELY, THIS RIDGE WILL BE QUITE DRY WITH PRECIPITATION
AND MOISTURE NO WHERE TO BE FOUND. AS A RESULT, RECORD WARMTH
COMBINED WITH SEASONAL DRYNESS WILL LEAD TO AFTERNOON MINIMUM
HUMIDITIES DROPPING INTO THE 10 TO 15% RANGE EVERY AFTERNOON
THROUGH SATURDAY, WITH OVERNIGHT HUMIDITY RECOVERIES EXPECTED TO
ONLY BE AROUND 30 TO 45%. WITH SEASONAL BREEZINESS EXPECTED,
THIS WILL BE THE PERFECT SET UP FOR CRITICAL FIRE DANGER EVERY
AFTERNOON WITH LIMITED RECOVERY OVERNIGHT. THE RED FLAG WARNING
WILL REMAIN IN EFFECT THROUGH SATURDAY EVENING, WITH VERY
DANGEROUS FIRE CONDITIONS EXPECTED. OUTDOOR BURNING IS NOT
RECOMMENDED, EVEN IN ENCLOSED FIRE PITS, ETC.
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/
ISSUED AT 1219 AM MDT WED MAR 18 2026
NO MAJOR CHANGES TO THE FORECAST. PLEASE SEE PREVIOUS
DISCUSSION...
THE UPPER-LEVEL RIDGE WILL DOMINATE THE PATTERN THROUGH MOST OF THE
WEEKEND. NAEFS PERCENTILES FOR 500MB GEOPOTENTIAL HEIGHTS ARE
CURRENTLY FORECASTED TO BE AT CLIMATOLOGICAL MAXIMUM. REGIONAL
SOUNDING SITE CLIMATOLOGY INDICATES RECORDED MAXIMUM 500MB HEIGHTS
FOR THIS PERIOD ARE NEAR 5,800 METERS WITH ENSEMBLES PREDICTING
HEIGHTS GREATER THAN 5,820 METERS THROUGH FRIDAY. ALL THIS TO SAY
THIS IS AN ANOMALOUS PATTERN, WITH VERY WARM WEATHER EXPECTED.
THIS RIDGE WILL BE RESPONSIBLE FOR PUSHING THE 700MB JET
NORTHWARD, WHICH SHOULD LESSEN THE WINDS BY SUNDAY, THOUGH FRIDAY
AND SATURDAY COULD STILL BE GUSTY. WARM AND DRY AIR FROM THE DESERT
SOUTHWEST WILL BE ADVECTED INTO THE INTERMOUNTAIN WEST. UNSEASONABLY
WARM CONDITIONS ARE THREATENING DAILY RECORD MAXIMUM TEMPERATURES
THURSDAY THROUGH SATURDAY. THE INTERMOUNTAIN BASINS MAY REACH THE
70S, WHILE AREAS ON THE PLAINS ARE PROGGED TO REACH THE 80S, AND IN
SOME VALLEY SPOTS OF THE NEBRASKA PANHANDLE COULD MAKE IT TO 90
SATURDAY.
THIS DRY AND WARM AIR WILL DRIVE DEWPOINTS INTO THE TEENS AND AT THE
HIGHEST ELEVATIONS INTO THE SINGLE DIGITS. RELATIVE HUMIDITY REMAINS
IMPRESSIVELY LOW DURING THE DAYTIME IN THE RANGE OF 10-15 PERCENT.
THE POOR OVERNIGHT RECOVERIES WILL DRY OUT MOST FUELS. THE RED FLAG
WARNING THAT STARTS WEDNESDAY MORNING WILL CONTINUE UNTIL 8 PM MDT
THIS SATURDAY FOR FORECAST ZONES NORTH AND WEST OF THE LARAMIE
RANGE. OVERNIGHT SATURDAY MAY MARK A DEPARTURE FROM THIS PATTERN IN
THE FORM OF A WEAK COLD FRONT PASSAGE. A MID-LEVEL MOISTURE
PLUME COULD SUPPORT SOME ENHANCED PRECIPITATION CHANCES,
ESPECIALLY AT HIGHER ELEVATIONS. LOCATIONS ALONG I-25 AND WEST
MAY BECOME SATURATED ENOUGH TO ALLOW SOME SHOWERS TO REACH THE
SURFACE. TEMPERATURES WILL DROP INTO THE 50S YET REMAIN ABOUT 5
DEGREES AVERAGE FOR THIS TIME OF YEAR. BEYOND THIS BRIEF
DISTURBANCE, RIDGING PATTERN APPEARS LIKELY TO REBUILD AND
LINGER INTO THE MIDDLE OF NEXT WEEK.
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 1123 AM MDT WED MAR 18 2026
EXPECT VFR CONDITIONS ARE EXPECTED FOR TERMINALS TODAY,
OVERNIGHT, AND INTO TOMORROW. HIGH LEVEL CLOUDS, CEILINGS AROUND
25000 FT, WITH SOME CLEAR SKIES INTERMITTENT. GUSTY WINDS ARE
EXPECTED TODAY, ESPECIALLY AT KCYS, KLAR, AND KRWL. WINDS WILL
SLOWLY DIMINISH THIS EVENING AFTER SUNSET, WHICH MAY CAUSE SOME
LOW-LEVEL WIND SHEAR CONCERNS AT KCYS AND KLAR TERMINALS IN THE
MORNING GIVEN STRONG WINDS ALOFT.
CYS WATCHES/WARNINGS/ADVISORIES
WY...RED FLAG WARNING UNTIL 8 PM MDT SATURDAY FOR WYZ417>419-
430>433.
HIGH WIND WARNING UNTIL 6 PM MDT THIS EVENING FOR WYZ110.
NE...RED FLAG WARNING UNTIL 8 PM MDT SATURDAY FOR NEZ434>437.
SHORT TERM...AM
LONG TERM...RV/AM
AVIATION...RV
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