970
FXUS65 KCYS 131107
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
507 AM MDT WED MAY 13 2026
KEY MESSAGES
- NEAR TO RECORD WARMTH EXPECTED WEDNESDAY UNDER HIGH PRESSURE
ALOFT. TEMPERATURES WILL INCREASE INTO THE MID-80S TO MID-90S.
- FIRE WEATHER WATCHES HAVE BEEN UPGRADED TO RED FLAG WARNINGS,
EXPANDED TO INCLUDE ALL OF WESTERN NEBRASKA, AND EXTENDED
THROUGH THURSDAY EVENING. CRITICAL FIRE CONDITIONS POSSIBLE
AGAIN ON FRIDAY AND SATURDAY.
- HIGH WIND WATCHES HAVE BEEN ISSUED FOR THE TYPICAL WIND PRONE
REGIONS OF SOUTHEAST WYOMING FROM LATE TONIGHT THROUGH
THURSDAY EVENING.
- NEXT CHANCE FOR PRECIPITATION RETURNS DURING THE WEEKEND
ALONGSIDE COOLER CONDITIONS.
SHORT TERM /THROUGH THURSDAY NIGHT/
ISSUED AT 109 AM MDT WED MAY 13 2026
UPPER-LEVEL RIDGING IS PROGGED TO REMAIN IN PLACE ACROSS THE CWA
TODAY WITH NEAR RECORD HIGH TEMPERATURES EXPECTED IN MANY AREAS.
700MB VALUES ARE MAXED OUT PER THE NAEFS MEAN TEMPERATURE FOR
THIS TIME OF YEAR, FURTHER SUGGESTING RECORD HIGHS THIS
AFTERNOON. MOSTLY CLEAR SKIES OVERNIGHT AND IN THE MORNING HOURS
WILL SLOWLY BECOMING MOSTLY CLOUDY, ESPECIALLY AS 700MB WARM AIR
ADVECTION LEADS TO SYNOPTIC SCALE RISING MOTION ACROSS MUCH OF
SOUTHEAST WYOMING AND WESTERN NEBRASKA. ADDITIONALLY, A DIFFUSE,
700MB SHORTWAVE WILL PROPAGATE ACROSS THE CWA TODAY, LEADING TO
ADDITIONAL SUPPORT FOR MORE CONCENTRATED RISING MOTION,
ESPECIALLY ALONG AND EAST OF THE LARAMIE RANGE. 99TH PERCENTILE
AND ABOVE 700MB TEMPERATURES COMBINE WITH SOUTHERLY FLOW AT THE
SURFACE ALLOWING FOR CONTINUED WARMING ACROSS THE REGION.
AFTERNOON TEMPERATURES LOOK TO MAX OUT IN THE LOW- TO MID-80S
WEST OF THE LARAMIE RANGE AND MID-80S TO MID-90S EAST OF THE
LARAMIE RANGE. UNFORTUNATELY, LIMITED MOISTURE IS ANTICIPATED
THIS AFTERNOON AS A DRIER AIR MASS MOVES IN. WITH VERY WARM
TEMPERATURES AND LITTLE ADDITIONAL MOISTURE, AFTERNOON MINIMUM
HUMIDITY VALUES WILL DROP INTO THE 10 TO 15 PERCENT RANGE WITH
BREEZY WINDS DEVELOPING THIS AFTERNOON ASSOCIATED WITH THE
DIFFUSE 700MB SHORTWAVE. THESE INGREDIENTS WILL COMBINE TO
CREATE CRITICAL FIRE CONCERNS ACROSS WESTERN NEBRASKA WHERE
FUELS REMAIN DRY AND NOT CURRENTLY IN GREEN-UP. AS A RESULT,
FIRE WEATHER WATCHES HAVE BEEN UPGRADED TO RED FLAG WARNINGS,
EXPANDED TO INCLUDE THE SOUTHERN NEBRASKA PANHANDLE, AND
EXTENDED THROUGH AT LEAST THURSDAY NIGHT.
WITH THE INCREASED SYNOPTIC ASCENT ACROSS THE REGION DUE TO
MODEST 700MB WAA AND CONCENTRATED LIFT FROM THE DIFFUSE 700MB
SHORTWAVE, AFTERNOON SHOWERS ARE ANTICIPATED TO DEVELOP, BUT THE
DRY SURFACE LEVEL WILL MAKE IT DIFFICULT FOR RAIN TO REACH THE
GROUND. IN ADDITION TO THIS, HIRES MODEL GUIDANCE SUGGESTS
MODEST MUCAPE VALUES ACROSS THE REGION THIS AFTERNOON, MAXING
OUT AROUND 200 J/KG. THIS WOULD BE ENOUGH INSTABILITY TO RESULT
IN A FEW RUMBLES OF THUNDER ACROSS THE CWA, ESPECIALLY EAST OF
THE LARAMIE RANGE. UNFORTUNATELY, SINCE PRECIPITATION WILL
STRUGGLE TO REACH THE GROUND DUE TO THE VERY DRY SURFACE LAYER,
ISOLATED, DRY LIGHTNING CANNOT BE RULED OUT. THE BEST CHANCE FOR
DRY LIGHTNING WILL BE LARGELY CONCENTRATED EAST OF THE LARAMIE
RANGE INTO THE WESTERN NEBRASKA PANHANDLE, WHERE FUELS ARE QUITE
DRY. FORECAST SOUNDINGS SUGGEST INVERTED-V PROFILES THIS
AFTERNOON, SO GUSTY AND ERRATIC WINDS GUST ARE LIKELY WITH ANY
SHOWER OR STORM THAT DEVELOPS THIS AFTERNOON. ALL IN ALL, THIS
WILL ONLY INCREASE FIRE CONCERNS AS ANY FIRE THAT STARTS FROM
DRY LIGHTNING COULD SPREAD EASILY WITH THE GUSTY AND ERRATIC
WINDS PRODUCED BY THE STORM ITSELF. THEREFORE, THE SOUTHERN
PANHANDLE WAS ADDED TO THE RED FLAG WARNINGS, DESPITE HUMIDITY
VALUES REMAINING SLIGHTLY ABOVE CRITICAL LEVELS, CLOSER TO 15 TO
20 PERCENT.
MOVING INTO THURSDAY, THE UPPER-LEVEL PATTERN STARTS TO SHIFT AS
AN UPPER-LEVEL TROUGH OVER SOUTHERN CANADA DIPS JUST FAR ENOUGH
SOUTH TO SLIGHTLY IMPACT THE REGION. UPPER-LEVEL WINDS WILL BE
LARGELY SOUTHWESTERLY TO ZONAL AS THE UPPER-LEVEL LOW MOVES
EASTWARD, WITH NORTHWESTERLY FLOW DEVELOPING LATE THURSDAY NIGHT
INTO EARLY FRIDAY MORNING. UNFORTUNATELY, THE BEST LIFT AND
MOISTURE ASSOCIATED WITH THIS SYSTEM WILL REMAIN WELL OFF TO OUR
NORTH AND EAST, LEADING TO YET ANOTHER DRY DAY ACROSS THE
REGION. 700MB TEMPERATURES COOL SLIGHTLY TOWARDS THE 7 TO 10C
RANGE FOR THURSDAY AS THE UPPER-LEVEL LOW BRIEFLY FUNNELS COOLER
AIR INTO THE REGION. AFTERNOON TEMPERATURES WILL REMAIN WARM,
THOUGH SIGNIFICANTLY COOLER THAN WEDNESDAY. AFTERNOON HIGHS WILL
REACH THE UPPER-60S TO MID-80S, WITH THE COOLEST TEMPERATURES
WEST OF THE LARAMIE RANGE. WITH THE BEST MOISTURE ASSOCIATED
WITH THE UPPER-LEVEL LOW MISSING THE REGION AND A VERY DRY AIR
MASS MOVING IN BEHIND IT, VERY LOW AFTERNOON HUMIDITY VALUES ARE
ANTICIPATED TO DEVELOP THURSDAY AFTERNOON, LIKELY 8 TO 12
PERCENT EVERYWHERE. ADDITIONALLY, 700MB HEIGHT GRADIENTS WILL
RESPOND TO THE NEARBY 700MB LOW OVER SOUTHERN CANADA, LEADING TO
A 55 TO 60KT 700MB JET THURSDAY MORNING, DECREASING TO AROUND 40
TO 45KTS BY THE EVENING HOURS. SURFACE WINDS ARE ANTICIPATED TO
RESPOND DUE TO MODEST DOWNWARD OMEGA VALUES ACROSS THE REGION
LEADING TO WIDESPREAD GUSTS OVER 40MPH, WITH HIGH WINDS POSSIBLE
IN THE WIND PRONE AREAS OF SOUTHEAST WYOMING. GIVEN THAT THIS IS
A SHOULDER SEASON, CONFIDENCE IS LOWER IN THE HIGH WINDS
MANIFESTING, BUT A HIGH WIND WATCH HAS STILL BEEN ISSUED FOR
ARLINGTON/ELK MOUNTAIN, BORDEAUX, AND THE I-80 SUMMIT FROM EARLY
THURSDAY MORNING THROUGH THE EVENING HOURS. COMBINED WITH VERY
DRY TEMPERATURES, THE RED FLAG WARNINGS WERE EXTENDED FOR
WESTERN NEBRASKA THROUGH THURSDAY NIGHT, AS OVERNIGHT HUMIDITY
RECOVERIES LOOK TO BE QUITE LOW. ADDITIONAL EXTENSION MAY BE
NEEDED INTO THE AFTERNOON/EVENING HOURS ON FRIDAY. WITH THE VERY
DRY AIR MASS IN THE REGION, MOSTLY CLEAR SKIES ARE EXPECTED WITH
LITTLE TO NO PRECIPITATION CHANCES ACROSS THE REGION, FURTHER
INCREASING FIRE CONCERNS.
LONG TERM /FRIDAY THROUGH TUESDAY/
ISSUED AT 109 AM MDT WED MAY 13 2026
NO MAJOR CHANGES WITH THIS FORECAST UPDATE. PLEASE SEE PREVIOUS
DISCUSSION FOR MORE DETAILS...
FRIDAY WILL BE LARGELY DOMINATED BY UPPER-LEVEL ZONAL
FLOW ACROSS MUCH OF THE REGION. TEMPERATURES WILL BE QUITE WARM
FRIDAY AND SATURDAY AS 700MB TEMPERATURES INCREASE ABOVE ABOUT 7 TO
10C EACH AFTERNOON. HIGHS ON FRIDAY ARE ANTICIPATED TO BE IN THE LOW-
70S TO MID-80S, WITH SATURDAY BEING SLIGHTLY WARMER IN THE MID-70S
TO LOW-90S. AFTERNOON MINIMUM HUMIDITY VALUES LOOK TO REMAIN QUITE
LOW FRIDAY AND SATURDAY, LIKELY BETWEEN 10 TO 15% EACH DAY. LUCKILY,
WINDS WILL BE ON THE LIGHTER SIDE ACROSS WESTERN NEBRASKA, WHERE
FUELS ARE READY TO BURN, AND BREEZIER ACROSS SOUTHEAST WYOMING,
WHERE GREEN-UP HAS DECREASED FIRE SPREAD POTENTIAL. THAT BEING SAID,
HOT AND DRY CONDITIONS MAY STILL FAVOR EASIER FIRE STARTS, THOUGH
RAPID FIRE SPREAD IS NOT ANTICIPATED AT THIS TIME. INSTABILITY WILL
START INCREASING SATURDAY AFTERNOON WITH THE CONTINUED, HOT PATTERN,
AS WELL AS A COLD FRONT PUSHING THROUGH THE AREA. AN ISOLATED
THUNDERSTORM OR TWO WILL BE POSSIBLE SATURDAY, ESPECIALLY ACROSS
WESTERN NEBRASKA, AS IS COMMON AS WE MOVE INTO THE SPRING AND SUMMER
MONTHS.
SATURDAY INTO SUNDAY, AN UPPER LEVEL TROUGH WILL PUSH ITS WAY INTO
THE PACIFIC NORTHWEST AND SEND A FRONT THROUGH THE INTERMOUNTAIN
WEST. SOME LOBES OF VORTICITY LOOKS TO ACCOMPANY THIS FRONT TO AIDE
IN THE SYNOPTIC LIFT TO HELP PRODUCE SOME WEAK SHOWERS IN THE LATE
AFTERNOON TO EVENING TIME PERIOD. BY SUNDAY AFTERNOON, THE TROUGH
BECOMES MORE POSITIVELY TILTED PUSHING SOME STRONG WARM AIR
ADVECTION AND VORTICITY LOBES TO GIVE US SOME POSSIBLY STRONG RAIN
SHOWERS THROUGH SUNDAY EVENING. AS THIS UPPER LEVEL TROUGH PUSHES
THROUGH THE INTERMOUNTAIN WEST SUNDAY NIGHT INTO MONDAY, THE 700MB
TEMPERATURE GRADIENT GOES FROM A WARM 8 TO 10C AND DROPS DOWN TO
ABOUT -6/-5C GIVING US A DECENT CHANCE FOR A RAIN/SNOW MIX TO
POSSIBLY SNOW SHOWERS IN THE HIGHER ELEVATIONS ABOVE 7,0000FT EARLY
MONDAY MORNING AND MONDAY NIGHT. DURING THE DAY THE SUMMER SUN IS
LIKELY TO KEEP ALL THE PRECIPITATION AS RAIN OUTSIDE THE MOUNTAIN
PEAKS FOR SOUTHEAST WYOMING. THIS TROUGH IS THE START OF AN ACTIVE
WEATHER PATTERN FOR THE WORK WEEK AS WE LOOK TO GET THE CHANCE FOR
PRECIPITATION ALMOST EVERY OTHER DAY.
AVIATION /12Z TAFS THROUGH 12Z THURSDAY/
ISSUED AT 507 AM MDT WED MAY 13 2026
VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE 12Z TAF PERIOD WITH
CLEAR SKIES THROUGH THE MORNING. CLOUDS BEGIN TO INCREASE WEST TO
EAST THROUGH THE AFTERNOON WITH THE POTENTIAL FOR ISOLATED SHOWERS.
MOST TERMINALS HAVE A SMALL CHANCE AT SEEING AN ISOLATED SHOWER OR
STORM THROUGHOUT THE AFTERNOON, BUT DIRECT TERMINALS IMPACTS ARE LOW
CONFIDENCE. GUSTY AND ERRATIC WINDS WILL BE POSSIBLE IN AND AROUND
AND SHOWERS OR STORMS THAT FORM THIS AFTERNOON.
CYS WATCHES/WARNINGS/ADVISORIES
WY...HIGH WIND WATCH FROM THURSDAY MORNING THROUGH THURSDAY
AFTERNOON FOR WYZ106-116.
HIGH WIND WATCH FROM LATE TONIGHT THROUGH THURSDAY AFTERNOON
FOR WYZ110.
NE...RED FLAG WARNING FROM NOON TODAY TO MIDNIGHT MDT THURSDAY
NIGHT FOR NEZ434>437.
SHORT TERM...AM
LONG TERM...MM/AM
AVIATION...AM
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