958
FXUS65 KCYS 182326
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
526 PM MDT THU JUN 18 2026
KEY MESSAGES
- DRY CONDITIONS WILL PERSIST THROUGH THE END OF THE WEEK, BUT
A WEAK PRESSURE GRADIENT WILL PROMOTE SLIGHTLY ABOVE NORMAL
TEMPERATURES WITH WINDS GENERALLY TOO WEAK FOR CRITICAL FIRE
CONCERNS.
- A RETURN TO MORE ACTIVE WEATHER WILL OCCUR OVER THE WEEKEND
AND ON MONDAY AS A SERIES OF WEATHER DISTURBANCES COMBINE WITH
ADEQUATE LOW AND MID LEVEL MOISTURE TO PRODUCE SCATTERED TO
NUMEROUS LATE DAY SHOWERS AND THUNDERSTORMS.
- SOMEWHAT DRIER AIR WILL MOVE INTO THE FORECAST AREA FOR
TUESDAY AND WEDNESDAY, PRODUCING A DECREASE IN AREAL SHOWER
AND THUNDERSTORM COVERAGE, ALONG WITH A WARMING TREND.
SHORT TERM /THROUGH FRIDAY NIGHT/
ISSUED AT 113 PM MDT THU JUN 18 2026
AT THE UPPER LEVELS, THE REGION WILL BE MOSTLY CONTROLLED BY A
WEAK RIDGE OF HIGH PRESSURE THAT WILL BE SHIFTING OVER THE
WESTERN US THROUGH THE FORECAST PERIOD, WHILE AT THE SURFACE AN
AREA OF LOW PRESSURE WILL BE BUILDING INTO EASTERN COLORADO
THROUGH FRIDAY. UNDER THIS PATTERN, WE SHOULD CONTINUE TO SEE
RELATIVELY QUIET WEATHER FOR THE SHORT TERM, AS OUR DAYTIME
HIGHS IN THE UPPER 70'S TO MID 80'S TODAY PERSISTS INTO
TOMORROW. DRY CONDITIONS AND LIMITED FORCING WILL KEEP SKIES
MOSTLY CLEAR, THOUGH SOME CHANCES OF PRECIPITATION AND CLOUDS
START TO RETURN FRIDAY NIGHT INTO SATURDAY MORNING THANKS TO
INCREASING MOISTURE AS SURFACE FLOW TURNS EASTERLY AND THEN
SOUTHEASTERLY THROUGH THE DAY. FINALLY, DRY AIR WILL REMAIN
FIRMLY ENTRENCHED OVER THE WESTERN PORTION OF THE CWA, BUT WITH
FUELS STILL REPORTED AS GREEN IN THE REGION AND WINDS GENERALLY
LIGHT, CRITICAL FIRE WEATHER CONDITIONS ARE NOT ANTICIPATED.
EAST OF THE LARAMIE RANGE, WHILE WINDS MAY PICK UP HERE BY
FRIDAY AS THE PRESSURE GRADIENT BEGINS TO TIGHTEN, THE INFLUX OF
MOISTURE SHOULD ALSO PRECLUDE THE NEED FOR HIGHLIGHTS AS WELL.
OVERALL ENJOY THE QUIET AND FAIR TO SLIGHTLY WARM WEATHER BEFORE
THE WEEKEND WHEN WE'LL SE A MORE ACTIVE PATTERN RETURN.
LONG TERM /SATURDAY THROUGH THURSDAY/
ISSUED AT 113 PM MDT THU JUN 18 2026
SATURDAY...A MORE ACTIVE PATTERN DEVELOPS, WHILE A SHORTWAVE TROUGH
ALOFT PASSES OVERHEAD NEAR PEAK HEATING, AND AN INFLUX OF LOW AND
MID LEVEL MOISTURE ALONG A SURFACE TROUGH AXIS HELPS TO DEVELOP A
SCATTERED TO NUMEROUS COVERAGE, 40 TO 70 PERCENT COVERAGE OF SHOWERS
AND THUNDERSTORMS IN THE AFTERNOON AND EVENING, MOST NUMEROUS EAST
OF INTERSTATE 25. SOME STRONG TO SEVERE THUNDERSTORMS WILL BE QUITE
POSSIBLE DUE TO FORECAST INSTABILITY AND WIND SHEAR PROFILES AND
CONCUR WITH THE STORM PREDICTION CENTER, SPC, OUTLOOK OF MARGINAL TO
SLIGHT RISK OF SEVERE STORMS OVER FAR SOUTHEAST WYOMING AND WESTERN
NEBRASKA, PARTICULARLY FOR OUR SOUTHERN NEBRASKA PANHANDLE COUNTIES.
AFTERNOON CAPE, CONVECTIVE AVAILABLE POTENTIAL ENERGY WILL BE FROM
1500 TO 2000 J/KG ACROSS THE NEBRASKA PANHANDLE, WITH BULK SHEAR
NEAR 45.
SUNDAY...WHILE A SHORTWAVE TROUGH ALOFT SLIDES EASTWARD ACROSS THE
DAKOTAS AND NEBRASKA IN THE AFTERNOON, ITS ASSOCIATED COLD FRONT
WILL BRING SOME HEAT RELIEF WITH 700 MB TEMPERATURES NEAR 7C
SUGGESTING MAXIMUM TEMPERATURES IN THE 70S TO LOWER 80S. CONTINUED
ADEQUATE LOW AND MID LEVEL MOISTURE FOR SCATTERED LATE DAY SHOWERS
AND THUNDERSTORMS, CLOSER TO THE DEEPER MOISTURE EAST OF INTERSTATE
25.
MONDAY...LOOKS LIKE A SIMILAR SETUP COMPARED TO SATURDAY, WITH A
SHORTWAVE TROUGH PASSAGE IN THE AFTERNOON, SPAWNING SCATTERED
SHOWERS AND THUNDERSTORMS FOR THE AFTERNOON AND EVENING FOCUSED
ALONG A SURFACE TROUGH AXIS WEST OF THE WYOMING-NEBRASKA STATE LINE.
SOME STRONG TO SEVERE THUNDERSTORMS LOOK LIKELY DUE TO EXPECTED
INSTABILITY AND WIND SHEAR PROFILES, MAINLY FOR SOUTHEAST WYOMING
EAST OF I-25. UPSLOPE FLOW IN THE LOW LEVELS WILL AID LIFT FOR STORM
GENERATION.
TUESDAY...DRIER AIR INFILTRATES OUR FORECAST AREA UNDER NORTHWEST
FLOW ALOFT, ALLOWING ONLY ISOLATED TO WIDELY SCATTERED AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS, PRIMARILY EAST OF I-25.
TEMPERATURES SLIGHTLY WARMER THAN MONDAY WITH 700 MB TEMPERATURES
NEAR 11C.
WEDNESDAY...RIDGING ALOFT MOVES OVERHEAD INDUCING WARMER HIGH
TEMPERATURES. A SURFACE TROUGH WILL DEVELOP EAST OF I-25, WITH
CONVERGENCE ALONG THE TROUGH AIDING IN ISOLATED TO WIDELY SCATTERED
LATE DAY SHOWERS AND THUNDERSTORMS EAST OF I-25.
THURSDAY...TYPICAL "BEWARE" NORTHWEST FLOW ALOFT WILL PREVAIL, WITH
DECENT SOUTHEASTERLY LOW LEVEL WINDS ADVECTING LOW LEVEL MOISTURE
NORTHWESTWARD ACROSS OUR EASTERN HALF OF COUNTIES, AND HELPING TO
SPAWN SCATTERED SHOWERS AND THUNDERSTORMS FOCUSED ALONG A LOW LEVEL
CONVERGENCE AXIS. DECENT SHEAR AND INSTABILITY SUGGEST POSSIBLE
ISOLATED TO WIDELY SCATTERED STRONG TO SEVERE THUNDERSTORMS IN THE
AFTERNOON AND EVENING EAST OF I-25.
AVIATION /00Z TAFS THROUGH 00Z SATURDAY/
ISSUED AT 525 PM MDT THU JUN 18 2026
VFR CONDITIONS ARE EXPECTED FOR THE TAF PERIOD WITH GENERALLY LIGHT
AND VARIABLE WINDS EXPECTED FOR MUCH OF THE NIGHT AT MOST TERMINALS.
MOSTLY SUNNY SKIES ARE EXPECTED DURING THE DAY FRIDAY WITH WINDS
INCREASING DURING THE MORNING HOURS.
CYS WATCHES/WARNINGS/ADVISORIES
WY...NONE.
NE...NONE.
SHORT TERM...CG
LONG TERM...RUBIN
AVIATION...SF
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