760
FXUS65 KCYS 120508
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1108 PM MDT SUN OCT 11 2026
KEY MESSAGES
- ABOVE AVERAGE TEMPERATURES AND CHANCES FOR GUSTY SHOWERS AND
SOME ISOLATED STORMS TODAY.
- A PATTERN CHANGE WILL BRING A GRADUAL COOL DOWN AND INCREASED
CHANCES FOR PRECIPITATION THIS WEEK. MODERATE TO HEAVY
RAINFALL POSSIBLE TUESDAY NIGHT THROUGH WEDNESDAY NIGHT WITH
SOME MOUNTAIN SNOW EXPECTED.
SHORT TERM /THROUGH MONDAY NIGHT/
ISSUED AT 200 PM MDT SUN OCT 11 2026
WE'VE HAD A NICE BIT OF CLEARING TODAY, ACHIEVING A BIT MORE
SUNSHINE OVERALL THAN EXPECTED. WE'LL SEE HOW THIS IMPACTS OUR
INSTABILITY OVER THE NEXT COUPLE OF HOURS WITH THE STRONGEST
CONDITIONS EXPECTED AROUND 6-7 PM HELPING TO FUEL THUNDERSTORM
POTENTIAL AND EVEN AN ISOLATED STRONGER STORM OR TWO. ANY STORMS
THAT DO OCCUR, AS WELL PRECIPITATION IN THE FORM OF SHOWERS
FURTHER EAST, WILL ALL HAVE THE POTENTIAL FOR GUSTY AND ERRATIC
WINDS, POSSIBLY NEARING SEVERE LEVELS. FOR THE MOISTURE EXPECTED
FROM THIS, WHILE THIS ACTIVITY IS FUELED BY THE REMNANTS OF
TROPICAL STORM RACHEL MOVING ACROSS THE REGION, THE BEST
FORCING WILL BE JUST TO OUR WEST. THAT'S NOT TO SAY WE WON'T
SEE FAIR AMOUNTS OF MOISTURE, AS PWAT VALUES THIS EVENING WILL
BE BETWEEN 0.6-0.9 INCH, ROUGHLY 200% OF NORMAL FOR THIS TIME OF
YEAR. MEANWHILE ON THE NOTE OF STRONG WINDS, THE HIGH WIND
WATCH HAS BEEN UPGRADED TO A WARNING FOR CARBON COUNTY AS
PRESSURE GRADIENTS CONTINUE TO TIGHTEN IN RESPONSE TO THE
APPROACHING SYSTEM. THE JET STREAK IS EXPECTED TO BE STRONGEST
BETWEEN 6 PM - 3 AM, BUT THE POTENTIAL FOR STRONG GUSTS WILL
EXIST FROM 3 PM THROUGH 6 AM. IN HOUSE GUIDANCE IS STILL NOT
FULLY CONVINCED WITH ONLY AROUND A 40% PROBABILITY FOR GUSTS
EXCEEDING 58 MPH, BUT HIGH RESOLUTION GUIDANCE SHOWS 50-60 KNOT
WINDS AT 700MB, AND WITH HOW WINDY CARBON COUNTY LIKES TO BE, A
WARNING SEEMED ALL BUT NECESSARY.
PRECIPITATION WILL MOSTLY DEPART BY THE MORNING HOURS ALONGSIDE
WINDS WEAKENING, THOUGH SOME LINGERING SHOWERS IN CARBON COUNTY
CAN'T BE RULED OUT. IT WILL BE A FAIR DAY WITH TEMPERATURES
AROUND 2 TO 5 DEGREES LOWER THAN SUNDAY, STILL SEVERAL DEGREES
ABOVE NORMAL THOUGH. WHILE THE DAY WILL START OUT PLEASANT, A
DEEP PACIFIC LOW WILL BEGIN SWINGING EASTWARDS AND WILL NOT ONLY
BRING A NOTABLE COOL DOWN, BUT ALSO BEGIN TO INCREASE OUR
PRECIPITATION ACROSS THE REGION ONCE AGAIN. SHOWERS SHOULD START
TO OVERSPREAD LATE IN THE DAY AND OVERNIGHT, BUT CONVECTIVE
PARAMETERS WILL BE MEAGER, SO EXPECT MOSTLY RAIN WITH AN
OCCASIONAL RUMBLE OF THUNDER. FINALLY AS WE MOVE OVERNIGHT INTO
TUESDAY, TEMPERATURES WILL FINALLY BEGIN TO DROP, WITH THE
MOUNTAINS NEARING FREEZING AND MOST LOWER TO MID ELEVATION
LOCATIONS IN THE 40'S TO UPPER 30'S. FALL IS FINALLY TRYING TO
SHOW UP AS WE MOVE INTO THE LONG TERM.
LONG TERM /TUESDAY THROUGH SUNDAY/
ISSUED AT 200 PM MDT SUN OCT 11 2026
A BIG PATTERN CHANGE IS STILL ON TRACK FOR MID TO LATE WEEK AS AN
AMPLIFIED RIDGE OVER THE INTERMOUNTAIN WEST IS REPLACED BY A DIGGING
TROUGH AND CLOSED LOW. AFTER SPENDING A COUPLE DAYS OVER THE PAC NW
AND GREAT BASIN, THE LOW ROUNDS THE FOUR CORNERS REGION AND EMERGES
ONTO THE PLAINS NEAR THE WY/NE/CO POINT WEDNESDAY INTO THURSDAY. A
100+ KT H3 JET STREAK, A STOUT MID-LEVEL SHORTWAVE, AND A SURFACE
COOL FRONT ALL PRECEDE THE LOW'S PASSAGE. WITH MOISTURE STREAMING
NORTHEASTWARD THROUGHOUT THIS PROCESS, WIDESPREAD PRECIPITATION AND
MUCH COOLER TEMPERATURES ARE IN ORDER.
TUESDAY... CONSIDERABLE MID-UPPER LEVEL MOISTURE WILL BE IN PLACE AS
THE CORE OF THE JET PASSES NEARBY, AND EAST/SOUTHEAST H85 FLOW HELPS
WITH OROGRAPHIC FORCING. TEMPERATURES SHOULD HOLD WARM ENOUGH
(PLAINS/VALLEYS HIGHS AROUND 60F) AND SNOW LEVELS HIGH ENOUGH
(10KFT) TO RESULT IN RAIN AS THE DOMINANT P-TYPE THROUGHOUT THE DAY.
IN FACT, RELATIVELY STEEP MID-LEVEL LAPSE RATES AND MARGINAL MUCAPE
ACROSS SOUTHERN WY MAY BE SUFFICIENT FOR A FEW RUMBLES OF THUNDER.
WEDNESDAY... THE H5 LOW IS KNOCKING ON OUR DOORSTEP AS THE H7 0C
THERM PRESSES EAST ACROSS WY. NEAR SURFACE FLOW TAKES ON A MORE
NORTHEASTERLY DIRECTION, AND FORCING STRENGTHENS AT MULTIPLE LEVELS.
THE NBM ENVELOPE HAS TRENDED COOLER CONSIDERABLY, NOW SUGGESTING 40S
FOR HIGHS IN WY AND LOWER 50S FOR NE. FORECAST SNOW LEVELS DROP
BELOW 9KFT BY THE EVENING TIME, SQUARELY PLACING THE SIERRA MADRES
AND SNOWY RANGE IN THE WINTER REGIME. AT THIS TIME, SNOW TOTALS
APPEAR TO HOLD RIGHT NEAR ADVISORY CRITERIA FOR THE HIGHER PEAKS.
WILL NEED TO MONITOR ANY FURTHER COOLING TREND AS THE EVENT DRAWS
NEARER HOWEVER, IF SNOW LEVELS DROP OR MORE TIME IS SPENT IN THE
DENDRITIC GROWTH ZONE. RAINFALL OUTSIDE THE RANGES COULD BE
SIGNIFICANT AS WELL, WITH SOME LOCATIONS APPROACHING 1" OF MOISTURE.
WED NIGHT MAY NECESSITATE FROST/FREEZE HEADLINES, ESPECIALLY FOR WY
AND NORTHERN PANHANDLE ZONES. THE MEDIAN OF THE NBM ENVELOPE
SUGGESTS UPPER 20S WEST FOR MOST OF CARBON AND ALBANY COS, LOWER/MID
30S FOR I-25 CORRIDOR AND INTO SIOUX CO.
THURSDAY... PRECIP TAPERS ACROSS THE FORECAST AREA, BUT WINDS REALLY
PICK UP AS NORTH/NORTHWEST FLOW FULLY TAKES OVER. 30+ KTS FLOW AT H5-
7 SHOULD EASILY TRANSLATE TO THE SURFACE VIA MECHANICAL MIXING, AND
HEIGHT GRADIENTS SURPASS 30M ACROSS WY/CO. TEMPERATURES ATTEMPT TO
REBOUND WITH GRADUAL CLEARING THROUGH THE DAY, WITH HIGHS GENERALLY
IN THE 50S (WY) AND LOWER 60S (NE).
FRIDAY AND BEYOND... THE UPPER RIDGE REBUILDS OVER THE WESTERN US,
AND A BROAD SURFACE HIGH SETTLES ONTO THE GREAT PLAINS. SEASONABLY
MILD AND DRY CONDITIONS COME RIGHT BACK NEXT WEEKEND, WITH HIGHS IN
THE 70S NEAR/EAST OF I-25 FOR SATURDAY AND SUNDAY.
AVIATION /06Z TAFS THROUGH 06Z TUESDAY/
ISSUED AT 1106 PM MDT SUN OCT 11 2026
WINDS HAVE DECREASED AT MOST TERMINALS TONIGHT, OTHER THAN KLAR
AND KRWL. WINDS WILL REMAIN LIGHT AND VARIABLE FOR THE TERMINALS
WITH WINDS INCREASING INTO THE AFTERNOON HOURS. KLAR AND KRWL
WILL REMAIN GUSTY THROUGHOUT THE NIGHT AND FOR MUCH OF THE DAY
TOMORROW. LOW CLOUDS STARTED TO MOVE INTO KCDR TONIGHT WITH LOW
CEILINGS EXPECTED TO CONTINUE FOR THE NEXT SEVERAL HOURS. KAIA
MAY ALSO SEE DECREASING CEILINGS AFTER 11Z WHEN UPPER-LEVEL
CLOUDS CLEAR OUT. IFR CEILINGS WILL BE POSSIBLE. ALL CEILINGS
IMPROVE AFTER 15Z IN THE MORNING.
CYS WATCHES/WARNINGS/ADVISORIES
WY...HIGH WIND WARNING UNTIL 6 AM MDT MONDAY FOR WYZ104-109>111.
NE...NONE.
SHORT TERM...CG
LONG TERM...DS
AVIATION...AM
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