370
FXUS65 KCYS 151139
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
539 AM MDT THU OCT 15 2026
KEY MESSAGES
- ACCUMULATING SNOW WILL CONTINUE ABOVE 7000 FT THIS MORNING.
SNOW LEVELS MAY LOWER DOWN TO 5500 TO 6000 FEET BRIEFLY BEFORE
PRECIPITATION ENDS LATER THURSDAY MORNING.
- A GROWING-SEASON-ENDING FREEZE EXPECTED THURSDAY NIGHT INTO
FRIDAY MORNING ACROSS THE ENTIRE AREA.
- DRIER AND MILDER WEATHER EXPECTED THIS WEEKEND INTO EARLY NEXT
WEEK.
SHORT TERM /THROUGH FRIDAY NIGHT/
ISSUED AT 200 AM MDT THU OCT 15 2026
FIRST WINTER-LIKE PACIFIC STORM ONGOING ACROSS SOUTHEAST WYOMING
WITH MAINLY RAIN BELOW 6000 FEET FOR FAR EASTERN WYOMING AND
WESTERN NEBRASKA EARLY THIS MORNING. IT IS CURRENTLY SNOWING IN
LARAMIE WITH A TEMPERATURES OF 32 DEGREES, SO SNOWLEVELS ARE
LIKELY BETWEEN 6500 TO 7000 FEET GIVEN CHEYENNE'S CURRENT
TEMPERATURE AT 100 AM OF 38 DEGREES. THE MOUNTAINS AND I-80
SUMMIT ARE SNOWING MODERATELY TO OCCASIONALLY HEAVY EARLY THIS
MORNING WITH ACCUMULATIONS ON GRASSY SURFACES, BRIDGES, AND
OVERPASSES. CURRENT WINTER WEATHER ADVISORY LOOKS GOOD AND NOT
PLANNING TO MAKE ANY CHANGES AT THIS TIME. BAND OF MODERATE
PRECIP IS COLOCATED WITH THE TROWAL FEATURE/WRAP AROUND PRECIP
BAND WHICH IS CURRENTLY OVER ALBANY COUNTY AND EXTENDS NORTHEAST
INTO EAST CENTRAL WYOMING AND THE NORTHERN NEBRASKA PANHANDLE.
THIS BAND IS SLOWLY TRANSLATING EASTWARD OVER THE I-25 CORRIDOR,
WITH THE EASTERN EXTENT OF THE BAND EARLY STATIONARY OVER THE
EASTERN PLAINS. FORECAST APPEARS ON TRACK, AT LEAST THE TIMING
AND EXPECTED SNOWFALL/AMOUNTS. STILL EXPECT A TRANSITION TO SNOW
AROUND ELEVATIONS OF 6000 FEET AND POSSIBLY AS LOW 5500 FEET
BEFORE THE PRECIPITATION ENDS LATER THIS MORNING. HIGH RES
MODELS AND SYNOPTIC MODELS HAVE FINALLY BACKED OFF ON THEIR
MASSIVE QPF AMOUNTS, SHOWING AMOUNTS THAT ARE A LITTLE MORE
REASONABLE WITH THIS TYPE OF SYSTEM. MODELS ALSO SHOW THE STORM
SYSTEM TRENDING MORE PROGRESSIVE AND EXITING THE AREA AS EARLY
AS 10:00 AM TO 1:00 PM TODAY. THIS MAKES SENSE GIVEN THE
POSITION OF THE NORTHERN BRANCH OF THE JET STREAM AND ASSOCIATED
UPPER LEVEL TROUGH/UPSTREAM KICKER SLIDING SOUTH ACROSS THE
NORTHERN PLAINS THIS MORNING. AFTER TRENDING QPF HIGHER THE LAST
COUPLE OF DAYS DUE TO MODEL PERSISTENCE/CONSISTENCY WITH HIGHER
PRECIP AMOUNTS, LOWERED QPF BACK IN LINE WITH A MORE FASTER
MOVING STORM SYSTEM. SNOWFALL SHOULD BE SIMILAR TO THE PREVIOUS
FORECAST WITH A SLIGHT LOWERING OF SNOWFALL TOTALS. THE ONLY
FORECAST CONCERN IS POSSIBLE AREAL EXTENSIONS OF THE WINTER
WEATHER ADVISORY FOR PORTIONS OF I-25, SOUTHERN LARAMIE RANGE
FOOTHILLS, ETC; AND MAYBE AN UPGRADE TO A WARNING FOR THE I-80
SUMMIT AND SNOWY RANGE. HOWEVER, CONFIDENCE IS LIMITED AT THIS
TIME.
BASED ON CURRENT TRENDS, EXPECT PRECIP TO END AROUND NOON
(EARLIER WEST OF I-25) WITH SKIES QUICKLY CLEARING BEHIND THE
UPPER LEVEL LOW AS IT BECOMES AN OPEN WAVE TROUGH AND EXITS TO
THE EAST. WILL LIKELY SEE SOME SUNSHINE BY MID TO LATE
AFTERNOON, SO EVEN WITH 700MB TEMPERATURES BELOW FREEZING,
EXPECT HIGH TEMPERATURES TO RECOVER SOMEWHAT INTO THE MID 60S
ACROSS WESTERN NEBRASKA, AND REMAINING IN THE 40S FOR MOST OF
SOUTHEAST WYOMING. CLEAR SKIES AND GOOD RADIATIONAL COOLING WITH
SET THE STAGE FOR OUR FIRST HARD FREEZE. IT'S NEARLY A CERTAINTY
AT THIS POINT THAT MOST PLACES WILL SEE LOW TEMPERATURES LATE
THURSDAY NIGHT AND FRIDAY MORNING BELOW 30 DEGREES, ESPECIALLY
WITH THE CANADIAN UPPER LEVEL TROUGH DIVING SOUTH WITH ANOTHER
COLD FRONT DIVING SOUTH ACROSS THE PLAINS WITH A 1036MB SURFACE
HIGH BEHIND IT. UPGRADED THE FREEZE WATCH TO A WARNING FOR AREAS
WEST OF THE INTERSTATE 25 CORRIDOR AND CONVERSE AND NIOBRARA
COUNTIES. WILL KEEP THE WATCH GOING FURTHER SOUTH AND EAST AFTER
COLLABORATION WITH NEIGHBORING OFFICES. KEPT TEMPERATURES
TONIGHT AROUND THE NBM AND GRAND ENSEMBLE 25TH PERCENTILE. WILL
LIKELY SEE SOME MID TO UPPER TEENS FOR THE MORE SHELTERED HIGH
VALLEYS, ESPECIALLY IF ANY SNOW ACCUMULATION REMAINS OVER THE
VALLEYS OF CENTRAL AND SOUTH CENTRAL WYOMING.
ALL MODELS SHOW THE EASTERN PACIFIC UPPER LEVEL RIDGE AXIS
SLIDING EASTWARD INTO THE INTERMOUNTAIN WEST DURING THE DAY.
EXPECT DRIER WEATHER AND MOSTLY SUNNY SKIES FOR THE FORECAST
AREA WITH TEMPERATURES ABOUT 10 DEGREES WARMER COMPARED TO THE
LAST FEW DAYS. HIGH TEMPERATURES IN THE 50S EXPECTED DURING THE
AFTERNOON WITH LIGHT SOUTHERLY WINDS. NOT AS COLD FRIDAY NIGHT,
BUT MOST OF WESTERN NEBRASKA AND SOUTH CENTRAL WYOMING WILL SEE
LOW TEMPERATURES BELOW OR NEAR FREEZING ONCE AGAIN.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
ISSUED AT 115 AM MDT THU OCT 15 2026
THE INTERMOUNTAIN WEST STARTS TO TAKE A TEMPORARY BREAK FROM
THE ACTIVE WEATHER PATTERN STARTING SATURDAY MORNING. A SLOW
MOVING RIDGE STARTS TO SET UP AND MEANDER EVERY SO SLIGHTLY
TOWARDS THE CENTRAL PLAINS. THE REGION WILL GRADUALLY WARM UP
DUE TO THIS RIDGE BUT DON'T EXPECT ANY SUMMER LIKE TEMPERATURES
FOR THE REST OF THE SEASON. THE GLOBAL MODELS HAVE 700MB
TEMPERATURES ONLY WARMING UP TO BETWEEN 6-10C THROUGH THE NEXT
WEEK AFTER THIS FREEZE FROM A VISIT FROM A POLAR AIRMASS. WITH
THE SUN ANGLE SLOWING DROPPING I'D WAGER THAT 80 DEGREE DAYS ARE
PROBABLY DONE FOR THIS FORECAST AREA. INSTEAD THE GREATER
GAMBLE WOULD BE ON WEARING SHORTS OR PANTS IN THE MORNING AS
TEMPERATURES START OUT IN THE 30'S AND 40'S AND CLIMBING INTO
THE 60'S AND 70'S BY THE AFTERNOON. BY THE MID-WEEK ANOTHER LOW
PRESSURE SYSTEM IS PROGGED TO SLIDE DOWN THE WEST COAST AS
ANOTHER LOW IS JUST HANGING AROUND THE EAST COAST TO PUT THE
INTERMOUNTAIN WEST ON THE FORWARD EDGE OF AN OMEGA BLOCK
CENTERED OVER THE CENTRAL PLAINS. THE LOW OFF THE WEST COAST
HOWEVER WILL BE A CRITICAL PLAYER TO OUR REGIONS FORECAST. THE
CYCLONIC ROTATION WILL BE FEEDING MOISTURE INTO OUR REGION TO
KEEP THE AFTERNOON RH VALUES HIGH ENOUGH TO NOT PRESENT ANY
CURRENT FIRE WEATHER CONCERNS WHILE ALSO STACKING THE CARDS ON
ANY NEEDED PRECIPITATION REACHING THE GROUND AS MULTIPLE
SHORTWAVES MOVE PAST THE ROCKIES FOR SOME PRECIPITATION CHANCES
LATE NEXT WEEK.
AVIATION /12Z TAFS THROUGH 12Z FRIDAY/
ISSUED AT 540 AM MDT THU OCT 15 2026
THIS LINE OF SHOWERS SHOULD BE CLEARING OUT OF OUR AREA AROUND
18Z. FOR KLAR AND KCYS A RAIN/SNOW MIX IS STILL POSSIBLY BUT AS
THE SUN COME BACK UP THE PRECIPITATION SHOULD BE ALL RAIN. THE
MIX OF IFR/LIFR SHOULD GRADUALLY DISSIPATE AFTER 18Z AND
EVENTUALLY CLEAR SKIES BY THE EVENING. THERE IS A FREEZE
WATCH/WARNING OUT FOR THE TERMINAL AS TEMPERATURES LOOK TO DROP
BELOW 30 DEGREES ALLOWING FOR FROST TO FORM ON ANY EXPOSED
PLANES/EQUIPMENT.
CYS WATCHES/WARNINGS/ADVISORIES
WY...FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR
WYZ107-108-117>119.
FREEZE WARNING FROM MIDNIGHT TONIGHT TO 9 AM MDT FRIDAY FOR
WYZ101-102-104>106-109>111-113-115-116.
WINTER WEATHER ADVISORY UNTIL NOON MDT TODAY FOR WYZ110-112-
114>116.
NE...FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR
NEZ002-003-019>021-054-055-095-096.
SHORT TERM...TJT
LONG TERM...MM
AVIATION...MM
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