816
FXUS65 KCYS 312338
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
438 PM MST FRI JAN 31 2025
KEY MESSAGES
- HIGH WIND WARNINGS AND WATCHES IN EFFECT TODAY THROUGH
SATURDAY FOR THE SOUTHEAST WYOMING WIND PRONES AND ADJACENT
AREAS.
- WINTER STORM WARNINGS ISSUED FOR THE SIERRA MADRE AND SNOWY
RANGES SATURDAY MORNING THROUGH SUNDAY FOR HEAVY ACCUMULATING
SNOW AND WINDY CONDITIONS; WINTER WEATHER ADVISORIES FOR
CENTRAL CARBON COUNTY AND NORTH SNOWY RANGE FOOTHILLS
INCLUDING ARLINGTON FOR LIGHT BLOWING SNOW AND POOR
VISIBILITIES.
- WIDESPREAD ELEVATED TO STRONG WINDS CONTINUE INTO NEXT WEEK.
SHORT TERM /THROUGH SATURDAY NIGHT/
ISSUED AT 213 PM MST FRI JAN 31 2025
THE LOW LEVEL JET IS ALREADY STARTING TO CRANK UP ACROSS THE
REGION AS OF THIS AFTERNOON, AND WINDS ARE ALREADY BEGINNING TO
INCREASE IN RESPONSE. ARLINGTON HAS ALREADY RECORDED GUSTS OF 57
MPH, WITH SEVERAL OTHER LOCATIONS INTO THE 40'S. WE WILL
CONTINUE TO SEE THESE PEAK AND OVERSPREAD AS THE JET CONTINUES
TO STRENGTHEN, STRONGEST OVERNIGHT TONIGHT INTO SATURDAY
MORNING. HIGH WIND WARNINGS HAVE CONTINUED TO BE ISSUED FOR OUR
WIND-PRONE AREAS AND JUST EASTWARD INCLUDING GOSHEN COUNTY, AND
THE EASTERN PORTION OF LARAMIE COUNTY HAS A WATCH OUT AS
UNCERTAINTY LIES IF WINDS CAN SPREAD THAT FAR EAST. THE NBM IS
ONLY PEAKING PROBABILITIES FOR GUSTS 50+ MPH AROUND 30-50%, BUT
THE CAVEAT TO THIS IS THAT THE BLEND HAS BEEN LOW ON ITS WIND
FORECAST. THEREFORE DUE TO THE UNCERTAINTY HELD, COULDN'T
JUSTIFY A WARNING AT THIS TIME, BUT HAVE ISSUED A WATCH STARTING
FOR THIS EVENING THAT CAN BE EVALUATED LATER FOR UPGRADE OR
CANCELLATION.
OUTSIDE OF THE STRONG WINDS, WINTRY PRECIP SAW A SLIGHT BUMP
ACROSS OUR SOUTHWESTERN MOUNTAIN ZONES WHERE WE HAD WATCH
PRODUCTS. ALTHOUGH SNOW RATIOS ARE LIKELY TOO HIGH FROM HOW WARM
THIS MOISTURE STREAM IS AND HAD TO BE TEMPERED DOWN, UPSLOPE
FLOW OVER THIS TERRAIN WITH PWAT VALUES 200-250% OF NORMAL HAVE
CAUSED A NOTABLE UPTICK TO QPF, AND EVEN TEMPERING THIS DOWN
STILL BROUGHT HIGHER TOTALS THAN THE PREVIOUS FORECAST BY
AROUND 1-2 INCHES. ALONGSIDE COLLABORATION WITH OUR NEIGHBORS
AND WITH THE THREAT OF BLOWING AND DRIFTING SNOW INCLUDING VERY
LIMITED VISIBILITIES, HAVE GONE AHEAD AND UPGRADED TO A WARNING
FOR THESE TWO ZONES. THE ADJACENT ZONES TO THE NORTH INCLUDING
RAWLINS AND ARLINGTON ALSO HAD WINTER WEATHER ADVISORIES ISSUED
FOR THE EVENT AS WE SEE GENERALLY LIGHT AMOUNTS OF SNOW
EXPECTED, AROUND 1-4 INCHES, BUT WITH THE STRONG WINDS EXPECTED
HERE PERIODS OF NOTABLY REDUCED VISIBILITIES WILL BE POSSIBLE.
OTHERWISE, UPSLOPE FLOW IS EXPECTED TO INITIALLY KEEP THIS
PRECIPITATION POTENTIAL RELEGATED TO THE WESTERN PORTIONS OF OUR
CWA. ONCE WE PUSH INTO SUNDAY THOUGH, THE ABUNDANT MOISTURE
SHOULD BE ABLE TO OVERCOME SHADOWING EFFECTS AND MORE WIDESPREAD
PRECIPITATION CHANCES WILL BE EXPECTED FOR ALL ZONES. WITH
TEMPERATURES NOTABLY ABOVE NORMAL BY AROUND 5 TO 10 DEGREES,
PARTICULARLY IN OUR EASTERN ZONES, SNOW LEVELS WILL JUMP TO
BETWEEN 5000-8000 FEET, SO THE BULK OF THIS ACTIVITY WILL BE
LIGHT RAIN.
LONG TERM /SUNDAY THROUGH FRIDAY/
ISSUED AT 213 PM MST FRI JAN 31 2025
FAIRLY MUDDLED LONG TERM FORECAST, WITH A DECENT AMOUNT OF
UNCERTAINTY DUE TO MODEL TO MODEL DISAGREEMENT/VARIATIONS INTO NEXT
WEEK. OVERALL SYNOPTIC PATTERN WILL SEE THE TRANSITION FROM ZONAL
FLOW EARLY IN THE EARLY PORTION OF THE WEEK TO WEAK UPPER LEVEL
RIDGING SLOWLY DEVELOPING ACROSS THE INTERMOUNTAIN WEST AND HIGH
PLAINS BY MIDWEEK. UNDER THIS SETUP, PLENTY OF MOISTURE ADVECTION
INTO THE REGION AND RESULTANT HIGH PWATS TAKING LITTLE TO GET
PRECIPITATION GOING WITH PWAT STANDARDIZED ANOMALIES UP TO 2.5 SIGMA
ABOVE CLIMATOLOGY THROUGH THURSDAY, WITH A FAIRLY DECENT ATMOSPHERIC
RIVER SIGNATURE FLOWING FROM THE PACIFIC TO THE INTERMOUNTAIN WEST.
MAIN CONCERN IS WITH THE FLOW DIRECTION, KEEPING MUCH OF THE
PRECIPITATION CONFINED TO THE MOUNTAIN ZONES WHERE UPSLOPE FLOW WILL
LIKELY PLAY A ROLE. INTO THE LOWER AREAS, DOWNSLOPING COMPONENT TO
THE WINDS ALONG WITH HIGHER TEMPERATURES WILL LIMIT ANY SNOW
DEVELOPING AS TEMPERATURES ARE EXPECTED TO REMAIN WELL ABOVE
FREEZING. THE NAEFS MEAN 700MB TEMPERATURES HAVE BEGUN PICKING UP ON
THESE WARMER TEMPERATURES, WITH 700MB TEMPERATURES IN THE
CLIMATOLOGICAL 90TH PERCENTILE FOR THE SOUTHERN COUNTIES IN THE CWA
MONDAY, AND UPWARDS TO 99TH PERCENTILE TUESDAY THROUGH EARLY
WEDNESDAY BEFORE MORE SEASONABLE TEMPERATURES RETURN MID THROUGH
LATE WEEK. AS A RESULT, IN THE EVENT PRECIPITATION CAN GET GOING
WITH PLENTY OF MOISTURE WITHIN THE COLUMN TO PRODUCE RAIN/SNOW
ACROSS THE AREA, WILL LIKELY SEE BETTER SNOW CHANCES ACROSS THE
MOUNTAINS AND NORTHERN COUNTIES WHERE COLDER TEMPERATURES ARE
PROGGED. REGARDLESS, WILL NEED TO CONTINUE TO MONITOR SNOW CHANCES
INTO THE LOWER AREAS, ESPECIALLY IN THE AREAS THE NBM ADVERTISES
HIGHER POPS WHERE TEMPERATURES COULD WET-BULB TO 0C AND SNOW WILL
LIKELY ENSUE.
AVIATION /00Z TAFS THROUGH 00Z SUNDAY/
ISSUED AT 426 PM MST FRI JAN 31 2025
STRONG AND MOIST WESTERLY FLOW ALOFT WILL CONTINUE, PRODUCING
WINDY CONDITIONS AND INCREASING CHANCES FOR SNOW ACROSS CARBON
AND ALBANY COUNTIES.
WYOMING TAFS...FOR RAWLINS, CEILINGS WILL LOWER FROM 15000 FEET
TO 2500 FEET AT 10Z, THEN LIGHT SNOW WILL DEVELOP AFTER 12Z,
LOWERING VISIBILITIES TO 4 MILES AND CEILINGS TO 1500 FEET.
EXPECT LOW LEVEL WIND SHEAR FROM 03Z TO 12Z. WINDS WILL GUST TO
38 KNOTS.
FOR LARAMIE, CEILINGS WILL LOWER TO 9000 FEET BY 03Z, THEN TO
4000 FEET BY 09Z, AND INCREASE AGAIN TO 15000 FEET BY 15Z. LOW
LEVEL WIND SHEAR OCCURS AFTER 03Z. WINDS WILL GUST TO 40 KNOTS.
FOR CHEYENNE, CEILINGS WILL BE NEAR 15000 FEET. LOW LEVEL WIND
SHEAR OCCURS FROM 06Z TO 16Z. WINDS WILL GUST TO 35 KNOTS AFTER
03Z.
NEBRASKA TAFS...CEILINGS WILL BE NEAR 15000 FEET. LOW LEVEL WIND
SHEAR OCCURS FROM 08Z TO 17Z. WINDS WILL GUST TO 24 KNOTS AT
CHADRON UNTIL 02Z, AND TO 35 KNOTS AT ALL TERMINALS AFTER 08Z.
CYS WATCHES/WARNINGS/ADVISORIES
WY...HIGH WIND WARNING UNTIL 5 PM MST SATURDAY FOR WYZ101-106.
HIGH WIND WARNING UNTIL 5 AM MST SUNDAY FOR WYZ104-110.
HIGH WIND WARNING UNTIL 5 PM MST SATURDAY FOR WYZ107-108-116-
117.
WINTER WEATHER ADVISORY FROM 5 AM SATURDAY TO 5 PM MST SUNDAY
FOR WYZ109-110.
WINTER STORM WARNING FROM 5 AM SATURDAY TO 5 PM MST SUNDAY FOR
WYZ112-114.
HIGH WIND WARNING FROM 8 PM THIS EVENING TO 5 PM MST SATURDAY
FOR WYZ118.
HIGH WIND WATCH FROM 8 PM MST THIS EVENING THROUGH SATURDAY
AFTERNOON FOR WYZ119.
NE...NONE.
SHORT TERM...CG
LONG TERM...MRD
AVIATION...RUBIN
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page