717
FXUS65 KRIW 180431
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
931 PM MST SUN NOV 17 2024
KEY MESSAGES
- GUSTY WINDS CONTINUE ACROSS CENTRAL WY TODAY AHEAD OF THE NEXT
SYSTEM. GUSTS ACROSS NATRONA WILL CONTINUE TO REACH 40 MPH
THROUGH THE REST OF THE AFTERNOON.
- THE NEXT BROAD WEATHER SYSTEM SWEEPS ACROSS THE STATE ON
MONDAY, BRINGING ANOTHER ROUND OF SNOW MAINLY TO THE HIGHER
ELEVATIONS OF WESTERN AND NORTHERN WY.
- ANOTHER COLD DAY TUESDAY BEHIND THE SYSTEM, BUT THE COLDEST
AIR WILL BE LIMITED TO AREAS WEST OF THE DIVIDE.
DISCUSSION
ISSUED AT 115 PM MST SUN NOV 17 2024
WINDS CONTINUE TO RACE ACROSS PARTS OF THE STATE AGAIN TODAY
AHEAD OF THE APPROACHING WINTER SYSTEM. WINDS AT KCPR CONTINUE
TO GUST 40 TO 50, WHILE AREAS JUST OFF THE WESTERN MOUNTAINS
(KCOD/KDUB) CONTINUE TO GUST 30 TO 35. WINDS WILL DECOUPLE SOME
TIME THIS EVENING, BUT SOME BREEZY SOUTHWEST FLOW WILL CONTINUE
OVERNIGHT, MAINLY ACROSS THE KCPR REGION.
THE NEXT TROUGH IS MOVING ACROSS IDAHO RIGHT NOW, AND WILL START
TO IMPACT THE WESTERN MOUNTAINS AROUND SUNSET. MIDLEVEL FLOW IS
IN GOOD ALIGNMENT FOR UPSLOPE SNOW PRODUCTION FOR THE WESTERN
MOUNTAINS TONIGHT AND MONDAY. MOISTURE IS NOT ABUNDANT WITH THIS
SYSTEM, AND THE SPEED IS FAIRLY QUICK, SO SNOWFALL AMOUNTS WILL
BE LIMITED AND FOCUSED ON THE HIGHER ELEVATIONS. OVERALL SNOW
FORECAST FOR THE WESTERN MOUNTAINS HAS REMAINED CONSISTENT WITH
THE PREVIOUS FORECAST, WITH 10 TO 14 INCHES FOR THE TETONS AND
WESTERN YNP, WITH THE REST OF THE PARK, THE GROS VENTRES AND THE
SALT/WYOMING RANGES STILL AT 4 TO 8 INCHES. HIGHLIGHTS REMAIN
FOCUSED ON THE WESTERN MOUNTAINS, WITH A WARNING FOR THE TETONS
AND ADVISORIES FOR YNP/SALTS/WYOMINGS. AS THE TROUGH PIVOTS TO
THE NORTHEAST MONDAY NIGHT, STEERING FLOW TURNS MORE FROM THE
NORTHWEST. THIS WILL PUSH A COLDER AIRMASS BACK ACROSS THE STATE
BY TUESDAY MORNING, WITH MOST AREAS BACK TO NEAR NORMAL
TEMPERATURES IN THE 20S AND 30S. THIS FLOW ALSO PUTS THE
SOUTHERN BIGHORN RANGE IN A BETTER ALIGNMENT FOR OROGRAPHIC SNOW
PRODUCTION. BUT AGAIN, THE MOISTURE REMAINS LIMITED, SO
ACCUMULATIONS REMAIN IN THE 3 TO 6 INCH RANGE BY MIDDAY TUESDAY.
THIS COLDER AIRMASS WILL ALSO BE A BRIEF PUSH, AS H5 RIDGING
BUILDS BACK ACROSS THE ROCKIES FOR THE LATTER HALF OF THE WEEK.
THIS WILL BRING TEMPERATURES BACK ABOVE NORMAL AGAIN, WITH MOST
AREAS SEEING HIGHS IN THE 40S AND LOW 50S THROUGH SATURDAY.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 930 PM MST SUN NOV 17 2024
WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS TERMINALS
CHANCES FOR SNOW CONTINUE TO INCREASE OVER THE FAR WESTERN
MOUNTAINS BY THE START OF THE TAF PERIOD. MARGINAL VFR
CONDITIONS EXPECTED AT KJAC TO START, WITH SNOW DEVELOPING
AROUND 07Z/08Z. MVFR CONDITIONS WILL DROP TO IFR AS THE SNOW
BECOMES STEADY. THIS ENHANCED BAND OF SNOW WILL PUSH SOUTHEAST
BETWEEN 08Z-12Z TO REACH KBPI/KPNA AND ON TO KRKS BETWEEN
13Z-16Z. THE BEST CHANCE FOR IFR CONDITIONS WILL BE AT KJAC
WITH THIS BAND, BUT KPNA AND POTENTIALLY KRKS COULD EACH SEE A
ONE- TO TWO-HOUR PERIOD OF IFR. TEMPO GROUP HAS BEEN ADDED AT
KPNA FOR THIS ENHANCED BAND. OROGRAPHIC MVFR SNOW CONTINUES
THROUGH AT LEAST MIDDAY AT KJAC, WHILE OTHER WESTERN TERMINALS
SEE CONDITIONS GRADUALLY RETURN TO VFR BY EARLY AFTERNOON. GUSTY
SOUTHWEST SURFACE WIND BEGINS LATE MONDAY MORNING AT KJAC,
WHILE OTHER TERMINALS FIND WESTERLY WIND INCREASE TO 20-30 KT
EARLY MONDAY AFTERNOON BEHIND PASSAGE OF THE SHORTWAVE. MOUNTAIN
TOPS WILL BE OBSCURED THROUGH THE FORECAST PERIOD.
EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL TERMINALS
TERMINALS TO REMAIN VFR THROUGH MIDDAY MONDAY AHEAD OF AN
APPROACHING SHORTWAVE TROUGH. WIND GUSTS AROUND 20 KT WILL
CONTINUE AT KCOD BEFORE DECREASING BY 11Z. A FAVORABLE PRESSURE
GRADIENT ALLOWS FOR GUSTY WIND (30-35 KT) TO CONTINUE OVERNIGHT
AT KCPR ALONG WITH A LAYER OF WIND SHEAR IN THE LOWEST 1,500 FT
AGL. A COLD FRONT PUSHES SOUTHWARD THROUGH KCOD AND KWRL
BETWEEN 16Z- 20Z WITH NORTHERLY/NORTHWESTERLY WIND AND
SCATTERED SNOW SHOWERS DEVELOPING DURING THAT TIME. KCOD AND
KWRL EACH HAVE A 40-60 PERCENT CHANCE OF MVFR CONDITIONS AFTER
21Z, AND HAVE TRENDED TOWARD PREVAILING LOW-END VFR OR PROB30
IN LIGHT SNOW AT BOTH TERMINALS. AHEAD OF THE FRONT, GUSTY
WESTERLY WIND CONTINUES AT KCPR, EVENTUALLY DEVELOPING AT KRIW
AND KLND AROUND 20Z BEHIND THE PASSAGE OF THE SHORTWAVE.
INSTABILITY FAVORS WIDELY SCATTERED LATE DAY SNOW SHOWERS OVER
CENTRAL WYOMING, BUT IMPACTS AT SPECIFIC TERMINALS WOULD BE
SHORT-LIVED. WINDS WILL GRADUALLY DECREASE BEHIND THE FRONT,
FIRST AT KCOD AFTER 00Z, THEN KWRL, KRIW AND KLND BETWEEN 03Z
AND 06Z/TUESDAY. THE COLD FRONT MAY REACH KCPR BY THE END OF THE
TAF PERIOD, TURNING WINDS MORE NORTH-NORTHWEST. THERE WILL BE A
CHANCE FOR THE AFOREMENTIONED SNOW SHOWERS TO IMPACT THE
TERMINAL WITH MVFR CONDITIONS AS WELL. MOUNTAIN TOPS WILL BE
INCREASING OBSCURED AFTER 12Z.
PLEASE SEE THE AVIATION WEATHER CENTER AND/OR CWSU ZDV AND ZLC FOR
THE LATEST INFORMATION ON SMOKE, ICING, AND TURBULENCE FORECASTS.
RIW WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY UNTIL 10 PM MST MONDAY FOR WYZ001-024.
WINTER STORM WARNING UNTIL 10 PM MST MONDAY FOR WYZ012.
DISCUSSION...STRAUB
AVIATION...LAVOIE
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