078
FXUS65 KRIW 161044
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
344 AM MST MON DEC 16 2024
KEY MESSAGES
- THE NEXT SYSTEM NEARS EARLY MONDAY MORNING WITH ANOTHER ROUND
OF SNOW THROUGH TUESDAY EVENING.
- SNOW COMES TO AN END EARLY WEDNESDAY WITH SEASONABLE
TEMPERATURES.
- WARMING AND DRY TREND BY WEEK'S END AND INTO THE WEEKEND.
DISCUSSION
ISSUED AT 1224 AM MST MON DEC 16 2024
IR CURRENTLY DEPICTS THE WEEKEND SYSTEM EXITING TO THE NORTHEAST
ACROSS THE NORTHER GREAT PLAINS WITH THE NEXT SYSTEM MAKING ITS
WAY ACROSS THE PACIFIC NORTHWEST INTO IDAHO. THIS WILL NEAR THE
CWA BY MID TO LATE MORNING WITH SNOW BEGINNING TO CROSS THE
BORDER INTO FAR WESTERN PORTIONS OF THE CWA AROUND THE LUNCH
HOUR MONDAY. THE MAIN FINGER OF THE PFJ CONTINUES TO DIG IN AT
THIS TROUGH WITH A COMPACT PATTERN BEING MORE PROGRESSIVE THAN
THIS PREVIOUS STORM. THE MOST IMPACTFUL PVA ANOMALY LOOKS TO
OCCUR AFTER SUNSET AND INTO THE OVERNIGHT HOURS WHERE THE
HIGHEST SNOWFALL RATES WILL OCCUR. BY MID DAY TUESDAY, THE
TROUGH LOOKS TO START EXITING TO THE EAST OF THE CWA WITH ONLY
LINGERING SNOWFALL WEST OF THE DIVIDE, REMAINING LIGHT IN
NATURE.
SNOWFALL TOTALS ARE A BIT LESS THAN THE WEEKEND BUT STILL HIGH
ENOUGH TO WARRANT WINTER HEADLINES, WARNING LEVEL FOR HIGHEST
ACCUMULATIONS ACROSS THE TETONS. OTHER AREAS WILL BE MUCH LESS
WARRANTING SOME ADVISORIES IN THE SAME AREAS AFFECTED THIS PAST
WEEKEND. UP TO 2 FEET FOR THE TETONS, WHERE PROBABILITIES SHOW
OVER 90 PERCENT CHANCE FOR 18 INCHES OR MORE. AROUND A FOOT
EXPECTED FOR OTHER WESTERN MOUNTAINS WHERE PROBABILITIES ARE
OVER 80 PERCENT FOR THE GROS VENTRES, SALTS, AND WESTERN WINDS.
ALL LOWER VALLEYS ARE EXPECTED TO SEE SOME LIGHT ACCUMULATIONS
WITH JACKSON HOLE SEEING THE HIGHEST PROBABILITIES OVER 4 INCHES
OVER 60 PERCENT, AND OVER 30 PERCENT FOR 6 INCHES OR MORE. WITH
THE MID AND UPPER LEVEL PATTERN BEING MORE ZONAL AND STRAIGHT
WESTERLY, SNOWFALL LOOKS TO HAVE AN IMPACT INTO THE VALLEY OUT
OF IDAHO WITH TETON PASS SEEING THE GREATEST IMPACT TO TRAVEL,
WITH MINOR HAZARDS FOR THE SALT RIVER AND SOUTH PASSES
RESPECTIVELY. A COLD FRONT WILL PASS ACROSS THE BIGHORNS TO THE
NORTHEAST AFTER MIDNIGHT MONDAY NIGHT LINGERING ACROSS INTO
WEDNESDAY MORNING THAT WILL BRING SOME LATE STORM SNOWFALL WITH
MINOR ACCUMULATIONS ACROSS THE BIGHORNS. OTHERWISE, A SURFACE
BOUNDARY EXTENDS TO THE DIVIDE BEFORE LIFTING AS THE MAIN UPPER
LEVEL DISTURBANCE EXITS INTO THE UPPER PLAINS.
WEDNESDAY AND BEYOND, AN UPPER LEVEL RIDGE BUILDS IN FROM THE
SOUTHWEST WITH INCREASING CONVERGENCE ALOFT EXTENDING TO THE
NORTHERN ROCKIES. THIS WILL PUSH THE MAIN PFJ TO THE NORTHEAST
AND THE COOLER AIR. WARMING TREND AND DRY CONDITIONS EXPECTED
THROUGH WEEK'S END AND OVER THE WEEKEND INTO THE UPCOMING
HOLIDAY WEEK. A MINOR SHORTWAVE COULD CLIP THE NORTHWESTERN CWA
WEDNESDAY NIGHT TO BRING SOME LIGHT SNOW TO NORTHWESTERN
MOUNTAINS BUT OTHERWISE, THE RIDGE SETS IN PLACE EXTENDING
FURTHER EAST BY FRIDAY. LONGER TERM MODELS INDICATE THE RIDGE TO
BREAK DOWN AND MOVE EAST BY SUNDAY MAKING WAY FOR THE NEXT
SYSTEM TO START HAVING AN IMPACT TO WESTERN MOUNTAINS AND POINTS
EAST EARLY NEXT WEEK. DETAILS ARE OF LOW CONFIDENCE AT THIS
POINT IN TIME BUT SOMETHING TO KEEP AN EYE ON HEADING INTO
HEAVY TRAVEL TIME AHEAD OF THE UPCOMING HOLIDAY SEASON.
AVIATION /12Z TAFS THROUGH 12Z TUESDAY/
ISSUED AT 340 AM MST MON DEC 16 2024
WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS TERMINALS.
VFR CONDITIONS IN PLACE TO START THE TAF PERIOD. THE NEXT
SYSTEM WILL FOLLOW QUICKLY, MOVING INTO WESTERN WYOMING AFTER
12Z. MVFR CONDITIONS ARE LIKELY AT KJAC BEFORE 18Z AS SNOW
REDEVELOPS. IFR/MVFR CONDITIONS BECOME LIKELY BY 21Z. WHILE
CEILINGS WILL LOWER AT KBPI AND KPNA DURING THE AFTERNOON, SNOW
IMPACTS ARE LARGELY EXPECTED TO HOLD OFF UNTIL AFTER 00Z
TUESDAY. IFR/MVFR CONDITIONS ARE THEN EXPECTED AT THESE
TERMINALS BY 03Z. SNOW SHOWERS MAY MOVE TOWARD KRKS MONDAY NIGHT
BUT NOT ENOUGH CONFIDENCE TO PREVAIL.
EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL TERMINALS.
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. AFTER A LULL, A
GUSTY SOUTHWEST WIND WILL DEVELOP AGAIN IN VICINITY OF KCPR BUT
NOT AS STRONG AS YESTERDAY. A SHOWER MAY APPROACH KCOD AFTER 06Z
TUESDAY BUT NOT ENOUGH CONFIDENCE TO INCLUDE IN THE FORECAST.
PLEASE SEE THE AVIATION WEATHER CENTER AND/OR CWSU ZDV AND ZLC FOR
THE LATEST INFORMATION ON ICING, AND TURBULENCE FORECASTS.
RIW WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 5 PM MST
TUESDAY FOR WYZ001-013.
WINTER STORM WARNING FROM 11 AM THIS MORNING TO 5 PM MST
TUESDAY FOR WYZ012.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 5 PM MST
TUESDAY FOR WYZ014.
WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 5 PM MST
TUESDAY FOR WYZ024.
DISCUSSION...LOWE
AVIATION...HATTINGS
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