229
FXUS65 KRIW 170453
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
953 PM MST SAT NOV 16 2024
KEY MESSAGES
- SNOW SHOWERS THIS AFTERNOON SHOULD DISSIPATE FOR MOST AREAS
AFTER SUNSET.
- GUSTY TO STRONG WIND WILL DEVELOP LATE TONIGHT AND SUNDAY IN
THE FAVORED SOUTHWESTERLY FLOW AREAS.
- THE NEXT PACIFIC TROUGH AND COLD FRONT WILL BRING THE NEXT
ROUND OF SNOW FROM LATE SUNDAY NIGHT THROUGH MONDAY.
DISCUSSION
ISSUED AT 118 PM MST SAT NOV 16 2024
HE MAIN THINGS THAT IS OCCURRING TODAY IS, TO QUOTE THE MOST WELL
KNOWN SONG FROM THE CLASSIC MOVIE "THE SOUND OF MUSIC", ONE OF MY
FAVORITE THINGS. HOWEVER, THIS IS ALSO COMBINED WITH A HEAVY DOSE OF
MY GEN X / NEW ENGLANDER SARCASM. THIS THING IS CONVECTIVE SNOW
BANDS, THE THINGS THAT MAKE MY PULL OUT WHAT IS REMAINING OF MY
THINNING HAIR.
THE MAIN CONCERNS HERE IS NEAR SOUTH PASS, WHERE AS I WRITE THIS
AROUND 12:30 PM, ONE APPEARS TO BE FORMING WITH THE FAVORABLE
NORTHWEST FLOW. THE HRRR CONTINUES TO DEPICT THIS WELL. HOWEVER, IT
HAS BACKED OFF SNOWFALL AMOUNTS. THERE WILL LIKELY BE A COUPLE
OF INCHES OF SNOW OVER THE PASS, BUT THE HEAVIEST AMOUNTS WOULD
STAY OVER THE HIGHER ELEVATIONS. IT COULD BE A ROUGH COUPLE OF
HOURS TRYING TO GO THROUGH THERE THOUGH. THIS SHOULD DISSIPATE
AROUND SUNSET AS WE LOSE THE INSTABILITY OF THE DAY. ANOTHER
AREA OF CONCERN MAY BE NEAR HIGHWAY 120 AND WEST WHERE SOME
NORTHEAST UPSLOPE FLOW MAY ENHANCE SNOW SHOWERS SOMEWHAT. AGAIN,
MOST OF THESE SHOULD END SHORTLY AFTER SUNSET.
THERE IS NO REST FOR THE WEARY THOUGH, AS THE NEXT PACIFIC TROUGH
AND COLD FRONT WILL BE ON ITS HEELS. THE FIRST IMPACT WILL BE STRONG
WIND, WHICH WILL ARRIVE LATER TONIGHT INTO TOMORROW IN THE FAVORED
SOUTHWEST FLOW AREAS. THIS IS MAINLY SOUTH PASS AND FROM MUDDY GAP
THROUGH CASPER. AS FOR HIGH WIND, IT IS QUESTIONABLE. THERE WILL BE
A 100 KNOT JET STREAK MOVING OVER THE AREA LATE TONIGHT. HOWEVER,
MOST GUIDANCE IS SHOWING 700 MILLIBAR KNOT WINDS REMAINING UNDER 50
KNOTS, WITH THE CORE OF THESE STRONGER WINDS REMAINING OVER CARBON
COUNTY. THERE IS A GREATER THAN 3 OUT OF 5 CHANCE OF WIND GUSTS PAST
40 MPH HERE THOUGH. SO FOR NOW, WE WILL HOLD OFF ON ANY HIGHLIGHTS.
THE OTHER CONCERN IS AROUND AND WEST OF CODY. AGAIN, THE CHANCE OF
WIND GUSTS PAST 40 MPH IS FAIRLY HIGH, GENERALLY GREATER THAN A 2
OUT OF 3 CHANCE. THE CHANCE OF HIGH WINDS, (GUSTS PAST 50 KNOTS),
IS LESS THAN 1 OUT OF 10 IN TOWN AND EVEN IN THE FAVORED AREAS TO
THE WEST, IT IS ONLY 1 OUT OF 10. SO AGAIN, NO WIND HIGHLIGHTS WOULD
BE NEEDED. THE MAIN TIME OF CONCERN HERE WOULD BE LATE TONIGHT, WITH
LESS OF A CHANCE THROUGH THE DAY ON SUNDAY.
THE MAIN CONCERN THEN SHIFTS TO SNOW. MOIST WESTERLY FLOW WILL KEEP
SNOW SHOWERS GOING IN THE NORTHWESTERN MOUNTAINS THROUGH SUNDAY,
BUT AMOUNTS WILL REMAIN LIGHT. THE STEADIER SNOW LOOKS TO BREAK OUT
AFTER MIDNIGHT AND CONTINUE THROUGH MONDAY BEFORE TAPERING OFF
MONDAY NIGHT AS THE TROUGH AXIS MOVES TO THE EAST. HIGHLIGHTS WILL
LIKELY BE NEEDED FOR THIS SYSTEM. RIGHT NOW, WE WOULD BE LEANING
TOWARD ADVISORIES RATHER THAN WARNINGS. PROBABILISTIC GUIDANCE SHOWS
GREATER THAN A 4 OUT OF 5 CHANCE OF 6 INCHES OR MORE IN THE TETONS
AND SOUTHWEST YELLOWSTONE, WITH GREATER THAN A 50 PERCENT CHANCE IN
PORTIONS OF THE SALT AND WYOMING RANGE AND WESTERN BIGHORN RANGE. AS
FOR WARNING LEVEL AMOUNTS, THE MOST LIKELY AREA IS SOUTHWEST
YELLOWSTONE, WITH A 3 OUT OF 5 CHANCE OF A FOOT OR MORE. HOWEVER,
IMPACTS FROM THIS WOULD BE MINIMAL SINCE YELLOWSTONE IS MOSTLY
CLOSED RIGHT NOW, ESPECIALLY THAT PORTION OF THE PARK. IN CONJUNCTION
WITH SURROUNDING OFFICES, WE WILL LET LATER SHIFTS MAKE THE
DECISION. SNOW SHOWERS WILL BE POSSIBLE IN THE LOWER ELEVATIONS
EAST OF THE DIVIDE AS WELL. HOWEVER, LIKE TODAY, THIS WOULD BE
SHOWERY OR BANDED SNOW THAT IS IMPOSSIBLE TO PINPOINT THIS FAR
OUT.
MAINLY LIGHTER SHOWERS CONTINUE INTO TUESDAY. FOLLOWING THAT,
RIDGING WILL LIKELY BUILD NORTHWARD AND BRING WARMER AND DRY WEATHER
FOR MOST OF THE AREA. THE QUESTION HERE IS WHETHER OR NOT THE RIDGE
WILL BE FLATTER AND ALLOW A COUPLE OF WAVES TO BRUSH BY TO THE
NORTH, BRINGING SOME LIGHTER PRECIPITATION TO THE NORTHERN MOUNTAINS.
GUIDANCE REMAINS IN POOR AGREEMENT WITH THE MAIN DETERMINISTIC
MODELS, THE GFS AND EUROPEAN, FLIP FLOPPING WITH THEIR SOLUTIONS.
FOR NOW, GIVEN THE UNCERTAINTY, WE HAVE MADE FEW CHANGE TO
CONTINUITY.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 952 PM MST SAT NOV 16 2024
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGHOUT MUCH OF THE TAF
PERIOD. A FEW LIGHT SNOW SHOWERS MAY LINGER NEARBY KJAC TO START THE
PERIOD BUT NO IMPACTS ARE EXPECTED. SCT/BKN CLOUDS WILL LINGER
ACROSS WESTERN TERMINALS SUCH AS KJAC, KBPI, AND KPNA THROUGH SUNDAY
MORNING. CEILINGS WILL INCREASE DURING THE DAY SUNDAY ACROSS MOST
TERMINALS WITH THE EXCEPTION BEING KJAC. GUSTY WINDS ARRIVE AROUND
18Z SUNDAY WITH FREQUENT GUSTS AROUND 30 TO 40 KNOTS AT KCOD/KCPR.
KRKS MAY SEE A BRIEF INCREASE IN WINDS AROUND THE SAME TIME WITH
GUSTS NEAR 25 KNOTS. KLND MAY SEE AN INCREASE IN WINDS AS WELL BUT
AT THIS TIME CONFIDENCE REMAINS LOW. WINDS DECREASE BY THE EVENING
WITH KCOD/KCPR SEEING GUSTS AROUND 25 KNOTS HEADING INTO THE END OF
THE PERIOD. CLOUDS WILL BEGIN TO MOVE INTO WESTERN WY NEAR THE END
OF THE TAF PERIOD WITH SNOW SHOWERS POSSIBLE AT KJAC. DUE TO A LACK
IN CONFIDENCE REGARDING TIMING AND IMPACTS OF THE SNOW SHOWERS, VCSH
HAS BEEN PUT AT KJAC TO END THE PERIOD.
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
NONE.
DISCUSSION...HATTINGS
AVIATION...DZIEWALTOWSKI
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