626
FXUS65 KRIW 190919
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
219 AM MST WED FEB 19 2025
KEY MESSAGES
- MAINLY DRY TODAY AND NOT AS COLD IN THE AFTERNOON.
- A WEATHER SYSTEM BRINGS LIGHT TO POSSIBLY MODERATE SNOW TO
WESTERN AND SOUTHERN WYOMING TONIGHT AND THURSDAY.
- A DRIER AND WARMER PATTERN IS LOOKING MORE LIKELY STARTING
FRIDAY AND CONTINUING INTO THE WEEKEND.
DISCUSSION
ISSUED AT 217 AM MST WED FEB 19 2025
WE ARE FINALLY ENTERING A SOMEWHAT QUIETER PATTERN. WE
STILL HAVE A COUPLE OF CONCERNS THOUGH, WE STILL HAVE A FEW
SNOWBANDS OUT THERE THIS MORNING BUT THESE ARE SLOWLY WEAKENING AND
SHOULD BE GONE BY SUNRISE. TRANSITORY RIDGING WILL MOVE ACROSS THE
AREA TODAY AND BRING MAINLY DRY CONDITIONS. THERE WILL STILL BE A
FEW MOUNTAIN SNOW SHOWERS BUT NOTHING OF CONSEQUENCE. WE ALSO HAVE
SOME VERY COLD TEMPERATURES ACROSS NORTHERN PORTIONS OF OUR AREA.
HOWEVER, WIND REMAINS LIGHT AND LINGERING CLOUD COVER HAS KEPT
THINGS A BIT WARMER. THIS SHOULD BE THE COLDEST NIGHT AS WELL.
TEMPERATURES TODAY WILL BE BELOW NORMAL FOR MOST LOCATIONS BUT MORE
SUNSHINE SHOULD BRING A WARMER DAY THAN ON TUESDAY.
THIS QUIET WEATHER WILL NOT LAST LONG THOUGH AS THE NEXT PACIFIC
SYSTEM APPROACHES FROM THE WEST. THIS ONE IS FORTUNATELY NOT AS
INTENSE AS THE PREVIOUS ONE AND IS A FASTER MOVER, IN AND OUT OF THE
AREA IN AROUND 24 HOURS. WE DID GIVE THOUGHT TO SOME WINTER WEATHER
ADVISORIES BUT DECIDED AGAINST IT FOR NOW. THE NEXT QUESTIONS,
OBVIOUSLY, IS WHY? REASON NUMBER 1 WAS THE STORM WE JUST HAD, WHEN
SOME LOCATIONS PICKED UP OVER 3 FEET OF SNOW. AMOUNTS ARE MUCH LESS
WITH THIS. PROBABILISTIC GUIDANCE GIVES AT MOST A 1 OUT OF 2 CHANCE
OF OVER 6 INCHES OF NEW SNOW ACROSS THE TETONS AND SALT AND WYOMING
RANGE AND THIS IS MAINLY ABOVE PASS LEVEL. THE ONLY LOCATION FOR
OVER 4 INCHES IN THE LOWER ELEVATIONS IS ALPINE AND EVEN HERE IT IS
ONLY 1 OUT OF 7. SO, IMPACTS WOULD BE MUCH LESS. IN ADDITION, THE
BEST JET SUPPORT REMAINS SOUTH OF WYOMING, SO FORCING WILL NOT BE
THAT GREAT. ONE AREA I AM A BIT MORE CONCERNED ABOUT IS SWEETWATER
COUNTY. THIS AREA WILL BE CLOSER TO THE LEFT FRONT QUADRANT OF THE
AFOREMENTIONED JET. THERE IS A DECENT CHANCE OF SOME ACCUMULATING
SNOW. HOWEVER, THE HEAVIEST AMOUNT WOULD FALL SOUTH OF INTERSTATE 80
WHERE IMPACTS WOULD BE LITTLE. FOR EXAMPLE, ROCK SPRINGS ONLY HAS A
1 OUT OF 5 CHANCE OF 2 INCHES OR MORE. MOST OF THIS SNOW WOULD
OCCUR ON THURSDAY, SO THERE IS STILL SOME TIME TO EVALUATE THIS. AS
FOR EAST OF THE DIVIDE, THERE COULD BE SOME LIGHT SNOW AS THE
MOISTURE CROSSES THE MOUNTAINS BUT THE CHANCE OF ANY ACCUMULATION OF
AN INCH OR MORE IS LESS THAN 1 OUT OF 10.
MOST OF THIS SNOW SHOULD END THURSDAY NIGHT. FOLLOWING THIS, WE
SHOULD SEE A PATTERN CHANGE AS RIDGING BUILDS INTO THE AREA STARTING
ON FRIDAY. THIS SHOULD MEAN A WARNING TREND, WITH HIGHS IN THE 50S
POSSIBLE FOR SOME LOCATIONS STARTING ON SUNDAY, ALTHOUGH MONDAY
LOOKS LIKE THE BEST CHANCE. THE BEST CHANCE WOULD BE ACROSS CENTRAL
WYOMING, ESPECIALLY IN PLACES THAT HAVE LITTLE SNOW COVER. EVEN IF
THIS DOESN'T HAPPEN, THERE IS A VERY HIGH LIKELIHOOD THAT LOW
ELEVATION SNOW COVER WOULD BE SUBSTANTIALLY REDUCED OVER THE WEEKEND
AND EARLY NEXT WEEK. THE MAIN FLY IN THE OINTMENT HERE ARE A COUPLE
OF PACIFIC SYSTEMS THAT MAY APPROACH LATER IN THE WEEKEND AND EARLY
NEXT WEEK. AT THIS TIME, IT LOOKS LIKE THE BEST FORCING WOULD REMAIN
OVER MONTANA WITH JUST GLANCING BLOWS TO NORTHWESTERN WYOMING. THIS
IS FAR FROM CERTAIN THOUGH. HOWEVER, WE HAVE FAIRLY HIGH CONFIDENCE
WE WILL BE ENTERING INTO A SOMEWHAT DRIER AND WARMER PATTERN FOR THE
LATTER PART OF FEBRUARY.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1002 PM MST TUE FEB 18 2025
WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS TERMINALS
ANY LINGERING SNOW SHOULD END RIGHT AROUND THE START OF THE TAF
PERIOD, WITH CONDITIONS REMAINING OR IMPROVING TO VFR. THERE IS A
CHANCE OF FOG AT KBPI/KPNA WEDNESDAY MORNING, BUT CONFIDENCE REMAINS
LOW (20-30%), SO ONLY HAVE VCFG FEW002 FOR THOSE TERMINALS. NOT MUCH
IN THE WAY OF WEATHER IMPACTS THROUGH WEDNESDAY AFTERNOON FOR ALL
TERMINALS, BUT THE NEXT WEATHER SYSTEM WILL BRING MORE SNOW INTO THE
AREA WEDNESDAY EVENING NEAR THE END OF THE TAF PERIOD. MOUNTAIN
OBSCURATION WILL OCCUR AT TIMES THROUGH WEDNESDAY MORNING, IMPROVING
WEDNESDAY AFTERNOON.
WIND WILL BE LIGHT AT MOST TERMINALS THROUGH THE TAF PERIOD. AT KRKS
ELEVATED WIND (15-20 KNOTS) WILL CONTINUE UNTIL ABOUT 10Z/WED BEFORE
DROPPING TO 10 KNOTS, BUT WILL INCREASE BY LATE MORNING THROUGH THE
AFTERNOON HOURS, ONCE AGAIN.
EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL TERMINALS
LIGHT SNOW LINGERS AT KCPR/KRIW/KLND FOR A FEW HOURS TO START THE
TAF PERIOD. THIS WILL RESULT IN PREVAILING MVFR (BRIEFLY DROPPING
DOWN TO IFR) CONDITIONS BEFORE SNOW FINALLY TAPERS OFF EARLY
WEDNESDAY MORNING. CIGS ARE EXPECTED TO REMAIN MVFR/IFR AT KCPR
UNTIL 12Z/WED. FOG IS POSSIBLE (30-40%) AT KCOD WEDNESDAY MORNING,
BUT THIS WILL DEPEND GREATLY ON HOW QUICKLY SKIES CLEAR OVERNIGHT.
CLOUDS AND SNOW HAS BEEN LINGERING LONGER THAN ORIGINALLY EXPECTED,
SO THIS MAY LIMIT FOG DEVELOPMENT WEDNESDAY MORNING. AFTER SUNRISE
CONDITIONS SHOULD IMPROVE TO VFR AT ALL TERMINALS AND REMAIN SO
THROUGH THE REST OF THE TAF PERIOD. MOUNTAIN OBSCURATION WILL
CONTINUE OVERNIGHT, IMPROVING WEDNESDAY MORNING. WIND WILL REMAIN
LIGHT AT TERMINALS FOR THE NEXT 24 HOURS.
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
NONE.
DISCUSSION...HATTINGS
AVIATION...ROWE
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