170
FXUS65 KRIW 170944
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
244 AM MST MON FEB 17 2025
KEY MESSAGES
- SNOW CONTINUES ACROSS WESTERN AND NORTHERN WYOMING TODAY AND
TONIGHT.
- SNOW AND COLDER AIR SPREADS INTO CENTRAL WYOMING ON TUESDAY.
- DRIER WEATHER IS EXPECTED FRIDAY INTO THE WEEKEND WITH A SLOW
WARMING TREND.
DISCUSSION
ISSUED AT 242 AM MST MON FEB 17 2025
STILL A LOT GOING ON TONIGHT AS THE ACTIVE PATTERN CONTINUES ACROSS
THE AREA. WITH THE CONTRASTS, WE WILL AGAIN SPLIT THE DISCUSSION
INTO WEST AND EAST OF THE DIVIDE,.
WEST OF THE DIVIDE...AS I WRITE THIS, THE AREA IS IN A BIT OF A LULL
WITH SNOWFALL INTENSITY. RADAR DOES SHOW MORE PRECIPITATION ACROSS
IDAHO THOUGH AND THESE WAVES OF PRECIPITATION WILL CONTINUE TO MAKE
THEIR WAY INTO THE REGION. SNOW WILL CONTINUE AT VARYING RATES
THROUGH THE DAY AND INTO TONIGHT. THE EPICENTER OF THE SNOW
CONTINUES TO BE AS, GEE WHAT A SURPRISE, THE TETONS WHERE THERE IS A
4 OUT OF 5 CHANCE OF ANOTHER 12 INCHES OF SNOW OVER THE NEXT 24
HOURS OR SO. THE OTHER MOUNTAIN RANGES HAVE LESS OF A CHANCE, BUT
THE POSSIBILITY OF 6 INCHES OR MORE REMAINS OVER 4 OUT OF 5 IN THESE
LOCATIONS. AS A RESULT, WE WILL CONTINUE THE HIGHLIGHTS FOR THE
MOUNTAINS AS IS. AS FOR THE VALLEY LOCATIONS, MOST LOCATIONS HAVE AT
LEAST A 1 IN 2 CHANCE OF 3 INCHES OR MORE. IT IS LESS THEN THAT
THOUGH, AT THE SOUTHERN ENDS OF THE VALLEYS, ESPECIALLY NEAR THE
TOWNS OF JACKSON, AFTON AND PINEDALE. MOST OF THESE LOCATIONS ONLY
HAVE ADVISORIES THOUGH, SO THESE LOOK FINE FOR NOW. AS FOR
SWEETWATER COUNTY, THERE WILL BE SOME SNOW SHOWERS AROUND BUT NOT A
LOT OF ACCUMULATION. THERE WILL BE A JET STREAK OVER NORTHERN
COLORADO THOUGH, AND THIS WILL BE ENOUGH TO KEEP GUSTY WINDS THE
AREA THROUGH TUESDAY BEFORE SUBSIDING FOR WEDNESDAY.
THE NEXT QUESTION IS THE QUESTION OF EXTENDING THE WARNINGS INTO
TUESDAY. MOST GUIDANCE SHOWS THE DEEPEST MOISTURE MOVING AWAY FROM
THE AREA BY SUNRISE TUESDAY. THE ENSEMBLE PROBABILISTIC
GUIDANCE IS SHOWING AT MOST A 1 IN 4 CHANCE OF 6 INCHES OR MORE
OVER THE 24 HOURS FROM TUESDAY 5 AM TO WEDNESDAY AT 5 AM WITH
THE MOST LIKELY ACCUMULATIONS IN THE MOUNTAINS OF 2 TO 4
ADDITIONAL INCHES. THE VALLEYS HAVE LESS THAN 1 IN 7 CHANCE OF 2
INCHES OR MORE THROUGH THE SAME PERIOD. THERE HAS BEEN SOME
INCONSISTENCY THOUGH IN HOW THIS EVOLVES THOUGH. WE WILL LET THE
DAY SHIFT TAKE ANOTHER LOOK AT THIS WITH ANY POSSIBLE
EXTENSIONS.
THE NEXT SYSTEM THEN APPROACHES FOR WEDNESDAY NIGHT INTO THURSDAY.
THIS SYSTEM HAS BEEN TRENDING WEAKER THOUGH. RIGHT NOW, ENSEMBLE
GUIDANCE ONLY GIVES AT MOST A 1 IN 3 CHANCE OF 6 INCHES OF SNOW OR
MORE ACROSS THE HIGHER ELEVATIONS OF THE TETONS AND SALT AND WYOMING
RANGE WITH AT MOST A 1 IN 5 CHANCE OF 4 INCHES OR MORE IN THE
VALLEYS. IF THIS WORKS OUT, NO HIGHLIGHTS WOULD BE NEEDED OR AT MOST
SOME WINTER WEATHER ADVISORIES FOR THE MOUNTAINS. THIS DEFINITELY
DOES NOT LOOK AS POTENT AS THE CURRENT SYSTEM.
QUIETER WEATHER SHOULD FOLLOW THIS AS MOST GUIDANCE SHOWS RIDGING
BUILDING INTO THE STATE FOR FRIDAY AND THE WEEKEND. THERE COULD BE A
FEW MOUNTAIN SNOW SHOWERS, BUT IMPACTS WOULD BE MINIMAL TO NONE.
EAST OF THE DIVIDE...THINGS REMAIN IN FLUX HERE. THE MILLION DOLLAR
QUESTION REMAINS THE EXTENT OF THE SNOW ACROSS NORTHERN WYOMING WITH
A STALLED FRONTAL BOUNDARY ACROSS NORTHERN WYOMING. THERE IS NOT A
TON OF JET SUPPORT AT THIS TIME, AND AS A RESULT, MOST OF THE
SNOWFALL RATES HAVE BEEN ON THE LIGHT SIDE. ENSEMBLE GUIDANCE
REMAINS SIMILAR TO YESTERDAY WITH THE MAXIMUM SNOWFALL AMOUNTS IN
THE LOWER ELEVATIONS LARGELY EAST OF A POWELL TO LOVELL LINE, WITH A
GREATER THAN 3 IN 4 CHANCE OF 2 INCHES OR MORE THROUGH TUESDAY
MORNING. OTHER LOCATIONS LIKE CODY AND BUFFALO HAVE AROUND A 1 IN 5
CHANCE AT THIS TIME. FURTHER SOUTH ACROSS CENTRAL WYOMING, THINGS
LOOK LARGELY QUIET. WE WILL ONCE AGAIN HAVE A CONTRAST IN
TEMPERATURES ACROSS THE AREA LIKE THE PAST COUPLE OF DAYS. THE
NORTHERN THIRD OF THE AREA WILL HAVE WELL BELOW NORMAL TEMPERATURES,
WITH SOME AREAS LIKELY STAYING AROUND 10 DEGREES. IN CENTRAL
WYOMING, BEING SOUTH OF THE FRONT AND HAVING LITTLE SNOW COVER,
TEMPERATURES WILL RISE INTO THE 30S FOR SOME LOCATIONS.
THIS AREA MAY NEED AN EXTENSION OF THE ADVISORY. A JET STREAK WILL
BE APPROACHING THE AREA ON TUESDAY AS THE BOUNDARY MOVES SOUTHWARD,
ENHANCING FORCING. HERE, I AM BECOMING INCREASINGLY CONCERNED ABOUT
CODY, AS THIS IS A GOOD PATTERN FOR THEM, ESPECIALLY WITH THE LOW
LEVEL NORTHEASTERLY FLOW PROVIDING THE UPSLOPE. THE DEEPER MOISTURE
WILL BE DEPARTING THOUGH. THE CHANCE OF 2 INCHES OF SNOW IN CODY
FROM TUESDAY MORNING TO WEDNESDAY MORNING IS NOW UP TO 2 OUT OF 5
AND THIS COULD BE UNDERDONE. THE JET STREAK WILL ALSO KICK THE
FRONTAL BOUNDARY SOUTH, SPREADING ARCTIC AIR ACROSS THE ENTIRE
REGION TUESDAY INTO TUESDAY NIGHT. THIS WILL ALSO SPREAD SOME SNOW
SOUTHWARD INTO CENTRAL WYOMING. MOISTURE IS LIMITED BUT WITH THE JET
ENERGY THERE COULD BE SOME CONVECTIVE SHOWERS THAT OVERPERFORM.
AMOUNTS SOUTH OF THE OWL CREEK RANGE LOOK SMALL THOUGH, GENERALLY AN
INCH OR LESS UNLESS BANDING DEVELOPS.
QUIETER WEATHER THEN RETURNS AS RIDGING BUILDS INTO THE AREA FOR
WEDNESDAY. THIS WILL BE VERY COLD DAY THOUGH WITH HIGH TEMPERATURES
AVERAGING 20 TO 25 DEGREES BELOW SEASONAL NORMALS. A PACIFIC SYSTEM
MAY THEN MOVE IN FOR THURSDAY. IT HAS A SMALL CHANCE OF BRINGING SOME
SHOWERS BUT THE PATTERN IS NOT FAVORABLE FOR A HEAVY SNOW. QUIETER
WEATHER IS THEN EXPECTED FOR FRIDAY AND INTO THE WEEKEND AS RIDGING
MOVES OVER THE AREA. TEMPERATURES SHOULD GRADUALLY WARM THROUGH THE
PERIOD, WITH THE SLOWEST WARM UP ACROSS NORTHERN AREAS WITH THE
DEEPEST SNOWPACK.
AVIATION /06Z TAFS THROUGH 06Z TUESDAY/
ISSUED AT 949 PM MST SUN FEB 16 2025
WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS TERMINALS.
MAIN SNOW IMPACTS WILL BE AT KJAC THROUGH THE PERIOD. CONFIDENCE IS
LOW AS GUIDANCE IS A BIT ALL OVER THE PLACE. SOME SHOW VISIBILITIES
UNDER A MILE, WHILE OTHERS KEEP IT LOW-END MVFR. HAVE OPTED FOR
PREVAILING MVFR AND IFR CONDITIONS THROUGH THE PERIOD. MODEL
REFLECTIVITY SHOWS HEAVIER SNOW AFTER 10Z. CEILINGS ARE ALSO
CHALLENGING, AGAIN WITH MODELS SHOWING VARIOUS SOLUTIONS; HAVE OPTED
FOR MIDDLE GROUND IN THE TAF.
THE OTHER PLACE OF NOTE IS KRKS, WHERE SOME AFTERNOON/EARLY EVENING
SNOW SHOWERS COULD IMPACT THE SITE, BRINGING BRIEF SNOW AND
VISIBILITY IMPACTS. LOW CONFIDENCE IN WHEN SNOW WILL END AT KPNA.
EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL TERMINALS.
SNOW CHANCES WILL MAINLY BE OVER NORTHERN WYOMING (KCOD/KWRL) FOR
MONDAY AFTERNOON. THERE IS A CHANCE A SNOW SHOWER COULD IMPACT ANY
SITE, BUT FOR KLND AND KRIW THOSE CHANCES ARE 15% OR LESS. WINDS
WILL MAINLY BE OUT OF THE NORTH/NORTHEAST THROUGH THE PERIOD.
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 STORM WARNING UNTIL 5 AM MST TUESDAY FOR WYZ001-002-012-
024.
WINTER WEATHER ADVISORY UNTIL 5 AM MST TUESDAY FOR WYZ004-008-
013-014-023-025.
DISCUSSION...HATTINGS
AVIATION...WITTMANN
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