626
FXUS65 KRIW 161230
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
630 AM MDT THU APR 16 2026
KEY MESSAGES
- A WEATHER SYSTEM WILL MOVE ACROSS THE STATE AND BRING SNOW AND
RAIN CHANGING TO SNOW TODAY AND TONIGHT. THE HIGHEST SNOWFALL
AMOUNTS WILL BE IN THE WESTERN MOUNTAINS. GUSTY WIND WILL
BRING BLOW AND DRIFT THE SNOW AT TIMES.
- A HARD FREEZE IS LIKELY (4 OUT OF 5 CHANCE) IN THE LOWER
ELEVATIONS TO THE EAST OF THE DIVIDE FRIDAY NIGHT.
- DRIER AND WARMER WEATHER RETURNS FOR SUNDAY AND EARLY NEXT
WEEK.
DISCUSSION
ISSUED AT 207 AM MDT THU APR 16 2026
THERE HAVE TIMES THROUGH MY RATHER LENGTHY METEOROLOGY CAREER THAT I
HAVE FELT GUILTY FOR THINGS. AND THIS IS A SYSTEM WHEN I AM HAVING
THESE FEELINGS. THE LAST TIME I DID THE FORECAST, BACK ON EARLY
MONDAY MORNING, IT LOOKED LIKE WE HAD A DECENT CHANCE OF SOME BADLY
NEEDED MOISTURE ACROSS THE AREA. HOWEVER, TRENDS FOR MUCH OF THE
AREA THAT NEED THE MOISTURE, LIKE THE GREEN RIVER, WIND RIVER AND
BIG HORN BASINS, HAVE BEEN FOR LESS AND LESS MOISTURE. AT THE TIME,
CHANCES LOOKED RATHER GOOD. NEEDLESS TO SAY, CHANCES HAVE DIMINISHED
SUBSTANTIALLY OVER THE PAST FEW DAYS.
RADAR NOW SHOWS THE FIRST AREA OF PRECIPITATION MOVING INTO
WESTERN WYOMING. THE COLD FRONT IS STILL BACK IN IDAHO, SO SNOW
LEVELS REMAIN FAIRLY HIGH RIGHT NOW, GENERALLY ABOVE 7500 FEET. SNOW
WILL LEVELS WILL GRADUALLY DROP THROUGH THE NIGHT AND DAY. AS FOR
HIGHLIGHTS IN WESTERN WYOMING, THESE STILL LOOK REASONABLE.
PROBABILISTIC GUIDANCE SHOWS AT LEAST A 2 OUT OF 3 CHANCE OF 8 INCHES
OR MORE ACROSS MOST OF THE WARNED AREA. THOUGHT ABOUT A WINTER
WEATHER ADVISORY FOR THE SALT AND WYOMING RANGE, BUT THE ONLY AREAS
WITH A GREATER THAN 1 IN 2 CHANCE OF 6 INCHES OF NEW SNOW OR MORE
ARE THE HIGHEST ELEVATION ABOVE THE MOUNTAIN PASSES. SO, WE WILL
HOLD OFF FOR NOW. IN THE VALLEYS AND LOWER ELEVATIONS, NO LOCATION
HAS MORE THAN A 1 IN 6 CHANCE OF 4 INCHES OR MORE, SO NO HIGHLIGHTS
HERE. SOME SNOW WILL CONTINUE THROUGH THURSDAY NIGHT, BUT THE BULK
OF THE SNOW WILL FALL THROUGH MIDNIGHT WITH LIGHT SNOW FOLLOWING
THAT. IN SWEETWATER COUNTY, WITH SOME SURFACE INSTABILITY, SNOW
SQUALLS WILL BE POSSIBLE LATE TODAY AND THIS EVENING WITH THE
FRONT, MAINLY TO THE EAST OF ROCK SPRINGS. AMOUNTS HERE SHOULD
REMAIN UNDER 3 INCHES THOUGH. THE ONLY AREAS WITH A GREATER THAN
1 IN 3 CHANCE ARE ACROSS FAR SOUTHERN SWEETWATER COUNTY WHERE
IMPACTS WILL BE SLIM TO NONE. ANY SNOW SQUALLS COULD BE HANDLED
BY SHORT FUSED STATEMENTS.
AND NOW ON THE AREA WHERE I FEEL GUILTY, EAST OF THE DIVIDE. TRENDS
CONTINUE TO BE DOWN IN THIS AREA. I GAVE SERIOUS THOUGHT TO
CANCELING THE ADVISORIES FOR THE WIND RIVER BASIN AND LANDER
FOOTHILLS. HOWEVER, I AM HOLDING OFF NOW FOR A FEW REASONS. FOR ONE,
GUIDANCE IS INDICATING SOME INSTABILITY, WITH UP TO 250 J/KG OF CAPE
THIS AFTERNOON WITH LIFTED INDICES AS LOW AS MINUS 1. IN ADDITION,
THE AREA WILL BE UNDER THE RIGHT REAR QUADRANT OF THE JET THIS
EVENING. THIS COULD LEAD TO SOME SNOW SQUALLS AS THE FRONT MOVES
THROUGH THE AREA THIS AFTERNOON AND EVENING. THE OTHER IS A FEATURE
I SAW ON THE GFS EARLY THIS MORNING. THERE IS THE PRESENCE OF A WEAK
700 MILLIBAR CIRCULATION AROUND MIDNIGHT TONIGHT NEAR THE NATRONA /
FREMONT COUNTY BORDER, GIVING A DECENT AMOUNT OF QPF (AS MUCH AS A
A QUARTER OF AN INCH). IF THIS FURTHER MOVES A BIT FURTHER WEST, IT
COULD IMPACT RIVERTON AND LANDER. EASTERN PORTIONS OF THE BASIN
STILL HAVE A 1 IN 2 CHANCE OF 3 INCHES OF SNOW AS WELL. SO, WE WILL
LEAVE THEM UP FOR NOW. HIGHLIGHTS STILL LOOK GOOD FOR JOHNSON AND
NATRONA COUNTIES THOUGH, WITH MOST PROBABILISTIC GUIDANCE GIVING AT
LEAST A 1 IN 2 CHANCE OF 3 INCHES OF SNOW OR MORE. IN THIS AREA, THE
HIGHEST IMPACT WILL BE THURSDAY NIGHT. WIND WILL ALSO BE AN ISSUE,
ESPECIALLY IN THE FAVORED NORTHWEST FLOW / COLD ADVECTION LOCATIONS,
LIKE JOHNSON COUNTY AND THE BIGHORN BASIN, BRING BLOWING SNOW AND
MORE IMPACTS WITH GUSTS OVER 40 MPH AT TIMES LATER THIS AFTERNOON
AND EVENING.
CONDITIONS SHOULD BEGIN TO IMPROVE ON FRIDAY AS THE TROUGH AND FRONT
MOVE AWAY TO THE EAST. UNSTABLE NORTHWEST FLOW AND CYCLONIC
CURVATURE WILL KEEP SNOW SHOWERS GOING THROUGH MUCH OF THE DAY. THEN
WE TURN TO FRIDAY NIGHT WITH THE POTENTIAL FOR A FREEZE. AS I HAVE
STATED BEFORE, THE CONCERN IS NOT WITH CROPS AND GARDENS AS WYOMING
RESIDENTS KNOW NOT TO PLANT THIS EARLY. THE MAIN CONCERN WILL BE FOR
FLOWER GARDENS, TREES AND SPRINKLER SYSTEMS. THE VARIABLES REMAIN
THE SAME. FIRST, IF IT CAN CLEAR OUT ENOUGH. CHANCES ARE BETTER FOR
THIS ACROSS THE NORTH AND WEST, WITH DECREASING CHANCES FURTHER
SOUTH. THE OTHER IS SNOW COVER, CHANCES OF LOWS BELOW 20 HAVE
DECREASED SOMEWHAT ACROSS THE BIGHORN BASIN AND WIND RIVER BASIN
WITH THE SMALLER AMOUNTS OF SNOW REDUCING ALBEDO. PROBABILISTIC
GUIDANCE STILL GIVES A GREATER THAN 2 IN 3 CHANCE OF LOWS BELOW 25
ACROSS ALMOST ALL THE AREA THOUGH. WE WILL HOLD OFF ON ANY FREEZE
PRODUCTS WITH THE GREATER CONCERN OF THE SNOW BUT SOME WILL LIKELY
BE NEEDED.
THE REMAINDER OF THE FORECAST PERIOD LOOKS LARGELY TRANQUIL AS
RIDGING BUILDS BACK OVER THE ROCKIES FOR THIS WEEKEND AND EARLY NEXT
WEEK. TEMPERATURES WILL BEGIN TO MODERATE SATURDAY AND LIKELY
RETURN TO NEAR TO ABOVE NORMAL LEVELS BY SUNDAY FOR MOST. MOST AREAS
LOOK DRY AND WARM FROM MONDAY THROUGH AT LEAST WEDNESDAY. THE NEXT
SYSTEM IS THE FORM OF AN UPPER LEVEL LOW MAY THEN APPROACH FOR LATER
NEXT WEEK WITH THE NEXT CHANCE OF MOISTURE BUT THESE ARE VERY FICKLE
THIS FAR OUT SO DETAILS ARE STILL HIGHLY UNCERTAIN.
AVIATION /12Z TAFS THROUGH 12Z FRIDAY/
ISSUED AT 630 AM MDT THU APR 16 2026
WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS TERMINALS
A SYSTEM CONTINUES TO IMPACT THE AREA THIS PERIOD. CONDITIONS
WILL HOVER RIGHT AROUND VFR/MVFR THROUGH MOST OF THE DAY, WITH
OCCASIONAL IFR IMPACTS DURING PERIODS OF HEAVIER SNOW.
CONDITIONS SHOULD IMPROVE THIS AFTERNOON BEFORE A SNOW BAND
MOVES IN THIS EVENING DROPPING CONDITIONS BACK TO MVFR/IFR AT
KJAC. AT KBPI AND KPNA CHANCES ARE TOO LOW FOR PREVAILING
PRECIPITATION, BUT THERE IS A 30% CHANCE OF SOME RAIN SHOWERS
LATE THIS MORNING INTO EARLY AFTERNOON. RAIN SHOWERS WILL
DEVELOP AT KRKS THIS AFTERNOON, WITH SOME ISOLATED THUNDER
POSSIBLE (30%). RAIN WILL TRANSITION TO SNOW AT KRKS LATE
THIS AFTERNOON, WITH SNOW ENDING BY 03Z FRIDAY.
A COLD FRONT WILL PASS THROUGH THIS AFTERNOON AND EVENING, WITH
WIND SHIFTING FROM SOUTHWEST TO NORTHWEST BEHIND THE FRONT.
WIND WILL REMAIN BREEZY THROUGH THE TAF PERIOD, WITH STRONG WIND
FROM MID-MORNING THURSDAY THROUGH THURSDAY AFTERNOON. MOUNTAIN
OBSCURATION WILL BE PREVALENT THROUGH THE TAF PERIOD.
EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL TERMINALS
VFR CONDITIONS PREVAIL THROUGH THIS MORNING, BUT RAIN WILL
SPREAD EAST OF THE CONTINENTAL DIVIDE THIS AFTERNOON AND
QUICKLY TRANSITION TO SNOW THIS EVENING. MOST TERMINALS WILL
HAVE MINIMAL IMPACTS THROUGH THE DAYLIGHT HOURS. KCPR IS THE
EXCEPTION AS CONVECTIVE RAIN/SNOW BANDS WILL DEVELOP THIS
AFTERNOON INTO THE EVENING. CONDITIONS WILL DROP TO IFR AT KCPR
THIS EVENING ONCE RAIN TRANSITIONS TO SNOW. AT KRIW, KLND, AND
KWRL PROB30 GROUPS HAVE BEEN ADDED FOR A RAIN/SNOW MIX. AT KCOD
AND KWRL THERE WILL BE A BETTER CHANCE FOR PREVAILING LIGHT
SNOW SHOWERS AND MVFR CONDITIONS THIS EVENING.
A COLD FRONT WILL PASS THROUGH THIS MORNING INTO THE AFTERNOON,
WITH WIND SHIFTING FROM SOUTHWEST TO NORTHWEST BEHIND THE
FRONT. WIND WILL REMAIN BREEZY THROUGH THE TAF PERIOD, WITH
STRONG WIND FROM MID-MORNING THROUGH THIS AFTERNOON. MOUNTAIN
OBSCURATION WILL BECOME MORE FREQUENT ONCE THE FRONT PASSES
THROUGH.
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 6 AM MDT FRIDAY FOR WYZ001-002-012.
WINTER WEATHER ADVISORY UNTIL 6 AM MDT FRIDAY FOR WYZ008-009.
WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM MDT FRIDAY FOR
WYZ010-011.
WINTER STORM WARNING UNTIL 6 PM MDT FRIDAY FOR WYZ014-015.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 6 AM MDT
FRIDAY FOR WYZ016>018.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO NOON MDT
FRIDAY FOR WYZ019-020-022.
DISCUSSION...HATTINGS
AVIATION...ROWE/MYERS
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