245
FXUS65 KRIW 170353
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
953 PM MDT THU APR 16 2026
KEY MESSAGES
- MODERATE TO HEAVY SNOW WILL CONTINUE FROM ROCK SPRINGS TO
MONETA TO BUFFALO AND EASTWARD THIS EVENING. THIS AREA OF SNOW
WILL SLOWLY PUSH EAST AND WEAKEN TONIGHT.
- A HARD FREEZE IS EXPECTED TO OCCUR ACROSS NEARLY ALL LOWER
ELEVATIONS WITH TEMPERATURES IN THE TEENS AND TWENTIES FRIDAY
AND SATURDAY MORNINGS.
- DRY AND WARM CONDITIONS GRADUALLY RETURN TO THE STATE OVER THE
WEEKEND INTO THE START OF NEXT WEEK.
UPDATE
ISSUED AT 136 PM MDT THU APR 16 2026
THE SYSTEM THAT HAS BEEN TALKED ABOUT ALL WEEK IS FINALLY WORKING
ITS WAY THROUGH THE AREA. THE PREVIOUS DISCUSSION IS STILL ON TRACK
WITH ONLY A FEW CAVEATS. THE ASSOCIATED COLD FRONT IS GRADUALLY
MAKING ITS WAY SOUTH ACROSS THE STATE CURRENTLY. UNFORTUNATELY, THE
TREND OF A WEAKER MORE DISORGANIZED SYSTEM PERSISTS AND AS A RESULT,
PRECIPITATION AMOUNTS AND SNOW ACCUMULATIONS CONTINUE TO LESSEN. THE
BRIGHT SIDE IS MOST HIGHER ELEVATION MOUNTAINS WILL SEE SOME
MUCH NEEDED MOISTURE, THE SAME CANNOT BE SAID FOR THE LOWER
ELEVATIONS. CONVECTIVE SHOWERS WILL CONTINUE TO POP UP THIS
AFTERNOON AHEAD OF THE FRONT WITH THE BEST CHANCES (40-70%)
REMAINING ACROSS PORTIONS OF CENTRAL WY MAINLY JOHNSON AND
NATRONA COUNTIES ALONG WITH PORTIONS OF THE BIGHORN BASIN.
PRECIPITATION LIKELY FALLS AS RAIN INITIALLY WITH THESE SHOWERS
BUT AS THE COLDER AIR APPROACHES THERE IS A GOOD CHANCE FOR SNOW
SQUALLS TO DEVELOP. THESE SQUALLS WILL CREATE SOME HAZARDOUS
CONDITIONS FOR A PERIOD OF TIME WITH LOWERED VISIBILITIES, GUSTY
WINDS, AND MODERATE TO HEAVY SNOWFALL. AN ISOLATED RUMBLE OF
THUNDER CANNOT BE RULED OUT NEARBY THESE DEVELOPING SQUALLS. A
QUICK COATING TO INCH OR TWO MAY BE POSSIBLE ON GRASSY SURFACES
WITH ANY SQUALLS BUT WARM SURFACES MAY LIMIT MOST ACCUMULATION.
ONCE THE SUN SETS THESE CONVECTIVE SHOWERS SHOULD DISSIPATE AND
THE NEXT PHASE OF THIS DISTURBANCE WILL BEGIN. THURSDAY NIGHT
INTO FRIDAY MORNING LOOKS TO BE THE BEST PERIOD TO SEE A
PROLONGED PERIOD OF LIGHT TO MODERATE SNOWFALL AS FLOW BECOMES
MORE FAVORABLE FOR PORTIONS OF NATRONA AND JOHNSON COUNTIES.
THIS IS WHERE THINGS WENT WRONG IN TERMS OF PRECIPITATION FOR
OTHER LOCATIONS, SUCH AS THE WIND RIVER BASIN. MODELS HAVE
CONTINUED TO SHOW A MORE NORTHWESTERLY FLOW DEVELOP, WHICH IS
RATHER UNFAVORABLE. AS A RESULT, THE PERIOD OF SNOW FOR PORTIONS
OF THE WIND RIVER BASIN HAS BECOME MORE AND MORE UNLIKELY. DUE
TO THIS,W SNOW ACCUMULATIONS HAVE DROPPED TO A GENEROUS 0.2 TO
1.0 INCHES. THIS IS LIKELY ON THE HIGHER SIDE AND ITS VERY
POSSIBLE THAT MANY AREAS MAY ONLY SEE A FEW FLAKES WITH THE
INITIAL FRONTAL PASSAGE. DUE TO THIS, WINTER WEATHER ADVISORIES
FOR THE WIND RIVER BASIN, LANDER FOOTHILLS, AND UPPER WIND RIVER
BASIN HAVE BEEN CANCELLED. THE OTHER ADVISORIES REMAIN IN PLACE
AS THEY STILL LOOK TO HAVE THE MOST FAVORABLE DYNAMICS.
ASIDE FROM SNOW, THE OTHER IMPACTFUL ASPECT OF THIS SYSTEM WILL BE
WELL BELOW FREEZING MORNING LOWS ON FRIDAY AND SATURDAY MORNINGS.
LOW TEMPERATURES CURRENTLY ARE FORECAST TO RANGE FROM THE MID TEENS
TO UPPER 20S FRIDAY MORNING. COLDER TEMPERATURES ARE POSSIBLE
SATURDAY MORNING AS SKIES LOOK TO CLEAR OUT ALLOWING FOR GREATER
RADIATIONAL COOLING. TEMPERATURES SATURDAY MORNING CURRENTLY LOOK TO
RANGE FROM THE LOW TO MID TEENS WEST OF THE DIVIDE AND LOW 20S TO
UPPER TEENS EAST OF THE DIVIDE. AS A RESULT, A HARD FREEZE IS LIKELY
FOR NEARLY ALL LOWER ELEVATIONS. DUE TO THE PROLONGED PERIOD OF
ABOVE NORMAL TEMPERATURES AND LACK OF BELOW FREEZING OVERNIGHT
TEMPERATURES THERE IS CONCERN FOR SENSITIVE VEGETATION. SO
FREEZE WARNINGS HAVE BEEN ISSUED FOR THE LOWER WIND RIVER BASIN,
LANDER FOOTHILLS, AND BIGHORN BASIN. OTHER LOCATIONS SUCH AS
JOHNSON AND NATRONA COUNTIES WILL LIKELY NEED FREEZE RELATED
HIGHLIGHTS AFTER WINTER WEATHER ADVISORIES EXPIRE ON FRIDAY.
OTHERWISE, THE PREVIOUS FORECAST DISCUSSION REMAINS OF TRACK FOR
THE WEEKEND THROUGH 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 /06Z TAFS THROUGH 06Z SATURDAY/
ISSUED AT 952 PM MDT THU APR 16 2026
WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS TERMINALS
SNOW TAPERS OFF, WITH CONDITIONS REMAINING OR IMPROVING TO VFR AT
ALL TERMINALS TO START THE PERIOD. FREQUENT MOUNTAIN OBSCURATION
WILL CONTINUE FOR THE NEXT 24 HOURS. CONVECTIVE SHOWERS IN NORTHWEST
FLOW WILL DEVELOP FRIDAY AFTERNOON. THEY WILL REMAIN SCATTERED
ENOUGH TO KEEP OUT OF THE TAFS FOR KBPI, KPNA, AND KRKS AT THIS
TIME. AT KJAC THE CHANCE (30-40%) IS HIGH ENOUGH FOR A PROB30 FROM
19Z FRIDAY TO 01Z SATURDAY. SOME SNOW SHOWERS MAY LINGER INTO FRIDAY
EVENING. WIND WILL REMAIN 10-15 KNOTS TONIGHT, BECOMING GUSTY FRIDAY
AFTERNOON, ONCE AGAIN.
EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL TERMINALS
SNOW WILL CONTINUE IN AND AROUND KCPR UNTIL MID-MORNING FRIDAY, WITH
CONDITIONS REMAINING IFR UNTIL THEN. LIGHT SNOW WILL DEVELOP AROUND
KWRL TONIGHT AND END BY 10Z. OVERALL CONDITIONS WILL REMAIN VFR, BUT
MAY DROP TO MVFR AT TIMES FROM 06-08Z FOR KWRL. THERE IS A DECENT
CHANCE (30%) OF LIGHT SNOW AT KLND AND KRIW EARLY FRIDAY MORNING,
WITH CONDITIONS DROPPING TO MVFR IF THIS OCCURS. CONVECTIVE SNOW
SHOWERS WILL DEVELOP FRIDAY AFTERNOON AND PERSIST INTO FRIDAY
EVENING. TERMINALS WITH THE BEST CHANCE (30-40%) OF SHOWERS
IMPACTING THEM ARE KCOD AND KWRL, BUT THERE IS ABOUT A 20% CHANCE AT
ANY TERMINAL FRIDAY AFTERNOON. WIND WILL DECREASE OR REMAIN LIGHTER
TONIGHT, BUT WILL INCREASE AT MOST TERMINALS AGAIN FRIDAY AFTERNOON.
FREQUENT MOUNTAIN OBSCURATION TONIGHT, WITH SOME IMPROVEMENTS BY
FRIDAY MORNING.
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.
FREEZE WARNING UNTIL 9 AM MDT SATURDAY FOR WYZ003>006-017-018.
WINTER WEATHER ADVISORY UNTIL 6 AM MDT FRIDAY FOR WYZ008>011.
WINTER STORM WARNING UNTIL 6 PM MDT FRIDAY FOR WYZ014-015.
WINTER WEATHER ADVISORY UNTIL NOON MDT FRIDAY FOR WYZ019-020-
022.
UPDATE...DZIEWALTOWSKI
DISCUSSION...HATTINGS
AVIATION...ROWE
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