668
FXUS65 KRIW 052217
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
417 PM MDT TUE MAY 5 2026
KEY MESSAGES
- SCATTERED SHOWERS EARLY TUESDAY BECOME MORE WIDESPREAD INTO
THE AFTERNOON WITH A FULL CHANGEOVER TO SNOW OVERNIGHT INTO
WEDNESDAY MORNING AS TEMPERATURES DROP.
- WINTER WEATHER ADVISORIES ARE IN EFFECT FOR THE GREEN
MOUNTAINS TO EASTERN SWEETWATER COUNTY DUE TO LIGHT
ACCUMULATING SNOW AND GUSTY WINDS UP TO AROUND 35 MPH.
- FREEZE WARNINGS ARE IN EFFECT FOR LOWER ELEVATIONS EAST OF THE
DIVIDE FOR WEDNESDAY MORNING, AS LOW TEMPERATURES ARE IN THE
20S.
- DRY AND WARMING TREND INTO THE WEEKEND AND NEXT WEEK.
UPDATE
ISSUED AT 1256 PM MDT TUE MAY 5 2026
TODAY'S WEATHER SYSTEM IS MAINLY ON TRACK. ONE POINT OF FOCUS WITH
THIS UPDATE IS SNOW POTENTIAL AROUND THE LANDER AREA. UPPER-LEVEL
DYNAMICS AND FAVORED FLOW HAS THE POTENTIAL TO BRING HEAVIER
PRECIPITATION TO THE LANDER AREA LATE THIS AFTERNOON AND INTO THE
EVENING. SOME HI-RES MODELS ARE DEPICTING SNOW TOTALS UP TO AROUND 8
INCHES, THOUGH THIS SCENARIO SEEMS UNLIKELY (10% CHANCE OR LESS). A
MORE REALISTIC ESTIMATE MAY BE 2 TO 4 INCHES, WHICH WOULD OCCUR IN A
FAIRLY QUICK TIME PERIOD THIS EVENING. ONE ADDITIONAL THING TO NOTE
IS THAT THERE WILL LIKELY BE A STEEP SNOW AMOUNT GRADIENT FROM
LANDER TOWN TO THE MOUNTAINS, SO AMOUNTS MAY QUICKLY CHANGE FROM 1
INCH TOTALS NORTH OF TOWN TO LIKE 6 INCHES TOWARDS SINKS CANYON. THE
MAJORITY OF SNOW SHOULD END BY MIDNIGHT, WITH LIGHT LINGERING SNOW
POSSIBLE THROUGH AROUND SUNRISE. OTHERWISE, HIGHLIGHTS REMAIN, WITH
A COMBINATION OF SNOW AND WIND BRINGING MINOR IMPACTS TO I-80 IN
SWEETWATER COUNTY AND NORTHWARD TO SOUTH PASS AND AROUND JEFFERY
CITY.
DISCUSSION
ISSUED AT 200 AM MDT TUE MAY 5 2026
INCREASING CLOUD COVER PUSHING IN FROM THE NORTH AS DEPICTED ON
IR. L/W TROUGH EXTENDS WITH A POSITIVE TILT NORTHEAST TO
SOUTHWEST TO THE UPPER LEVEL LOW ACROSS THE SIERRA NEVADAS. THIS
HAS GIVEN WAY TO INCREASING DIVERGENCE ALOFT THROUGH NORTHERN
UTAH TO SOUTHERN WYOMING AS THE LOW DEEPENS WITH MODELS HAVING
IT EMBEDDED INTO L/W PATTERN. THE PFJ BECOMES CONTORTED ACROSS
THIS AREA WITH MUCH OF THE PVA ANOMALY EXTENDING ACROSS
SOUTHERN PORTIONS OF THE CWA AND POINTS EAST INTO THE HIGH
PLAINS. AS SUCH, WINTER WEATHER ADVISORIES HAVE BEEN ADDED
ACROSS THE GREEN MOUNTAINS AND EASTERN SWEETWATER COUNTY FOR
LATER TUESDAY EVENING INTO WEDNESDAY MORNING AS THIS TROUGH
PUSHES NORTHEAST. WINDS WILL BE THE MAIN DRIVER WITH THIS AREA
SEEING GUSTS UP TO 30 TO 35 MPH LIKELY CREATING A CROSSWIND
ACROSS I-80 AND HIGHWAY 287 THROUGH JEFFREY CITY TO MUDDY GAP.
LIKELY SNOW AMOUNTS WON'T BE MUCH BUT EXPECTING AROUND 2 TO 3
INCHES (60-70% CONFIDENCE) INDICATIVE OF SOME BLOWING SNOW TO
HINDER VISIBILITY IN THESE AREAS.
OTHERWISE, ONGOING SHOWER ACTIVITY THROUGH SOUTHERN BIGHORN
BASIN INTO EASTERN PORTIONS OF FREMONT COUNTY. MODELS HAVE
PUSHED BACK THE ONSET OF MORE WIDESPREAD PRECIPITATION, BUT
CAMS ARE NOT HANDLING THIS VERY WELL AND THUS, SHOWING POPS TO
QPF BEING WELL OVERDONE WITH THE NBM RUNS. WHAT PRECIPITATION IS
ONGOING LOOKS TO MIX IN WITH, OR CHANGE OVER TO, SNOW THROUGH
SUNRISE TUESDAY MORNING BUT NOT EXPECTING AN ACCUMULATION AT
THIS POINT IN TIME TO HINDER MORNING COMMUTES WITH TEMPERATURES
STILL ABOVE THE FREEZING MARK. WITH AMPLE CLOUD COVER THROUGHOUT
THE DAY AND REINFORCEMENT OF COOLER AIR, EXPECT TEMPERATURES TO
SHOW NOT MUCH OF AN AFTERNOON WARMUP, STRUGGLING TO BREAK THE
40 DEGREE MARK FOR MANY BASINS EAST OF THE DIVIDE.
BETTER CHANCES FOR PRECIPITATION CHANGING OVER TO SNOW TUESDAY
EVENING AFTER SUNSET AND OVERNIGHT AS THE AFOREMENTIONED UPPER
LEVEL LOW BECOMES PROGRESSIVE AS IT PASSES TO THE SOUTH. THIS
MODEL SHIFT AS PULLED BACK SOME QPF AMOUNTS AS THE MORE AMPLE
ACCUMULATIONS WILL BE EASTWARD AND INTO COLORADO EXTENDING TO
THE HIGH PLAINS, REACHING AS FAR AS WESTERN PORTIONS OF
NEBRASKA AND KANSAS. PRECIPITATION LINGERS INTO LATER PARTS OF
WEDNESDAY BUT MOST ACTIVITY WILL END AS THE UPPER TROUGH PUSHES
EAST AND LIFTS OUT OF THE STATE. WEDNESDAY MORNING WILL BE THE
COLDEST OF THE WEEK, WITH FREEZE WARNINGS UPGRADED FOR MANY
LOWER ELEVATIONS EAST OF THE DIVIDE.
BEYOND WEDNESDAY, EXPECT UPPER LEVEL RIDGING TO BUILD IN FROM
THE WEST WITH INCREASING CONVERGENCE ALOFT. THIS WILL PUSH THE
MAIN FINGER OF THE PFJ TO PUSH NORTHEAST FOR THE DAKOTAS AND
INTO THE GREAT LAKE/MISSOURI RIVER BASIN AREAS OF THE COUNTRY.
MODELS HAVE BACKED OFF ON THIS EXTENDING A BIT SOUTHWEST FOR
NORTHEASTERN PORTIONS OF THE CWA FOR SATURDAY, LOOKING TO
REMAIN AT BEST, FOR FAR NORTHEASTERN PARTS OF THE STATE ITSELF.
RIDGING AND NORTHWEST FLOW DOMINATES THE WEATHER PATTERN FOR
THE WEEKEND AND BEYOND INTO NEXT WEEK WITH DRY CONDITIONS AND A
WARMING TREND IN STORE GOING FORWARD.
AVIATION /00Z TAFS THROUGH 00Z THURSDAY/
ISSUED AT 416 PM MDT TUE MAY 5 2026
WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS TERMINALS.
THE AREA CONTINUES TO BE UNDER THE INFLUENCE OF A LOW OVER THE
SOUTHWESTERN CONUS AND A BROADER TROUGH ACROSS THE NORTHERN CONUS.
THIS WILL LEAD TO SCATTERED RAIN AND SNOW SHOWERS FOR KBPI, KPNA,
AND KRKS LATE THIS AFTERNOON AND EVENING; MVFR TO IFR CONDITIONS ARE
POSSIBLE AT THESE TERMINALS, WITH KRKS EXPECTED TO SEE THE MOST
PERSISTENT IMPACTS THROUGH TONIGHT. KRKS WILL ALSO SEE AN INCREASED
EAST TO NORTHEAST WIND TONIGHT WITH GUSTS TO AROUND 30 KNOTS. KJAC
IS EXPECTED TO REMAIN VFR AND LARGELY MISS OUT ON THIS ACTIVITY,
THOUGH SURROUNDING MOUNTAINS WILL BE FREQUENTLY OBSCURED. CONDITIONS
WILL IMPROVE BY SUNRISE WEDNESDAY AS SKIES CLEAR, WITH LIGHTER WINDS
AND VFR CONDITIONS EXPECTED THROUGH THE AFTERNOON.
EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL TERMINALS.
THE AREA CONTINUES TO BE UNDER THE INFLUENCE OF A LOW OVER THE
SOUTHWESTERN CONUS AND A BROADER TROUGH ACROSS THE NORTHERN CONUS.
THIS WILL LEAD TO SCATTERED RAIN AND SNOW SHOWERS FOR TERMINALS
THROUGH TONIGHT. THE MOST PERSISTENT MVFR TO IFR CONDITIONS ARE
EXPECTED AT KLND AND KRIW. CONDITIONS ARE EXPECTED TO BEGIN TO
IMPROVE AFTER AROUND 08Z, WITH SKIES CLEARING FURTHER THROUGH THE
REST OF WEDNESDAY MORNING. THIS WILL LEAD TO MOSTLY SUNNY OR
SCATTERED SKIES AND VFR CONDITIONS THROUGH WEDNESDAY AFTERNOON.
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
FREEZE WARNING FROM 1 AM TO 9 AM MDT WEDNESDAY FOR WYZ003>006-
010-011-017-018-020.
WINTER WEATHER ADVISORY UNTIL 1 AM MDT WEDNESDAY FOR WYZ009-
015.
WINTER WEATHER ADVISORY UNTIL 7 AM MDT WEDNESDAY FOR WYZ019-
030.
UPDATE...WITTMANN
DISCUSSION...LOWE
AVIATION...MYERS
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