795
FXUS65 KRIW 160351
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
951 PM MDT WED APR 15 2026
KEY MESSAGES
- BREEZY SOUTHWEST WIND CONTINUES TONIGHT. LOWER ELEVATION RAIN
IN WESTERN VALLEYS WILL TRANSITION TO SNOW TONIGHT. SNOW WILL
CONTINUE ACROSS WESTERN MOUNTAINS.
- PRECIPITATION (RAIN THEN SNOW) SPREADS EAST ACROSS THE ENTIRE
AREA MIDDAY ON THURSDAY. STRONG WINDS AND SNOW COULD CREATE
HAZARDOUS TRAVEL CONDITIONS THURSDAY EVENING THROUGH FRIDAY
MORNING, ESPECIALLY ALONG I-25, US 20/26, AND US 287.
- THERE IS HIGH CONFIDENCE (95%+) IN A HARD FREEZE (28 DEGREES
OR BELOW) FRIDAY MORNING AND SATURDAY MORNING. WIDESPREAD
MORNING LOWS IN THE LOW 20S AND TEENS ARE EXPECT ON SATURDAY
MORNING.
UPDATE
ISSUED AT 1257 PM MDT WED APR 15 2026
1PM/19Z RADAR IMAGERY SHOWS LIGHT SNOW SHOWERS OVER THE TETONS,
INDICATING THAT THE FIRST PUSH OF PACIFIC MOISTURE, ASSOCIATED WITH
THE WINTER WEATHER SYSTEM, HAS ARRIVED. EXPECT ONLY RAIN ACROSS
JACKSON VALLEY AND STAR VALLEY THIS AFTERNOON WITH TEMPERATURES IN
THE 40S. SNOWFALL RATES FOR THE NORTHWEST MOUNTAINS AND THE WIND
RIVER MOUNTAINS WILL INCREASE BY 6PM MDT TODAY AS THE UPPER LEVEL
TROUGH BEGINS TO PUSH INTO THE NORTHERN ROCKIES, WITH MODERATE TO
HEAVY SNOW EXPECTED. ANTICIPATE WINTER TRAVEL CONDITIONS ACROSS
TETON PASS, TOGWOTEE PASS, AND SOUTH PASS WITH SNOW AND GUSTY 30 TO
50 MPH WINDS. AS FOR THE WESTERN VALLEYS, TEMPERATURES ARE FORECAST
TO REMAIN ABOVE FREEZING UNTIL AFTER MIDNIGHT TONIGHT. THIS MEANS
THAT RAIN WILL CHANCE OVER TO SNOW AFTER MIDNIGHT AS WELL. EXPECT
ONLY LIGHT ACCUMULATIONS OF 1 TO 3 INCHES FOR THE WESTERN VALLEYS
THROUGH THURSDAY NIGHT.
AS MENTIONED IN THE MORNING DISCUSSION, PRECIPITATION WILL SPREAD
EAST ACROSS THE STATE DURING THE DAY ON THURSDAY AS THE POTENT COLD
FRONT PUSHES EAST. EXPECT PRECIPITATION TO BEGIN AS RAIN AHEAD OF
THE COLD FRONT WITH TEMPERATURES IN THE 50S. ON THURSDAY, THE COLD
FRONT IS EXPECTED TO PASS THROUGH SOMETIME IN THE NOON TO 3PM
TIMEFRAME FOR JOHNSON COUNTY AND 3PM AND 7PM TIMEFRAME ELSEWHERE AND
QUICKLY DROP TEMPERATURES. RAIN WILL QUICKLY CHANGE OVER TO SNOW DUE
TO THE QUICK TEMPERATURE DROP DURING THESE TIMEFRAMES. ALSO,
WIDESPREAD WINDY CONDITIONS ARE EXPECTED DUE TO THE TIGHT
TEMPERATURE GRADIENT BOTH AHEAD AND BEHIND THE FRONT. GUSTY 30 TO 50
MPH ARE FORECAST FOR MOST LOW ELEVATIONS. NEAR AND IN BUFFALO,
NORTHERLY GUSTS OF 60 MPH ARE POSSIBLE BEHIND THE FRONT THURSDAY
NIGHT.
ALTHOUGH SNOW AMOUNTS FOR FREMONT, NATRONA, AND JOHNSON COUNTIES ARE
IN THE GENERALLY IN THE 1 TO 5 INCH RANGE, WINTER WEATHER ADVISORIES
HAVE BEEN ISSUED FOR THESE AREAS DUE TO WIND AND SNOW. THE GUSTY 30
TO 50 MPH WINDS COMBINED WITH LIGHT SNOW WILL NO DOUBT CAUSE REDUCED
VISIBILITIES AND PERIODS OF HAZARDOUS TRAVEL. ADDITIONALLY, DUE TO
THE STRONG TEMPERATURE DROP WITH THE COLD FRONT, AND THUS INCREASED
FRONTOGENESIS, CONVECTIVE SNOW BANDS/SNOW SQUALLS ARE POSSIBLE
ACROSS EASTERN FREMONT, JOHNSON, AND NATRONA COUNTIES ALONG THE
FRONT THURSDAY EVENING AND OVERNIGHT. THIS BANDING COULD ALSO OCCUR
ACROSS EASTERN SWEETWATER, INCLUDING ALONG I-80, BUT CONFIDENCE IS
TOO LOW TO INCLUDE THIS AREA IN THE HAZARD. ANY SNOW SQUALL OR
CONVECTIVE SNOW BAND WILL CAUSE SUDDEN DROPS IN VISIBILITY AND
CREATE VERY HAZARDOUS TRAVEL CONDITIONS. CONFIDENCE REMAINS VERY
HIGH (95%+) IN A HARD FREEZE (28 DEGREES OR LESS) FRIDAY MORNING AS
WELL. IT IS NECESSARY TO NOTE THAT WINTER WEATHER ADVISORIES HAVE
ALSO BEEN ISSUED FOR THE BIGHORNS, CASPER MOUNTAIN, AND THE
RATTLESNAKE MOUNTAINS FOR THE SAME REASONS.
DISCUSSION
ISSUED AT 109 AM MDT WED APR 15 2026
FOR MOST OF THE STATE, THE MILD TEMPERATURES WILL BELIE THE
ABRUPT AND SHIFT WEATHER SHIFT APPROACHING. MOST OF THE STATE
WILL AGAIN SEE MILD TEMPERATURES AND GUSTY WINDS TODAY, WITH
HIGHS IN THE 60S.
AND THEN THE BOTTOM FALLS OUT OF THE FORECAST. THE NEXT WINTER
SYSTEM IS COMING ASHORE ALONG THE PACNW THIS MORNING, AND WILL
ALREADY START TO SPREAD SNOWFALL INTO THE NW MOUNTAINS BY THIS
AFTERNOON. THIS SNOWFALL WILL ONLY INCREASE THROUGH THE NIGHT
TONIGHT AS THE COLD AIR PUSHES INTO THE STATE. THE MAIN COLD
FRONT WILL RACE ACROSS THE STATE DURING THE DAY THURSDAY,
BRINGING A STUNNING DROP IN TEMPERATURES FROM THE LOW TO MID 50S
AROUND NOON TO THE UPPER 30S BY 6PM. AS THE FRONT SWEEPS
THROUGH, PRECIPITATION WILL COME ALONG AS WELL. PRECIP WILL
START AS RAIN FOR THE LOWER ELEVATIONS BRIEFLY, BEFORE SWITCHING
TO ALL SNOW BY EARLY EVENING. SNOW WILL CONTINUE ACROSS THE
STATE THROUGH THE NIGHT INTO FRIDAY, CONTINUING THROUGH SUNSET
BEFORE TAPERING OFF. MAIN FORECAST ISSUE IS HOW MUCH OF THE
INITIAL SNOWFALL WILL MELT OFF, DUE TO GROUND TEMPERATURES
ALREADY BEING VERY WARM. PUTTING ALL THESE FACTORS TOGETHER,
HAVE GONE AHEAD AND UPGRADED CURRENT WINTER WATCHES TO WINTER
STORMS WARNINGS FOR THE NW MOUNTAINS, INCLUDING THE WIND RIVER
RANGE. WILL NEED TO CLOSELY MONITOR THE SNOW FORECAST FOR THE
BIGHORNS, ALONG WITH LOWER ELEVATIONS OF JOHNSON, NATRONA, AND
FREMONT COUNTIES FOR LAST MINUTE MODEL SHIFTS FOR ACCUMULATIONS.
AS THIS SYSTEM SWEEPS SOUTHEAST, SKIES WILL GRADUALLY CLEAR WEST
TO EAST FRIDAY NIGHT. THE COLD POOL MOVING IN BEHIND THE SYSTEM
IS PARTICULARLY COLD FOR THIS TIME OF YEAR, AND A COUPLE FACTORS
WILL DETERMINE JUST HOW COLD TEMPERATURES FALL. FIRST IS HOW
FAST CLOUD COVER CLEARS OUT, ALLOWING BETTER RADIATIONAL
COOLING. SECOND IS IF THERE'S ANY CONSIDERABLE SFC SNOWPACK
INSULATING THE COLD POOL AS IT MOVES THROUGH. CURRENT FORECAST
IS FOR LOWS IN THE MID TO UPPER TEENS. WITH CLOUDS CLEARING SELL
BEFORE SUNRISE, AND SNOWPACK HOLDING FOR MOST AREAS. CURRENT
FORECAST HAS TEMPERATURES IN MOST LOWER ELEVATIONS FALLING
BELOW 28 DEGREES (HARD FREEZE) FOR 9 TO 12 HOURS. THIS WILL HAVE
A SIGNIFICANT IMPACT ON ALREADY FLOWERING PLANT LIFE, ANIMALS,
LAWN SPRINKLER AND IRRIGATION SYSTEMS, AND THE LIKE. PLEASE TAKE
ANY AND ALL PRECAUTIONS FOR A LATE-SEASON COLD SNAP.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 951 PM MDT WED APR 15 2026
WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS TERMINALS
ACROSS WESTERN WYOMING RAIN WILL TRANSITION TO SNOW BY THURSDAY
MORNING. CONDITIONS WILL HOVER RIGHT AROUND VFR/MVFR THROUGH MOST OF
THE TAF PERIOD, BUT A HEAVIER BAND OF SNOW IS POSSIBLE (30%) FROM 09-
13Z THURSDAY MORNING, WHICH MAY DROP CONDITIONS TO IFR. CONDITIONS
SHOULD IMPROVE THURSDAY AFTERNOON BEFORE A SNOW BAND MOVES IN
THURSDAY 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 THURSDAY MORNING
INTO EARLY THURSDAY AFTERNOON. RAIN SHOWERS WILL DEVELOP AT KRKS
THURSDAY AFTERNOON, WITH SOME ISOLATED THUNDER POSSIBLE (30%). RAIN
WILL TRANSITION TO SNOW AT KRKS LATE THURSDAY AFTERNOON, WITH SNOW
ENDING BY 03Z FRIDAY.
A COLD FRONT WILL PASS THROUGH THURSDAY AFTERNOON INTO THURSDAY
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 THURSDAY MORNING, BUT RAIN WILL
SPREAD EAST OF THE CONTINENTAL DIVIDE THURSDAY AFTERNOON AND QUICKLY
TRANSITION TO SNOW THURSDAY EVENING. MOST TERMINALS WILL HAVE
MINIMAL IMPACTS. KCPR IS THE EXCEPTION AS CONVECTIVE RAIN/SNOW BANDS
WILL DEVELOP THURSDAY AFTERNOON INTO THURSDAY EVENING. CONDITIONS
WILL DROP TO MVFR AT A MINIMUM AND PROBABLY IFR AT KCPR THURSDAY
EVENING ONCE RAIN TRANSITIONS TO SNOW. DEPENDING ON HOW INTENSE THE
BANDS ARE RAIN MAY TRANSITION TO SNOW LATE THURSDAY AFTERNOON AT
KCPR. AT KRIW, KLND, AND KWRL PROB30 GROUPS HAVE BEEN ADDED THURSDAY
AFTERNOON FOR A RAIN/SNOW MIX. AT KCOD AND KWRL THERE WILL BE A
BETTER CHANCE FOR PREVAILING LIGHT SNOW SHOWERS AND MVFR
CONDITIONS THURSDAY EVENING.
A COLD FRONT WILL PASS THROUGH THURSDAY MORNING INTO THURSDAY
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 THURSDAY THROUGH THURSDAY AFTERNOON. MOUNTAIN
OBSCURATION WILL BECOME MORE FREQUENT ONCE THE FRONT PASSES THROUGH
THURSDAY 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
WINTER STORM WARNING UNTIL 6 AM MDT FRIDAY FOR WYZ001-002-012.
WINTER WEATHER ADVISORY FROM 9 AM THURSDAY TO 6 AM MDT FRIDAY
FOR WYZ008-009.
WINTER WEATHER ADVISORY FROM NOON THURSDAY 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 THURSDAY TO 6 AM MDT FRIDAY
FOR WYZ016>018.
WINTER WEATHER ADVISORY FROM 3 PM THURSDAY TO NOON MDT FRIDAY
FOR WYZ019-020-022.
UPDATE...GERHARDT
DISCUSSION...STRAUB
AVIATION...ROWE
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page