098
FXUS65 KRIW 151728
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1128 AM MDT WED APR 15 2026
KEY MESSAGES
- WINDY SOUTHWEST WINDS ARE EXPECTED TODAY, WITH WIDESPREAD
GUSTS OF 25 TO 40 MPH. WIND PRONE LOCATIONS COULD SEE GUSTS UP
TO 50 MPH. OTHERWISE, TEMPERATURES TODAY WILL BE MILD ACROSS
THE AREA.
- SNOW CHANCES (70-90%) INCREASE THIS AFTERNOON ACROSS WEST AND
NORTHWEST WYOMING. 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
LOWS IN THE LOW 20S AND TEENS ARE EXPECT ON SATURDAY MORNING.
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 /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 1127 AM MDT WED APR 15 2026
VFR CONDITIONS ACROSS NEARLY ALL TERMINALS TO START THE TAF PERIOD.
KJAC IS THE ONLY EXCEPTION AS SHOWERS BEGIN TO MOVE INTO THE AREA
LEADING TO LOWERED CEILINGS AND MVFR CONDITIONS. A NEARING
DISTURBANCE WILL BRING ROUNDS OF PRECIPITATION TO WESTERN TERMINALS
AND INCREASED WINDS TO NEARLY ALL TERMINALS THIS TAF PERIOD. KJAC AS
MENTIONED EARLIER WILL SEE SHOWERS THROUGH THE AFTERNOON INTO THE
EVENING. THERE MAY BE SOME SPOTTY SHOWERS AFTER 02Z THURSDAY WITH
ANOTHER ROUND OF PRECIPITATION LIKELY BY 09Z. BY THIS TIME
TEMPERATURES SHOULD DROP TO NEAR OR BELOW FREEZING LEADING TO SNOW
SHOWERS. OTHERWISE, WINDS INCREASE FOR THE START OF THE PERIOD
AT NEARLY ALL TERMINALS WITH GUSTS OF 20 TO 35 KNOTS POSSIBLE
THROUGH THE EVENING. WINDS DECREASE SLIGHTLY AFTER SUNSET WITH
BREEZY WINDS OF 10 TO 20 KNOTS PERSISTING THROUGH THE OVERNIGHT.
A COLD FRONT BEGINS TO ENTER THE STATE THURSDAY MORNING WHICH
WILL BRING PRECIPITATION CHANCES TO KCOD, KPNA, KBPI, AND KJAC
AROUND THE END OF THE TAF PERIOD. WINDS WILL START TO INCREASE
AHEAD OF THE FRONTAL PASSAGE WITH MANY TERMINALS SEEING WINDS
INCREASE BY AROUND 15Z THURSDAY. ASIDE FROM INCREASING WINDS ALL
TERMINALS WILL LIKELY SEE LOWERING CEILINGS AROUND THIS TIME.
MOUNTAIN OBSCURATION WILL BE PERSISTENT THROUGH THE TAF PERIOD
ESPECIALLY ACROSS WESTERN MOUNTAINS WITH OBSCURATION INCREASING
BY THE END OF THE TAF 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 FROM 6 PM THIS EVENING TO 6 AM MDT FRIDAY
FOR WYZ001-002-012.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MDT FRIDAY
FOR WYZ014-015.
DISCUSSION...STRAUB
AVIATION...DZIEWALTOWSKI
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