111
FXUS65 KRIW 140829
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
229 AM MDT TUE APR 14 2026
KEY MESSAGES
- LOW PRESSURE PASSING BY WILL BRING A LOW CHANCE FOR SHOWERS
AGAIN TODAY, MAINLY FOR THE WESTERN MOUNTAINS, THE BIGHORNS,
AND CASPER MOUNTAIN. ACCUMULATIONS WILL BE MINIMAL.
- A MORE POTENT LATE WINTER SYSTEM SWEEPS INTO WESTERN WYOMING
STARTING WEDNESDAY AND CONTINUING THROUGH FRIDAY. AMPLE COLD
TEMPERATURES WILL BRING SNOWFALL TO MOST OF THE REGION,
INCLUDING LOWER ELEVATIONS.
- A HARD FREEZE IS EXPECTED EAST OF THE DIVIDE THURSDAY NIGHT
AND FRIDAY NIGHT. THE LIKELIHOOD OF TEMPERATURES FALLING
BELOW 28 DEGREES IS HIGH (>90%), WITH TEMPERATURES POSSIBLY
FALLING INTO THE TEENS.
DISCUSSION
ISSUED AT 145 AM MDT TUE APR 14 2026
FINALLY A MORE ACTIVE PATTERN ACROSS WYOMING TRYING TO BRING
PRECIPITATION! THE LATEST SYSTEM IS A TROUGH EJECTING INTO THE
CENTRAL PLAINS FROM THE SOUR CORNERS REGION. THIS SYSTEM IS SET
A LITTLE TOO FAR SOUTH TO BRING A SIGNIFICANT AMOUNT OF PRECIP,
BUT STILL ENOUGH ENERGY TO PRODUCE PRECIP FOR AREAS OF CASPER
MOUNTAIN, THE BIGHORNS, AND HIGHER ELEVATIONS OF THE TETONS.
BUT THIS DOES SET THE TABLE FOR A POTENT LATE WINTER STORM
DIVING OUT OF THE PACNW INTO THE NORTHERN ROCKIES. THIS SYSTEM
STARTS TO SPREAD PRECIP INTO THE NW MOUNTAINS DURING THE DAY
WEDNESDAY BEFORE SLOWLY MOVING EAST THURSDAY AND FRIDAY. THE
SYSTEM WILL BE ACCOMPANIED BY AMPLE MOISTURE, SO THE POTENTIAL
FOR MEANINGFUL ACCUMULATIONS IS IMPROVING. THE SYSTEM WILL ALSO
BE ACCOMPANIED BY A STRONG PUSH OF COLDER AIR, SO MOST PRECIP
WILL BE SNOWFALL, ESPECIALLY THURSDAY NIGHT INTO FRIDAY. THIS
INCLUDES MOST OF THE LOWER ELEVATIONS AS WELL, WITH THE CURRENT
FORECAST TOTALS OF 2 TO 5 INCHES. WINTER STORM WATCHES HAVE BEEN
POSTED FOR THE NORTHWESTERN MOUNTAINS AND YNP FOR THIS SYSTEM,
AND MAY NEED TO BE EXPANDED IS THE SNOW FORECAST INCREASES WITH
LATER UPDATES.
THE OTHER CONCERN WITH THIS NEXT SYSTEM IS THE SIGNIFICANT COLD
AIR PUSH COMING WITH AND BEHIND THE NEXT SYSTEM. COLD
TEMPERATURES WILL ARRIVE DURING THE DAY THURSDAY, WITH LOWS
THURSDAY NIGHT IN THE LOW TO MID 20S EAST OF THE DIVIDE AND IN
THE TEENS WEST OF THE DIVIDE. THE MAIN CORE OF THE COLD AIR THEN
SETTLES IN ON FRIDAY, WITH THE CORE OF THE COLD AIR SETTING IN
FRIDAY NIGHT. PROBABILITIES OF TEMPERATURES FALLING BELOW 28
DEGREES ARE HIGH (>90%), WITH CURRENT FORECAST LOWS REACHING THE
TEENS. THE COMPLICATING FACTOR WILL BE HOW QUICKLY CLOUD COVER
CLEARS OUT BEHIND THE WEATHER SYSTEM, ALLOWING FOR RADIATIONAL
COOLING. IF CLOUDS HOLD LONGER, THESE TEENS WOULD LIKELY NOT BE
ACHIEVED.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 1027 PM MDT MON APR 13 2026
WEST OF THE DIVIDE...KJAC/KRKS/KPNA/KBPI TERMINALS
A TIGHT, COMPACT SHORTWAVE ALONG THE WESTERN WYOMING BORDER ROTATES
EASTWARD OVERNIGHT. THE LEADING EDGE OF THIS SHORTWAVE PRODUCED A
TWO-HOUR PERIOD OF INTENSE SNOWFALL AT KJAC, BUT THESE ARE BEGINNING
TO FADE LATE MONDAY EVENING. ISOLATED SNOW SHOWERS, PRODUCING
INTERMITTENT IFR/MVFR CONDITIONS COME TO AN END EARLY IN THE PERIOD
AS THE SHORTWAVE FIZZLES AND HEADS EAST. HOWEVER, THE NOW MOISTENED
BOUNDARY LAYER COULD LEAD TO WIDESPREAD IFR/MVFR CEILINGS AND PATCHY
FOG AT KJAC OVERNIGHT AND INTO TUESDAY MORNING. CEILINGS GRADUALLY
RISE TO VFR AFTER SUNRISE TUESDAY AND IMPROVE FURTHER AROUND MIDDAY.
A FEW SHOWERS SKIRT SOUTHERN WYOMING IN THE VICINITY OF KRKS UNTIL
SUNRISE TUESDAY. ALL OTHER TERMINALS TO BE VFR. WEST-NORTHWEST
SURFACE WIND 12-22KTS DEVELOPS AROUND 19Z/TUESDAY AT ALL TERMINALS
EXCEPT KJAC, WHERE A SOUTHWEST WIND 8-11KTS BEGINS AROUND MIDDAY.
ALL WINDS DECREASE BETWEEN 01Z-02Z/TUESDAY. MOUNTAIN TOPS OBSCURED
ACROSS NORTHWEST WYOMING UNTIL 20Z/TUESDAY.
EAST OF THE DIVIDE...KCPR/KCOD/KRIW/KLND/KWRL TERMINALS
ALL TERMINALS TO BE VFR THROUGH THE PERIOD. SURFACE WIND SPEEDS
TUESDAY ARE TO BE MUCH LESS THAN THOSE OF THE PREVIOUS FEW DAYS.
AFTER A MORNING LULL, WESTERLY WIND 15-25KTS MIXES TO THE SURFACE AT
KCOD BETWEEN 20Z-22Z/TUESDAY, WITH KRIW SEEING WEST-NORTHWEST
SURFACE WIND 15-25KTS DEVELOPING AROUND 23Z/TUESDAY. OTHERWISE,
SPEEDS REMAIN 11KTS OR LESS AT OTHER TERMINALS.
PLEASE SEE THE AVIATION WEATHER CENTER AND/OR CWSU ZLC AND ZDV FOR
THE LATEST INFORMATION ON ICING AND TURBULENCE FORECASTS.
RIW WATCHES/WARNINGS/ADVISORIES
WINTER STORM WATCH FROM WEDNESDAY EVENING THROUGH LATE
THURSDAY NIGHT FOR WYZ001-002-012.
DISCUSSION...STRAUB
AVIATION...CNJ
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page