354
FXUS65 KRIW 141519
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
919 AM MDT TUE APR 14 2026
KEY MESSAGES
- LIGHT SNOW SHOWER CHANCES (20%) EXIST THROUGH 6PM MDT ACROSS
THE WESTERN MOUNTAINS, THE BIGHORNS, AND CASPER MOUNTAIN. A
LIGHT DRIZZLE CANNOT BE RULED OUT IN CASPER.
- A POTENT WINTER STORM IS FORECAST TO BRING WIDESPREAD
PRECIPITATION, WIND, AND FREEZING TEMPERATURES TO THE ENTIRE
AREA BEGINNING LATE WEDNESDAY UNTIL FRIDAY EVENING. CONFIDENCE
IN MEASURABLE SNOWFALL CONTINUES TO INCREASE FOR LOW
ELEVATIONS.
- THERE IS HIGH (90% +) CONFIDENCE IN A HARD FREEZE (28 DEGREES
OR BELOW) ACROSS LOW ELEVATIONS FRIDAY MORNING AND SATURDAY
MORNING, WITH THE POTENTIAL FOR WIDESPREAD LOWS IN THE TEENS
ON SATURDAY MORNING.
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 FOUR 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 /12Z TAFS THROUGH 12Z WEDNESDAY/
ISSUED AT 510 AM MDT TUE APR 14 2026
WEST OF THE DIVIDE...KJAC/KRKS/KPNA/KBPI TERMINALS
THE MAIN CONCERN THIS MORNING IS IN VICINITY OF KJAC WHERE
EVENING SNOW SHOWERS HAVE BROUGHT AREAS OF FOG, OCCASIONAL IFR
TO LIFR CEILINGS WILL BE POSSIBLE UNTIL AROUND 14Z THIS MORNING
WHEN FOG SHOULD BURN OFF WITH VFR CONDITIONS RETURNING BY 16Z.
VFR CONDITIONS ARE EXPECTED TO PREVAIL ELSEWHERE. THERE IS
AROUND A 1 IN 5 CHANCE OF A SHOWER ACROSS SOUTHERN SWEETWATER
COUNTY IN VICINITY OF KRKS, BUT NOT ENOUGH CONFIDENCE TO INCLUDE
IN THE TAFS AT THIS TIME. A GUSTY BREEZE DEVELOPS AFTER 16Z
TODAY AT ALL TERMINALS EXCEPT KJAC WITH GUSTS OVER 20 KNOTS
POSSIBLE.
EAST OF THE DIVIDE...KCPR/KCOD/KRIW/KLND/KWRL TERMINALS
ALL TERMINALS TO BE VFR THROUGH THE PERIOD. SURFACE WIND SPEEDS
ARE TO BE MUCH LESS THAN THOSE OF THE PREVIOUS FEW DAYS. AFTER
A MORNING LULL, WESTERLY WIND OF 15 TO 25 KNOTS MIXES IS LIKELY
AT KCOD BETWEEN 20Z-22Z ON TUESDAY, WITH KRIW SEEING WEST-
NORTHWEST SURFACE WIND OF 15 TO 25 KNOTS DEVELOPING AFTER 22 TO
23Z THIS AFTERNOON. 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...HATTINGS
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