616
FXUS65 KRIW 301109
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
509 AM MDT SUN MAR 30 2025
KEY MESSAGES
- PRECIPITATION WILL BE WIDESPREAD ALONG AND EAST OF THE
CONTINENTAL DIVIDE THIS MORNING. AREAS OF RAIN CONTINUE THIS
MORNING WITH A SMALL WINDOW FOR SNOW REMAINING POSSIBLE
BEFORE SUNRISE. MOUNTAIN AREAS WILL REMAIN ALL SNOW.
- A WINTER WEATHER ADVISORY REMAINS IN EFFECT FOR THE EASTERN
SLOPES OF THE WIND RIVER MOUNTAINS AND BIGHORN MOUNTAINS AND
THE ABSAROKAS FOR SNOW AMOUNTS BETWEEN 6-12 INCHES.
- SHOWERS AND ISOLATED THUNDERSTORMS WILL REMAIN POSSIBLE FOR
MUCH OF THE FORECAST AREA MONDAY AND TUESDAY, WITH LIGHT SNOW
OVERNIGHT, ESPECIALLY WESTERN AND NORTHERN PORTIONS.
DISCUSSION
ISSUED AT 111 AM MDT SUN MAR 30 2025
PRECIPITATION WILL CONTINUE (BASICALLY) ALONG AND EAST OF THE DIVIDE
THROUGH THE REST OF THE MORNING, WHICH WOULD BE FROM YELLOWSTONE TO
THE WIND RIVER MOUNTAINS AND FAR NORTHERN PORTIONS OF SWEETWATER
COUNTY. SNOW WILL BE ONGOING OVER THESE AREAS THROUGH EARLY IN
THE AFTERNOON, ALTHOUGH ACCUMULATIONS WILL BE CONFINED TO GRASSY
AREAS AFTER SUNRISE. ADDITIONAL ISOLATED SHOWERS WILL REDEVELOP
ACROSS THE FORECAST AREA, ESPECIALLY NORTHWESTERN PORTIONS,
THROUGH THE AFTERNOON.
A RIDGE WILL BUILD OVER THE REGION TONIGHT INTO MONDAY IRT ANOTHER
STRONG UPPER LOW OFF THE PACNW COAST. THIS WILL KEEP PACIFIC
MOISTURE STREAMING OVER THE REGION AND TROUGHS EJECTING FROM THIS
SYSTEM MOVE OVER THE CWA. ADDITIONAL SHOWERS WILL REACH FAR WESTERN
PORTIONS MONDAY MORNING, WITH ANOTHER ROUND OF SHOWERS DEVELOPING
OVER SOUTHERN PORTIONS IN THE AFTERNOON. ISOLATED THUNDERSTORMS
COULD OCCUR IN THESE AREAS THROUGH THE AFTERNOON. ISOLATED SHOWERS
AND THUNDERSTORMS WILL ALSO BE POSSIBLE EAST OF THE DIVIDE, AS THE
SHORTWAVE TROUGH MOVES EASTWARD. THIS ACTIVITY WILL CONTINUE THROUGH
THE EVENING. SNOW LEVELS WILL AVERAGE BETWEEN 6000 AND 7000FT ACROSS
MOST OF THE FORECAST AREA, BUT AGAIN ANY SNOW THAT FALLS DURING THE
DAY WILL HAVE LITTLE TO NO IMPACT AND ACCUMULATE IN GRASSY AREAS.
THE AFOREMENTIONED SHORTWAVE TROUGH WILL SLOW DOWN MONDAY NIGHT AND
BECOME BETTER ORGANIZED INTO A MIDLEVEL LOW, DROPPING TEMPERATURES
AND ALLOW FOR RAIN TO CHANGE OVER TO SNOW OVER WESTERN PORTIONS.
THIS ACTIVITY WILL CONTINUE THROUGH MUCH OF THE DAY TUESDAY, AS THE
LOW SLOWLY MOVES OVER THE BIGHORN BASIN AND JOHNSON/NATRONA
COUNTIES. AS A RESULT, MOST OF THE PRECIPITATION OVER NORTHERN
PORTIONS WILL OCCUR UNDER A DEVELOPING BAROCLINIC LEAF FROM THE
MIDLEVEL LOW. RAIN/SNOW TO SNOW WILL PUSH INTO NORTHERN PORTIONS OF
THE BIGHORN BASIN AND NORTHERN JOHNSON COUNTY TUESDAY EVENING. THIS
ACTIVITY WILL SPREAD SOUTHWARD THROUGH THE NIGHT AS THE LOW TRACKS
OVER THE BLACK HILLS.
FORECAST DETAILS BECOME LESS CLEAR BY WEDNESDAY. SHOWERS REMAIN
POSSIBLE FOR MUCH OF THE AREA, BUT WILL BE DEPENDENT ON HOW MUCH
INFLUENCE FROM THE EXITING LOW/STORM REMAINS. ADDITIONALLY, THE
REMNANTS FROM THE PACNW LOW LOOK TO DIVE SOUTHWARD OVER THE FOUR
CORNERS REGION, SO FORECAST DETAILS ARE HIGHLY IN FLUX THROUGH THE
REST OF THE PERIOD. NO CLEAR SIGNAL FOR WET CONDITIONS TO CONTINUE
OR MORE DRIER CONDITIONS TO OCCUR.
AVIATION /12Z TAFS THROUGH 12Z MONDAY/
ISSUED AT 507 AM MDT SUN MAR 30 2025
SNOW CONTINUES TO SPREAD EAST OF THE DIVIDE THIS MORNING WITH MVFR
TO IFR CONDITIONS AT KCPR, KLND, KRIW, KCOD, AND KWRL TO START THE
TAF PERIOD. SNOW IS EXPECTED TO START DISSIPATING SHORTLY AFTER 13-
14Z AT KRIW/KLND WITH LOW CEILINGS LINGERING THROUGH MOST OF THE
MORNING. KCOD, KWRL, AND KCPR WILL SEE SNOW PREVAIL INTO THE MID TO
LATE MORNING, MOSTLY ENDING SHORTLY AFTER 18Z SUNDAY. WESTERN
TERMINALS WILL SEE CEILINGS GRADUALLY LIFT THROUGH THE MORNING
AS THE SYSTEM PULLS OUT TO THE EAST. REMAINING INSTABILITY WILL
CREATE THE CHANCE FOR SOME ISOLATED CONVECTIVE SHOWERS THIS
AFTERNOON. CONFIDENCE IN ANY OF THESE SHOWERS IMPACTING
TERMINALS IS RATHER LOW SO IT HAS BEEN LEFT OUT OF THE TAF.
WINDS WILL BE LIGHT WITH SOME TERMINALS SEEING PERIODIC BREEZES
OF 10 TO 15 KNOTS AT TIMES. THE NEXT DISTURBANCE BEGINS TO MOVE
INTO WESTERN WY NEAR THE END OF THE TAF PERIOD. KJAC IS
CURRENTLY THE ONLY TERMINAL WITH A PROB30 TO REPRESENT
DEVELOPING SNOW SHOWERS AS A RESULT OF THIS DISTURBANCE.
MOUNTAIN OBSCURATION WILL BE PREDOMINANT ACROSS THE AREA THROUGH
MUCH OF THE MORNING WITH GRADUAL IMPROVEMENT EXPECTED BY THE
AFTERNOON/EVENING.
PLEASE SEE THE AVIATION WEATHER CENTER AND/OR CWSU ZDV AND ZLC FOR
THE LATEST INFORMATION ON SMOKE, ICING, AND TURBULENCE
FORECASTS.
RIW WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY UNTIL NOON MDT TODAY FOR WYZ002-015.
WINTER WEATHER ADVISORY UNTIL 6 PM MDT THIS EVENING FOR WYZ009.
DISCUSSION...LAVOIE
AVIATION...DZIEWALTOWSKI
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