345
FXUS65 KMSO 310859
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
259 AM MDT MON MAR 31 2025
DISCUSSION
KEY MESSAGES:
- SNOW TONIGHT INTO TUESDAY LEADING TO WINTER DRIVING CONDITIONS
ALONG THE DIVIDE AND IN SOUTHWEST MT.
- COOL AND SHOWERY PATTERN CONTINUES WEDNESDAY/THURSDAY. PASS
LEVEL SNOW IMPACT POTENTIAL DURING OVERNIGHT/MORNING PERIODS.
- RIDGING RETURNS AROUND APRIL 6TH, WARMER AND DRIER FOR SEVERAL
DAYS.
SEVERAL ROUNDS OF SHOWERS WILL SPREAD ACROSS THE NORTHERN ROCKIES
IN SOUTHWEST FLOW TODAY. AN INCH OR TWO OF SNOW THIS MORNING FOR
ID/MT BORDER PASSES, MAY RESULT IN BRIEF SLICK ROADS BUT A MINOR
IMPACT OVERALL. BY THIS AFTERNOON, IT WILL BE UNSTABLE ENOUGH FOR
A FEW THUNDERSTORMS, PARTICULARLY SOUTH OF I-90.
AN UPPER LEVEL TROUGH WILL SETTLE OVERHEAD TONIGHT THROUGH WEDNESDAY
AS PERIODS OF SHOWERS CONTINUE. THERE ARE HINTS OF A MID-LEVEL
LOW CONSOLIDATING JUST EAST OF THE DIVIDE PROVIDING A FOCUS FOR
WRAP AROUND MOISTURE INTO WESTERN MONTANA. THERE IS CONSIDERABLE
UNCERTAINTY ON POSITION AND STRENGTH OF THE MID LEVEL LOW BUT
THERE IS A POTENTIAL FOR SEVERAL INCHES OF SNOW ABOVE 4000 FEET,
IF PRECIPITATION BECOMES FOCUSED IN A WRAP AROUND BAND. CURRENTLY,
MOST HIGH RESOLUTION MODELS SHOW SOUTHWEST MONTANA AS THE MOST
LIKELY PLACE FOR MODERATE SNOW IMPACTS, THUS WINTER WEATHER
ADVISORIES WERE ADDED. GLOBAL MODELS INDICATED NORTHWEST MONTANA
COULD BE A FOCUS AS WELL, SOMETHING TO KEEP AN EYE ON. SNOW
LEVELS DROP NEAR LOWER VALLEY FLOORS ON TUESDAY MORNING BUT GIVEN
THE RELATIVELY WARM ROAD TEMPERATURES, MODERATE IMPACTS SHOULD BE
LIMITED TO HIGHER VALLEYS AND PASSES.
GENERAL TROUGHING CONTINUES LATE THIS WEEK FOR ADDITIONAL SHOWERS,
PERHAPS OCCASIONAL SNOW COVERED PASS ROADWAYS DURING OVERNIGHT/EARLY
MORNING HOURS. SEASONAL TEMPERATURES WILL ALSO CONTINUE WITH
VALLEY HIGHS IN THE MID 40S TO LOW 50S.
MOST ENSEMBLE MODELS (ABOUT 90%) INDICATE THE RETURN OF HIGH-
PRESSURE RIDGING AROUND APRIL 6TH, BRINGING WARMER AND DRIER
WEATHER TO THE REGION FOR SEVERAL DAYS.
AVIATION
WAVES OF SHOWERS WILL PASS THROUGH THE NORTHERN ROCKIES
TODAY UNDER SOUTHWEST FLOW WITH OCCASIONAL REDUCED VISIBILITY AND
LOWERED CEILINGS AT TERMINAL SITES. MOUNTAIN OBSCURATIONS WILL BE
COMMON IN PRECIPITATION EPISODES. THERE WILL ALSO BE ENOUGH
INSTABILITY FOR ISOLATED THUNDERSTORMS THIS AFTERNOON.
AN UPPER LEVEL TROUGH WILL SETTLE OVERHEAD TONIGHT INTO WEDNESDAY
AS PERIODS OF SHOWERS CONTINUE. THERE ARE HINTS OF A MID-LEVEL LOW
CONSOLIDATING JUST EAST OF THE DIVIDE PROVIDING A FOCUS FOR WRAP
AROUND MOISTURE INTO WESTERN MONTANA. THERE IS CONSIDERABLE
UNCERTAINTY ON POSITION AND STRENGTH OF THE MID LEVEL LOW BUT
THERE IS A POTENTIAL FOR SEVERAL INCHES OF SNOW ABOVE 4000 FEET IF
PRECIPITATION BECOMES FOCUSED IN A DEFORMATION BAND.
MSO WATCHES/WARNINGS/ADVISORIES
MT...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON MDT
TUESDAY FOR BITTERROOT/SAPPHIRE MOUNTAINS.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT MDT
TUESDAY NIGHT FOR BUTTE/BLACKFOOT REGION.
ID...NONE.
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