687
FXUS65 KMSO 300759
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
159 AM MDT SUN MAR 30 2025
DISCUSSION
KEY MESSAGES:
- SNOW IMPACTS FOR SOUTHWEST MONTANA AND LEMHI COUNTY ENDING LATER THIS
MORNING.
- ACTIVE PATTERN WITH COOL AND SHOWERY WEATHER MOST OF THIS COMING
WEEK. PASS LEVEL SNOW IMPACT POTENTIAL DURING OVERNIGHT/MORNING
PERIODS.
- RIDGING RETURNS AROUND APRIL 6TH, WARMER AND DRIER FOR SEVERAL
DAYS.
SNOW CONTINUES IN SOUTHWEST MONTANA AND LEMHI COUNTY EARLY THIS
MORNING WITH SLICK CONDITIONS OVER THE PASSES. IN FACT, HEAVY SNOW
RATES NEAR 1 INCH/HOUR HAVE IMPACTED HOMESTAKE PASS WITH SEVERAL
MORE HOURS OF MODERATE TO HEAVY SNOW ANTICIPATED EARLY THIS
MORNING. AS THE MID LEVEL LOW SHIFTS EASTWARD, SNOW WILL SEE A
GRADUAL DIMINISHING TREND TOWARD SUNRISE. OTHERWISE, THERE WILL
BE PARTIAL CLEARING THROUGHOUT TODAY WITH SEASONABLE TEMPERATURES.
THE NEXT WAVE OF MOISTURE ARRIVES THIS EVENING IN NORTH-CENTRAL
IDAHO AND SPREADS NORTHEASTWARD INTO MONDAY MORNING WITH A ROUND
OF SHOWERS ACROSS THE NORTHERN ROCKIES. SNOW LEVELS WILL VARY FROM
3500-4500 FEET BUT IMPACTS WILL BE LIMITED TO PASS LEVEL AND MINOR
AT THAT, AS ONLY 1-2 INCHES OF SNOW ARE ANTICIPATED FOR ID/MT
BORDER PASSES. MONDAY WILL BE QUITE CONVECTIVE WITH SCATTERED
SHOWERS AND A FEW THUNDERSTORMS THROUGH THE DAY UNDER SOUTHWEST
FLOW.
A LARGE PACIFIC TROUGH MOVES ACROSS THE NORTHERN ROCKIES MONDAY
NIGHT THROUGH WEDNESDAY MORNING WITH PERIODS OF RAIN AND SNOW.
NBM MEAN FORECAST VALUES SHOW ANOTHER 1-3 INCHES OF SNOW ON THE
PASSES BY TUESDAY MORNING, WATCH FOR SLICK ROADS. NOTHING MORE
THAN WET ROADS ARE ANTICIPATED FOR VALLEYS EVEN IF SNOW MIXES IN.
THERE ARE HINTS OF ANOTHER MID LEVEL LOW FORMING NEAR SOUTHWEST
MONTANA WHICH COULD FOCUS SNOWFALL IN THAT REGION TUESDAY,
CERTAINLY SOMETHING TO KEEP ON EYE.
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
MODERATE TO HEAVY SNOW CONTINUES IN SOUTHWEST MONTANA
AND LEMHI COUNTY BUT WITH A GRADUAL DIMINISHMENT TOWARD SUNRISE
AS A MID LEVEL LOW TRACKS EAST OF THE REGION. MOUNTAIN
OBSCURATIONS WILL GRADUALLY BREAK UP THROUGH THE MORNING HOURS AS
WELL WITH VFR CONDITIONS FOR MUCH OF THE NORTHERN ROCKIES THIS
AFTERNOON. THE GRADIENT FLIPS TO EASTERLY WITH SOME BREEZES OF
15-20 KTS INTO THIS EVENING. THE NEXT WAVE OF MOISTURE ARRIVES
THIS EVENING LASTING INTO MONDAY MORNING WITH PERIODIC SHOWERS AS
SNOW LEVELS VARY FROM 3500-4500 FEET.
MSO WATCHES/WARNINGS/ADVISORIES
MT...WINTER WEATHER ADVISORY UNTIL 9 AM MDT SUNDAY FOR
BUTTE/BLACKFOOT REGION.
ID...WINTER WEATHER ADVISORY UNTIL 9 AM MDT SUNDAY FOR EASTERN LEMHI
COUNTY...WESTERN LEMHI COUNTY.
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