201
FXUS65 KMSO 131826
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
1226 PM MDT SAT SEP 13 2025
DISCUSSION
KEY MESSAGES:
- SCATTERED AFTERNOON SHOWERS MAINLY ALONG I-90 TODAY, NEAR
PERFECT LATE SUMMER DAY FOR MOST.
- CONFIDENCE IS INCREASING FOR WIDESPREAD SHOWERS SUNDAY INTO
MONDAY, FOR SOME A BENEFICIAL RAIN.
A FEW SHOWERS OR A THUNDERSTORM WILL SLOWLY MOVE SOUTHEAST ALONG
I-90 TODAY. MAINLY HUGGING THE TERRAIN. FOR MOST TODAY WILL BE A
NEAR PERFECT LATE SUMMER DAY WITH LIGHT BREEZES, NEAR NORMAL
TEMPERATURES, AND PLENTY OF SUNSHINE.
TOMORROW WITH THE INCLUSION OF HIGH RESOLUTION MODELS THERE IS
INCREASING CONFIDENCE THAT THE NEXT SYSTEM WILL BRING WIDESPREAD
SHOWERS AND BENEFICIAL RAIN TO AT LEAST NORTH-CENTRAL IDAHO AND
POTENTIALLY PARTS OF WESTERN MT. THE HIGHER TERRAIN OF IDAHO
COUNTY COULD HAVE TOTALS OF 0.20 TO 0.60" BY MONDAY MORNING, WHILE
CLEARWATER COUNTY IS CLOSER TO 0.10 TO 0.45". WE ARE STILL IN
CONVECTIVE SEASON SO IT IS QUITE REASONABLE TO BELIEVE ONE
RIDGELINE WILL RECEIVE THE HIGH END WHILE THE NEXT RIDGE OVER WILL
RECEIVE THE LOW END. EVEN THE LOW LANDS HAVE TOTALS BETWEEN 0.10
TO 0.40", ALL DEPENDENT ON HOW CLOSE YOU ARE TO STRONGER CORES.
WESTERN MONTANA IS A DIFFERENT STORY. THERE STILL REMAINS SOME
UNCERTAINTY OF HOW ORGANIZED THE SYSTEM WILL BECOME. THE STRETCH
OF AREA ALONG US-93 SOUTH OF POLSON TO LEMHI COUNTY ID, HAS A 25TH
TO 75TH PERCENTILE RANGE OF 0.10 TO 0.40", WITH LOCALIZED AMOUNTS
AS HIGH AS 0.60". THE HIGHER TERRAIN OF THE BITTERROOTS,
SAPPHIRE, RATTLESNAKE, AND MISSION MOUNTAINS MAY RECEIVE AMOUNTS
EQUAL TO IDAHO COUNTY, 0.20 TO 0.60". THE AMOUNTS NORTH OF POLSON
AND SOUTHWEST MT WILL BE DEPENDENT ON HOW ORGANIZED THIS SYSTEM
BECOMES WITH 0.00 TO 0.15" RANGE OF TOTALS.
THE NORTHERN ROCKIES BECOMES STUCK BETWEEN DEEP TROUGHS DURING
THE MIDDLE OF NEXT WEEK AND TEMPERATURES BLOSSOM 4 TO 8 DEGREES
ABOVE NORMAL, WITH DRYING CONDITIONS, AND LIGHT BREEZES. THIS WILL
BE SHORT-LIVED POTENTIALLY AS MODELS DIVERGE GREATLY AROUND THE
18TH AND 19TH, MORE TO COME IN FUTURE FORECASTS.
AVIATION
A SMALL BAND OF SHOWERS/ THUNDERSTORMS WILL SLOWLY
MOVE SOUTHEAST ALONG I-90 AND GRADUALLY DIMINISH DURING THE
AFTERNOON. BEYOND MENTION OF SHOWERS IN THE VICINITY OF KMSO AND
KBTM BETWEEN 13/1900 AND 14/0000Z, VFR CONDITIONS WILL PREVAIL
WIDESPREAD. INCREASING MID TO UPPER LEVEL CLOUDS ON SUNDAY WILL
SIGNAL THE NEXT PERIOD OF CONVECTION AFFECTING NORTH-CENTRAL IDAHO
BEFORE 15/0000Z AND WEST-CENTRAL MT AFTER.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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