306
FXUS65 KMSO 140808
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
208 AM MDT MON SEP 14 2026
DISCUSSION
KEY MESSAGES:
- WIDESPREAD RAIN SHOWERS, HIGH ELEVATION SNOW AND BREEZY
CONDITIONS TODAY
- DRYING AND WARMING CONDITIONS BY MID-WEEK.
- TRENDING WETTER LATE THURSDAY INTO FRIDAY.
A LOW PRESSURE SYSTEM MOVING ALONG THE NORTHWEST MONTANA
AND CANADIAN BORDER WILL SLOWLY SHIFT EASTWARD TODAY. THIS
SYSTEM IS PRODUCING WIDESPREAD RAIN SHOWERS ACROSS ALL OF WESTERN
MONTANA AND NORTH-CENTRAL IDAHO, WITH HEAVIER SHOWERS FOCUSING ON
NORTHWEST MONTANA AND NORTH-CENTRAL IDAHO TODAY. SNOW LEVELS
DROPPED TO ROUGHLY 6,500 FEET OVERNIGHT, RESULTING IN LIGHT SNOW
ACCUMULATIONS FROM THE CONTINENTAL DIVIDE SOUTHWARD TO THE
BITTERROOTS. ADDITIONALLY, BREEZY WESTERLY WINDS WILL DEVELOP ONCE
AGAIN ACROSS WESTERN MONTANA, WITH GUSTS OF 20 TO 30 MPH.
BACKCOUNTRY RECREATIONISTS SHOULD PREPARE FOR COLD, RAW CONDITIONS
AND A HEIGHTENED RISK OF HYPOTHERMIA TODAY.
AS THE SYSTEM EXITS BY TOMORROW MORNING, THE REGION WILL
EXPERIENCE A BRIEF WARMING AND DRYING TREND THROUGH MID-WEEK,
THOUGH ISOLATED SHOWERS MAY LINGER NEAR THE CANADIAN BORDER.
CLEARING SKIES EARLY TUESDAY WILL CAUSE TEMPERATURES TO DROP
SIGNIFICANTLY, BRINGING CHILLY CONDITIONS TO AREAS ALONG AND SOUTH
OF INTERSTATE 90. SUBFREEZING TEMPERATURES ARE EXPECTED IN THE
HIGHER VALLEYS OF SOUTHWEST MONTANA AND ALONG THE CONTINENTAL
DIVIDE, WHILE FROST WILL LIKELY DEVELOP IN THE TYPICALLY COLDER
LOCATIONS OF THE MISSOULA, BITTERROOT, AND CLEARWATER VALLEYS.
FORECAST MODELS INDICATE ANOTHER LOW-PRESSURE SYSTEM WILL MOVE
INLAND FROM THE PACIFIC COAST WEDNESDAY NIGHT, TRACKING ACROSS
WESTERN MONTANA AND NORTH-CENTRAL IDAHO THURSDAY INTO FRIDAY. THIS
INCOMING SYSTEM IS EXPECTED TO INTERACT WITH ABUNDANT MOISTURE FROM
THE SOUTH, LEADING TO INCREASING PRECIPITATION AND THUNDERSTORM
CHANCES LATE IN THE WEEK, PARTICULARLY FOR AREAS SOUTH OF INTERSTATE
90. WHILE A MAJORITY OF FORECAST MODELS (NEARLY 80%) SUPPORT A
WETTER SCENARIO, CONFIDENCE REGARDING THE EXACT TIMING AND SPECIFIC
LOCAL IMPACTS REMAINS LOW AT THIS TIME.
AVIATION
AVIATION OPERATIONS ACROSS WESTERN MONTANA AND NORTH
CENTRAL IDAHO WILL ENCOUNTER DEGRADED FLIGHT CONDITIONS TODAY AS
A LOW PRESSURE SYSTEM TRACKS EASTWARD ALONG THE NORTHWEST MONTANA
AND CANADIAN BORDER. THIS SYSTEM IS GENERATING WIDESPREAD SHOWERS
ACROSS ALL OF WESTERN MONTANA AND NORTH-CENTRAL IDAHO, WITH THE
MOST CONCENTRATED PRECIPITATION, AND HIGHEST PROBABILITY FOR MVFR
TO LOCALIZED IFR RESTRICTIONS FOCUSING OVER NORTHWEST MONTANA AND
NORTH-CENTRAL IDAHO. WITH SNOW LEVELS HAVING FALLEN TO NEAR 6,500
FEET MSL OVERNIGHT, PILOTS SHOULD ANTICIPATE LIGHT HIGH-ELEVATION
SNOW ACCUMULATIONS AND WIDESPREAD MOUNTAIN OBSCURATIONS. AN
INCREASING PRESSURE GRADIENT WILL PROMOTE BREEZY WESTERLY SURFACE
WINDS ACROSS WESTERN MONTANA THIS AFTERNOON, PRODUCING GUSTS OF 15
TO 25 KTS.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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