539
FXUS65 KMSO 240920
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
320 AM MDT THU SEP 24 2026
DISCUSSION
KEY MESSAGES:
- UNSEASONABLY WARM TODAY, WITH TEMPERATURES 10-15 DEGREES ABOVE
NORMAL.
- COLD FRONT FRIDAY AFTERNOON BRINGS STRONG WEST WINDS, CHOPPY
LAKES, AND ELEVATED FIRE WEATHER CONCERNS.
- CUTOFF LOW THIS WEEKEND BRINGS RAIN SHOWERS TO NORTHWEST
MONTANA AND SNOW TO HIGH PEAKS OF GLACIER NATIONAL PARK.
THE NORTHERN ROCKIES WILL BE UNDER THE INFLUENCE OF A SOUTHWESTERLY
FLOW PATTERN ALOFT TODAY, WITH TEMPERATURES RUNNING 10-15 DEGREES
ABOVE NORMAL. AN UPPER LEVEL RIDGE AXIS ALONG AND EAST OF THE
DIVIDE WILL LEAD TO DRY CONDITIONS, WITH PLENTY OF SUNSHINE.
SOUTHERLY WINDS WILL DEVELOP BY THE AFTERNOON, AS A LOW PRESSURE
SYSTEM REACHES THE OREGON COASTLINE. THE STRONGEST GUSTS (20-30
MPH) WILL BE FELT ACROSS THE HIGHER ELEVATIONS AND SOUTHERN IDAHO
COUNTY, ID.
A SIGNIFICANT CHANGE ARRIVES FRIDAY AS A DRY COLD FRONT
APPROACHES FROM THE WEST, ASSOCIATED WITH THE AFOREMENTIONED LOW
PRESSURE SYSTEM. THE FRONT WILL BRING GUSTY TO LOCALLY STRONG
WINDS ACROSS WESTERN MONTANA, CROSSING THE US-93 CORRIDOR BETWEEN
400-700 PM MDT. MOST LOCATIONS WILL SEE PEAK WIND GUSTS OF 30-40
MPH, WITH LOCALIZED GUSTS OF 45 MPH OR GREATER ACROSS THE
BITTERROOT VALLEY AND IN SOUTHWEST MONTANA. THE BITTERROOT VALLEY
IN PARTICULAR WILL EXPERIENCE LOCALIZED WIND CHANNELING EFFECTS
AS STRONGER GUSTS (45+ MPH) DESCENT FROM NARROW WEST-EAST
ORIENTATED CANYONS TOWARDS THE VALLEY FLOOR. THESE STRONGER GUSTS
MAY LEAD TO LOCALIZED POWER OUTAGES FRIDAY EVENING. HIGHER GUSTS
OF 45-60 MPH WILL BE FELT ACROSS MOUNTAIN RIDGETOPS AND THE
HIGHER PEAKS FRIDAY EVENING. FURTHERMORE, CHOPPY CONDITIONS ON
REGIONAL LAKES AND ELEVATED FIRE WEATHER CONDITIONS ARE EXPECTED.
A BRIEF LINE OF HIGH-BASED SHOWERS WILL ACCOMPANY THE FRONT,
ALONG AND NORTH OF THE I-90 CORRIDOR, BUT LITTLE TO ANY
PRECIPITATION IS EXPECTED.
A SHORTWAVE TROUGH WILL TRACK ALONG THE USA-CANADA BORDER FRIDAY
NIGHT INTO SATURDAY MORNING, FOCUSING SHOWER ACTIVITY ACROSS
NORTHWEST MONTANA AND IN CLEARWATER COUNTY, IDAHO. SNOW LEVELS
WILL LOWER TO AROUND 6,000 FEET BY SATURDAY MORNING. SNOW SHOWERS
WILL BRING LOCALIZED SNOW ACCUMULATIONS TO MOUNTAIN RANGES IN
NORTHWEST MONTANA, AND THE HIGHER TERRAIN OF GLACIER NATIONAL
PARK, INCLUDING LOGAN PASS. THIS SYSTEM WILL BRING A SIGNIFICANT
WEATHER CHANGE, INCREASING THE RISK OF HYPOTHERMIA FROM COLDER
TEMPERATURES AND SNOWFALL FOLLOWING RECENT WARM AND DRY
CONDITIONS. SEASONABLY COOL AND BREEZY CONDITIONS WILL PERSIST
THROUGH SUNDAY.
AVIATION
THE NORTHERN ROCKIES AIRSPACE WILL BE UNDER THE
INFLUENCE OF A WARM AND DRY SOUTHWESTERLY FLOW PATTERN TODAY.
SOUTH-SOUTHEAST WINDS WILL DEVELOP BY THIS AFTERNOON FOR MOST
TERMINALS, WITH GUSTS OF 10-15 KTS FROM 24/2000-25/0000Z. HIGH
CLOUDS WILL PERIODICALLY PASS THROUGH THE AREA, WITH VFR
CONDITIONS EXPECTED.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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