566
FXUS65 KMSO 141810
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
1210 PM MDT WED OCT 14 2026
DISCUSSION
KEY MESSAGES:
- COLD MORNINGS AND PLEASANT AFTERNOONS THE REST OF THE WEEK.
- GUSTY WINDS AND CHOPPY LAKES ON SATURDAY, ESPECIALLY NORTHWEST
MT.
-PATTERN SHIFT EARLY NEXT WEEK, GRADUALLY COOLING AND A CHANCE OF
SHOWERS.
TODAY THROUGH FRIDAY: A WEAK PASSING DISTURBANCE WILL PRODUCE
TRANSIENT MID- TO HIGH-LEVEL CLOUD COVER ACROSS THE NORTHERN
ROCKIES THROUGH THIS EVENING. EXPECT SIGNIFICANT CLEARING BY THIS
EVENING, PAVING THE WAY FOR STRONG RADIATIONAL COOLING AND A
CHILLY, SEASONABLE NIGHT. FOR THURSDAY AND FRIDAY, AN AMPLIFYING
UPPER- LEVEL RIDGE WILL BUILD ACROSS THE REGION, YIELDING MOSTLY
SUNNY SKIES ASIDE FROM PATCHY MORNING VALLEY FOG. NOTE THAT
FRIDAY'S HIGH TEMPERATURE GUIDANCE MAY BE SLIGHTLY OVER- AMPLIFIED
FOR VALLEY LOCATIONS; LIMITED ATMOSPHERIC MIXING UNDER THE RIDGE
AXIS SUGGESTS ACTUAL HIGH TEMPERATURES MAY FALL SHORT OF THE
WARMEST GUIDANCE. NONETHELESS, OVERALL CONDITIONS WILL REMAIN VERY
PLEASANT FOR MID- OCTOBER.
SATURDAY THROUGH TUESDAY: THE RIDGE BEGINS TO BREAK DOWN ON
SATURDAY AS A NORTHERN-STREAM DISTURBANCE TRACKS ALONG THE
CANADIAN BORDER. THIS WILL INDUCE AN INCREASINGLY WELL-MIXED
WESTERLY FLOW, DRIVING DAYTIME TEMPERATURES UPWARD. SURFACE WIND
GUSTS OF 30 TO 40 MPH ARE ANTICIPATED, WHICH WILL GENERATE CHOPPY
LAKE WATERS AND POSE A HAZARD TO SMALL WATERCRAFT. WHILE A FEW
SHOWERS MAY CLIP NORTHWEST MONTANA, THE SYSTEM IS LARGELY
MOISTURE-STARVED, KEEPING REGIONAL PRECIPITATION TOTALS
NEGLIGIBLE. A TRAILING COLD FRONT WILL SWEEP THROUGH SATURDAY
NIGHT, INTRODUCING MODEST COLD AIR ADVECTION FOR SUNDAY, THOUGH
HIGH TEMPERATURES WILL REMAIN SLIGHTLY ABOVE SEASONAL NORMALS.
LOOKING AHEAD TO EARLY NEXT WEEK, GLOBAL ENSEMBLES ARE IN BROAD
AGREEMENT ON A PATTERN SHIFT FEATURING A LONGWAVE UPPER-LEVEL
TROUGH DIGGING INTO THE WESTERN U.S., A TREND WELL-SUPPORTED BY
RECENT CPC 6-10 DAY OUTLOOKS. HOWEVER, ENSEMBLE CLUSTERS CONTINUE
TO EXHIBIT SIGNIFICANT SPREAD REGARDING THE EXACT AMPLITUDE,
TIMING, AND EVOLUTION OF THIS TROUGH. AT A MINIMUM, EXPECT A
TRANSITION TO A MORE UNSETTLED WEATHER REGIME ACROSS THE NORTHERN
ROCKIES, CHARACTERIZED BY RETURNING PRECIPITATION CHANCES AND HIGH
TEMPERATURES TRENDING BACK DOWN TO NEAR-CLIMATOLOGICAL AVERAGES.
AVIATION
A FEW UPPER LEVEL DISTURBANCES WILL CONTINUE TO BRING
MID-CLOUD COVER THROUGH THE EVENING HOURS. UPPER-LEVEL RIDGING
WILL BEGIN TO BUILD OVER THE REGION THURSDAY INTO FRIDAY,
GENERALLY FAVORING VFR CONDITIONS. HOWEVER, A COOLER CANADIAN AIR MASS
ACCOMPANIED BY A 1042 MILLIBAR SURFACE HIGH, WILL BUILD INTO
CENTRAL MONTANA ON THURSDAY. THIS WILL ESTABLISH A MODERATE
EASTERLY WIND GRADIENT ACROSS NORTH-CENTRAL IDAHO AND WESTERN
MONTANA LASTING FROM 0600 MDT THURSDAY (1200UTC) THROUGH 0800 MDT
FRIDAY (1400 UTC). EXPECT BREEZY EASTERLY WINDS UP TO 20 KNOTS IN
THE GAPS AND CHANNELS EXTENDING WESTWARD FROM THE CONTINENTAL
DIVIDE. HIGH RESOLUTION FORECAST SOUNDINGS SUGGEST THAT KBTM MAY
BE DECOUPLED AND MOIST ENOUGH FOR FOG DEVELOPMENT TO FORM BY
DAYBREAK THURSDAY, THOUGH CONFIDENCE REMAINS LOW.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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