460
FXUS65 KMSO 230904
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
204 AM MST FRI JAN 23 2026
DISCUSSION
KEY MESSAGES:
- A TRANSITION TO COLDER AND BLUSTERY CONDITIONS CONTINUES TODAY
AS AN ARCTIC BOUNDARY SLIDES INTO WESTERN MONTANA.
- FREEZING SPRAY POTENTIAL (FLATHEAD LAKE): GUSTY NORTHEAST
WINDS AND HIGH LAKE LEVELS MAY GENERATE FREEZING SPRAY ALONG
THE SOUTH AND WEST SHORES OF FLATHEAD LAKE THIS MORNING.
- WEEKEND UNCERTAINTY: A SNEAKY ROUND OF LIGHT SNOW CANNOT BE
RULED OUT WITH A DISTURBANCE DROPPING OUT OF CANADA THIS
WEEKEND.
THE PRIMARY STORY FOR TODAY IS THE ARRIVAL OF THE COLD FRONT AND
THE ASSOCIATED WINDS GUSTING 20-30 MPH IN FAVORED VALLEYS
INCLUDING MISSOULA AND FLATHEAD.
FLATHEAD LAKE: EAST AND NORTHEAST WIND GUSTS OF 15-25 MPH ARE
INTERACTING WITH UNSEASONABLY HIGH LAKE LEVELS CREATING WAVE
HEIGHTS SUFFICIENTLY HIGH TO GENERATE FREEZING SPRAY. THERE IS AN
INCREASED RISK FOR ICE ACCUMULATION ON DOCKS AND SHORELINE
PROPERTY. THERE IS ALSO AN ISOLATED RISK FOR SLICK SPOTS TO
DEVELOP ON ROADWAYS IMMEDIATELY ADJACENT TO THE LAKE (SUCH AS HWY
93 THROUGH THIS MORNING. WINDS AND WAVE HEIGHTS WILL TAPER OFF
THIS AFTERNOON.
WATER VAPOR SATELLITE IMAGERY REVEALS A SWATH OF MOISTURE
CURRENTLY ROTATING AROUND THE RIDGE IN THE NORTHERN TERRITORIES OF
CANADA, AIMING SOUTH TOWARD THE NORTHERN ROCKIES. MODELS OFTEN
HANDLE THESE NORTHERLY FLOW DISTURBANCES POORLY, AND THERE IS
LITTLE CONSENSUS ON THE TIMING, OR DEPTH OF THIS MOISTURE AS IT
ARRIVES THIS WEEKEND. IF THE MOISTURE HOLDS TOGETHER AND IS DEEP
ENOUGH, THERE IS POTENTIAL FOR A SURPRISE LIGHT SNOW SATURDAY OR
SATURDAY NIGHT. IF THE MOISTURE SHEARS APART UPON ENCOUNTERING THE
RIDGE, WE WILL SIMPLY SEE INCREASED CLOUD COVER AND PERHAPS A FEW
FLURRIES ALONG THE CONTINENTAL DIVIDE.
BOTTOM LINE: WHILE SNOW IS NOT IN THE FORECAST, DON'T BE
SURPRISED IF SATURDAY ENDS UP GRAYER AND FLAKIER THAN THE RAW
MODEL OUTPUT SUGGESTS.
WE EXPECT A RETURN TO DRIER CONDITIONS AS THE WEEKEND DISTURBANCE
EXITS. TEMPERATURES WILL REMAIN BELOW NORMAL, WITH HIGHS IN THE
20S. IF SKIES CLEAR SUNDAY NIGHT, MONDAY MORNING LOWS COULD PLUNGE
WELL INTO THE SINGLE DIGITS OR BELOW ZERO IN THE COLDER VALLEYS.
MONDAY THROUGH THURSDAY: THE FORECAST REMAINS LOW CONFIDENCE
REGARDING THE NEXT PATTERN SHIFT. THE MODELS CONTINUE TO DIVERGE
ON HOW A PACIFIC TROUGH WILL INTERACT WITH THE COLD AIR
ESTABLISHED OVER THE CONTINENT. CURRENT MODEL TRENDS FAVOR A
DRIER SOLUTION, SUGGESTING THE HIGH PRESSURE WILL BLOCK
MOST OF THE PACIFIC MOISTURE. HOWEVER, SHOULD THE PACIFIC ENERGY
OVERRIDE THE COLD DOME, A PERIOD OF OVERRUNNING LIGHT SNOW OR
FREEZING RAIN REMAINS POSSIBLE MID TO LATE WEEK. WE HAVE
MAINTAINED LOW-END POPS TO ACCOUNT FOR THIS POSSIBILITY.
AVIATION
GUSTS OF 20-30 KTS WILL BE COMMON IN FAVORED VALLEYS
INCLUDING KMSO AND KGPI INTO THIS AFTERNOON. KBTM AND KHRF BEGIN
THE PERIOD WITH MVFR CEILINGS, BUT THE INFLUX OF DRY, EASTERLY
DOWNSLOPE FLOW WILL EFFECTIVELY SCOUR THE VALLEY STRATUS,
TRANSITIONING ALL TERMINALS TO VFR BY THIS AFTERNOON. MOUNTAIN
OBSCURATIONS CURRENTLY AFFECTING NORTH-CENTRAL IDAHO THROUGH WEST-
CENTRAL MONTANA, AND LOW CEILINGS IN NORTH-CENTRAL IDAHO ARE
EXPECTED TO IMPROVE RAPIDLY THIS AFTERNOON AS CEILINGS LIFT AND
SCATTER WITH INCOMING DRIER AIR.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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