431
FXUS65 KTFX 261015
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
415 AM MDT MON OCT 26 2026
KEY MESSAGES
- DENSE FOG WILL CONTINUE TO AFFECT SOUTHWEST MT THROUGH THIS
MORNING.
- LIGHT RAIN AND SNOW WILL MOVE FROM WEST TO EAST ACROSS THE CWA
OVERNIGHT TONIGHT.
- ANOTHER ROUND OF LIGHT RAIN OR SNOW SHOWERS IS EXPECTED TO END
THE WORK WEEK.
- OVERALL, AFTERNOON TEMPERATURES WILL GENERALLY BE NEAR TO A BIT
BELOW NORMAL ALL WEEK.
DISCUSSION
- METEOROLOGICAL OVERVIEW:
LOW CLOUDS AND DENSE FOG CONTINUE TO AFFECT SOUTHWEST MT THIS
MORNING. INCREASING HIGH CLOUDS WILL PREVENT THE DENSE FOG FROM
EXPANDING IN AREAL COVERAGE, BUT WILL ALSO PREVENT THE DENSE FOG
FROM BURNING OFF QUICKLY THIS MORNING. THUS THE NO CHANGES TO THE
CURRENT DENSE FOG ADVISORY STATEMENT. OTHERWISE, THE MAIN CONCERN
LATER TODAY/TONIGHT WILL BE THE INCREASING CHANCES FOR RAIN/SNOW
AS THE NEXT UPPER LEVEL TROF APPROACHES FROM THE WEST. THE
HEAVIEST PRECIPITATION SHOULD FALL IN THE MOUNTAINS WITH THIS
SYSTEM, WITH THE SOUTHWEST MOUNTAINS BEING THE FAVORED AREA. THUS
A WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR TONIGHT FOR THE
SOUTHWEST MOUNTAINS AROUND PONY, BIG SKY AND WEST YELLOWSTONE.
THIS WILL BE A QUICK MOVING TROF, WITH MOST OF THE PRECIPITATION
ENDING BY EARLY TUESDAY MORNING. FOR THE REST OF TUE/WED, THE
AIRMASS WILL REMAIN A BIT UNSTABLE FOR A FEW PASSING LIGHT
RAIN/SNOW SHOWERS, BUT MOST/IF ANY OF THE PRECIPITATION THAT FALLS
SHOULD BE IN THE MOUNTAINS.
FOR LATER IN THE WORK WEEK...MOSTLY THU INTO FRI...AN UPPER LEVEL
LOW WILL DEVELOP OFF THE COAST OF THE PACIFIC NORTHWEST, BUT
GENERALLY STALL OVER THAT REGION. THIS WILL RESULT IN A MOIST
SOUTHWESTERLY FLOW ALOFT DEVELOPING OVER MT, WHICH WILL ALLOW FOR
SCATTERED RAIN/SNOW SHOWERS TO MOVE THROUGH THE CWA FROM TIME TO
TIME. THE UPPER LEVEL TROF WILL BEGIN TO MOVE SLOWLY EASTWARD OVER
THE WEEKEND, AND THEN MOVING ACROSS MT EARLY NEXT WEEK. THUS THE
CHANCES FOR LIGHT RAIN/SNOW SHOWERS WILL CONTINUE FOR SEVERAL
DAYS.
OVERALL, AFTERNOON TEMPERATURES WILL GENERALLY BE A BIT BELOW
NORMAL ACROSS THE CWA, WITH A FEW LOCATIONS POSSIBLY SEEING NEAR
NORMAL TEMPERATURES TUE/WED.
- FORECAST CONFIDENCE & SCENARIOS:
THE MAIN CONCERN TONIGHT WILL BE THE LIGHT SNOW ACROSS SOUTHWEST
MT. OVERALL SNOW ACCUMULATIONS LOOK TO BE ON THE LIGHTER SIDE,
THUS A WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR ONE MOUNTAIN
ZONE...330...FOR THIS SYSTEM. RAIN IS LIKELY TO CHANGE TO SNOW AT
ALL ELEVATIONS BY TUE MORNING, BUT ANY SNOW ACCUMULATIONS AT LOWER
ELEVATIONS GENERALLY LOOK TO BE LESS THAN AN INCH AT THIS TIME.
PERIODS OF LIGHT SNOW ARE EXPECTED IN THE MOUNTAINS LATER THIS
WEEK AND INTO THIS WEEKEND. OVERALL MOST OF THE SNOW ACCUMULATIONS
WILL CONTINUE TO BE ON THE LIGHT SIDE, BUT A WINTER STATEMENT
MIGHT BE NEEDED FROM TIME TO TIME OVER PORTIONS OF THE CWA LATER
THIS WEEK AND INTO THIS WEEKEND. BRUSDA
AVIATION
26/12Z TAF PERIOD
THE MAIN CONCERN THIS MORNING WILL BE AREAS OF DENSE FOG OVER
SOUTHWEST MT, WITH VISIBILITY BELOW 1/2SM AT TIMES. THE FOG WILL
BE A BIT SLOW TO BURN OFF, THINKING LATE MORNING, WITH LOW
CEILINGS CONTINUING INTO MID AFTERNOON. THEN THE NEXT ROUND OF
LIGHT RAIN/SNOW MOVES INTO THE WESTERN PORTIONS OF THE CWA BY 00Z
TUE. EXPECT THIS BAND OF PRECIPITATION TO MOVE FROM WEST TO EAST
ACROSS THE CWA TONIGHT. MOUNTAINS/PASSES WILL BE OBSCURED BY
CLOUDS/PRECIPITATION ACROSS THE CWA THROUGH THE PERIOD. BRUSDA
PRELIMINARY POINT TEMPS/POPS
GTF 43 32 51 35 / 0 60 20 0
CTB 43 26 50 28 / 0 40 30 0
HLN 48 33 51 28 / 0 90 10 0
BZN 51 29 47 23 / 0 90 20 0
WYS 48 19 37 15 / 10 100 60 20
DLN 52 31 45 24 / 0 80 0 0
HVR 52 29 50 29 / 0 40 70 40
LWT 49 30 47 29 / 0 60 40 0
TFX WATCHES/WARNINGS/ADVISORIES
DENSE FOG ADVISORY UNTIL NOON MDT TODAY FOR BEAVERHEAD AND
WESTERN MADISON BELOW 6000FT-CANYON FERRY AREA-ELKHORN AND
BOULDER MOUNTAINS-GALLATIN VALLEY-GALLATIN AND MADISON COUNTY
MOUNTAINS AND CENTENNIAL MOUNTAINS-MADISON RIVER VALLEY-MISSOURI
HEADWATERS-NORTHWEST BEAVERHEAD COUNTY.
WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 6 AM MDT
TUESDAY FOR GALLATIN AND MADISON COUNTY MOUNTAINS AND CENTENNIAL
MOUNTAINS.
HTTP://WWW.WEATHER.GOV/GREATFALLS
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