163
FXUS65 KTFX 112047
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
247 PM MDT SAT OCT 11 2025
KEY MESSAGES
- IT WILL BE WINDY THIS AFTERNOON AND SUNDAY WITH SHOWERS AND
THUNDERSTORMS PRIMARILY IN SOUTHWESTERN AND CENTRAL MONTANA.
- TONIGHT THROUGH MONDAY IT WILL BE SIGNIFICANTLY COLDER WITH
MOUNTAIN SNOW AND LOWER ELEVATION SNOW/RAIN WITH MOST OF THE
LOWER ELVATION SNOW EXPECTED SUNDAY NIGHT INTO MONDAY MORNING.
- TUESDAY THROUGH FRIDAY IT WILL WARM UP WITH DAILY PRECIPITATION
CHANCES.
DISCUSSION
- METEOROLOGICAL OVERVIEW:
THIS AFTERNOON THERE IS AN UPPER LEVEL TROUGH AND AN ASSOCIATED
COLD FRONT THAT HAVE MOVED ACROSS MOST OF NORTH CENTRAL, CENTRAL
AND SOUTHWESTERN MONTANA. AHEAD OF AND ALONG THE FRONT THERE IS
THE RISK FOR ISOLATED THUNDERSTORMS WITH THE GREATEST RISK IN
SOUTHWESTERN MONTANA. AHEAD OF AND ALONG THE FRONT THERE WILL BE
SHOWERS. TONIGHT COLD AIR FROM CANADA WILL MOVE INTO NORTH
CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA BEHIND THE FRONT THIS
WILL LOWER-SNOW LEVELS ACROSS THE AREA AND BRING A RAIN/SNOW MIX
TO MOST LOWER ELEVATIONS OF NORTH CENTRAL MONTANA AND RAIN TO THE
VALLEYS OF CENTRAL AND SOUTHWESTERN MONTANA AND HEAVY MOUNTAIN
SNOW. ON SUNDAY THE UPPER LEVEL TROUGH REMAINS OVER THE AREA IN
THE MORNING BEFORE AN UPPER LEVEL RIDGE MOVES OVER THE AREA. DUE
TO THE COLD FRONT ON SUNDAY TEMPERATURES ACROSS NORTH CENTRAL
MONTANA WILL BE WELL BELOW SEASONAL AVERAGES AND BELOW SEASONAL
AVERAGES ACROSS CENTRAL AND SOUTHWESTERN MONTANA. ACROSS MOST
LOCATIONS THERE WILL BE A PRECIPITATION LULL BETWEEN NOON SUNDAY
AND SUNDAY EVENING. SUNDAY EVENING THERE WILL BE A WARM FRONT
SITUATED ACROSS CENTRAL MONTANA. THIS COMBINED WITH LOW LEVEL
EASTERLY FLOW WILL ALLOW FOR ANOTHER ROUND OF SNOWFALL DUE TO
ISENTROPIC LIFT. THIS ROUND OF SNOWFALL WILL PRIMARILY EFFECT
NORTH CENTRAL AND CENTRAL MONTANA SUNDAY EVENING THROUGH NOON ON
MONDAY.
ON MONDAY THE UPPER LEVEL RIDGE REMAINS OVER NORTH CENTRAL, CENTRAL,
AND SOUTHWESTERN MONTANA. THIS WILL ALLOW THE AREA TO DRY OUT FOR
THE MOST PART ON MONDAY. ON TUESDAY THE UPPER LEVEL RIDGE REMAINS
OVER NORTH CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. THIS WILL
ALLOW TEMPERATURES TO BEGIN TO WARM UP ACROSS THE AREA WITH MOSTLY
DRY WEATHER. WEDNESDAY THROUGH FRIDAY AN UPPER-LEVEL TROUGH MOVES
OVER NORTH CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. THIS WILL
ALLOW TEMPERATURES TO WARM UP SOME WITH DAILY PRECIPITATION CHANCES.
IG
- FORECAST CONFIDENCE & SCENARIOS:
THERE IS GREATER THAN A 60% CHANCE FOR 8 INCHES OR MORE SNOWFALL
ACROSS MOST OF THE MOUNTAINS OF NORTH CENTRAL, CENTRAL, AND
SOUTHWESTERN MONTANA THROUGH NOON ON MONDAY. ALONG THE ROCKY
MOUNTAIN FRONT THERE IS A GREATER THAN A 80% CHANCE FOR 12 INCHES
OF SNOW OR GREATER THROUGH NOON ON MONDAY. AS A RESULT WINTER
STORM WARNINGS ARE IN EFFECT FOR THE ROCKY MOUNTAIN FRONT FROM
THIS EVENING THROUGH NOON ON MONDAY AND WINTER WEATHER ADVISORIES
ARE IN EFFECT FOR MACDONALD PASS/LINCOLN AND THE LITTLE
BELTS/HIGHWOODS FROM THIS EVENING THROUGH NOON ON MONDAY AND FOR
THE MADISON AND GALLATIN MOUNTAINS THROUGH NOON ON SUNDAY. THERE
IS GREATER THAN A 60% CHANCE FOR 4 INCHES OF SNOW OR GREATER ALONG
THE NORTHERN AND SOUTHERN HIGH PLAINS ADJACENT TO THE ROCKY
MOUNTAIN FRONT FROM THIS EVENING THROUGH NOON ON MONDAY. AS A
RESULT WINTER WEATHER ADVISORIES WERE ISSUED FOR THOSE AREAS FROM
THIS EVENING THROUGH NOON ON MONDAY. ALONG I-15 FROM CUT BANK TO
HELENA AND ALONG THE US HIGHWAY 87/MONTANA HIGHWAY 200 CORRIDOR
BETWEEN GREAT FALLS AND LEWISTOWN THERE IS GREATER THAN A 50%
CHANCE FOR 2 INCHES OF SNOWFALL OR GREATER FROM SUNDAY EVENING
THROUGH NOON ON MONDAY. FOR THE LOWER ELEVATIONS BETWEEN GREAT
FALLS AND GEYSER SOUTH TO THE HELENA VALLEY THERE IS A 30 TO 50%
CHANCE FOR 4 INCHES OF SNOW OR GREATER FROM SUNDAY EVENING THROUGH
NOON ON MONDAY.
ACROSS THE LOWER ELEVATIONS OF NORTH CENTRAL MONTANA IT IS EXPECTED
THAT AT LEAST SOME OF THE SNOW THAT FALLS TONIGHT INTO SUNDAY
MORNING WILL MELT. THERE REMAINS UNCERTAINTY IN HOW MUCH SNOW ACROSS
NORTH CENTRAL AND CENTRAL MONTANA WILL MELT INITIALLY SUNDAY
NIGHT INTO MONDAY MORNING. DUE TO THE EXPECTED IMPACTS FROM THE
SNOW AT MOST LOWER ELEVATION LOCATIONS BEING MORE THAN 24 HOURS
OUT, AT THIS TIME NO ADDITIONAL WINTER WEATHER ADVISORIES ARE
BEING ISSUED. FUTURE SHIFTS WILL CONTINUE TO EVALUATE THE NEED FOR
WINTER WEATHER ADVISORIES FOR LOWER ELEVATION LOCATIONS. IG
AVIATION
11/18Z TAF PERIOD
VFR CONDITIONS WILL PREVAIL ACROSS ALL TERMINALS DURING THE
BEGINNING OF THIS TAF PERIOD BEFORE RAIN AND/OR SNOW CAUSE
VISIBILITY AND CEILINGS LOWER TO AT LEAST MVFR LEVELS. AT ALL BUT
THE KGTF, KCTB, AND KHVR TERMINALS BETWEEN NOW AND 12/06Z THERE IS A
15 - 30% CHANCE FOR THUNDERSTORMS. ANY THUNDERSTORM WILL PRODUCE A
HEAVY DOWNPOUR, LIGHTNING, AND GUSTY, ERRATIC WINDS. AFTER 12/12Z
ACROSS ALL TERMINALS EXCEPT FOR THE KBZN TERMINAL THERE WILL BE A
RAIN/SNOW MIX OR ALL SNOW WITH AT LEAST MVFR-LEVEL VISIBILITY AND
CEILINGS. DURING THE MAJORITY OF THIS TAF PERIOD THERE WILL BE
ISOLATED INSTANCES OF LOW-LEVEL WIND SHEAR AND MOUNTAIN WAVE
TURBULENCE. DURING THE MAJORITY OF THIS TAF PERIOD THERE WILL BE
MOUNTAIN OBSCURATION. -IG
HYDROLOGY
AS SHOWERS AND THUNDERSTORMS PUSH INTO THE AREA TODAY, A FEW OF
THE SHOWERS AND STORMS MAY PRODUCE SOME HIGHLY LOCALIZED HEAVY
RAINFALL. WHILE WIDESPREAD FLOODING IS NOT EXPECTED AT THIS TIME,
THERE IS A LOW (5% OR SO) CHANCE THAT A BURN SCAR FLASH FLOOD
COULD OCCUR AT EITHER HORSE GULCH OR WEST FORK BURN SCARS.
PRELIMINARY POINT TEMPS/POPS
GTF 32 39 26 35 / 70 80 90 70
CTB 24 34 21 32 / 70 70 80 70
HLN 36 42 26 38 / 80 80 100 50
BZN 34 47 27 43 / 100 60 60 20
WYS 23 37 17 51 / 100 60 20 10
DLN 32 49 29 47 / 80 30 40 10
HVR 26 42 23 41 / 60 50 40 30
LWT 29 39 23 37 / 90 50 70 30
TFX WATCHES/WARNINGS/ADVISORIES
WINTER STORM WARNING FROM 6 PM THIS EVENING TO NOON MDT MONDAY
FOR EAST GLACIER PARK REGION-SOUTHERN ROCKY MOUNTAIN FRONT.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO NOON MDT MONDAY
FOR LITTLE BELT AND HIGHWOOD MOUNTAINS-NORTHERN HIGH PLAINS-
SOUTHERN HIGH PLAINS-UPPER BLACKFOOT AND MACDONALD PASS.
WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO NOON MDT
SUNDAY FOR GALLATIN AND MADISON COUNTY MOUNTAINS AND CENTENNIAL
MOUNTAINS.
HTTP://WWW.WEATHER.GOV/GREATFALLS
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