159
FXUS65 KTFX 130504
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1104 PM MDT SUN OCT 12 2025
AVIATION SECTION UPDATED.
KEY MESSAGES
- TONIGHT THROUGH MONDAY MORNING THERE WILL BE ANOTHER ROUND OF
SNOW FOR MOST OF NORTH CENTRAL AND CENTRAL MONTANA.
- IT WILL BE WINDY THIS AFTERNOON AND EVENING ACROSS NORTH
CENTRAL MONTANA.
- TUESDAY THROUGH FRIDAY IT WILL WARM UP WITH DAILY PRECIPITATION
CHANCES WITH THE GREATEST PRECIPITATION CHANCES ON WEDNESDAY
AND THURSDAY.
UPDATE
/ISSUED 813 PM MDT SUN OCT 12 2025/
MOIST MID LEVEL AIR WITHIN A MID-LEVEL WARM AIR ADVECTION REGIME
IS OVERRUNNING A COOL SURFACE AIR MASS ACROSS NORTHERN AND WESTERN
PORTIONS OF THE REGION THIS EVENING, RESULTING IN WIDESPREAD SNOW.
AREAS MOST FAVORED FOR HEAVIER SNOW CONTINUE TO BE ALONG THE ROCKY
MOUNTAIN FRONT AND ACROSS PORTIONS OF THE SOUTHERN HIGH PLAIN INTO
THE GATES OF THE MOUNTAINS AREA WHERE A WINTER STORM WARNING
REMAINS IN EFFECT. LIGHTER, BUT STILL IMPACTFUL SNOW IS FORECAST
SURROUNDING THESE AREAS, HENCE THE ONGOING WINTER WEATHER
ADVISORIES REMAIN UNCHANGED.
CONSIDERATION WAS GIVEN TO ADDING THE BIG BELTS TO THE WINTER
WEATHER ADVISORY, AS AREAS NEAR AND NORTH OF DEEP CREEK PASS LOOK
TO PICK UP AT LEAST A FEW INCHES OF NEW SNOW THROUGH THE
OVERNIGHT. CONVERSELY, AREAS SOUTH OF DEEP CREEK PASS DOWN TO
BOZEMAN PASS ARE FORECAST TO SEE LITTLE, IF ANY SNOW. GIVEN THE
NORTH/SOUTH EXTENT OF THIS FORECAST ZONE WITH WIDELY VARYING SNOW
AMOUNTS, IN ADDITION TO HOW FEW HIGHER VOLUME ROADWAYS (MAINLY
DEEP CREEK PASS) WILL SEE MINOR SNOW ACCUMULATION, I WILL HOLD OFF
FROM ISSUING AN ADDITIONAL WINTER WEATHER ADVISORY WITH THIS
UPDATE.
THE FORECAST WAS NUDGED TOWARD LATEST TRENDS WITH LATEST GUIDANCE
ALSO INCORPORATED THIS EVENING. UPDATES WERE MINIMAL OVERALL. -AM
DISCUSSION
/ISSUED 813 PM MDT SUN OCT 12 2025/
- METEOROLOGICAL OVERVIEW:
THIS AFTERNOON AN UPPER LEVEL RIDGE MOVES OVER NORTH CENTRAL,
CENTRAL, AND SOUTHWESTERN MONTANA. HOWEVER, DUE TO THE COLD FRONT
THAT MOVED THROUGH YESTERDAY TEMPERATURES ACROSS NORTH CENTRAL AND
CENTRAL MONTANA WILL BE WELL BELOW SEASONAL AVERAGES AND ACROSS
SOUTHWESTERN MONTANA BELOW SEASONAL AVERAGES THIS AFTERNOON.
ACROSS MOST LOCATIONS THERE WILL BE A PRECIPITATION LULL BETWEEN
NOW AND THIS EVENING. SUNDAY EVENING THERE WILL BE A COLD 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 MONDAY AFTERNOON AND EVENING. 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 WITH DAILY
PRECIPITATION CHANCES. ON SATURDAY AN UPPER LEVEL RIDGE BUILDS IN
OVER NORTH CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. THIS WILL
ALLOW TEMPERATURES TO WARM UP FURTHER WITH MOSTLY DRY WEATHER. IG
- FORECAST CONFIDENCE & SCENARIOS:
FROM TONIGHT THROUGH NOON TOMORROW THERE IS A 50 TO 80% CHANCE FOR 2
INCHES OF SNOWFALL OR GREATER ACROSS MOST OF THE PLAINS ADJACENT
TO THE ROCKY MOUNTAIN FRONT (INCLUDING THE HELENA VALLEY) AND
ALONG THE US HIGHWAY 87/MONTANA HIGHWAY 200 CORRIDOR BETWEEN GREAT
FALLS AND HOBSON. FROM TONIGHT THROUGH NOON TOMORROW THERE IS
GREATER THAN A 60% CHANCE FOR 8 INCHES OF SNOW OR GREATER ALONG
THE ROCKY MOUNTAIN FRONT. AS A RESULT WINTER WEATHER ADVISORIES
AND OR A WINTER STORM WARNING WERE ISSUED FOR MOST OF THOSE AREAS.
SEE THE TFX WATCHES/WARNINGS/ADVISORIES SECTION BELOW FOR
DETAILS.
WEDNESDAY MORNING THROUGH SATURDAY MORNING THERE IS A GREATER THAN A
60% CHANCE FOR A QUARTER INCH OF PRECIPITATION OR GREATER ACROSS
MOST OF NORTH CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. IG
AVIATION
13/06Z TAF PERIOD
INITIAL CONCERN THIS TAF PERIOD WILL BE FOR PERSISTENT SNOW AND LOW
CLOUDS NORTH OF I-90 THROUGH THE MORNING. SNOW DIMINISHES THROUGH
THE LATE MORNING HOURS INTO EARLY MONDAY AFTERNOON, THOUGH LOW
CLOUDS LOOK TO HANG AROUND A BIT LONGER. MOUNTAINS WILL REMAIN
OBSCURED NORTH OF I-90 THROUGH THE TAF PERIOD.
THERE IS A CONDITIONAL RISK FOR FOG AT KWYS THIS MORNING, DEPENDENT
ON HOW QUICKLY MID LEVEL CLOUDINESS MOVES AWAY FROM THE TERMINAL.
-AM
PRELIMINARY POINT TEMPS/POPS
GTF 25 34 25 43 / 100 70 20 20
CTB 19 32 23 41 / 90 70 20 10
HLN 24 36 26 46 / 100 70 30 30
BZN 25 41 24 50 / 60 10 20 30
WYS 17 48 24 54 / 40 10 40 60
DLN 29 44 26 51 / 40 10 20 40
HVR 21 40 24 51 / 40 40 0 10
LWT 23 36 23 48 / 100 40 20 20
TFX WATCHES/WARNINGS/ADVISORIES
WINTER STORM WARNING UNTIL NOON MDT MONDAY FOR EAST GLACIER PARK
REGION-GATES OF THE MOUNTAINS-SOUTHERN HIGH PLAINS-SOUTHERN
ROCKY MOUNTAIN FRONT.
WINTER WEATHER ADVISORY UNTIL NOON MDT MONDAY FOR CASCADE COUNTY
BELOW 5000FT-EASTERN PONDERA AND EASTERN TETON-ELKHORN AND
BOULDER MOUNTAINS-HELENA VALLEY-JUDITH BASIN COUNTY AND JUDITH
GAP-LITTLE BELT AND HIGHWOOD MOUNTAINS-NORTHERN HIGH PLAINS-
UPPER BLACKFOOT AND MACDONALD PASS.
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