998
FXUS65 KTFX 152354
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
554 PM MDT WED OCT 15 2025
AVIATION SECTION UPDATED.
KEY MESSAGES
- MOUNTAIN SNOW ACROSS PORTIONS OF SOUTHWEST MONTANA ALONG WITH A
BIT MORE WIDESPREAD LOWER ELEVATION RAIN TONIGHT INTO
THURSDAY.
- TRENDING MILDER TOWARD THE END OF THE WEEK INTO THE WEEKEND,
WITH A FEW SHOWERS AROUND AND BREEZY PERIODS AT TIMES.
DISCUSSION
/ISSUED 215 PM MDT WED OCT 15 2025/
- METEOROLOGICAL OVERVIEW:
BROAD, ELONGATED TROUGHING ACROSS THE INTERIOR WEST WILL CONTINUE TO
NUDGE EASTWARD THROUGH THE REMAINDER OF THE DAY AND OVERNIGHT. AN
EMBEDDED, MORE POTENT WAVE IS LIFTING NORTHEASTWARD WITHIN THIS
TROUGHING, MOVING ACROSS WY AND INTO EASTERN MT DURING THE DAY
THURSDAY. ALTHOUGH THE MAJORITY OF THE UPPER LEVEL SUPPORT FOR
PRECIPITATION WILL MISS THE REGION TO THE EAST, EASTERN AREAS WILL
STILL SEE A ROUND OF PRECIPITATION INTO THE DAY THURSDAY. AS SLIGHTLY
COOLER AIR WORKS IN TONIGHT, SNOW LEVELS LOOK TO FALL TO AROUND
6,000-6,500 FT, AND PERHAPS A BIT LOWER AT TIMES. MOST MOUNTAIN
SNOW LOOKS TO BE LIGHT, THOUGH THE MADISON AND GALLATIN RANGES AND
VICINITY DO LOOK TO SEE AT LEAST A COUPLE INCHES OF ACCUMULATION
ABOVE PASS LEVEL. GIVEN THE LACK OF FORECAST IMPACTS AT PASS
LEVEL, NO WINTER WEATHER ADVISORIES ARE BEING CONSIDERED AT THIS
TIME. MAINLY LIGHT RAIN IS FORECAST AT TIMES AT LOWER ELEVATIONS
INTO THURSDAY WITH THIS SYSTEM, LARGELY IN EASTERN AREAS.
A NORTHWESTERLY FLOW DEVELOPS IN WAKE OF THE DEPARTING TROUGHING
HEADING INTO THURSDAY NIGHT. A WAVE DIVING SOUTHEASTWARD FROM BC
WITHIN THE DEVELOPING NW FLOW ALOFT WILL PASS ACROSS THE REGION
FRIDAY NIGHT INTO SATURDAY. INITIAL IMPACTS FROM THIS SYSTEM WILL BE
FOR A PERIOD OF BREEZY WINDS, MOSTLY OVER THE PLAINS FRIDAY. AS THE
MAIN PORTIONS OF THE WAVE MOVES OVERHEAD FRIDAY EVENING AND INTO
EARLY SATURDAY, A QUICK PERIOD OF PRECIPITATION DEVELOPS. SNOW IN
THE MOUNTAINS WITH THIS SYSTEM LOOKS TO BE BRIEF, HENCE THE
WINDOW FOR ACCUMULATIONS LOOKS TO BE RATHER NARROW. THE CHANCE FOR
2 INCHES NEW SNOW PEAKS AROUND 60% ALONG THE ROCKY MOUNTAIN FRONT.
UPPER LEVEL RIDGING BRIEFLY BUILDS IN FOR SATURDAY INTO EARLY SUNDAY
BEFORE ANOTHER UPPER LEVEL TROUGH BEGINS TO APPROACH FROM THE WEST.
BEFORE PRECIPITATION ARRIVES WITH THIS SYSTEM ANOTHER PERIOD OF
BREEZY WINDS LOOKS TO DEVELOP, AGAIN MOST FAVORED OVER THE PLAINS.
THE DOWNSLOPE NATURE OF THE WINDS LOOKS TO LIMIT PRECIPITATION OVER
THE PLAINS WITH THIS SYSTEM LATE SUNDAY INTO MONDAY, WITH AREAS
ALONG THE CONTINENTAL DIVIDE AND ACROSS SOUTHWEST MONTANA MOST
FAVORED FOR PRECIPITATION.
A RATHER PROGRESSIVE PATTERN CONTINUES AFTER MONDAY. CLUSTER
GUIDANCE DOES NOT LEND MUCH CONFIDENCE IN SPECIFICS, AS THERE IS
ROUGHLY A 50/50 SPLIT BETWEEN RIDGING AND TROUGHING TOWARD THE
MIDDLE OF NEXT WEEK. -AM
- FORECAST CONFIDENCE & SCENARIOS:
SNOW TONIGHT INTO THURSDAY IN THE MADISONS, GALLATINS AND VICINITY:
OVERALL THE CHANCE FOR MORE THAN 3 INCHES OF SNOW IS ONLY GREATER
THAN 50% AT THE HIGHEST PEAKS. AT LOWER ELEVATIONS THE CHANCE IS
MUCH LOWER, ONLY AROUND 10% OR SO IN BIG SKY. HENCE, GIVEN THE LACK
OF CONFIDENCE IN ANY MEANINGFUL IMPACTS AT THIS POINT, NO WINTER
WEATHER ADVISORIES ARE BEING CONSIDERED AT THIS TIME. REGARDLESS,
THOSE PLANNING TO RECREATE IN THE MOUNTAINS IN THESE AREAS SHOULD
BE PREPARED FOR COLD/RAW CONDITIONS.
WIND:
TWO PERIODS OF GUSTY WINDS ARE FAVORED. THE FIRST LOOKS TO BE
THURSDAY NIGHT INTO FRIDAY. THE CHANCE FOR A 58 MPH GUST BETWEEN CUT
BANK AND BROWNING IS BETWEEN 10 AND 20% FOR THIS TIMEFRAME.
FOR THE SECOND PERIOD OF WIND LATE WEEKEND THE CHANCE FOR A 58 MPH
GUST IS HIGHER, CLOSER TO 40% OVER THE AFOREMENTIONED AREA.
MOUNTAIN SNOW SUNDAY INTO MONDAY:
CONFIDENCE IN ACCUMULATING MOUNTAIN SNOW IS GREATEST ALONG THE
CONTINENTAL DIVIDE AND ACROSS SOUTHWEST MONTANA OVER THIS
TIMEFRAME. MOST TERRAIN IN THESE AREAS HAS A 50% CHANCE OR
GREATER FOR 3 INCHES OF SNOW WITH THIS EVENT. ELSEWHERE ACROSS
MUCH OF CENTRAL MT TERRAIN AND OVER THE ISLAND RANGES ON THE
PLAINS THE CHANCE FOR 3 INCHES SNOW IS MUCH LOWER, MOSTLY LESS
THAN 20%. -AM
AVIATION
16/00Z TAF PERIOD
LOW CLOUDS PERSIST ACROSS EASTERN PORTIONS OF SOUTHWEST AND
CENTRAL MT INCLUDING AREAS FROM KEKS NORTH THROUGH KBZN AND KLWT
WHERE PREVAILING MVFR CONDITIONS WILL LIKELY DEGRADE TO IFR AT
TIMES AS ADDITIONAL PRECIPITATION LIFTS THROUGH THOSE AREAS
OVERNIGHT INTO THURSDAY MORNING. LOWER CLOUD CEILINGS ARE BREAKING
UP FROM KHLN NORTH TO KGTF AND KHVR THIS EVENING WITH MAINLY
CLEAR SKIES AT KCTB. HOWEVER, WITH LITTLE CHANGE IN THE MID-UPPER
LEVEL PATTERN TO PUSH CLEARING FURTHER EAST THE RISK FOR AT LEAST
SOME PERIODS OF MVFR CLOUD CEILINGS WILL EXIST THROUGH THE
OVERNIGHT PERIOD IN THESE AREAS. IN ADDITION, LOW LEVEL MOISTURE
REMAINS ELEVATED WITH THE POTENTIAL FOR FOG DEVELOPMENT AT NORTH-
CENTRAL MT TERMINALS, ESPECIALLY WHERE LOWER CLOUDS PARTIALLY
CLEAR. HOENISCH
PRELIMINARY POINT TEMPS/POPS
GTF 33 54 37 57 / 20 20 0 20
CTB 29 58 36 53 / 0 0 0 40
HLN 34 53 35 58 / 10 20 0 20
BZN 33 48 29 57 / 50 50 10 10
WYS 28 43 23 45 / 40 60 30 10
DLN 32 51 29 56 / 20 30 0 0
HVR 33 54 34 55 / 20 20 0 20
LWT 32 46 33 53 / 30 50 20 20
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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