790
FXUS65 KTFX 091735
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1135 AM MDT WED SEP 9 2026
AVIATION SECTION UPDATED.
KEY MESSAGES
- WARMER AND DRIER WEDNESDAY AND THURSDAY.
- NEXT WEATHER SYSTEM ARRIVES FRIDAY, BRINGING COOLER
TEMPERATURES ALONG WITH SOME PERIODS OF RAIN/MOUNTAIN SNOWFALL.
- ANOTHER WEATHER SYSTEM BRINGS EVEN COOLER TEMPERATURES AND
MORE WIDESPREAD PRECIPITATION TO MONTANA, WITH MORE CHANCES FOR
MOUNTAIN SNOWFALL.
DISCUSSION
/ISSUED 527 AM MDT WED SEP 9 2026/
- METEOROLOGICAL OVERVIEW:
IN THE WAKE OF A SERIES OF UPPER LEVEL SYSTEMS EARLIER THIS WEEK,
A WEAK RIDGE EMBEDDED IN NORTHWESTERLY FLOW WILL BRING A PERIOD
OF WARMER BUT BREEZY WEATHER TO NORTH CENTRAL MONTANA WEDNESDAY
AND THURSDAY. THIS PERIOD OF WARMER WEATHER WILL COME TO A QUICK
END ON FRIDAY AS A DECAYING UPPER LEVEL TROUGH MOVES THROUGH
SOUTHERN BRITISH COLUMBIA AND ALBERTA INTO MONTANA, WHICH WILL
BRING COOLER TEMPERATURES, ALONG WITH SOME SHOWERS OF RAIN AND
MOUNTAIN SNOWFALL AS IT PUSHES THROUGH. THE COOLER TEMPERATURES
WILL LINGER BEHIND THIS SYSTEM, WHICH WILL SET UP THE NEXT,
STRONGER SYSTEM TO PRODUCE WIDESPREAD PRECIPITATION WITH SNOW
EXPECTED ABOVE 7000 FEET, WHICH WOULD INCLUDE SOME OF THE HIGHER
MOUNTAIN PASSES. A BRIEF PERIOD OF WARMER AND DRIER WEATHER IS
EXPECTED LATE SUNDAY AND MONDAY BEFORE THE UNSETTLED PATTERN
RESUMES BY THE MIDDLE OF NEXT WEEK.
- FORECAST CONFIDENCE & SCENARIOS:
WINDS TODAY AND THURSDAY: WESTERLY, CROSS BARRIER FLOW WILL BRING
SOME GUSTY WINDS TO NORTH CENTRAL AND SOUTHWESTERN MONTANA
WEDNESDAY AND THURSDAY. WHILE WINDS ARE NOT EXPECTED TO BE STRONG
ENOUGH TO REACH HIGH WIND CRITERIA (58 MPH FOR MOST, 75 MPH ALONG
THE ROCKY MOUNTAIN FRONT), GUSTS TO 35-50 MPH WILL BE POSSIBLE
ACROSS THE AREA, ESPECIALLY ON THURSDAY WHEN WINDS WILL BE
STRONGEST.
MOUNTAIN SNOWFALL THIS WEEKEND: A STRONG UPPER LEVEL LOW WILL MOVE
INTO THE TREASURE STATE OVER THE WEEKEND, BRINGING WELL BELOW
AVERAGE TEMPERATURES ALONG WITH COPIOUS AMOUNTS OF MOISTURE. THE
COOLER TEMPERATURES WILL BRING SNOW LEVELS DOWN TO 7000 FEET ABOVE
SEA LEVEL, WHICH WILL RESULT IN WIDESPREAD MOUNTAIN SNOWFALL TO
AREAS ABOVE 7000 FEET. CURRENT FORECASTS KEEP SNOWFALL AMOUNTS
UNDER 6 INCHES AT THE MOMENT, BUT SOME OF THE HIGHEST TERRAIN
STILL HAVE AROUND A 10 PERCENT CHANCE OF SNOWFALL AMOUNTS OVER A
FOOT OVER THE WEEKEND. LUDWIG
AVIATION
09/18Z TAF PERIOD
VFR CONDITIONS WILL DOMINATE THE REGION THROUGH THE PERIOD. WINDS
WILL PREVAIL OUT OF THE WEST-SOUTHWEST THIS AFTERNOON WITH GUSTS
UP TO 25 KT TO 30 KT THROUGHOUT THE REGION. THERE IS A 60%
PROBABILITY FOR WIND SHEAR CONDITIONS AT KCTB, KHVR, AND KLWT
TONIGHT FROM 10/02Z TO 10/11Z AS BOUNDARY LAYER DECOUPLING IS
POSSIBLE FOR SOME AREAS WITH STRONGER SYNOPTIC FORCING INFLUENCE
ABOVE. THURSDAY MORNING INTO AFTERNOON WILL SEE GUSTY WINDS AGAIN
AS THE MIXED LAYER SETS BACK UP.
FOR KGTF: VFR CONDITIONS WILL PERSIST WITH SOUTHWESTERLY WINDS
GUSTING TO 25 KT WHICH WILL YIELD 15 KT CROSSWIND EXCEEDANCE AT
TIMES UNTIL TONIGHT AFTER SUNSET. THERE IS A 30% CHANCE FOR WIND
SHEAR CONDITIONS TO SET UP OVERNIGHT HOWEVER BOUNDARY LAYER MIXING
IS PRIMARILY EXPECTED TO CONTINUE. A STRONG INVERSION SETUP WITH
TEMPERATURES COOLING BELOW EXPECTED WILL BE THE DIFFERENCE FOR
WIND SHEAR. - AKINS
PRELIMINARY POINT TEMPS/POPS
GTF 54 81 47 63 / 0 0 70 60
CTB 50 71 41 56 / 0 0 60 60
HLN 49 83 52 69 / 0 0 60 30
BZN 44 83 47 72 / 0 0 10 20
WYS 29 71 35 70 / 0 0 0 0
DLN 41 81 44 74 / 0 0 0 0
HVR 49 81 43 65 / 0 0 30 50
LWT 49 83 45 62 / 0 0 60 70
TFX WATCHES/WARNINGS/ADVISORIES
HTTP://WWW.WEATHER.GOV/GREATFALLS
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