670
FXUS65 KTFX 221013
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
413 AM MDT THU OCT 22 2026
KEY MESSAGES
- TODAY WILL BE THE LAST MILD DAY FOR AWHILE.
- RAIN AND SNOW DEVELOP OVER THE CWA ON FRIDAY, ALONG WITH MUCH
COOLER TEMPERATURES.
- GENERALLY DRY CONDITIONS, ALONG WITH MORE FALL TEMPERATURES
EXPECTED SATURDAY THROUGH TUESDAY.
DISCUSSION
- METEOROLOGICAL OVERVIEW:
THE UPPER LEVEL RIDGE THAT HAS BEEN OVER THE CWA FOR THE PAST FEW
DAYS WILL BEGIN TO MOVE EASTWARD TODAY, AS TWO UPPER LEVEL
DISTURBANCES APPROACH THE CWA FOR FRIDAY, ONE FROM THE NORTH AND
ONE FROM THE SOUTH. TODAY WILL BE THE LAST WELL ABOVE NORMAL
TEMPERATURE DAY FOR AWHILE, WITH MANY AREAS HAVING HIGH
TEMPERATURES IN THE UPPER 60S OR LOWER 70S TODAY. THERE WILL BE A
FEW MORNING SPRINKLES OVER SOUTHWEST MT, BUT THOSE SHOULD DIMINISH
EARLY THIS MORNING. OTHERWISE, RAIN SHOWERS START TO APPROACH THE
CWA FROM THE SOUTHWEST THIS EVENING AND OVERNIGHT. AT THE SAME
TIME, COLDER AIR WILL TRY TO MOVE SOUTHWARD FROM CANADA OVERNIGHT.
THE COLDER AIR WILL BE NEAR THE US/CANADIAN BORDER BY DAYBREAK ON
FRIDAY, AS PRECIPITATION CONTINUES TO OVERSPREAD THE WESTERN
PORTIONS OF THE CWA. ON FRIDAY, EXPECT THE WARMEST TEMPERATURES IN
THE MORNING, WITH TEMPERATURES FALLING DURING THE AFTERNOON HOURS
AS COLDER AIR MOVES IN. SNOW LEVELS WILL START OUT ABOVE 10,000
FEET TONIGHT, BUT THEN FALL THROUGH OUT THE DAY ON FRIDAY, LIKELY
FALLING TO NEAR THE VALLEY/PLAINS FLOOR BY FRIDAY EVENING. SOME
SHORT PERIODS OF HEAVY PRECIPITATION IS POSSIBLE ON FRIDAY AS THE
FRONT MOVES THROUGH. THE FRONT FROM THE NORTH WILL HAVE SOME
STRONG NORTH WINDS, AND THESE STRONG WINDS COULD MIX DOWN AS THE
PRECIPITATION MOVES THROUGH. THUS A HIGH WIND WATCH HAS BEEN
ISSUED FOR PORTIONS OF NORTH CENTRAL MT. AT THE SAME TIME, SNOW
LEVELS WILL BE FALLING, WITH THE BEST ACCUMULATING SNOWFALL ABOVE
4500 FEET. THUS SOME MOUNTAIN RANGES OVER CENTRAL/SOUTHWEST MT
HAVE A WINTER WEATHER ADVISORY IN PLACE FOR FRIDAY
AFTERNOON/EVENING FOR SEVERAL INCHES OF SNOWFALL. AT LOWER
ELEVATIONS, GIVEN THE SHORT DURATION OF THE PRECIP AND THE TIME IT
TAKES FOR THE RAIN TO CHANGE TO SNOW, NO ADVISORY WILL BE ISSUED
AT THIS TIME.
THIS WILL BE A VERY QUICK MOVING WEATHER SYSTEM, WITH BOTH
DISTURBANCES EXITING THE REGION BY EARLY SATURDAY MORNING.
GENERALLY DRY CONDITIONS, BUT MORE FALL LIKE TEMPERATURES ARE
EXPECTED FROM SATURDAY THROUGH TUESDAY. THE NEXT WEATHER SYSTEM
ARRIVES NEXT WEDNESDAY, WITH A MIX OF RAIN/SNOW ACROSS THE CWA.
- FORECAST CONFIDENCE & SCENARIOS:
CHANCE FOR THUNDER...THERE IS A SMALL CHANCE FOR A LIGHTNING
STRIKE WITH THE FRONTAL PASSAGE ON FRIDAY. HOWEVER, WITH A
PROBABILITY MOSTLY LESS THAN 10 PERCENT, THUNDER WAS JUST CONFINED
TO FAR SOUTHWEST MT FOR NOW.
THE MAIN CONCERNS ON FRIDAY WILL BE WIND, RAIN CHANGING TO SNOW,
AND SNOW ACCUMULATIONS.
STRONG NORTH WINDS ARE POSSIBLE BETWEEN CUT BANK AND HAVRE ON
FRIDAY, ESPECIALLY IN THE GAP AREAS OF THE SWEET GRASS HILLS. WITH
A 70 PERCENT CHANCE FOR HIGH WIND GUSTS IN THE FAVORED WINDY SPOTS
BETWEEN CUT BANK AND HAVRE, A HIGH WIND WATCH HAS BEEN ISSUED FOR
PORTION OF THE DAY ON FRIDAY FOR THIS AREA.
THE OTHER MAIN CONCERN WILL BE RAIN CHANGING TO SNOW, SNOWFALL
RATES AND SNOW ACCUMULATIONS ON FRIDAY. THIS SYSTEM WILL BE QUICK
MOVING, AND THE RAIN SHOULD CHANGE TO SNOW WITHIN A FEW HOURS OF
FRONTAL PASSAGE. ADDITIONALLY, SOME PERIODS OF HEAVY PRECIPITATION
ARE POSSIBLE, WITH SNOWFALL RATES EXCEEDING 1 INCH PER HOUR AT
TIMES. THE HEAVY SNOWFALL RATES COULD EXCEED THE WARM PAVEMENT
MELTING, COMBINED WITH THE HIGHER SNOWFALL RATES FALLING DURING
THE FRIDAY EVENING COMMUTE, SOME IMPACTS ARE LIKELY. THUS A WINTER
WEATHER ADVISORY HAS BEEN ISSUED FOR THE MOUNTAIN AREAS OVER
PORTIONS OF CENTRAL AND SOUTHWEST MT. IT IS POSSIBLE ADDITIONAL
WINTER WEATHER ADVISORIES MIGHT BE NEEDED FOR POOR DRIVING
CONDITIONS AT LOWER ELEVATIONS ON FRIDAY EVENING, SHOULD THE RAIN
CHANGE OVER TO SNOW QUICKER, WITH THE SNOW STARTING TO AFFECT THE
FRIDAY EVENING COMMUTE AT LOWER ELEVATIONS. BRUSDA
AVIATION
22/12Z TAF PERIOD
OVERALL VFR CONDITIONS ARE EXPECTED THROUGH 00Z FRIDAY, BEFORE
CONDITIONS SLOWLY START TO DECREASE. A FEW MORNING SPRINKLES
AROUND ENNIS/WEST YELLOWSTONE WILL GENERALLY DIMINISH BY 13Z
TODAY. OTHERWISE, EXPECT INCREASING CLOUDS THIS EVENING, WITH RAIN
AND SNOW DEVELOPING OVER THE WESTERN PORTIONS OF THE CWA BY 06Z
FRI. THE RAIN AND SNOW CONTINUE TO PUSH EASTWARD OVERNIGHT AND
SHOULD REACH CENTRAL MT BY MID DAY FRIDAY. SNOW LEVELS WILL
CONTINUE TO LOWER TO VALLEY/PLAINS FLOOR BY FRIDAY EVENING. EXPECT
CEILINGS TO LOWER WITH IFR/LIFR CONDITIONS POSSIBLE BY FRIDAY
AFTERNOON. MOUNTAINS/PASSES WILL START TO BECOME OBSCURED AFTER
00Z FRIDAY. BRUSDA
PRELIMINARY POINT TEMPS/POPS
GTF 73 43 53 28 / 0 20 100 70
CTB 69 36 47 22 / 0 30 100 10
HLN 70 43 52 25 / 0 20 100 80
BZN 70 40 53 23 / 10 10 100 90
WYS 62 32 46 18 / 10 70 100 100
DLN 67 42 50 27 / 10 80 100 90
HVR 73 40 56 24 / 0 0 90 80
LWT 74 44 63 23 / 0 0 90 100
TFX WATCHES/WARNINGS/ADVISORIES
HIGH WIND WATCH FROM FRIDAY MORNING THROUGH FRIDAY AFTERNOON FOR
EASTERN GLACIER, WESTERN TOOLE, AND CENTRAL PONDERA-EASTERN
PONDERA AND EASTERN TETON-EASTERN TOOLE AND LIBERTY-HILL COUNTY-
WESTERN AND CENTRAL CHOUTEAU COUNTY.
WINTER WEATHER ADVISORY FROM 6 PM FRIDAY TO 3 AM MDT SATURDAY
FOR BEARS PAW MOUNTAINS AND SOUTHERN BLAINE-SNOWY AND JUDITH
MOUNTAINS.
WINTER WEATHER ADVISORY FROM NOON FRIDAY TO MIDNIGHT MDT FRIDAY
NIGHT FOR ELKHORN AND BOULDER MOUNTAINS-GALLATIN AND MADISON
COUNTY MOUNTAINS AND CENTENNIAL MOUNTAINS-LITTLE BELT AND
HIGHWOOD MOUNTAINS-NORTHWEST BEAVERHEAD COUNTY.
HTTP://WWW.WEATHER.GOV/GREATFALLS
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