176
FXUS65 KTFX 200959
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
359 AM MDT FRI JUN 20 2025
KEY MESSAGES
- PERIODS OF SHOWERS AND THUNDERSTORMS TODAY. SOME STORMS COULD
PRODUCE HEAVY RAINFALL AND STRONG WINDS THIS AFTERNOON.
- HEAVY SNOW DEVELOPS IN GLACIER PARK ON SATURDAY AND CONTINUES
INTO SATURDAY NIGHT.
- SNOWFALL LIKELY IN MANY MOUNTAIN RANGES OVER NORTH CENTRAL AND
SOUTHWEST MT SATURDAY NIGHT INTO SUNDAY, WITH SNOW LEVELS DOWN
TO 5000 FEET AT TIMES.
- A RETURN TO MORE JUNE LIKE CONDITIONS EXPECTED BY THE MIDDLE OF
NEXT WEEK.
DISCUSSION
- METEOROLOGICAL OVERVIEW:
OVERALL THE CURRENT FORECAST WEATHER PATTERN EXPECTED FOR THIS
WEEKEND CONTINUES TO BE RIGHT ON TRACK FROM PREVIOUS DAYS. EXPECT
WAVES OF SHOWERS AND THUNDERSTORMS TO MOVE FROM SOUTHWEST TO
NORTHEAST THROUGH THE CWA TODAY. SOME STORMS THIS AFTERNOON AND
EVENING COULD PRODUCE HEAVY RAINFALL AND GUSTY WINDS.
STRONG WINDS ARE LOOKING LIKELY TODAY AROUND NORRIS HILL FROM THIS
AFTERNOON THROUGH THIS EVENING. THUS THE HIGH WIND WATCH WAS
CHANGED TO A HIGH WIND WARNING.
THE PRECIPITATION BECOMES HEAVIER TONIGHT OVER GLACIER PARK, WITH
SNOW LEVELS LOWERING. PERIODS OF SNOW, HEAVY AT TIMES IS EXPECTED
SATURDAY AND SATURDAY NIGHT IN GLACIER PARK. SNOW LEVELS OVER THE
REST OF NORTH CENTRAL AND SOUTHWEST MT WILL LOWER ON SATURDAY
NIGHT. AT TIMES, SNOW LEVELS COULD BE DOWN TO NEAR 5000 FEET BY
SUNDAY MORNING. THE LAST JUNE STORM OF THIS STRENGTH WAS 3 YEARS
AGO AROUND JUNE 15, 2022.
IN THE CUT BANK AND SHELBY AREAS, THERE IS ABOUT 60 PERCENT
CONFIDENCE OF WIND GUSTS OVER 60 MPH AT TIMES SATURDAY. WITH BOTH
THE GFS/NAM MODELS SHOWING EVEN HIGHER POTENTIAL, THE HIGH WIND
WATCH WAS CHANGED TO A HIGH WIND WARNING FOR SATURDAY.
PERIODS OF PRECIPITATION ARE EXPECTED ACROSS THE REMAINDER OF THE
CWA, ESPECIALLY ON SUNDAY. OVERALL, TOTAL PRECIPITATION AMOUNTS OF
ABOUT A HALF INCH TO JUST OVER AN INCH LOOK LIKELY IN MANY AREAS.
THE MOUNTAINS IN GLACIER PARK ARE LIKELY TO RECEIVE A TOTAL OF 2
TO 4 INCHES OF LIQUID, WITH ISOLATED HIGHER AMOUNTS ACROSS THE
CWA. ALL OF THIS PRECIPITATION IS DO TO A SLOW MOVING UPPER LEVEL
LOW THAT WILL MOVE FROM THE PACIFIC NORTHWEST LATER TODAY TOWARDS
THE WEST YELLOWSTONE AREA BY SUNDAY MORNING, RESULTING IN GOOD
UPSLOPE CIRCULATION OVER MT, THUS THE WIDESPREAD PRECIPITATION
EXPECTED.
TEMPERATURES WILL CONTINUE THE COOLING TREND TODAY THROUGH SUNDAY,
WITH SUNDAY BEING THE COLDEST DAY. AFTERNOON HIGHS ON SUNDAY WILL
BE 20 OR MORE DEGREES COLDER THAN NORMAL IN MOST AREAS.
FOR NEXT WEEK, EXPECT A SLOW RETURN TO MORE TYPICAL JUNE
CONDITIONS. AFTERNOON HIGHS WILL RETURN TO AROUND 80 DEGREES BY
LATE IN THE WEEK, WITH A CHANCE FOR MOSTLY AFTERNOON AND EVENING
SHOWERS/THUNDERSTORMS.
- FORECAST CONFIDENCE & SCENARIOS:
THE THREAT FOR SEVERE STORMS TODAY IS GOING TO BE COMPLICATED BY
THE NUMEROUS SHOWERS/THUNDERSTORMS. INSTABILITY WILL HAVE TO
DEVELOP IN BETWEEN THE BREAKS OF SHOWERS/THUNDERSTORMS. THUS IT IS
LOOKING LIKE AREAS EAST OF A LINE FROM HELENA TO HAVRE WILL HAVE
THE BEST CHANCE TO SEE A MORE UNSTABLE AIRMASS THIS AFTERNOON.
NOTE, WITH ALL THE PRECIPITATION FALLING, THE STORMS WILL BECOME
WETTER AND MORE HEAVIER RAIN PRODUCERS LATER THIS
AFTERNOON/EVENING.
FROM LATER TONIGHT THROUGH SUNDAY, THE MAIN CONCERN WILL BE ON LOW
DO SNOW LEVELS GET AND HOW HEAVY IS THE SNOWFALL IN THE MOUNTAINS.
IT CONTINUES TO LOOK LIKE GLACIER PARK WILL SEE A SIGNIFICANT SNOW
STORM SATURDAY INTO SATURDAY NIGHT. SNOWFALL RATES OF 2 INCHES OR
MORE PER HOUR WILL BE POSSIBLE AT TIMES ON SATURDAY IN GLACIER
PARK AT THE HIGHER ELEVATIONS. ELSEWHERE, BY SUNDAY MORNING, SNOW
LEVELS COULD LOWER TO AROUND 5000 FEET, THUS RESULTING IN SOME
SNOW ACCUMULATIONS AROUND SOME BIGGER COMMUNITIES, SUCH AS DILLON
OR LEWISTOWN. THE KINGS HILL AND BIG SKY AREA ARE LIKELY TO BE
AFFECTED BY THIS SNOWFALL. THUS THE WINTER WEATHER ADVISORY WAS
EXPANDED TO INCLUDE MANY MOUNTAIN RANGES ACROSS THE CWA. BRUSDA
AVIATION
20/12Z TAF PERIOD
A PARADE OF SHOWERS/THUNDERSTORMS WILL MOVE FROM SOUTHWEST TO
NORTHEAST THROUGH THE CWA TODAY. A FEW STORMS COULD PRODUCE BRIEF
HEAVY RAINFALL/GUSTY WINDS. EXPECT THE PRECIPITATION TO BECOME
MORE WIDESPREAD OVER NORTH CENTRAL MT DURING THE DAY THOUGH.
MOUNTAINS/PASSES WILL BE OBSCURED ACROSS MUCH OF THE CWA THROUGH
THE PERIOD. BRUSDA
REFER TO WEATHER.GOV/ZLC FOR
MORE DETAILED REGIONAL AVIATION WEATHER AND HAZARD INFORMATION.
PRELIMINARY POINT TEMPS/POPS
GTF 71 46 63 42 / 90 90 60 80
CTB 58 44 52 38 / 90 90 90 90
HLN 71 46 63 42 / 90 90 60 80
BZN 82 43 67 39 / 70 90 50 80
WYS 73 36 60 30 / 50 50 20 70
DLN 75 38 59 35 / 70 80 60 90
HVR 71 50 64 43 / 90 90 80 60
LWT 70 46 63 39 / 80 90 50 60
TFX WATCHES/WARNINGS/ADVISORIES
HIGH WIND WARNING FROM NOON TODAY TO 8 PM MDT THIS EVENING FOR
MADISON RIVER VALLEY.
HIGH WIND WARNING FROM 9 AM SATURDAY TO 3 AM MDT SUNDAY FOR
EASTERN GLACIER, WESTERN TOOLE, AND CENTRAL PONDERA-EASTERN
TOOLE AND LIBERTY.
WINTER STORM WARNING FROM 9 AM SATURDAY TO NOON MDT SUNDAY FOR
EAST GLACIER PARK REGION.
WINTER WEATHER ADVISORY FROM 6 PM SATURDAY TO NOON MDT SUNDAY
FOR BIG BELT, BRIDGER AND CASTLE MOUNTAINS-ELKHORN AND BOULDER
MOUNTAINS-GALLATIN AND MADISON COUNTY MOUNTAINS AND CENTENNIAL
MOUNTAINS-LITTLE BELT AND HIGHWOOD MOUNTAINS-NORTHWEST
BEAVERHEAD COUNTY-RUBY MOUNTAINS AND SOUTHERN BEAVERHEAD
MOUNTAINS-SOUTHERN ROCKY MOUNTAIN FRONT.
HTTP://WWW.WEATHER.GOV/GREATFALLS
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