973
FXUS65 KTFX 100448
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1048 PM MDT TUE JUN 9 2026
AVIATION SECTION UPDATED.
KEY MESSAGES
- COOL AND UNSETTLED WEATHER PATTERN CONTINUES WITH PERIODS OF
SHOWERS AND POSSIBLE AFTERNOON THUNDERSTORMS THROUGH WEDNESDAY
NIGHT AND LIKELY AGAIN FRIDAY NIGHT INTO SATURDAY.
- BREEZY TO WINDY CONDITIONS THROUGH WEDNESDAY WITH LOCALLY
STRONG WINDS POSSIBLE ACROSS PORTIONS OF CENTRAL MONTANA ON
WEDNESDAY.
- ACCUMULATING SNOW FOR ELEVATIONS ABOVE 5500 FEET, ESPECIALLY
ACROSS THE MOUNTAINS OF GLACIER NATIONAL PARK.
UPDATE
UPDATED FORECAST IS OUT. ONLY CHANGE THIS EVENING WAS TO ADD SOME
LIGHT SHOWERS FOR A FEW MORE HOURS IN THE HAVRE/HARLEM AREAS.
OVERALL, MOST OF THE THUNDERSTORMS HAVE DIMINISHED, BUT AN
ISOLATED LIGHTNING STRIKE CAN'T BE RULED OUT OVERNIGHT.
FOR THE HIGH WIND WATCH, LATEST GUIDANCE IS FAVORING A SMALL AREA
FOR HIGH WINDS, MAINLY EAST OF MACDONALD PASS AND THE LOWER
ELEVATIONS OF JUDITH BASIN COUNTY. WE WILL TAKE A CLOSER LOOK
WHEN ALL OF THE 00Z MODELS COME IN THIS EVENING BEFORE MAKING A
FINAL DECISION. OTHERWISE, THE REST OF THE FORECAST IS ON TRACK.
BRUSDA
DISCUSSION
- METEOROLOGICAL OVERVIEW:
A SECONDARY PUSH OF COLDER AIR IN THE MID-UPPER LEVELS SURGES EAST
ACROSS THE AREA THIS AFTERNOON AND EVENING SUPPORTING SCATTERED TO
NUMEROUS SHOWERS AND A FEW THUNDERSTORMS, FAVORING AREAS FROM
SOUTHWEST MT THROUGH EASTERN PORTIONS OF CENTRAL MT. THE MAIN UPPER
LEVEL LOW/TROUGH WITH THIS INITIAL SERIES OF SHORTWAVES SHIFTS
ACROSS THE NORTHERN ROCKIES WEDNESDAY, BRINGING ADDITIONAL COOLING
ALONG WITH WINDY CONDITIONS AND SOME SHOWERS, MAINLY ACROSS NORTH-
CENTRAL MT LATER WEDNESDAY AFTERNOON AND OVERNIGHT AS MOISTURE WRAPS
AROUND THE BACK SIDE OF THE UPPER TROUGH. SNOW LEVELS WILL LOWER TO
AROUND 7000 FT TODAY AND MAY FALL TO AS LOW AS 6000 FT WEDNESDAY,
THOUGH ANY MOUNTAIN SNOWFALL IS LIKELY TO BE BRIEF WITH LITTLE
ACCUMULATION. A DRIER PERIOD FOLLOWS THURSDAY THROUGH AT LEAST EARLY
FRIDAY BEFORE THE NEXT SERIES OF SHORTWAVES BEGINS TO MOVE IN FROM
THE NW LATER FRIDAY AND SATURDAY.
CONFIDENCE IN THE UPPER LEVEL PATTERN DECREASES LATER THIS WEEKEND
INTO NEXT WEEK, BUT MOST LONGER RANGE MODEL ENSEMBLES FAVOR UPPER
LEVEL RIDGING BRIEFLY AMPLIFYING OFFSHORE OF THE PACIFIC NW/BC BY
EARLY NEXT WEEK. THIS COULD BRING SOME WARMING BUT ALSO MAINTAINS A
NORTHWESTERLY FLOW ALOFT WITH POTENTIAL FOR ADDITIONAL DISTURBANCES
TO MOVE THROUGH AND A RISK FOR SHOWERS AND THUNDERSTORMS. HOENISCH
- FORECAST CONFIDENCE & SCENARIOS:
ACCUMULATING SNOW TONIGHT THROUGH WEDNESDAY EVENING...
SNOW LEVELS FALLING TO BETWEEN 5500FT TO 6500FT THROUGHOUT THE
TIMEFRAME WILL ALLOW RAIN TO MIX IN WITH OR COMPLETELY CHANGEOVER TO
SNOW ACROSS THE MOUNTAINS OF SOUTHWEST THROUGH NORTH CENTRAL
MONTANA, WITH ACCUMULATING SNOW EXPECTED ABOVE 6500FT. NBM5.0
PROBABILITIES FOR SNOWFALL ACCUMULATIONS GREATER THAN 2" OF SNOW FOR
LOCATIONS ABOVE 6500FT, MOST NOTABLY ALONG THE CONTINENTAL DIVIDE,
LITTLE BELTS, TOBACCO ROOTS, AND GALLATIN/MADISON RANGES, ARE IN
EXCESS OF A 60% CHANCE WITH 20-40% CHANCE FOR ACCUMULATIONS TO
EXCEED 4" ACROSS MOST OF THESE LOCATIONS. THE ONE EXCEPTION IS
ACROSS THE MOUNTAINS OF GLACIER NATIONAL PARK WHERE PROBABILITIES
ARE SIGNIFICANTLY HIGHER AT AROUND A 70% CHANCE FOR 4" OR MORE OF
SNOW, WITH EVEN A 10% CHANCE THAT AMOUNTS EXCEED 12" OR MORE OF
SNOW.
STRONG WINDS ON WEDNESDAY...
CLIMATE ANOMALY INDICATORS SUCH AS THE NAEFS AND ECMWF EFIS CONTINUE
TO SUGGEST THE POTENTIAL FOR A CLIMATOLOGICALLY UNUSUAL TO VERY
UNUSUAL, WITH RESPECT TO JUNE CLIMATOLOGY, WIND EVENT ACROSS
PORTIONS OF SOUTHWEST THROUGH NORTH CENTRAL MONTANA. H700 WIND
SPEEDS OF 30-40KTS, WITH SPEEDS IN EXCESS OF 50KTS WITHIN THE
CRITICAL LAYER, ARE EXPECTED TO OVERSPREAD THE NORTHERN ROCKIES FROM
LATE THIS EVENING THROUGH WEDNESDAY AFTERNOON. THE CORE OF THESE
STRONG WINDS IS STILL EXPECTED TO MOVE OVER CENTRAL MONTANA DURING
THIS TIMEFRAME, JENELLE ALONG AND NORTH OF THE US HWY 12 AND
MONTANA HWY 200 CORRIDORS BUT ALSO INCLUDING THE ROCKY MOUNTAIN
FRONT SOUTH OF US HWY 2. UNCERTAINTY BEGINS TO RISE IN HOW
PRECIPITATION OVERSPREADING THE AFOREMENTIONED AREAS WILL AFFECT
MIXING DURING THE EVENT, ESPECIALLY EARLY ON WITH RESPECT TO
MOUNTAIN WAVE ACTIVITY. NBM5.0 PROBABILITIES FOR WIND SPEEDS OF
34KTS OR GREATER RANGE FROM A 30-40% CHANCE ACROSS JUDITH BASIN AND
MUCH OF THE ROCKY MOUNTAIN FRONT, WITH PROBABILITIES FOR WIND GUSTS
GREATER THAN 50KTS VARYING FROM A 10-30% CHANCE BETWEEN THE US HWY
12 AND MT HWY 200 CORRIDORS TO A 40-80% CHANCE ALONG THE ROCKY
MOUNTAIN FRONT. AT THIS TIME IT IS LIKELY THAT ISOLATED WINDS UP TO
HIGH WIND CRITERIA WILL OCCUR, BUT WITH COVERAGE BEING SO ISOLATED I
AM HESITANT TO UPGRADE THE HIGH WIND WATCH. AT THE SAME TIME THIS
EVENT HAS THE POTENTIAL TO BE A HIGH IMPACT/LOW MAGNITUDE EVENT
GIVEN THAT VEGETATION IS LEAFED OUT AND SUMMER RECREATION IS
UNDERWAY. FOR NOW WE WILL MAINTAIN THE HIGH WIND WATCH GIVEN THE
UNCERTAINTY. - MOLDAN
AVIATION
10/06Z TAF PERIOD
LIGHT SHOWERS ARE DIMINISHING OVER THE EASTERN PORTIONS OF THE
CWA, WHILE LIGHT RAIN/SNOW SHOWERS CONTINUE ALONG THE ROCKY
MOUNTAIN FRONT. EXPECT GUSTY SURFACE WINDS TO DEVELOP OVERNIGHT
OVER MUCH OF THE CWA AND THEN CONTINUE THRU THE DAY ON WED.
SHOWERS/ISOLATED THUNDERSTORMS WILL ALSO REDEVELOP ON WED
AFTERNOON OVER NORTH CENTRAL MT, AND MOVE SOUTHWARD INTO CENTRAL
MT BY WED EVENING. MOUNTAINS/PASSES WILL BE OBSCURED AT TIMES
ACROSS THE CWA THROUGH THE PERIOD. BRUSDA
PRELIMINARY POINT TEMPS/POPS
GTF 45 60 46 72 / 10 40 70 0
CTB 42 55 42 67 / 20 80 50 0
HLN 43 59 44 72 / 40 20 30 0
BZN 36 57 38 70 / 70 50 30 0
WYS 27 51 25 63 / 70 60 10 0
DLN 36 56 33 71 / 40 40 10 0
HVR 45 60 44 71 / 20 90 80 20
LWT 39 58 39 66 / 40 10 90 10
TFX WATCHES/WARNINGS/ADVISORIES
HIGH WIND WATCH FROM 3 AM MDT WEDNESDAY THROUGH LATE WEDNESDAY
NIGHT FOR BIG BELT, BRIDGER AND CASTLE MOUNTAINS-FERGUS COUNTY
BELOW 4500FT-GATES OF THE MOUNTAINS-HELENA VALLEY-JUDITH BASIN
COUNTY AND JUDITH GAP-LITTLE BELT AND HIGHWOOD MOUNTAINS-MEAGHER
COUNTY VALLEYS-UPPER BLACKFOOT AND MACDONALD PASS.
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