037
FXUS65 KTFX 221829
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1229 PM MDT WED APR 22 2026
AVIATION SECTION UPDATED.
KEY MESSAGES
- ONE LAST MILD DAY, WITH AFTERNOON SHOWERS AND THUNDERSTORMS.
- COLD FRONT ARRIVES THIS EVENING AND TONIGHT, BRINGING A SHARP TRANSITION
TO COLDER/WETTER CONDITIONS THROUGH THURSDAY, INCLUDING
IMPACTFUL SNOWFALL IN THE MOUNTAINS AND AT SOME LOWER ELEVATION
LOCATIONS.
- ADDITIONAL SNOW LINGERS NEAR THE CONTINENTAL DIVIDE AND ACROSS
SOUTHWEST MONTANA INTO FRIDAY BEFORE SLOWLY SUBSIDING.
- REMAINING UNSETTLED THROUGH THE WEEKEND INTO EARLY NEXT WEEK.
DISCUSSION
/ISSUED 512 AM MDT WED APR 22 2026/
- METEOROLOGICAL OVERVIEW:
THE FIRST OF SEVERAL EMBEDDED WAVES WITHIN BROAD TROUGHING ACROSS
THE WEST MOVES OVERHEAD TODAY ACROSS THE REGION. INITIAL IMPACT IS
FOR GUSTY SOUTH TO SOUTHWEST WINDS IN MANY AREAS DEVELOPING THIS
MORNING. PRECIPITATION LARGELY NEAR THE CONTINENTAL DIVIDE THIS
MORNING SLOWLY SPREAD EASTWARD IN THE FORM OF SHOWERS AND
THUNDERSTORMS IN THE AFTERNOON AND EVENING. A FEW OF THE MOST ROBUST
THUNDERSTORMS WILL POSE A GUSTY WIND THREAT, BUT THE CONFIDENCE IN
TIMING AND LOCATION OF ANY OF THESE THUNDERSTORMS IS LOW AT THIS
TIME.
A COLD FRONT THEN BEGINS TO MOVE IN LATE DAY AND INTO THE EVENING,
BRINGING SHARPLY COLDER TEMPERATURES TO THE ENTIRE REGION, ALONG WITH
GUSTY NORTHWEST WINDS OVER THE PLAINS. A MORE WIDESPREAD
PRECIPITATION DEVELOPS ALONG AND BEHIND THE FRONT, IMPACTING
MOUNTAIN AREAS AND MUCH OF THE PLAINS. SNOW LEVELS FALL QUICKLY
BEHIND THIS FRONT, THOUGH RAIN LOOKS TO PERSIST BEHIND THE FRONT
FOR A COUPLE HOURS AT LOWER ELEVATIONS BEFORE THE SUFFICIENTLY
COLD AIR ARRIVES TO TRANSITION PRECIPITATION TYPE TO SNOW.
IMPACTFUL SNOW IS FORECAST TO DEVELOP IN MANY MOUNTAIN AREAS
THIS EVENING AND PERSIST INTO THURSDAY. AREAS AT LOWER ELEVATIONS
OF GREATEST CONCERN FOR IMPACTS WILL BE IN THE ARMINGTON JUNCTION
AREA AND ADJACENT AREAS NEAR THE LITTLE BELTS, AS WELL AS NEAR
LEWISTOWN AS THE NORTHWEST WINDS COMBINE WITH SNOW. THERE IS SOME
UNCERTAINTY WITH JUST HOW IMPACTFUL THIS SNOW AND WIND WILL BE FOR
THESE AREAS, WHICH IS LARGELY DEPENDENT ON HOW QUICKLY SNOW
LEVELS FALL IN THESE AREAS. MORE ABOUT THIS CONCERN WILL BE
DISCUSSED IN THE UNCERTAINTY SECTION.
LINGERING GUSTY NORTHWEST WINDS NEAR AND EAST OF US-87 DURING THE
DAY THURSDAY WILL SLOWLY SUBSIDE TOWARD THURSDAY EVENING AND NIGHT.
ALL THE WHILE, ANOTHER WAVE WITHIN THE BROAD UPPER TROUGHING WILL
KEEP SNOW IN THE FORECAST ALONG THE CONTINENTAL DIVIDE AND ACROSS
SOUTHWEST MONTANA THURSDAY NIGHT INTO FRIDAY AS PRECIPITATION
FURTHER EAST WANES THURSDAY EVENING. ADDITIONAL IMPACTS FROM THE
SNOW ARE MOST FAVORED IN THE TERRAIN IN THESE AREAS, BUT WILL REACH
THE VALLEY FLOORS AT TIMES INTO FRIDAY.
ALTHOUGH THE BULK OF THE UPPER TROUGHING MOVES EAST/NORTHEAST THIS
WEEKEND INTO EARLY NEXT WEEK, AN UNSETTLED NORTHERLY OR
NORTHWESTERLY FLOW ALOFT DEVELOPS. TEMPERATURES LARGELY LOOK TO
REMAIN ON THE COOLER SIDE, WITH AT LEAST LOW-END OPPORTUNITIES FOR
PRECIPITATION MOST DAYS THROUGH THE WEEKEND. -AM
- FORECAST CONFIDENCE & SCENARIOS:
THUNDERSTORMS TODAY:
WHILE LATEST HIGH-RESOLUTION ENSEMBLES DO NOT FAVOR ANY ONE AREA
OVER ANOTHER BY TOO MUCH IN TERMS OF INSTABILITY THIS AFTERNOON, ANY
STRONGER THUNDERSTORMS THAT DO DEVELOP WILL BE CAPABLE OF
PRODUCING GUSTY AND ERRATIC WINDS. IF THERE WAS ONE AREA THAT WAS
SLIGHTLY FAVORED OVER THE REST FOR DEVELOPMENT OF GREATEST
INSTABILITY IT LOOKS TO BE ACROSS THE HI-LINE IN THE SHELBY AREA
WHERE THERE IS APPROXIMATELY A 70% PROBABILITY FOR 250+ J/KG CAPE
TODAY.
POTENTIAL FOR BLIZZARD CONDITIONS IN/NEAR THE LITTLE BELTS LATE
TONIGHT AND EARLY THURSDAY:
THE MAIN SOURCE OF UNCERTAINTY STEMS FROM HOW LONG OF AN OVERLAP
THERE WILL BE BETWEEN THE STRONGEST WINDS AND HEAVIEST SNOWFALL IN
THESE AREAS TONIGHT. HIGH RESOLUTION GUIDANCE FAVORS THE STRONGEST
WINDS IN BETWEEN ARMINGTON JUNCTION AND GEYSER THIS EVENING BEFORE
SLOWLY SUBSIDING THROUGH THE OVERNIGHT. MEANWHILE THIS SAME SET OF
GUIDANCE KEEPS PRECIPITATION TYPE AS RAIN IN THIS AREA THROUGH
MIDNIGHT OR SO. A SCENARIO THAT FEATURES TEMPERATURES THAT ARE
QUICKER TO COOL OR THAT HAS THE STRONGER WINDS LINGERING LONGER
WOULD RESULT IN AT LEAST A FEW HOURS OF BLIZZARD CONDITIONS IN THIS
AREA TONIGHT.
SOUTH OF ARMINGTON JUNCTION ON US-89 ON THE WAY TO KINGS HILL PASS
PRECIPITATION LOOKS TO FLIP OVER TO SNOW QUICKER THAN ON 87. THAT
SAID, THE WINDS DO NOT APPEAR QUITE AS STRONG. ALL THAT TO SAY THERE
IS STILL QUITE A BIT OF UNCERTAINTY IN THE HIGHER-END IMPACT
SCENARIO AT THIS TIME. REGARDLESS OF WHETHER BLIZZARD CONDITIONS
MATERIALIZE IN THESE AREAS, IMPACTFUL SNOW IS STILL FORECAST, WHICH
WILL WARRANT SOME SORT OF WINTER HIGHLIGHT (WHETHER IT BE A WINTER
WEATHER ADVISORY, WINTER STORM WARNING, OR BLIZZARD WARNING IS TO BE
DETERMINED).
THERE ALSO APPEARS TO BE A CONDITIONAL RISK FOR LOCALIZED
BLIZZARD CONDITIONS NEAR LEWISTOWN LATE TONIGHT AND THURSDAY
MORNING, BUT UNCERTAINTY IN OVERALL SNOW AMOUNTS ARE KEEPING
CONCERNS LOWER FOR NOW.
POTENTIAL FOR STRONG NORTHWEST WINDS TONIGHT AND THURSDAY:
LATEST HIGH RESOLUTION GUIDANCE FAVORS AREAS ACROSS THE PLAINS
DOWNWIND OF TERRAIN AS THE MOST LIKELY TO SEE GUST OF 60 MPH
MATERIALIZE TONIGHT INTO EARLY THURSDAY. AREAS WITH A GREATER THAN
50% PROBABILITY TO OBSERVE A 60 MPH GUST ARE IN EASTERN FERGUS
COUNTY AND ACROSS A SOUTHERN AND EASTERN BLAINE COUNTY. -AM
AVIATION
22/18Z TAF PERIOD
GUSTY WINDS WILL CONTINUE ACROSS SOUTHWEST MONTANA THROUGH THE
REST OF THE AFTERNOON, DIMINISHING THIS EVENING AS THE FRONT MOVES
SOUTH. THERE IS A 15% CHANCE FOR SCATTERED THUNDERSTORMS THIS
AFTERNOON ACROSS THE REGION WITH THE MAIN CONCERNS BEING LIGHTNING
AND GUSTY, ERRATIC WINDS. THE THREAT IS GENERALLY EXPECTED TO
PERSIST THROUGH 23/03Z BEFORE TAPERING OFF AS DAYTIME HEATING
STARTS TAPERING OFF.
THE COLD FRONT IS EXPECTED TO MOVE THROUGH THIS EVENING INTO THE
OVERNIGHT HOURS SHIFTING THE WINDS TOWARDS THE WEST/NORTHWEST.
BEHIND THE FRONT, MORE STRATIFORM PRECIPITATION WILL START OFF AS
A RAIN/SNOW MIX BEFORE QUICKLY TRANSITIONING TO SNOW AND THE
COLDER AIR FILTERS IN. MOUNTAIN OBSCURATION WILL REMAIN A CONCERN
THROUGH MOST OF THE PERIOD. -THOR
PRELIMINARY POINT TEMPS/POPS
GTF 71 29 41 26 / 70 100 70 40
CTB 65 26 40 22 / 70 90 30 20
HLN 67 29 39 24 / 80 100 90 60
BZN 62 31 42 21 / 80 100 90 70
WYS 45 24 37 17 / 90 100 90 80
DLN 55 32 43 25 / 80 90 80 70
HVR 78 30 44 25 / 30 80 30 10
LWT 71 28 37 21 / 40 100 60 20
TFX WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM MDT
THURSDAY FOR BIG BELT, BRIDGER AND CASTLE MOUNTAINS-EAST GLACIER
PARK REGION-NORTHERN HIGH PLAINS.
HIGH WIND WATCH FROM MIDNIGHT MDT TONIGHT THROUGH THURSDAY
AFTERNOON FOR BEARS PAW MOUNTAINS AND SOUTHERN BLAINE-EASTERN
TOOLE AND LIBERTY-FERGUS COUNTY BELOW 4500FT-HILL COUNTY-
NORTHERN BLAINE COUNTY-WESTERN AND CENTRAL CHOUTEAU COUNTY.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM MDT
THURSDAY FOR BEARS PAW MOUNTAINS AND SOUTHERN BLAINE-FERGUS
COUNTY BELOW 4500FT-SNOWY AND JUDITH MOUNTAINS.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON MDT
FRIDAY FOR ELKHORN AND BOULDER MOUNTAINS-GATES OF THE MOUNTAINS-
NORTHWEST BEAVERHEAD COUNTY-RUBY MOUNTAINS AND SOUTHERN
BEAVERHEAD MOUNTAINS-SOUTHERN ROCKY MOUNTAIN FRONT-UPPER
BLACKFOOT AND MACDONALD PASS.
WINTER STORM WATCH FROM 6 PM MDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR LITTLE BELT AND HIGHWOOD MOUNTAINS.
HIGH WIND WARNING UNTIL 6 PM MDT THIS EVENING FOR BEAVERHEAD AND
WESTERN MADISON BELOW 6000FT-MADISON RIVER VALLEY-MISSOURI
HEADWATERS.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MDT THURSDAY
FOR GALLATIN AND MADISON COUNTY MOUNTAINS AND CENTENNIAL
MOUNTAINS.
WINTER STORM WATCH FROM MIDNIGHT MDT TONIGHT THROUGH THURSDAY
AFTERNOON FOR JUDITH BASIN COUNTY AND JUDITH GAP.
WINTER STORM WATCH FROM THURSDAY EVENING THROUGH FRIDAY MORNING
FOR GALLATIN VALLEY.
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