229
FXUS65 KTFX 160521
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1121 PM MDT WED APR 15 2026
AVIATION SECTION UPDATED.
KEY MESSAGES
- CHANCES FOR LOWER ELEVATION RAIN/ISOLATED THUNDER AND MOUNTAIN
SNOW INCREASES THIS AFTERNOON AND EVENING.
- A COLD FRONT WILL TRANSITION RAIN TO SNOW, BRINGING COLD
TEMPERATURES THURSDAY AND A SLIGHT CHANCE FOR SNOW SQUALLS
ALONG I-90 TONIGHT.
- ISOLATED TO SCATTERED SNOW SHOWERS CONTINUE THURSDAY AFTERNOON
INTO FRIDAY MORNING.
- A WARMING TREND AND DRIER CONDITIONS TRENDING FOR THE WEEKEND
AND INTO THE BEGINNING OF NEXT WEEK.
DISCUSSION
/ISSUED 551 PM MDT WED APR 15 2026/
- METEOROLOGICAL OVERVIEW:
WITH THE UPPER LEVEL TROUGH TRANSLATING EAST ACROSS THE WESTERN
U.S., ISOLATED LOWER ELEVATION RAIN AND MOUNTAIN SNOW SHOWERS
HAVE DEVELOPED. PRECIPITATION WILL CONTINUE TO DEVELOP, BECOMING
SCATTERED AHEAD OF THE FRONT. WEAK INSTABILITY THIS AFTERNOON
POSES AN ISOLATED RISK FOR WEAK THUNDERSTORMS. GUSTY WINDS ACROSS
THE MADISON RIVER AND BEAVERHEAD COUNTY VALLEYS ALSO INCREASES
AHEAD OF THE FRONT AS WINDS INCREASES ALOFT. THE COLD FRONT
PASSAGE LATER TODAY WILL BRING WIDESPREAD PRECIPITATION ACROSS
THE REGION. STRONG COLD AIR ADVECTION BEHIND THE FRONT COMBINED
WITH WEAK INSTABILITY BRINGS A SLIGHT RISK FOR SNOW SQUALLS ALONG
AND SOUTH OF THE I-90 CORRIDOR THIS EVENING. THE MAIN IMPACTS
WILL BE SUDDEN REDUCTIONS IN VISIBILITY AND MINOR, SLUSHY
ACCUMULATIONS ON ROADS.
SNOW LEVELS DROPPING BEHIND THE FRONT WILL HELP TRANSITION RAIN TO
SNOW WIDESPREAD ACROSS THE REGION LATE TONIGHT AND INTO THURSDAY
MORNING. CHILLY TEMPERATURES DURING THE DAY THURSDAY WILL KEEP
LINGERING SNOW SHOWERS THROUGHOUT THE DAY, MAINLY IN SOUTHWEST MT
WITH MORE ISOLATED SNOW SHOWERS ACROSS NORTH-CENTRAL MT.
INCREASING WINDS ALOFT WRAPPING AROUND THE COLD UPPER-LEVEL LOW
ALONG THE HI-LINE THURSDAY WILL ALSO BRING BREEZY TO GUSTY WINDS
TO NORTH-CENTRAL MT. -WILSON
ON FRIDAY, NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA
REMAIN UNDER THE INFLUENCE OF THE UPPER-LEVEL TROUGH. THIS WILL
CAUSE TEMPERATURES TO REMAIN ON THE CHILLIER SIDE WITH LOWS IN THE
TEENS AND ANOTHER ROUND OF SNOW SHOWERS FRIDAY MORNING. AS THE
TROUGH MOVES TO THE EAST, AN UPPER LEVEL RIDGE OF HIGH PRESSURE TO
THE WEST BEGINS TO BUILD, ALLOWING TEMPERATURES TO WARM IN THE
AFTERNOON AND PRECIPITATION CHANCES TO DECREASE. THE UPPER LEVEL
RIDGE WILL MOVE EAST OVER MONTANA ON SATURDAY AND SUNDAY AND BRING
MILDER AND DRIER WEATHER ACROSS THE REGION. EARLY NEXT WEEK THE
BENIGN CONDITIONS CONTINUE UNTIL TROUGHING BRINGS INCREASED SHOWER
ACTIVITY BY THE MIDDLE OF NEXT WEEK. - DZOMBA
- FORECAST CONFIDENCE & SCENARIOS:
WINDS IN SOUTHWEST MT THROUGH THE REST OF THE DAY:
GUSTY WINDS CONTINUE THIS AFTERNOON IN THE MADISON AND BEAVERHEAD
COUNTY VALLEYS. THE THREAT FOR HIGH WINDS REMAIN MARGINAL, WITH
BEST CHANCES BEING WITH A SHOWER/THUNDERSTORM OR ALONG THE
FRONTAL PASSAGE. THEREFORE, NO CHANGES WERE MADE TO THE CURRENT
HIGH WIND WARNING.
SNOW THROUGH THURSDAY:
WARMER PAVEMENT TEMPERATURES ARE CURRENTLY LIMITING SNOW
ACCUMULATIONS TO ABOVE PASS LEVEL. THE COLD FRONT WILL HELP LOWER
TEMPERATURES, WITH MODERATE TO HEAVY SNOW ALONG THE FRONT HELPING
CRASH PAVEMENT TEMPERATURES TO FREEZING. THE MAIN CHANGES TO THE
FORECAST WAS UPGRADING THE MADISON AND GALLATIN COUNTY MOUNTAINS
TO A WINTER STORM WARNING AND DOWNGRADING THE WINTER STORM WATCH
TO A WINTER WEATHER ADVISORY FOR THE GALLATIN COUNTY VALLEY. ONE
UNCERTAINTY LIES IN THE AMOUNT OF QPF THIS SYSTEM PRODUCES, AS
PROBABILITIES HAVE DOWN TRENDED RECENTLY IN MODEL RUNS. THOUGH
SYNOPTIC NUDGES LIKE THE STRONG COLD ADVECTION AND ALOFT AND
FRONTOGENESIS ALONG THE FRONT GAVE ENOUGH CONFIDENCE TO UPGRADE
THE MADISON AND GALLATIN COUNTY MOUNTAINS TO A WINTER STORM
WARNING. THE MAIN IMPACTS WILL BE ALONG HIGHWAY 191 SOUTH OF THE
GALLATIN GATEWAY TO WEST YELLOWSTONE. TIMING OF THE FRONT BEING AT
NIGHT IS IDEAL FOR MODERATE TO HEAVY SNOW ALONG THE FRONTAL
PASSAGE TO CRASH ROAD TEMPERATURES IN THE GALLATIN VALLEY QUICKLY.
HOWEVER, THERE WASN'T A HIGH ENOUGH CONFIDENCE IN HIGH MOISTURE
AMOUNTS TO PRODUCE A BROADER 6-7" OF SNOW FOR A WINTER STORM
WARNING. THERE IS A SLIGHT CHANCE FOR THOSE AMOUNTS STILL,
ESPECIALLY AREAS NEAR THE HIGHER TERRAIN THAT COULD GET SOME
UPSLOPE ENHANCEMENT. A TIGHT SNOW GRADIENT WILL LIKELY DEVELOP IN
THE VALLEY/THE CITY OF BOZEMAN AS A RESULT. THE MADISON RIVER
VALLEY COULD SEE MINOR SLUSHY SNOW ACCUMULATIONS THURSDAY, SO
THEY WERE ADDED TO THE WINTER WEATHER ADVISORIES AS WELL. -WILSON
AVIATION
16/12Z TAF PERIOD
A SPRING STORM WILL BRING LOW CIGS AND REDUCED VIS TO TERMINALS
ACROSS SOUTHWEST MONTANA FOR MUCH OF THE NEXT 24 HOURS, WITH
TERMINALS ACROSS CENTRAL AND NORTH CENTRAL MONTANA SEEING
FLUCTUATIONS IN CIGS/VIS OVER THIS SAME TIMEFRAME. WITH RESPECT TO
SOUTHWEST MONTANA PERSISTENT SNOW OR A RAIN/SNOW MIX ACROSS THE
KWYS, KEKS, AND KBZN TERMINALS WILL BRING LIFR/IFR/MVFR CONDITIONS
THROUGH 15-18Z THURSDAY, WITH CONDITIONS ONLY IMPROVING TO
MVFR/LOW-VFR THEREAFTER. FURTHER NORTH AN AREA OF PRECIPITATION
WILL GRADUALLY EXIT THROUGH THE KGTF, KLWT, AND KHVR TERMINALS
THROUGH 09-12Z THURSDAY; HOWEVER, SNOW SHOWERS WILL RE-DEVELOP
DURING THE LATE MORNING/AFTERNOON HOURS ON THURSDAY AND PERSIST
THROUGH THE EVENING HOURS HERE AND AT THE KCTB AND KHLN TERMINALS.
WIDESPREAD MOUNTAIN OBSCURATION WILL CONTINUE THROUGH THE DAY ON
THURSDAY. - MOLDAN
PRELIMINARY POINT TEMPS/POPS
GTF 28 39 22 45 / 80 30 40 50
CTB 19 30 14 44 / 40 50 20 20
HLN 27 43 25 46 / 90 40 40 70
BZN 25 39 19 43 / 90 80 50 70
WYS 25 34 12 36 / 100 90 70 70
DLN 25 38 19 43 / 80 70 20 30
HVR 26 37 17 46 / 80 70 30 0
LWT 27 38 17 42 / 90 50 30 40
TFX WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY UNTIL NOON MDT THURSDAY FOR BIG BELT,
BRIDGER AND CASTLE MOUNTAINS-EAST GLACIER PARK REGION-LITTLE
BELT AND HIGHWOOD MOUNTAINS-SOUTHERN ROCKY MOUNTAIN FRONT.
WINTER STORM WARNING UNTIL MIDNIGHT MDT THURSDAY NIGHT FOR
GALLATIN AND MADISON COUNTY MOUNTAINS AND CENTENNIAL MOUNTAINS.
WINTER WEATHER ADVISORY UNTIL 6 PM MDT THURSDAY FOR GALLATIN
VALLEY-MADISON RIVER VALLEY.
WINTER WEATHER ADVISORY UNTIL 6 AM MDT THURSDAY FOR NORTHWEST
BEAVERHEAD COUNTY.
HTTP://WWW.WEATHER.GOV/GREATFALLS
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