029
FXUS65 KTFX 222325
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
525 PM MDT WED APR 22 2026
AVIATION SECTION UPDATED.
KEY MESSAGES
- SHOWER AND THUNDERSTORM ACTIVITY CONTINUES TO EXPAND
NORTHEASTWARD THIS AFTERNOON AND GRADUALLY TRANSITIONS TO AREAS
OF WIDESPREAD RAIN AND SNOW TONIGHT.
- SNOW AND GUSTY TO STRONG NORTHWESTERLY WINDS BECOME MORE WIDESPREAD
TONIGHT INTO THURSDAY, WITH THE GREATEST IMPACTS, INCLUDING
BRIEF WHITEOUT CONDITIONS, OVER THE LITTLE BELT MOUNTAINS AND
THEIR NORTHWEST FACING FOOTHILLS THURSDAY MORNING.
- ANOTHER ROUND OF ACCUMULATING SNOW DEVELOPS THURSDAY NIGHT INTO FRIDAY
MORNING, MOSTLY IMPACTING AREAS ALONG THE CONTINENTAL DIVIDE
AND SOUTHWEST MONTANA.
- COOLER AND UNSETTLED CONDITIONS CONTINUE THIS WEEKEND, WITH
TEMPERATURES WARMING CLOSER TO AVERAGE BY EARLY NEXT WEEK.
DISCUSSION
/ISSUED 240 PM MDT WED APR 22 2026/
- METEOROLOGICAL OVERVIEW:
DEEP SOUTHERLY FLOW ALOFT CONTINUES TO BRING GUSTY TO STRONG
WINDS OVER SOUTHWEST AND PORTIONS OF CENTRAL MT THIS AFTERNOON,
ESPECIALLY OVER THE NARROW SOUTH TO NORTH ORIENTED C/SW VALLEYS
AND EXPOSED RIDGE TOPS. SHOWER AND THUNDERSTORM ACTIVITY WILL
CONTINUE INCREASING FROM THE SOUTHWEST THIS AFTERNOON WITH
LOCALIZED WIND GUSTS BEING THE PRIMARY HAZARD DUE TO MOMENTUM
SURFACE TRANSFER FROM 30 TO 50 KT H700/850 FLOW. THE COLDER AIR
ALOFT MOVING IN WILL ALSO SUPPORT SOME INSTANCES OF SMALL HAIL
WITH THE STRONGER CORES. CONVERGENCE OF LOW LEVEL WINDS IN ADVANCE
OF THE APPROACHING TROUGH MAY EVEN INITIALIZE AN ISOLATED AND
WEAK COLD AIR FUNNEL CLOUD, MOSTLY ALONG THE CONTINENTAL DIVIDE
AND OVER SOUTHWEST MT. MILD TEMPERATURES THIS AFTERNOON QUICKLY
TRANSITION TO CHILLY AND WET CONDITIONS THIS EVENING AND TONIGHT
FOLLOWING A COLD FRONTAL PASSAGE.
PRECIPITATION BECOMES WIDESPREAD THIS EVENING AND TONIGHT AS A
TROWEL DEVELOPS ON THE NORTHWEST SIDE OF THE MID- LEVEL LOW. H700
TEMPERATURES BECOMES COLD ENOUGH FOR SNOW AT ALL ELEVATIONS OVER
CENTRAL/NORTH-CENTRAL AND SOUTHWEST MT BY THURSDAY MORNING, THOUGH
SNOWFALL AMOUNTS AND OVERALL IMPACTS STILL LOOK TO BE GREATEST
OVER THE NORTH/NORTHWEST FACING FOOTHILLS OF THE CENTRAL ISLAND
RANGES WHERE GUSTY NORTHWESTERLY WINDS AND SNOW WILL OVERLAP.
OTHER AREAS THAT WILL OBSERVE ACCUMULATING SNOW IMPACTS INCLUDE
AREAS ALONG THE CONTINENTAL DIVIDE AND OVER THE HIGHER TERRAIN OF
SOUTHWEST MT. THE SNOW WILL BECOME MORE SCATTERED AND CONVECTIVE
IN NATURE DURING THE DAY ON THURSDAY WHILE DIURNAL HEATING BEGINS
TO EASE IMPACTS. FORTY TO 50 KT H850 FLOW WRAPPING AROUND THE LOW
PRESSURE SYSTEM WILL BRING GUSTY TO STRONG NORTHWESTERLY SURFACE
WINDS ALONG THE HI-LINE AND PLAINS EAST OF I15 TONIGHT INTO
THURSDAY, ESPECIALLY ON THE SOUTH/SOUTHEAST DOWNSLOPE AREAS OF THE
SWEETGRASS HILLS, BEAR'S PAW, AND SNOWY MOUNTAINS.
A SECONDARY SHORTWAVE MOVES IN THURSDAY NIGHT INTO FRIDAY AND
BRINGS ADDITIONAL SNOW AND SNOW SHOWER ACTIVITY. ALTHOUGH MODELS
HAVE LOST INTEREST IN A SMALLER SCALE CLOSED CIRCULATION
DEVELOPING OVER THE SOUTHWEST, H500/H700 TEMPERATURES AROUND
(-30C/-15C) AND SUFFICIENT FRONTOGENESIS WILL BE SUPPORTIVE OF
ACCUMULATING SNOW AT ALL ELEVATIONS ALONG THE CONTINENTAL DIVIDE
AND SOUTHWEST MT. COLD AND MOIST NORTHWESTERLY FLOW ALOFT WILL
ALSO INITIATE SOME PERIODS OF LESS IMPACTFUL LIGHT SNOW FOR MOST
LOCATIONS FRIDAY INTO SATURDAY, ESPECIALLY ALONG THE HI-LINE.
BROAD TROUGHING CONTINUES THROUGH THE WEEKEND AND GRADUALLY
TRANSITIONS TO A NORTHWESTERLY FLOW ALOFT NEXT WEEK AS RIDGING
ATTEMPTS TO DEVELOP ALONG THE PACIFIC COAST. THIS WILL MAINTAIN
DAILY OPPORTUNITIES OF RAIN/SNOW SHOWER ACTIVITY, ESPECIALLY FOR
AREAS OVER OR NEAR HIGHER TERRAIN. TEMPERATURES WILL SLOWLY TREND
TOWARDS THE SEASONAL AVERAGE BY EARLY NEXT WEEK. - RCG
- FORECAST CONFIDENCE & SCENARIOS:
SNOW AND WINDS THROUGH FRIDAY...
THE THREAT FOR STRONG SOUTH/SOUTHWESTERLY SURFACE WINDS OVER THE
NARROW SOUTH TO NORTH ORIENTED C/SW VALLEYS AND EXPOSED RIDGE TOPS
DECREASES BY THIS EVENING AS WILL THE THREAT FOR LOCALIZED
CONVECTIVE WIND GUSTS AND ISOLATED INSTANCES OF SMALL HAIL ALONG
THE THE LEADING EDGE OF SHOWERS AND THUNDERSTORMS. THIS WILL SHIFT
THE FOCUS TO SNOW AND WIND IMPACTS TONIGHT THROUGH FRIDAY
MORNING.
COLD NORTHWESTERLY FLOW ON THE BACKSIDE OF THE LOW PRESSURE
SYSTEM WILL QUICKLY RAMP UP THE SNOW AND SURFACE WINDS TONIGHT
INTO THURSDAY. NORTHERN AREAS WILL INITIALLY BE MOST IMPACTED,
ESPECIALLY OVER AND NEAR THE CENTRAL ISLAND RANGES WHERE THE
COMBINATION OF WINDS OVER 50 MPH AND HEAVY WET SNOW WET SNOW LOOK
TO CAUSE INSTANCES OF POWER OUTAGES AND TREE DAMAGE IN ADDITION TO
BRIEF WHITEOUT CONDITIONS. THE IMPACTS WILL BE SLIGHTLY LESS FOR
OTHER MOUNTAIN AREAS, THOUGH SNOW WILL BECOME MODERATE TO HEAVY
OVER AND NEAR THE MADISON AND GALLATIN BY THURSDAY MORNING.
UNCERTAINTY REMAINS HIGH IN TERMS OF LOWER ELEVATION IMPACTS,
ESPECIALLY OVER THE PLAINS AND IN THE GALLATIN VALLEY. IN THE
MOUNTAINS, THE UNCERTAINLY WAS PRIMARILY IN REGARDS TO BLIZZARD
CONDITIONS IN THE LITTLE BELTS AND THE NEARBY NORTHWESTERLY
FOOTHILLS, ESPECIALLY IN THE GEYSER AREA. THE WET TEXTURE OF THE
SNOW SHOULD PRECLUDE EXTENDED PERIODS OF WHITEOUT CONDITIONS,
THOUGH THERE LOOKS TO BE AT LEAST ISOLATED POWER OUTAGES AND TREE
DAMAGE. WINTER IMPACTS BEGIN TO EASE HEADING TOWARDS THE AFTERNOON
HOURS WITH THE SNOW BECOMING MORE SCATTERED IN NATURE AND THE
COMMENCEMENT OF DIURNAL HEATING.
THE WINTER STORM WATCHES FOR THE LITTLE BELT'S AND JUDITH BASIN
LOWER ELEVATIONS WERE UPGRADED TO WARNINGS. ALSO ADVISORIES WERE
ADDED FOR THE HELENA VALLEY AND CASCADE COUNTY. AN AREA OF
FRONTOGENESIS SETS UP BETWEEN HELENA AND GREAT FALLS AND MAY BRING
LOCALLY HEAVY SNOW TOTALS UP TO AROUND 4 TO 6 INCHES. NOTE THAT
THERE WILL BE A SHARP GRADIENT WITH SOME AREAS SEEING LITTLE TO NO
SNOW AT ALL. FOR EXAMPLE, THE NORTHERN AND WESTERN PORTIONS OF
CASCADE COUNTY LOOK TO SEE NEGLIGIBLE SNOWFALL WHILE THE SOUTH AND
EASTERN PORTIONS SEE TOTALS IN EXCESS OF AND ASSOCIATED IMPACTS.
SIMILARLY THE SOUTH AND WESTERN PORTIONS OF THE HELENA VALLEY WILL
SEE THE HIGHER TOTALS WITH LESSER AMOUNTS ELSEWHERE.
THERE WILL BE BE GUSTY TO STRONG WINDS THAT DEVELOP OVER MUCH OF
CENTRAL/NORTH-CENTRAL MT TONIGHT INTO THURSDAY DRIVEN BY H700/850
40 TO 60 KT NORTHWESTERLY FLOW. THE HIGH WIND WATCH WAS CONVERTED
TO A HIGH WIND WARNING AND AND WILL ROUGHLY ENCOMPASS THE SAME
AREA WITH THE EXCEPTION OF CHOUTEAU COUNTY. LOCATIONS ESPECIALLY
SUSCEPTIBLE TO SUSTAINED WINDS ABOVE 40 MPH AND GUSTS OVER 60 MPH
WILL BE THE SOUTHEAST ASPECTS FOR THE SWEETGRASS HILL, BEAR'S PAW,
AND THE SNOWY MOUNTAINS. WITH WINDS LOOKING TO START A LITTLE
EARLIER, ESPECIALLY OVER THE SWEETGRASS HILLS, THE WARNING START
TIME WILL BE 9 PM THIS EVENING.
A SECONDARY WAVE MOVES THROUGH THURSDAY NIGHT INTO FRIDAY AND
DELIVERS ANOTHER ROUND OF SNOW, BUT WITH LESS WIND. THIS ONE WILL
MOSTLY IMPACT AREAS ALONG THE CONTINENTAL DIVIDE AND SOUTHWEST MT.
EVEN THOUGH THE EXPECTATIONS FOR A CLOSED CIRCULATION OVER THE
SOUTHWEST HAS FALLEN THROUGH, UPPER LEVEL TEMPERATURES WILL BE
MUCH COLDER ENSURING LOWER ELEVATION SNOW ACCUMULATION EFFICIENCY.
THE WINTER STORM WARNING FOR THE MADISON AND GALLATIN MOUNTAIN
ZONE WAS EXTENDED THROUGH NOON ON FRIDAY. NEARLY ALL LOWER
ELEVATIONS FOR THE SOUTHWEST WERE ASSIGNED WINTER WEATHER
ADVISORIES FOR THURSDAY NIGHT THROUGH FRIDAY MORNING TO COVER THE
LIGHT TO MODERATE IMPACTS, THIS INCLUDES THE HELENA AND BOZEMAN
AREAS. - RCG
AVIATION
23/00Z TAF PERIOD
FOR THE FIRST FEW HOURS OF THIS TAF PERIOD THERE WILL BE ISOLATED
SHOWERS AND THUNDERSTORMS AROUND THE KCTB, KGTF, KHVR, AND KLWT
TERMINALS. THE PRIMARY HAZARDS WITH ANY THUNDERSTORM WILL BE FREQUENT
LIGHTNING AND GUSTY, ERRATIC WINDS. AT THE KGTF, KHVR, AND KLWT
TERMINALS THERE IS A 10 - 30% CHANCE FOR THUNDER BETWEEN NOW AND
23/06Z. A COLD FRONT WILL MOVE THROUGH THIS EVENING AND SHIFT WINDS
TO THE WEST/NORTHWEST. ASSOCIATED WITH THIS COLD FRONT THERE IS THE
POTENTIAL FOR A BRIEF HEAVY BURST OF PRECIPITATION THAT HAS THE
POTENTIAL TO REDUCE VISIBILITY BRIEFLY TO LOW-MVFR LEVELS. AT THE
KBZN, KEKS, AND KWYS TERMINALS BETWEEN 23/18Z AND 23/24Z THERE IS A
10 - 20% CHANCE FOR THUNDERSTORMS. DURING THE MAJORITY OF THIS TAF
PERIOD THERE WILL BE RAIN AND SNOW AROUND ALL OF THE TERMINALS.
DURING THE MAJORITY OF THIS TAF PERIOD THERE WILL BE MOUNTAIN
OBSCURATION ACROSS NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA.
BETWEEN 23/06Z AND 23/15Z THERE WILL BE ISOLATED INSTANCES OF LOW-
LEVEL WIND SHEAR AND MOUNTAIN WAVE TURBULENCE ACROSS SOUTHWESTERN
MONTANA. -IG
PRELIMINARY POINT TEMPS/POPS
GTF 29 41 26 39 / 100 70 40 50
CTB 26 40 22 35 / 90 30 20 40
HLN 29 39 24 40 / 100 90 60 70
BZN 31 42 21 40 / 100 90 70 70
WYS 24 37 17 37 / 100 90 80 80
DLN 32 43 25 40 / 90 80 70 60
HVR 30 44 25 38 / 80 30 10 50
LWT 28 37 21 35 / 100 60 20 50
TFX WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY UNTIL 6 PM MDT THURSDAY FOR EAST GLACIER
PARK REGION-NORTHERN HIGH PLAINS.
HIGH WIND WARNING FROM MIDNIGHT TONIGHT TO 6 PM MDT THURSDAY 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 UNTIL NOON MDT FRIDAY FOR BIG BELT,
BRIDGER AND CASTLE MOUNTAINS-ELKHORN AND BOULDER MOUNTAINS-GATES
OF THE MOUNTAINS-HELENA VALLEY-NORTHWEST BEAVERHEAD COUNTY-RUBY
MOUNTAINS AND SOUTHERN BEAVERHEAD MOUNTAINS-SOUTHERN ROCKY
MOUNTAIN FRONT-UPPER BLACKFOOT AND MACDONALD PASS.
WINTER STORM WARNING UNTIL 6 PM MDT THURSDAY 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 UNTIL NOON MDT FRIDAY FOR GALLATIN AND
MADISON COUNTY MOUNTAINS AND CENTENNIAL MOUNTAINS.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO NOON MDT
THURSDAY FOR CASCADE COUNTY BELOW 5000FT.
WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 PM MDT THURSDAY
FOR JUDITH BASIN COUNTY AND JUDITH GAP.
WINTER WEATHER ADVISORY FROM 6 PM THURSDAY TO NOON MDT FRIDAY
FOR BEAVERHEAD AND WESTERN MADISON BELOW 6000FT-CANYON FERRY
AREA-GALLATIN VALLEY-MADISON RIVER VALLEY-MISSOURI HEADWATERS.
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