910
FXUS65 KTFX 122012
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
212 PM MDT WED MAR 12 2025
KEY MESSAGES
- SNOW, HEAVY AT TIMES, EXPECTED ACROSS SOUTHWESTERN MONTANA ON
THURSDAY.
- NEXT NOTABLE SYSTEM ARRIVES SUNDAY AND MONDAY, BRINGING GUSTY
WINDS AND WIDESPREAD SNOWFALL TO THE AREA.
- QUIETER WEATHER EXPECTED FOR MID NEXT WEEK AS HIGH PRESSURE
SETS UP ACROSS THE AREA.
DISCUSSION
- METEOROLOGICAL OVERVIEW:
AN UPPER LEVEL RIDGE CURRENTLY SITUATED OVER THE NORTHERN ROCKIES
TODAY WILL GRADUALLY SHIFT EASTWARD AND GIVE WAY TO A SHORTWAVE
TROUGH THAT WILL PUSH ITS WAY THROUGH THE AREA ON THURSDAY. AS
THIS TROUGH PUSHES THROUGH, SOME HIGHER ELEVATION AREAS OF
SOUTHWESTERN MONTANA WILL SEE PERIODS OF MODERATE TO HEAVY
SNOWFALL, WITH SOME BURSTS OF MODERATE TO HEAVY SNOW POSSIBLE AT
THE LOWER ELEVATIONS NEAR AND SOUTH OF I-90. AFTER THIS SYSTEM
CLEARS THE AREA ON FRIDAY, STRONG WESTERLY FLOW WILL REMAIN ACROSS
THE AREA, WHICH WILL RESULT IN BREEZY AND CLOUDY CONDITIONS
ACROSS THE AREA WITH A FEW AREAS OF MOUNTAIN SNOW SHOWERS. ANOTHER
UPPER LEVEL TROUGH WILL PUSH THROUGH THE AREA SUNDAY AND MONDAY,
BRINGING ANOTHER ROUND OF INCREASED WIND AND WIDESPREAD SNOWFALL
TO NORTH CENTRAL AND SOUTHWESTERN MONTANA BEFORE UPPER LEVEL
RIDGING RETURNS FOR MID WEEK.
- FORECAST CONFIDENCE & SCENARIOS:
THURSDAY: AS THE UPPER LEVEL TROUGH PUSHES THROUGH THE AREA,
CONVECTIVE SNOW SHOWERS WILL DEVELOP ACROSS SOUTHWESTERN MONTANA.
GIVEN THE CONVECTIVE NATURE OF THESE SNOW SHOWERS, SNOWFALL
AMOUNTS WILL BE HIGHLY VARIABLE AND HARD TO PIN DOWN, BUT WE CAN
GET SOME IDEAS FOR THE IMPACTS WE EXPECT. FOR STARTERS, CONVECTIVE
SNOW SHOWERS LIKE THESE ARE NOTORIOUS FOR PRODUCING BRIEF BURSTS
OF HEAVIER SNOWFALL THAT CAN RAPIDLY REDUCE VISIBILITY AND QUICKLY
CHANGE ROAD CONDITIONS, AND WITH THE SETUP TOMORROW I EXPECT WE
WILL SEE THIS PLAY OUT ACROSS AREAS ALONG AND SOUTH OF I-90.
SNOWFALL ACCUMULATIONS ACROSS THE HIGHER ELEVATIONS WILL GENERALLY
REACH 6-8 INCHES OR SO, BUT AREAS THAT SEE TRAINING SNOW SHOWERS
COULD SEE LOCALLY HIGHER AMOUNTS, WITH THE POSSIBILITY OF SOME
AREAS SEEING OVER A FOOT, PARTICULARLY THE PEAKS AND HIGHER
PASSES.
SUNDAY THROUGH TUESDAY: OUR NEXT WEATHER SYSTEM WILL ARRIVE EARLY
NEXT WEEK, BRINGING GUSTY WINDS TO SOUTHWESTERN MONTANA, WHERE
THE NBM HAS BEEN GIVING A WIDESPREAD 50% CHANCE OF 55 MPH WIND
GUSTS AT SOME POINT ON SUNDAY. WHILE THIS DOES MEET THE TYPICAL
CRITERIA FOR A HIGH WIND WATCH, WE ARE A BIT FAR OUT FOR THAT TO
BE ISSUED, THOUGH WE WILL NEED TO WATCH THIS CLOSELY OVER THE NEXT
24 HOURS TO SEE IF THESE PROBABILITIES CONTINUE TO HOLD FAST.
SNOWFALL WILL BE THE OTHER PART OF THIS SYSTEM, WITH CURRENT
OPERATIONAL AND ENSEMBLE BLENDS SHOWING WIDESPREAD SNOWFALL WITH
SOME LOWER ELEVATION RAINFALL SPREADING OVER THE AREA SUNDAY NIGHT
AND MONDAY. THERE DOES REMAIN SOME UNCERTAINTY WITH HOW FAR NORTH
THE SNOWFALL WILL REACH, HOWEVER, AS MOST MODELS HAVE TENDED TO
KEEP THE PRECIPITATION OVER THE MOUNTAIN VALLEY REGION OF
SOUTHWESTERN MONTANA AND ALONG THE CONTINENTAL DIVIDE IN NORTHERN
MONTANA. HOWEVER, THERE IS AROUND 30-40% OF THE ENSEMBLE SPACE
THAT BRINGS THE PRECIPITATION A BIT FURTHER NORTH, WHICH COULD
BRING A LIGHT COATING OF SNOWFALL TO THE PLAINS. LUDWIG
AVIATION
12/18Z TAF PERIOD
A WESTERLY TO SOUTHWESTERLY FLOW ALOFT IS RESULTING IN
PRECIPITATION ALONG THE CONTINENTAL DIVIDE LATE THIS MORNING, BUT
IS STRUGGLING TO REACH AREAS FURTHER EASTWARD. THE PRIMARY CONCERN
THIS TAF PERIOD WILL BE FOR LOWERING CEILINGS HEADING INTO
TOMORROW, INITIALLY ACROSS SOUTHWEST MONTANA AND ALONG THE
CONTINENTAL DIVIDE. GUSTY SOUTHERLY TO SOUTHWESTERLY WINDS WILL
BE AROUND ACROSS SOUTHWEST MONTANA TODAY, PERSISTING INTO THE
OVERNIGHT IN NORTH-SOUTH ORIENTED VALLEYS, INCLUDING KEKS.
ALTHOUGH NOT WIDESPREAD, INSTANCES OF LOW-LEVEL WIND SHEAR WILL
BE AROUND TONIGHT AS SOUTHWEST MONTANA VALLEYS DECOUPLE. -AM
REFER TO WEATHER.GOV/ZLC FOR MORE DETAILED REGIONAL AVIATION
WEATHER AND HAZARD INFORMATION.
PRELIMINARY POINT TEMPS/POPS
GTF 58 37 57 30 / 10 10 20 20
CTB 51 29 52 23 / 10 0 10 0
HLN 56 36 52 26 / 0 10 60 30
BZN 53 32 50 21 / 0 0 60 80
WYS 44 28 41 15 / 0 50 80 90
DLN 53 32 47 21 / 0 10 80 60
HVR 55 29 58 24 / 0 10 20 20
LWT 54 34 55 26 / 0 10 40 70
TFX WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY FROM 6 AM THURSDAY TO 6 AM MDT FRIDAY
FOR GALLATIN AND MADISON COUNTY MOUNTAINS AND CENTENNIAL
MOUNTAINS.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT MDT
THURSDAY NIGHT FOR NORTHWEST BEAVERHEAD COUNTY.
HTTP://WWW.WEATHER.GOV/GREATFALLS
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