515
FXUS65 KTFX 110527
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1127 PM MDT MON MAR 10 2025
AVIATION SECTION UPDATED.
KEY MESSAGES
- WINDS CONTINUE TO DECREASE THIS AFTERNOON AND EVENING.
- SNOW BANDS MAY INCREASE ALONG AND NORTH OF THE LITTLE BELT
MOUNTAINS AND BRING LOCALIZED WINTER WEATHER IMPACTS TO THE
HIGHWAY 87 CORRIDOR BETWEEN GREAT FALLS AND LEWISTOWN THROUGH
EARLY THIS EVENING
- PERIODS OF LIGHT SNOW CONTINUE ALONG THE HIGHER TERRAIN OF
THE CONTINENTAL DIVIDE THROUGH WEDNESDAY.
- SOUTHERLY WINDS INCREASE AND BECOME STRONG AT TIMES OVER SOUTHWEST
MONTANA WEDNESDAY INTO THURSDAY, PARTICULARLY FOR THE NARROW
SOUTH TO NORTH ORIENTED VALLEYS.
- A PACIFIC TROUGH MOVES IN THURSDAY AND FRIDAY AND BRINGS THE
NEXT CHANCE FOR WIDESPREAD RAIN AND SNOW, WITH THE HIGHEST
CONFIDENCE FOR WINTER WEATHER IMPACTS OVER THE SOUTHWEST
MOUNTAINS.
UPDATE
/ISSUED 720 PM MDT MON MAR 10 2025/
SLIGHT ADJUSTMENTS WERE MADE TO THE WINDS, PRECIPITATION CHANCES,
AND TEMPERATURES BASED ON UPDATED MODEL GUIDANCE. BUT OTHERWISE NO
SIGNIFICANT CHANGES WERE NEEDED TO THE GOING FORECAST. LIGHT SNOW
IS EXPECTED TO CONTINUE ALONG THE HIGHER ELEVATIONS OF THE
NORTHERN ROCKIES THROUGH WEDNESDAY MORNING BUT AS OF NOW
SIGNIFICANT IMPACTS AT PASS LEVEL ARE NOT EXPECTED. -THOR
DISCUSSION
/ISSUED 720 PM MDT MON MAR 10 2025/
- METEOROLOGICAL OVERVIEW:
A COLD FRONTAL BOUNDARY WILL MAINTAIN SCATTERED RAIN/SNOW SHOWER
ACTIVITY OVER THE PLAINS THROUGH THE EARLY EVENING HOURS, WITH THE
MOST PERSISTENT SNOW STILL EXPECTED ALONG THE HIGHWAY 87 CORRIDOR
BETWEEN GREAT FALLS AND LEWISTOWN. TEMPERATURES BEHIND THE FRONT
ARE FALLING INTO THE 20S, BUT THE CENTRAL ISLAND RANGES WILL
PROVIDE A BARRIER AND PREVENT THE THESE COLDER TEMPERATURES FROM
ADVANCING MUCH BEYOND THESE MOUNTAINS. WINDS ARE ALSO DECREASING
BEHIND THE FRONT, WITH THE LAST OF HIGH WIND WARNING SINCE BEING
LIFTED.
MOIST WESTERLY FLOW WILL CONTINUE OVER THE NEXT COUPLE OF DAYS,
ESSENTIALLY MAINTAINING BREEZY CONDITIONS AND PERIODS OF MOSTLY
MOUNTAIN LIGHT SNOW. HOWEVER, TODAY'S COOL DOWN WILL BE TEMPORARY
WITH HIGHS REBOUNDING BACK ABOVE AVERAGE FOR TUESDAY AND
WEDNESDAY.
THE GENERAL FLOW ALOFT TURNS MORE SOUTHWESTERLY ON WEDNESDAY IN
ADVANCE OF THE APPROACHING PACIFIC TROUGH. THE PRIMARY IMPACT FROM
THIS WILL BE A SLIGHT INCREASE IN MOUNTAIN PRECIPITATION AND
GUSTY TO POTENTIALLY STRONG WINDS IN SOUTHWEST MONTANA.
THE SPLITTING PACIFIC TROUGH HEADS INTO THE INTERIOR WEST
THURSDAY AND FRIDAY AND BRINGS THE NEXT CHANCE FOR WIDESPREAD
PRECIPITATION. WHILE THERE HAS BEEN UNANIMOUS AGREEMENT WITH THE
MOST IMPACTFUL MOISTURE AND ENERGY DIVING SOUTHWARD INTO THE GREAT
BASIN AND SOUTHWESTERN CONUS, THERE WERE SOME MODEL ENSEMBLES
THAT MAINTAINED A FAVORABLE SETUP FOR SNOW AND COLDER AIR TO
ENVELOP THE NORTHERN ROCKIES. THIS HAS NOW SHIFTED TOWARD A WARMER
AND DRIER SOLUTION WITH MORE OF A WESTERLY FLOW FOR THE DURATION
OF THE TROUGH PASSAGE. NOW THERE IS HIGHER CONFIDENCE THAT MOST OF
THE WINTER WEATHER IMPACTS WILL BE OVER THE HIGHER TERRAIN OF THE
SOUTHWEST. ENSEMBLES ALSO FAVOR THE GENERAL UNSETTLED WEATHER
PATTERN TO CONTINUE INTO THE WEEKEND. - RCG
- FORECAST CONFIDENCE & SCENARIOS:
THIS AFTERNOON'S SNOW IN THE LITTLE BELTS AND ALONG THE HIGHWAY
87 CORRIDOR BETWEEN GREAT FALLS AND LEWISTOWN :
SNOW SHOWERS WILL CONTINUE IN THIS AREA THROUGH THE EVENING
HOURS. HIRES GUIDANCE GENERAL FAVORS ACCUMULATIONS AROUND 1 INCH
OR LESS; HOWEVER, THE NORTHWESTERLY UPSLOPE MAY RESULT IN
LOCALIZED AREAS SEEING AMOUNTS IN THE 1 TO 3 INCH RANGE. SOME
WINTER WEATHER IMPACTS ARE ANTICIPATED LATER THIS AFTERNOON AS
TEMPERATURES DROP BELOW FREEZING. THE SNOW DIMINISHES AND ENDS
EARLY THIS EVENING.
MID- WEEK STRONG WIND POTENTIAL IN SOUTHWEST MONTANA :
THE INCREASED SOUTHWESTERLY FLOW ALOFT ON WEDNESDAY AND THURSDAY
WILL RESULT IN GUSTY TO AT TIMES STRONG SOUTHERLY SURFACE WINDS.
THE NARROW SOUTH TO NORTH ORIENTED VALLEYS AND THE HIGHER MOUNTAIN
PEAKS WILL BE MOST LIKELY TO SEE THE STRONGER WINDS.
PROBABILITIES IN THESE AREAS ARE RUNNING AROUND 50 TO 70% FOR
SUSTAINED WINDS IN EXCESS OF 40 MPH/GUSTS 55 MPH LATE WEDNESDAY
THROUGH EARLY THURSDAY.
ACCUMULATING SNOW POTENTIAL THURSDAY AND FRIDAY :
WITH CONFIDENCE SHIFTING A WARMER AND DRIER SOLUTION,
PROBABILISTIC GUIDANCE NOW FAVORS THE GALLATIN AND MADISON RANGES
FOR THE GREATEST AMOUNTS OF SNOW AND OVERALL IMPACTS. CURRENTLY,
THERE IS A 60 TO 80% CHANCE FOR SNOWFALL AMOUNTS EXCEEDING 4
INCHES. - RCG
AVIATION
11/06Z TAF PERIOD
VFR CONDITIONS WILL PREVAIL DURING ALL OF THIS TAF PERIOD AT ALL
TERMINALS. WINDS WILL BE LIGHT DURING THE BEGINNING OF THIS
TERMINAL, INCREASE IN THE MIDDLE, AND BE LIGHT AT THE END OF THIS
TAF PERIOD ACROSS ALL TERMINALS EXCEPT FOR THE KEKS AND KHLN
TERMINALS. MID-LEVEL CLOUDS WILL BE AROUND ALL TERMINALS EXCEPT
FOR THE KHVR TERMINAL DURING AT LEAST A PORTION OF THIS TAF
PERIOD. AT THE KLWT TERMINAL THERE IS A 10 - 20% CHANCE FOR RAIN
BETWEEN 11/12Z AND 11/16Z. -IG
REFER TO WEATHER.GOV/ZLC FOR MORE DETAILED REGIONAL AVIATION
WEATHER AND HAZARD INFORMATION.
PRELIMINARY POINT TEMPS/POPS
GTF 29 53 36 59 / 10 10 0 10
CTB 24 47 31 53 / 0 0 0 10
HLN 32 53 32 57 / 10 10 0 10
BZN 27 51 28 54 / 10 0 0 10
WYS 18 43 19 44 / 0 0 0 10
DLN 29 55 30 52 / 0 0 0 10
HVR 24 53 30 58 / 0 10 0 0
LWT 26 48 31 54 / 20 20 10 0
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
HTTP://WWW.WEATHER.GOV/GREATFALLS
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