627
FXUS65 KTFX 161134
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
534 AM MDT THU OCT 16 2025
AVIATION SECTION UPDATED.
KEY MESSAGES
- SCATTERED LIGHT RAIN SHOWERS AND MOUNTAIN SNOW CONTINUE
TODAY, MOSTLY FOR CENTRAL AND SOUTHWESTERN AREAS EAST OF I15.
- A QUICK MOVING TROUGH AND ATTENDANT COLD FRONT BRINGS BREEZY
TO WINDY CONDITIONS AND SCATTERED RAIN AND SNOW SHOWERS TONIGHT
THROUGH EARLY SATURDAY.
- MORE UNSETTLED CONDITIONS WITH PERIODS OF SHOWERS, MOUNTAIN
SNOW,AND OR BREEZY TO WINDY CONDITIONS ARE EXPECTED SUNDAY INTO
EARLY NEXT WEEK WHILE TEMPERATURES GENERALLY TREND NEAR
AVERAGE.
DISCUSSION
/ISSUED 338 AM MDT THU OCT 16 2025/
- METEOROLOGICAL OVERVIEW:
LINGERING SURFACE MOISTURE AND PARTIAL CLEARING SKIES HAVE
RESULTED IN PATCHY FOG DEVELOPMENT OVER PORTIONS OF CENTRAL AND
NORTH-CENTRAL MT DURING THE OVERNIGHT HOURS, WHICH WILL CONTINUE
THROUGH MID- TO LATE MORNING DEPENDING ON CLOUD COVER. AN
ELONGATED MID-LEVEL TROUGH CENTERED OVER THE GREAT BASIN WILL
CONTINUE TO TREK NORTHEAST INTO EASTERN MT BY THIS EVENING. THE
MAIN PRECIPITATION AREA WITH THIS SYSTEM HAS SHIFTED EAST OF THE
FORECAST AREA, ALTHOUGH THERE WILL BE SCATTERED SHOWER ACTIVITY
AND LIGHT MOUNTAIN SNOW THOUGH THIS AFTERNOON, ESPECIALLY OVER THE
MADISON AND GALLATIN MOUNTAIN RANGES.
A FAST MOVING TROUGH AND ATTENDANT COLD FRONT THEN QUICKLY DIVES
SOUTHEASTWARD OUT OF BC/AB AND BRINGS BREEZY TO WINDY CONDITIONS
AND SCATTERED RAIN/SNOW SHOWERS TONIGHT THROUGH EARLY SATURDAY.
WINDS WILL INCREASE ALONG THE ROCKY MOUNTAIN FRONT TONIGHT BEFORE
SPREADING EASTWARD ONTO THE PLAINS ON FRIDAY. THEN A QUICK ROUND
OF RAIN AND SNOW SHOWERS SWEEP THOUGH IN A NORTHWEST TO SOUTHEAST
FASHION FRIDAY EVENING AND NIGHT. H700 TEMPERATURES WILL BE COLD
ENOUGH TO LOWER SNOW LEVEL DOWN TO THE PLAINS/VALLEY FLOORS, BUT
ACCUMULATIONS LOOKS TO BE NEGLIGIBLE FOR MOST LOCATIONS.
TRANSIENT RIDGING PASSES THROUGH THE NORTHERN ROCKIES LATER
SATURDAY INTO SUNDAY FOR A BRIEF PERIOD OF MILD AND DRIER
CONDITIONS. ANOTHER PACIFIC TROUGH THEN BRINGS ANOTHER ROUND OF
WINDS, SHOWERS, AND MOUNTAIN SNOW LATER SUNDAY INTO EARLY NEXT
WEEK WHILE TEMPERATURES GENERALLY REMAIN NEAR AVERAGE. THE
PROGRESSIVE PATTERN CONTINUES FOR MUCH OF NEXT WEEK, BUT THERE A
DISCREPANCIES WITH THE RIDGE AND TROUGH PHASING AMONG ENSEMBLE
MEMBERS. - RCG
- FORECAST CONFIDENCE & SCENARIOS:
RAIN, MOSTLY MOUNTAIN SNOW, AND WINDS THROUGH EARLY NEXT WEEK...
PRECIPITATION ASSOCIATED WITH THE TROUGH MOVING OUT OF THE GREAT
BASIN IS EXPECTED TO LARGELY STAY EAST OF THE FORECAST AREA. THERE
WILL BE SOME SCATTERED SHOWERS THIS AFTERNOON OVER THE PLAINS
EAST OF GREAT FALLS TO HAVRE LINE. OTHERWISE, THE BULK OF THE
SHOWERS AND MOUNTAIN SNOW IS EXPECTED OVER AND NEAR THE MADISON
AND GALLATIN RANGES WHERE LIGHT ACCUMULATING SNOW MAY POSE MINOR
IMPACTS TO THOSE WITH MOUNTAIN OUTDOOR INTERESTS.
THE NEXT OPPORTUNITY FOR RAIN AND SNOW SHOWERS WILL MOVE THROUGH
THE REGION FROM NORTHWEST TO SOUTHEAST LATE FRIDAY AFTERNOON
THROUGH EARLY SATURDAY. FRONTOGENESIS SUPPORTED BY H700
TEMPERATURES AROUND -10C WILL DROP SNOW LEVELS DOWN TO THE PLAINS
AND VALLEY FLOORS,ESPECIALLY FOR NORTHERN AREAS; HOWEVER, THIS
SYSTEM IS RATHER MOISTURE STARVED AND ITS FAST MOTION WILL LIMIT
PRECIPITATION RESIDENCE TIME. NBM SNOWFALL EXCEEDANCE
PROBABILITIES ARE NOT VERY IMPRESSIVE EITHER, WITH MOUNTAIN AREAS
SEEING A 30 TO 50% CHANCE FOR ACCUMULATIONS OVER 1 INCH. THE
PRIMARY IMPACT HERE WILL BE SHORT TERM VISIBILITY REDUCTIONS FROM
LOCALIZED HEAVIER SNOW BURSTS.
THE NEXT TROUGH ARRIVES LATER SUNDAY INTO MONDAY, WITH MOUNTAIN
AREAS AND THE CENTRAL AND SOUTHWESTERN VALLEYS SEEING THE BEST
PRECIPITATION POTENTIAL. MOST OF THESE AREAS HAVE 30 TO 50% CHANCE
FOR A QUARTER INCH OF RAIN OR LIQUID EQUIVALENT PRECIPITATION.
THESE PROBABILITIES DROP TO NEAR ZERO OVER THE PLAINS DUE TO
DOWNSLOPING WINDS. IMPACTFUL SNOW ACCUMULATIONS IN THE MOUNTAINS
LOOK TO MOSTLY STAY ABOVE PASS LEVEL WHERE THERE IS AROUND A 50%
CHANCE FOR SNOWFALL OVER 3 INCHES.
PERIODS OF WINDIER CONDITIONS ARE EXPECTED THURSDAY NIGHT THROUGH
SUNDAY. MOUNTAIN WAVE ACTIVITY WILL INCREASE WINDS ALONG THE
ROCKY MOUNTAIN FRONT TONIGHT BEFORE DEEP LAYER MIXING MOVES THESE
WINDS ONTO THE PLAINS ON FRIDAY. PROBABILITIES FOR WIND GUSTS OVER
50 MPH ARE RUNNING IN THE 70 TO 90% RANGE ALONG THE ROCKY
MOUNTAIN FRONT AND AROUND 50% IN THE EASTERN GLACIER/WESTERN TOOLE
ZONE. THE NORTH- CENTRAL PLAINS WILL GENERALLY SEE GUSTS IN THE
30 TO 50 MPH RANGE ON FRIDAY, STRONGEST SOUTHEAST OF A GREAT FALLS
TO HAVRE LINE.
ALL AREAS LOOK TO SEE INCREASED WINDS SATURDAY NIGHT INTO SUNDAY.
ONCE AGAIN MOUNTAIN WAVE ACTIVITY WILL BE RESPONSIBLE FOR
STRONGER WINDS SATURDAY NIGHT, NOT ONLY FOR LOCATIONS ALONG THE
ROCKY MOUNTAIN FRONT, BUT ALSO FOR THE EAST/NORTHEAST SLOPES OF
THE CENTRAL RANGES. BY SUNDAY, THE WINDY CONDITIONS MOVE EAST ONTO
THE PLAINS AND EVEN OVER THE CENTRAL AND SOUTHWEST VALLEYS. THE
HIGHEST PROBABILITIES FOR GUSTS OVER 50 MPH WILL BE ALONG THE
ROCKY MOUNTAIN FRONT AND OVER SOUTH TO NORTH ORIENTED SOUTHWEST
VALLEYS. - RCG
AVIATION
16/12Z TAF PERIOD
SCATTERED AREAS OF RAIN/SNOW, PATCHY FOG, AND LOW STRATUS WILL
MAINTAIN WIDESPREAD MVFR/IFR/LIFR CONDITIONS THROUGH 16/19Z,
MOSTLY FOR LOCATIONS EAST OF A KDLN TO KHVR LINE. FLIGHT
CATEGORIES BEGIN TO TREND TOWARDS VFR THIS AFTERNOON INTO
TONIGHT. WESTERLY WINDS BECOME STRONG AND GUSTY ALONG THE ROCKY
MOUNTAIN FRONT AND NEARBY PLAINS TONIGHT AS MOUNTAIN WAVE
TURBULENCE INCREASES. - RCG
PRELIMINARY POINT TEMPS/POPS
GTF 56 38 59 29 / 10 0 10 40
CTB 59 37 53 27 / 0 0 40 20
HLN 56 34 60 32 / 10 0 10 40
BZN 50 28 59 27 / 50 10 0 40
WYS 44 24 45 20 / 70 20 0 40
DLN 51 29 59 27 / 20 0 0 10
HVR 57 34 57 27 / 20 0 20 20
LWT 47 32 57 28 / 50 10 10 60
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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