020
FXUS65 KTFX 091100
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
500 AM MDT FRI OCT 9 2026
AVIATION SECTION UPDATED.
KEY MESSAGES
- ONE LAST DAY OF WARM, BREEZY, AND DRY CONDITIONS WILL BRING
ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS TODAY.
- A WEATHER SYSTEM SATURDAY THROUGH MONDAY WILL BRING A BIG DROP
IN TEMPERATURES ALONG WITH MODERATE TO HEAVY WET MOUNTAIN SNOW
AND LOWER ELEVATION RAIN/SNOW.
- COOLER AND WETTER CONDITIONS LOOK TO CONTINUE INTO MID NEXT WEEK.
DISCUSSION
/ISSUED 1207 AM MDT FRI OCT 9 2026/
- METEOROLOGICAL OVERVIEW:
THE NEXT INCOMING TROUGH COMING DOWN FROM CANADA WILL BRING AN
INCREASE IN WINDS ALOFT TODAY. THESE STRONGER WINDS ALOFT WILL
MIX DOWN TO THE SURFACE FROM DAY TIME VERTICAL MIXING. THE
COMBINATION OF THE WARM, BREEZY, AND DRY CONDITONS WILL BRING
ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS TO THE REGION.
TEMPERATURES ARE ALSO EXPECTED TO PEAK TODAY, WITH NUMEROUS LOWER
ELEVATION LOCATIONS REACHING INTO THE 80S.
SATURDAY, AN ELONGATED TROUGH COMING IN FROM CANADA WILL BRING A
MULTI-DAY WEATHER SYSTEM THROUGH MONTANA. A COLD FRONT PASSING
FROM NORTH TO SOUTH SATURDAY MORNING BRING THE FIRST RUSH OF
COOLER AIR TO THE REGION ALONG WITH MOUNTAIN SNOW AND LOWER
ELEVATION RAIN/SNOW. LEE TROUGHING WITH NORTHERLY COLD AIR
ADVECTION CONTINUES BEHIND THE FRONT, AND TRANSITIONS RAIN TO SNOW
AT LOWER ELEVATIONS BY SATURDAY EVENING. MEANWHILE THE FRONT
PROGRESSION SLOWS DOWN HEADING INTO SOUTHWEST MT, WHICH DELAYS THE
SWITCH OVER THE SNOW LATER THAN NORTH-CENTRAL MT. STRONG
CONVERGENCE AND FRONTOGENESIS ALSO OCCURS ALONG THIS FRONT AS IT
HEAD INTO NORTH-CENTRAL/CENTRAL MT, WHICH CAN DEVELOP MODERATE TO
HEAVY SNOW BANDING. NORTHERLY FLOW IN NORTH-CENTRAL MT WILL ALLOW
FOR ENHANCED SNOWFALL FOR NORTHERLY UPSLOPE AREAS OF THE LITTLE
BELTS/CENTRAL CONTINENTAL DIVIDE. TEMPERATURES DON'T LOOK TO WARM
UP MUCH HEADING INTO SUNDAY. INCREASING MOISTURE FROM THE
REMNANT SOUTHWEST TROPICAL STORM SYSTEM WILL CONTINUE TO FEED
MOISTURE INTO THIS STORM SYSTEM SUNDAY INTO MONDAY BEFORE EXITING
LATER IN THE DAY MONDAY.
BEHIND THIS SYSTEM, ANOTHER QUICK MOVING TROUGH LOOKS TO SWING
THROUGH WEDNESDAY INTO THURSDAY, WHICH WILL KEEP THE COOLER
TEMPERATURES AND CHANCES OF PRECIPITATION. HOWEVER, DETAILS WITH
THIS WILL BE HEAVILY DEPENDENT ON WHAT HAPPENS THIS
WEEKEND/MONDAY.
- FORECAST CONFIDENCE & SCENARIOS:
EVEN THOUGH WE ARE CLOSER IN TIME TO THIS NEXT WEATHER SYSTEM, THERE
REMAINS SOME UNCERTAINTY IN THE PROGRESSION OF THIS SYSTEM. THIS
IS DUE TO THE REMNANT OF THE TROPICAL SYSTEM RACHEL LIFTING NORTH
FROM THE SOUTHWEST U.S. AND INTO THE ROCKIES. THE FIRST
UNCERTAINTY IS THE COLD FRONT TIMING SATURDAY. SOME RECENT TRENDS
SLOW DOWN THE FRONT PROGRESSION LATER INTO THE AFTERNOON SATURDAY
ACROSS NORTH-CENTRAL MT WHICH WILL BRING A SLOWER TRANSITION TO
RAIN TO SNOW. SOME SOLUTIONS HAVE THIS EARLIER COLD FRONT TIMING
SATURDAY MORNING, WHICH BRING A QUICKER TRANSITION TO RAIN TO
SNOW AS TEMPERATURES WILL STRUGGLE TO HEAT UP WITH DIURNAL
DAYTIME HEATING. ANOTHER FACTOR IS IF ANY MODERATE TO HEAVY SNOW
BANDING CAN DYNAMICALLY COOL THE ATMOSPHERE QUICKER, LEADING TO A
QUICKER RAIN TO SNOW TRANSITION.
THE SECOND UNCERTAINTY IS WHERE THE BETTER CONVERGENCE AND
FRONTOGENESIS ENHANCED SNOW BANDING SETS UP. MODELS WERE TRENDING
TOWARDS CENTRAL/NORTH-CENTRAL MT, BUT SOME RECENT RUNS HAVE THAT
COLD FRONT AND SURFACE LOW STALLING BY THE MT AND ID BORDER. AS A
RESULT, THERE ALSO COULD BE MODERATE TO HEAVY SNOWFALL IN
SOUTHWEST MT SUNDAY INTO MONDAY. FOR CENTRAL/NORTH-CENTRAL MT,
ANY MODERATE TO HEAVIER SNOW BANDING CAN CRASH SURFACE/ROAD
TEMPERATURES, LEADING TO QUICKER ACCUMULATIONS. PROBABILITIES FOR
6" OF SNOW ALONG THE MONTANA HIGHWAY 200 CORRIDOR AND NORTHERLY
UPSLOPE AREAS OF CASCADE AND JUDITH BASIN COUNTIES RUN 50%
CHANCES. HOWEVER, THE CONCERNS OF THESE SNOW BANDS DEVELOPING GAVE
THE NUDGES TO EXPAND THE WINTER STORM WATCHES INTO THOSE AREAS
AND THE MEAGHER COUNTY VALLEY. THAT FRONT STALLING OUT NEAR THE
MT/ID BORDER COMBINED WITH THE WARM, MOIST TROPICAL AIRMASS
OVERRIDING THE BOUNDARY MAY ALSO BRING CONCERNS FOR A WINTRY MIX
ALONG THE STATE BORDER.
THE MAIN IMPACTS FROM THIS WEATHER SYSTEM WILL BE WET SNOW
WEIGHING DOWN POWER LINES AND TREES, LEADING TO POWER OUTAGES AND
DAMAGED TREES. TEMPERATURES DROPPING INTO THE 20S SUNDAY MORNING
WILL ALLOW FOR WET PAVEMENTS TO FREEZE AND BECOME SLIPPERY. COLDER
TEMPERATURES WILL ALSO IMPACT ANY OUTDOOR RECREATION IN THE
MOUNTAINS/BACK COUNTRY AND TRAVEL OVER MOUNTAIN PASSES WILL BE
IMPACTED BY HEAVY, WET SNOW. -WILSON
AVIATION
09/12Z TAF PERIOD.
THE INITIAL CONCERN THIS TAF PERIOD WILL BE FOR BREEZY WINDS
DEVELOPING THROUGH THE MORNING AND LASTING THROUGH EARLY EVENING.
ATTENTION THEN TURNS TO A CANADIAN COLD FRONT MOVING SOUTHWARD
ACROSS THE REGION LATE TONIGHT. A WIND SHIFT TO A MORE NORTHERLY
DIRECTION WILL ACCOMPANY THIS FRONT, ALONG WITH LOW CEILINGS.
MOUNTAINS BECOME INCREASINGLY OBSCURED THROUGH THE NIGHT TONIGHT. -AM
FIRE WEATHER
A RED FLAG WARNING HAS BEEN ISSUED FOR PORTIONS OF NORTH CENTRAL
AND SOUTHWEST MT FOR FRIDAY BECAUSE OF LOW HUMIDITY, GUSTY WINDS
AND WARM TEMPERATURES. A COLD FRONT WILL MOVE SOUTHWARD THROUGH
THE CWA ON FRIDAY NIGHT, WHICH WILL BRING IN COOLER AIR AND HIGHER
HUMIDITY. BRUSDA
PRELIMINARY POINT TEMPS/POPS
GTF 81 43 51 29 / 0 0 90 100
CTB 72 33 44 24 / 0 10 50 100
HLN 82 43 54 28 / 0 0 80 100
BZN 82 43 62 28 / 0 30 90 100
WYS 70 36 58 30 / 0 0 80 100
DLN 81 45 67 28 / 0 20 70 100
HVR 84 36 54 26 / 0 10 40 90
LWT 83 42 55 27 / 0 20 70 100
TFX WATCHES/WARNINGS/ADVISORIES
WINTER STORM WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY
AFTERNOON FOR GATES OF THE MOUNTAINS-SOUTHERN HIGH PLAINS-
SOUTHERN ROCKY MOUNTAIN FRONT-UPPER BLACKFOOT AND MACDONALD PASS.
WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY
AFTERNOON FOR CASCADE COUNTY BELOW 5000FT-ELKHORN AND BOULDER
MOUNTAINS-HELENA VALLEY-JUDITH BASIN COUNTY AND JUDITH GAP-
LITTLE BELT AND HIGHWOOD MOUNTAINS-MEAGHER COUNTY VALLEYS.
RED FLAG WARNING FROM NOON TODAY TO 9 PM MDT THIS EVENING FOR
CENTRAL AND EASTERN LEWIS AND CLARK NATIONAL FOREST AREAS-HELENA
AND TOWNSEND RANGER DISTRICTS OF THE HELENA NATIONAL FOREST.
WINTER STORM WATCH FROM SATURDAY EVENING THROUGH LATE SUNDAY
NIGHT FOR BIG BELT, BRIDGER AND CASTLE MOUNTAINS-GALLATIN AND
MADISON COUNTY MOUNTAINS AND CENTENNIAL MOUNTAINS.
HTTP://WWW.WEATHER.GOV/GREATFALLS
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