902
FXUS65 KTFX 141812
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1212 PM MDT SUN SEP 14 2025
AVIATION SECTION UPDATED.
KEY MESSAGES
- MILD TODAY, WITH SHOWERS AND THUNDERSTORMS MOSTLY LIMITED TO THE
CONTINENTAL DIVIDE.
- TEMPERATURES TREND AROUND TEN DEGREES COOLER IN MOST AREAS FOR
MONDAY AS A PERIOD OF RAIN MOVES ACROSS THE REGION.
- TRENDING WARMER AND DRIER FOR WEDNESDAY AND MOST OF THURSDAY.
UPDATE
/ISSUED 823 AM MDT SUN SEP 14 2025/
TODAY IT WILL BE WARM WITH SHOWERS AND THUNDERSTORMS MOVING INTO
SOUTHWESTERN MONTANA LATE THIS AFTERNOON THROUGH THIS EVENING.
FOR THE UPDATE, POPS ACROSS SOUTHWESTERN MONTANA WERE ADJUSTED
LATE THIS AFTERNOON THROUGH THIS EVENING TO BETTER REFLECT THE
LATEST HI-RES MODEL GUIDANCE. THE REST OF THE FORECAST IS ON
TRACK. -IG
DISCUSSION
/ISSUED 823 AM MDT SUN SEP 14 2025/
- METEOROLOGICAL OVERVIEW:
BROAD TROUGHING IS IN PLACE ACROSS THE INTERIOR WESTERN CONUS, WITH
SLOW MOVING EMBEDDED WAVES JUST NORTH OF THE REGION IN CANADA AS
WELL AS ACROSS WY/CO. WHILE BOTH WAVES ARE AT LEAST RELATIVELY CLOSE
BY, A QUICKER MOVING, MORE ROBUST WAVE MOVING ONSHORE ACROSS THE
PACIFIC NORTHWEST WILL BE THE MAIN DRIVER OF WEATHER TODAY. THE
ARRIVAL OF THE WAVE (MAINLY LATE EVENING INTO TONIGHT) IS NOT TIMED
WELL WITH DIURNAL HEATING, SO DAYTIME SHOWER AND THUNDERSTORM
COVERAGE LOOKS RELATIVELY MINIMAL. THERE CERTAINLY WILL STILL BE
SHOWERS AND THUNDERSTORMS AROUND HOWEVER, MOST FAVORED ALONG THE
CONTINENTAL DIVIDE LATE AFTERNOON AND INTO EVENING.
AS THE MAIN PORTION OF THE WAVE APPROACHES TONIGHT, THE COMBINATION
OF FORCING AND SUFFICIENT ELEVATED INSTABILITY WILL RESULT IN A
PERIOD OF SHOWERS AND THUNDERSTORMS, MOST FAVORED ACROSS SOUTHWEST
MONTANA.
THE WAVE SLOWS DOWN/STALLS ACROSS THE REGION MONDAY INTO AT LEAST
TUESDAY MORNING, WHICH WILL KEEP OPPORTUNITIES FOR PRECIPITATION IN
PLACE ACROSS THE REGION UNTIL IT DEPARTS TUESDAY AFTERNOON OR
EVENING. TEMPERATURES MONDAY AND TUESDAY GENERALLY COOL AROUND 10
DEGREES OR SO (PLUS OR MINUS A BIT IN A FEW AREAS) COMPARED TO
SUNDAY.
A BRIEF PERIOD OF NARROW, HIGH AMPLITUDE RIDGING BUILDS IN FOR
WEDNESDAY AS THE REGION IS BETWEEN UPPER LEVEL TROUGHS. WEDNESDAY
INTO THURSDAY LOOKS DRY AS A RESULT, WITH TEMPERATURES REBOUNDING
BACK TO NEAR OR A TOUCH ABOVE AVERAGE.
CONFIDENCE IN THE EVOLUTION OF THE PATTERN DECREASES SIGNIFICANTLY
TOWARD FRIDAY AND THE WEEKEND. CONFIDENCE IS MODERATELY HIGH FOR
TROUGHING TO BE IN PLACE JUST OFF THE PACIFIC NW COAST FRIDAY,
THOUGH THERE ARE SIGNIFICANT DISCREPANCIES IN THE EVOLUTION OF THIS
TROUGHING (WHETHER IT SPLITS OR NOT, AS WELL AS ANY INTERACTIONS
WITH ADDITIONAL TROUGHING THAT SNEAKS UP THE CA COASTLINE). THE MAIN
TAKEAWAY AT THIS POINT FOR FRIDAY INTO THE WEEKEND WILL BE FOR AT
LEAST LOW-END OPPORTUNITIES FOR AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS, WITH TEMPERATURES IN THE VICINITY OF AVERAGE. -AM
- FORECAST CONFIDENCE & SCENARIOS:
THE FRIDAY INTO THE WEEKEND TIMEFRAME IS WHERE THE GREATEST
UNCERTAINTY LIES. THE DIFFERENCE BETWEEN REASONABLE LOW-END AND HIGH-
END (10TH TO 90TH PERCENTILE) HIGH TEMPERATURES FRIDAY AND SATURDAY
IS MORE THAN 20 DEGREES IN MANY LOCATIONS. WEAKER/NON-EXISTANT
TROUGHING WOULD FAVOR THE WARMER SOLUTION, WHILE A MORE ROBUST, NON
SPLITTING TROUGH WOULD FAVOR THE COOLER SCENARIO. -AM
AVIATION
14/18Z TAF PERIOD
WHILE VFR CONDITIONS ARE EXPECTED TO PREVAIL OVER THE NEXT 24
HOURS, EXPECT CLOUDS TO INCREASE AND LOWER FROM SOUTHWEST TO
NORTHEAST THIS AFTERNOON AS OUR NEXT WEATHER SYSTEM PUSHES INTO
THE AREA. AS WE GET PAST 0Z, SHRA AND A FEW EMBEDDED TSRA WILL
START PUSHING IN FROM THE WEST, BRINGING LOWERED CEILINGS, BUT
VISIBILITY SHOULD GENERALLY REMAIN OVER 6SM. HOWEVER, WATCH FOR
MOUNTAIN OBSCURATION, EVEN IF JUST MOUNTAIN PEAKS. LUDWIG
PRELIMINARY POINT TEMPS/POPS
GTF 82 52 70 53 / 0 20 40 60
CTB 79 52 67 48 / 10 20 50 50
HLN 80 51 67 50 / 10 50 60 40
BZN 79 45 65 44 / 10 30 60 30
WYS 68 35 57 32 / 10 30 70 20
DLN 74 42 61 40 / 20 60 60 20
HVR 84 53 75 53 / 0 10 20 50
LWT 78 50 69 49 / 0 20 50 60
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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