308
FXUS65 KTFX 150435
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1035 PM MDT SUN SEP 14 2025
AVIATION SECTION UPDATED.
KEY MESSAGES
- SHOWERS AND THUNDERSTORMS WILL AFFECT SOUTHWESTERN MONTANA THIS
AFTERNOON THROUGH THIS EVENING.
- TONIGHT THROUGH TUESDAY THERE WILL BE WIDESPREAD SHOWERS AND THUNDERSTORMS.
- IT WILL BE WARM TODAY WITH TEMPERATURES COOLING DOWN THROUGH
THE MIDDLE OF THE WEEK.
UPDATE
/ISSUED 831 PM MDT SUN SEP 14 2025/
MAIN CONCERN THIS EVENING IS THUNDERSTORMS MOVING WEST TO EAST
THROUGH THE CWA. ISOLATED WIND GUSTS AROUND 60 MPH HAVE OCCURRED A
FEW TIMES, THUS THE SEVERE THUNDERSTORM WARNINGS. THE POTENTIAL
FOR A FEW SEVERE STORMS WILL CONTINUE UNTIL ABOUT MIDNIGHT, WITH
THE HRRR PROGGING A FEW STRONG STORMS UNTIL THEN, BEFORE THE
AIRMASS COOLS A BIT. BRUSDA
DISCUSSION
/ISSUED 831 PM MDT SUN SEP 14 2025/
- METEOROLOGICAL OVERVIEW:
THIS AFTERNOON THERE IS A WEAK UPPER-LEVEL SHORTWAVE OVER NORTH-
CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA BEFORE AN UPPER-LEVEL
TROUGH ASSOCIATED WITH A SURFACE COLD FRONT BEGINS TO MOVE OVER THE
AREA THIS EVENING. UNTIL THIS EVENING ACROSS NORTH-CENTRAL, CENTRAL,
AND SOUTHWESTERN MONTANA IT WILL BE WARM AND MOSTLY DRY. LATE
THIS AFTERNOON THROUGH THIS EVENING ISOLATED SHOWERS AND
THUNDERSTORMS WILL AFFECT SOUTHWESTERN MONTANA. SHOWERS WILL
INCREASE IN COVERAGE ACROSS NORTH-CENTRAL, CENTRAL, AND
SOUTHWESTERN MONTANA TONIGHT. ON MONDAY THE UPPER-LEVEL TROUGH
REMAINS OVER THE AREA. THIS COMBINED WITH THE SURFACE COLD FRONT
WILL COOL TEMPERATURES DOWN TO SLIGHTLY BELOW SEASONAL AVERAGES
ON MONDAY. ON MONDAY THERE WILL BE WIDESPREAD SHOWERS ACROSS
NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. MONDAY
AFTERNOON AND EVENING THERE WILL ALSO BE ISOLATED THUNDERSTORMS
ACROSS THE AREA.
ON TUESDAY THE UPPER-LEVEL TROUGH REMAINS OVER NORTH-CENTRAL,
CENTRAL, AND SOUTHWESTERN MONTANA. THIS WILL BRING SHOWERS TO THE
AREA WITH ABOUT SEASONAL AVERAGES FOR TEMPERATURES. THE SHOWERS WILL
MOVE OUT OF NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA BY
TUESDAY EVENING. ON WEDNESDAY AN UPPER-LEVEL RIDGE BUILDS IN OVER
NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. THIS WILL BRING
DRY WEATHER WITH TEMPERATURES WARMING UP ACROSS THE AREA. ON
THURSDAY THE UPPER-LEVEL RIDGE REMAINS OVER NORTH-CENTRAL, CENTRAL
AND SOUTHWESTERN MONTANA WHICH WILL KEEP THE DRY AND WARM WEATHER
FOR THE AREA ON THURSDAY. FRIDAY THROUGH SATURDAY AN UPPER-LEVEL
TROUGH WILL MOVE OVER NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN
MONTANA WHICH WILL BRING COOLER TEMPERATURES AND PRECIPITATION
CHANCES TO THE AREA. -IG
- FORECAST CONFIDENCE & SCENARIOS:
ON MONDAY THERE IS A 15 - 30% CHANCE FOR THUNDERSTORMS ACROSS NORTH-
CENTRAL MONTANA AND A 25 - 45% CHANCE FOR THUNDERSTORMS IN
CENTRAL AND SOUTHWESTERN MONTANA WITH THE HIGHEST PROBABILITIES IN
SOUTHWESTERN MONTANA. ON TUESDAY THERE IS A 15 - 30% CHANCE FOR
THUNDERSTORMS IN JUDITH BASIN, FERGUS, MEAGHER, AND GALLATIN
COUNTIES. ON MONDAY THERE IS A 20 - 50% CHANCE FOR A QUARTER INCH
OF RAIN ACROSS NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA
ALONG AND SOUTH OF A CUT BANK TO LEWISTOWN LINE. ON TUESDAY THERE
IS A 20 - 50% CHANCE FOR A QUARTER INCH OF RAIN ACROSS NORTH-
CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA SOUTH OF THE HI-LINE
EAST OF I-15. -IG
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
15/06Z TAF PERIOD.
INITIAL CONCERN THIS TAF PERIOD WILL BE FOR GUSTY OUTFLOW WINDS,
MOSTLY ACROSS THE PLAINS OF NORTH-CENTRAL MONTANA. THESE WINDS
SHOULD SLOWLY SUBSIDE THROUGH 09Z OR SO. ATTENTION THEN TURNS TO
INTERMITTENT SHOWERS THROUGH THE REMAINDER OF THE TAF PERIOD, WITH A
FEW THUNDERSTORMS POSSIBLE IN THE AFTERNOON AND EARLY EVENING
MONDAY. -AM
PRELIMINARY POINT TEMPS/POPS
GTF 52 72 52 73 / 40 40 70 20
CTB 51 67 49 73 / 20 50 40 10
HLN 51 69 50 73 / 50 60 50 30
BZN 45 68 45 68 / 30 60 40 30
WYS 35 60 32 62 / 30 60 30 20
DLN 42 63 40 68 / 50 60 20 10
HVR 54 76 52 77 / 10 20 40 20
LWT 49 71 49 69 / 20 40 70 60
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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