133
FXUS65 KTFX 101951
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
151 PM MDT MON AUG 10 2026
KEY MESSAGES
- IT WILL BE HOT, DRY, AND HAZY THROUGH TUESDAY.
- A BRIEF COOL DOWN IS EXPECTED WEDNESDAY THROUGH NEXT FRIDAY
WITH ISOLATED SHOWERS AND THUNDERSTORMS RETURNING TO THE AREA.
- THIS WEEKEND THERE WILL BE ISOLATED SHOWERS AND THUNDERSTORMS
WITH WARMER TEMPERATURES.
DISCUSSION
- METEOROLOGICAL OVERVIEW:
THIS AFTERNOON THERE IS AN UPPER-LEVEL RIDGE OVER NORTH-CENTRAL,
CENTRAL, AND SOUTHWESTERN MONTANA. THIS WILL KEEP WARM AND MOSTLY
DRY WEATHER FOR THE AREA ON MONDAY. ISOLATED SHOWERS HAVE THE
POTENTIAL TO SLIDE SOUTH FROM CANADA AND AFFECT THE HI-LINE THIS
AFTERNOON AND EVENING. ON TUESDAY THE UPPER-LEVEL RIDGE REMAINS
OVER NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN MONDAY. THIS WILL
WILL KEEP WARM AND MOSTLY DRY WEATHER FOR THE AREA ON TUESDAY.
ISOLATED SHOWERS HAVE THE POTENTIAL TO SLIDE SOUTH FROM CANADA AND
AFFECT THE HI-LINE TUESDAY AFTERNOON AND EVENING. ON WEDNESDAY
THE UPPER-LEVEL RIDGE REMAINS OVER NORTH-CENTRAL, CENTRAL, AND
SOUTHWESTERN MONTANA WITH AN UPPER-LEVEL TROUGH APPROACHING THE
AREA. THIS WILL BEGIN TO BRING COOLER AIR AND MONSOONAL MOISTURE
TO THE AREA ON WEDNESDAY. ON WEDNESDAY THERE WILL BE SHOWERS AND
THUNDERSTORMS ALONG THE HI-LINE.
THURSDAY THROUGH FRIDAY AN UPPER-LEVEL TROUGH MOVES OVER NORTH-
CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. THIS WILL BRING
SHOWERS AND THUNDERSTORMS AND COOLER TEMPERATURES (WELL-BELOW
SEASONAL AVERAGES) TO THE AREA THURSDAY THROUGH FRIDAY. SEE THE
FORECAST CONFIDENCE & SCENARIOS SECTION FOR DETAILS. THIS WEEKEND
AN UPPER-LEVEL RIDGE BUILDS BACK IN OVER NORTH-CENTRAL, CENTRAL,
AND SOUTHWESTERN MONTANA WITH SOUTHWEST FLOW ALOFT. THIS WILL
BRING DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS WITH
TEMPERATURES WARMING UP ON SATURDAY AND SUNDAY. -IG
- FORECAST CONFIDENCE & SCENARIOS:
THIS AFTERNOON AND TOMORROW AFTERNOON ACROSS NORTH-CENTRAL, CENTRAL,
AND SOUTHWESTERN MONTANA MINIMUM AFTERNOON HUMIDITY WILL BE NEAR
CRITICAL LEVELS. THIS COMBINED WITH WINDS THAT WILL BE AROUND 20
MPH WILL BRING ELEVATED FIRE WEATHER CONDITIONS TO THE AREA. THE
WIND DIRECTION WILL ALSO PERIODICALLY SHIFT OVER THE NEXT 24
HOURS. THE GREATEST RISK FOR ELEVATED TO NEAR CRITICAL FIRE
WEATHER CONDITIONS WILL BE IN SOUTHWESTERN MONTANA THIS AFTERNOON
AND TOMORROW AFTERNOON.
WEDNESDAY THROUGH FRIDAY THERE IS GOOD AGREEMENT BETWEEN ENSEMBLE
MEMBERS AND DETERMINISTIC MODELS IN THE TRACK OF THE UPPER-LEVEL
TROUGH. ON WEDNESDAY THERE IS A 20 - 35% CHANCE FOR THUNDERSTORMS
ACROSS NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. ON
THURSDAY THERE IS A 30 - 50% CHANCE FOR THUNDERSTORMS ACROSS
NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. ON FRIDAY THERE
IS A 35 - 55% CHANCE FOR THUNDERSTORMS ACROSS CENTRAL AND
SOUTHWESTERN MONTANA. WEDNESDAY THROUGH FRIDAY THERE IS A 50 -
80% CHANCE FOR ONE HALF INCH OF RAIN OR GREATER ACROSS NORTH-
CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA WITH THE HIGHEST
PROBABILITIES ALONG THE HI-LINE. WEDNESDAY THROUGH FRIDAY THERE IS
A 50 - 70% CHANCE FOR ONE INCH OF RAIN OR GREATER ALONG THE HI-
LINE AND ACROSS JUDITH BASIN AND FERGUS COUNTIES. ON THURSDAY AND
FRIDAY THERE IS GREATER THAN A 60% CHANCE FOR HIGH TEMPERATURES OF
70 DEGREES OR LOWER ACROSS THE PLAINS OF NORTH-CENTRAL MONTANA.
-IG
AVIATION
10/18Z TAF PERIOD
WILDFIRE SMOKE WILL REMAIN THE MAIN WEATHER CONCERN THROUGH THE
TAF PERIOD WITH IMPACTS TO SLANTWISE VISIBILITY EXPECTED FOR ALL
TERMINALS. MOUNTAINS/PASSES WILL BE OBSCURED ACROSS THE REGION AT
TIMES. THE HIGHEST PROBABILITY FOR SURFACE VISIBILITY IMPACTS WILL
BE ACROSS SOUTHWEST MONTANA, PARTICULARLY AT KBZN AND KEKS. THE
LATEST SMOKE MODELS HAVE A PUSH OF SMOKE ARRIVING THIS AFTERNOON
WHICH COULD EASILY REDUCE VISIBILITY INTO MVFR/IFR TERRITORY.
ISOLATED THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON ALONG THE
CANADIAN BORDER BUT CONFIDENCE IS NOT HIGH IN IMPACTS FOR KHVR.
SHOULD ANY THUNDERSTORM DEVELOP IN THE VICINITY THE MAIN CONCERNS
WILL BE LIGHTNING AND GUSTY, ERRATIC WINDS.
FOR KGTF: SURFACE WINDS WILL PICK UP THIS AFTERNOON OUT OF THE
WEST AND GRADUALLY SHIFT TO THE NORTHWEST AS THE DAY PROGRESSES.
OVERALL WIND SPEEDS ARE EXPECTED TO REMAIN UNDER 15KTS BUT AN
OCCASIONAL GUST UP TO 20KTS COULD CAUSE SOME ISSUES, ESPECIALLY
BETWEEN 10/23Z AND 11/03Z. CURRENTLY THE PROBABILITY OF EXCEEDING
THE CROSSWIND CRITERIA IS AROUND 30%. OTHERWISE THE MAIN CONCERN
WILL BE SMOKE IMPACTING SLANTWISE VISIBILITY THROUGH THE DAY.
-THOR
PRELIMINARY POINT TEMPS/POPS
GTF 54 86 54 77 / 0 0 0 0
CTB 50 79 49 67 / 0 0 40 50
HLN 54 89 54 80 / 0 0 0 20
BZN 52 90 52 85 / 0 0 10 10
WYS 42 85 45 79 / 0 0 0 10
DLN 50 88 52 83 / 0 0 0 10
HVR 53 86 52 78 / 20 0 20 40
LWT 52 83 51 76 / 0 0 0 30
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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