635
FXUS65 KTFX 092257
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
457 PM MDT SUN AUG 9 2026
AVIATION SECTION UPDATED.
KEY MESSAGES
- IT WILL BE HOT, DRY, AND HAZY THROUGH TUESDAY.
- A BRIEF COOL DOWN IS EXPECTED WEDNESDAY THROUGH NEXT FRIDAY
WITH ISOLATED SHOWERS RETURNING.
- NEXT WEEKEND THERE WILL BE ISOLATED SHOWERS AND THUNDERSTORMS
WITH WARMER TEMPERATURES.
DISCUSSION
/ISSUED 257 PM MDT SUN AUG 9 2026/
- METEOROLOGICAL OVERVIEW:
THIS AFTERNOON THERE IS AN UPPER-LEVEL RIDGE OVER NORTH-CENTRAL,
CENTRAL, AND SOUTHWESTERN MONTANA. THIS WILL BRING SLIGHTLY COOLER
TEMPERATURES TO THE AREA WITH DRY WEATHER. ON MONDAY AND TUESDAY
THE UPPER-LEVEL RIDGE REMAINS OVER NORTH-CENTRAL, CENTRAL, AND
SOUTHWESTERN MONTANA. THIS WILL WILL KEEP WARM AND DRY WEATHER FOR
THE AREA ON MONDAY AND TUESDAY. SMOKE FROM REGIONAL WILDFIRES
WILL BE AROUND THROUGHOUT THE NEXT FEW DAYS. 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.
THURSDAY THROUGH FRIDAY AN UPPER-LEVEL TROUGH MOVES OVER NORTH-
CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. THIS WILL BRING
PRECIPITATION CHANCES AND COOLER TEMPERATURES (WELL-BELOW SEASONAL
AVERAGES) TO THE AREA THURSDAY THROUGH FRIDAY. SEE THE FORECAST
CONFIDENCE & SCENARIOS SECTION FOR DETAILS. NEXT 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 NEXT SUNDAY. -IG
- FORECAST CONFIDENCE & SCENARIOS:
TODAY AND TOMORROW ACROSS NORTH-CENTRAL, CENTRAL, AND
SOUTHWESTERN MONTANA MINIMUM AFTERNOON HUMIDITY WILL BE NEAR
CRITICAL LEVELS. THIS COMBINED WIND GUSTS THAT WILL PEAK AT AROUND
20 MPH WILL BRING ELEVATED FIRE WEATHER CONDITIONS TO THE AREA.
THE WIND DIRECTION WILL ALSO PERIODICALLY SHIFT OVER THE NEXT 24
TO 48 HOURS. THE GREATEST RISK FOR ELEVATED TO NEAR CRITICAL FIRE
WEATHER CONDITIONS IS IN SOUTHWESTERN MONTANA THIS AFTERNOON
THROUGH TUESDAY.
WEDNESDAY THROUGH FRIDAY THERE ARE DIFFERENCES IN THE TRACK OF
THE UPPER-LEVEL TROUGH IN ENSEMBLES AND DETERMINISTIC MODELS. ON
THURSDAY AND FRIDAY ONE CLUSTER HAS ZONAL FLOW OVER MONTANA WHILE
THE OTHER THREE HAVE AN UPPER-LEVEL TROUGH APPROACHING MONTANA. IN
THE ZONAL FLOW SCENARIO TEMPERATURES WILL REMAIN AT ABOUT
SEASONAL AVERAGES WITH A FEW ISOLATED SHOWERS. IN THE UPPER-LEVEL
TROUGH SCENARIO TEMPERATURES WILL COOL OFF TO AT LEAST BELOW
SEASONAL AVERAGES WITH MORE WIDESPREAD SHOWERS. ANOTHER AREA OF
UNCERTAINTY WITH THIS TROUGH IS HOW FAR SOUTH IT TRACKS. THE
FURTHER SOUTH IT TRACKS, THE FURTHER SOUTH THE PRECIPITATION WILL
BE AND IT WILL RESULT IN COOLER TEMPERATURES THAN A MORE NORTHERLY
TRACK.
ON WEDNESDAY THERE IS A 30 - 45% CHANCE FOR THUNDERSTORMS ACROSS
THE HI-LINE AND A 20 - 30% CHANCE FOR THUNDERSTORMS ACROSS THE
REST OF NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. ON
THURSDAY THERE IS A 20 - 40% CHANCE FOR THUNDERSTORMS ACROSS MOST
OF NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. ON FRIDAY
THERE IS A 35% CHANCE FOR THUNDERSTORMS ACROSS CENTRAL AND
SOUTHWESTERN MONTANA. WEDNESDAY THROUGH FRIDAY THERE IS A 40 - 80%
CHANCE FOR A QUARTER 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 HALF INCH OR RAIN OR GREATER ALONG THE
HI-LINE AND ACROSS CHOTEAU, JUDITH BASIN, AND FERGUS COUNTIES. ON
THURSDAY AND FRIDAY THERE IS GREATER THAN A 50% CHANCE FOR HIGH
TEMPERATURES OF 70 DEGREES OR LOWER ACROSS THE PLAINS OF NORTH-
CENTRAL MONTANA. -IG
AVIATION
10/00Z TAF PERIOD
INITIAL CONCERN WILL BE FOR CONTINUED WILDFIRE SMOKE REDUCING BOTH
SLANT-RANGE AND SURFACE VISIBILITY ACROSS THE REGION. THE SMOKE
LOOKS TO REMAIN MOST DENSE ACROSS SW MT AND VICINITY THROUGH THE TAF
PERIOD. A FEW SHOWERS OR THUNDERSTORMS CANNOT BE RULED OUT ACROSS
THE HI-LINE AND ADJACENT AREAS TOMORROW AFTERNOON, BUT THE
PROBABILITY OF THESE OCCURRING AT A TERMINAL WAS TOO LOW TO INCLUDE
MENTION AT THIS TIME.
FOR KGTF: PROBABILITY OF A 15KT CROSSWIND WILL REMAIN ESSENTIALLY
ZERO THROUGH THE MORNING MONDAY. THERE IS LOWER THAN AVERAGE
CONFIDENCE IN THE WIND DIRECTION BY MONDAY AFTERNOON, WITH THE MOST
AGGRESSIVELY MIXED SCENARIOS RESULTING IN A WESTERLY WIND BY
EARLY AFTERNOON, WITH OCCASIONAL GUSTS IN EXCESS OF 20 KTS. -AM
PRELIMINARY POINT TEMPS/POPS
GTF 54 89 54 84 / 0 0 0 0
CTB 51 81 50 77 / 0 0 0 10
HLN 55 90 54 88 / 0 0 0 0
BZN 52 87 52 89 / 0 0 0 0
WYS 44 81 42 86 / 0 0 0 0
DLN 51 87 50 89 / 0 0 0 0
HVR 53 88 52 84 / 0 0 0 0
LWT 52 86 52 82 / 0 0 0 0
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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