063
FXUS65 KTFX 112041
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
241 PM MDT THU SEP 11 2025
KEY MESSAGES
- ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS THIS
AFTERNOON, SOME OF WHICH COULD PRODUCE SOME GUSTY WINDS OR
LOCALIZED HEAVY RAIN.
- BRIEFLY WARMER SUNDAY.
- COOL AND UNSETTLED WEATHER RETURNS ON MONDAY.
DISCUSSION
- METEOROLOGICAL OVERVIEW:
A BROAD, SLOW MOVING, AND GRADUALLY WEAKENING UPPER LEVEL TROUGH
CURRENTLY OVER THE WESTERN US WILL KEEP US COOL AND UNSETTLED THE
NEXT FEW DAYS BEFORE ANOTHER TROUGH APPROACHES FROM THE WEST AND
FORCES IT TO MOVE NORTHWARD ON SUNDAY. WITH THIS TROUGH TO THE
WEST, EXPECT SUNDAY TO BE SLIGHTLY WARMER HIGHS GENERALLY 3-5
DEGREES WARMER THAN THE PREVIOUS FEW DAYS. SHOWERS AND
THUNDERSTORMS WILL CONTINUE TO BE AROUND, HOWEVER, ESPECIALLY
LATER IN THE DAY AS AFTERNOON HEATING COMBINES WITH THE
APPROACHING UPPER LEVEL TROUGH. THIS TROUGH WILL SETTLE OVERHEAD
FOR THE FIRST HALF OF THE WEEK, BRINGING COOL AND UNSETTLED TO THE
AREA FOR THE FIRST HALF OF NEXT WEEK.
- FORECAST CONFIDENCE & SCENARIOS:
THE MAIN IMPACTS OVER THE NEXT FEW DAYS WILL BE THE LOW END RISK
FOR AN ISOLATED STRONG AND/OR HEAVY THUNDERSTORM, PARTICULARLY
THIS AFTERNOON AND FRIDAY AFTERNOON. FORECAST SOUNDINGS THE NEXT
TWO DAYS TEND TO SHOW A “TALL, SKINNY” CAPE PROFILE (CAPE BEING A
MEASURE OF INSTABILITY), WHICH INDICATES AN ELEVATED CHANCE FOR
SOME HEAVY RAIN OUT OF ANY SHOWER OR THUNDERSTORM. WPC DOES ALIGN
WITH THIS EXPECTATION, AS WE ARE UNDER A MARGINAL (⅕) RISK FOR
EXCESSIVE RAINFALL. FOR THE MOST PART, THE MAIN CONCERN WILL BE
ANY RECENT BURN SCARS (SUCH AS THE HORSE GULCH OR ANY ACTIVE
FIRES). IN ADDITION TO THE RAIN, A FEW STRONGER WIND GUSTS WILL BE
POSSIBLE FROM SOME OF THE STORMS AS WELL, PARTICULARLY FURTHER
EAST ACROSS THE PLAINS (GENERALLY EAST OF A GREAT FALLS TO HAVRE
LINE).
LOOKING INTO NEXT WEEK, THERE ISN’T MUCH IMPACTFUL WEATHER
EXPECTED AT THIS TIME, THOUGH SHOWERS AND THUNDERSTORMS ARE
EXPECTED MOST DAYS. ALSO OF NOTE, WITH THE UPPER LEVEL LOW ACROSS
THE AREA IN THE FIRST PART OF NEXT WEEK, I CAN’T REALLY RULE OUT
SOME SNOW FALLING AT THE HIGHER ELEVATIONS OF BEAVERHEAD, MADISON,
AND GALLATIN COUNTIES. WHILE ANY SNOW ACCUMULATIONS WILL BE LIGHT
AND ISOLATED TO THE HIGHEST TERRAIN, IT IS STILL NOTEWORTHY AS
SOME OF THE FIRST SNOW OF THE SEASON. LUDWIG
AVIATION
11/18Z TAF PERIOD
VFR CONDITIONS WILL PREVAIL ACROSS ALL TERMINALS THROUGH THE TAF
PERIOD OUTSIDE OF SHOWER/THUNDERSTORM ACTIVITY. THE MAIN THREATS
WITH ANY THUNDERSTORM THAT DEVELOPS WILL BE FREQUENT LIGHTNING,
LOCALLY HEAVY DOWNPOURS, AND GUSTY/ERRATIC WINDS. MOUNTAIN
OBSCURATION WILL BE A CONCERN THROUGH MUCH OF THE PERIOD,
ESPECIALLY BETWEEN NOW AND 12/06Z.
NORTH-CENTRAL/CENTRAL MONTANA (KCTB, KHVR, KGTF, KLWT, KHLN):
THERE WILL BE A 20-50% CHANCE FOR SHOWERS AND THUNDERSTORMS ACROSS
THE REGION THROUGHOUT MUCH OF THE TAF PERIOD. THUNDERSTORMS TODAY
HAVE THE POTENTIAL TO BE STRONGER, PARTICULARLY TOWARDS THE EAST
AFFECTING KHVR AND KLWT WHICH MAY INCLUDE SMALL HAIL IN ADDITION
TO THE PREVIOUSLY MENTIONED THREATS.
SOUTHWEST MONTANA (KBZN, KEKS, KWYS): THE MAIN THREAT FOR SHOWERS
AND THUNDERSTORMS WILL BE FROM NOW THROUGH 12/00Z. OVERNIGHT,
CLOUDS WILL START TO CLEAR OUT WITH A SLIGHT CHANCE FOR FOG
THROUGH THE MORNING HOURS, PARTICULARLY AT KWYS. THERE WILL BE
ANOTHER 20-40% CHANCE FOR SCATTERED SHOWERS ACROSS THE REGION TOMORROW
AFTER 12/18Z.
-THOR
HYDROLOGY
A FEW HEAVY SHOWERS AND THUNDERSTORMS ARE POSSIBLE TODAY. WHILE
UNLIKELY, SHOULD ONE OF THE HEAVIEST RAIN SHOWERS HIT A BURN SCAR
SOME FLASH FLOODING MAY BE POSSIBLE. LUDWIG
PRELIMINARY POINT TEMPS/POPS
GTF 50 77 49 78 / 40 30 20 20
CTB 48 76 46 77 / 20 30 20 10
HLN 49 77 49 76 / 40 40 20 30
BZN 43 76 44 71 / 20 30 10 30
WYS 33 70 34 63 / 10 30 20 50
DLN 41 72 41 70 / 20 30 10 20
HVR 54 78 51 78 / 40 40 30 20
LWT 48 75 47 71 / 30 40 40 50
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
HTTP://WWW.WEATHER.GOV/GREATFALLS
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