861
FXUS65 KTFX 030615
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1215 AM MDT THU SEP 3 2026
KEY MESSAGES
- BREEZY AT TIMES ON FRIDAY, ESPECIALLY ACROSS SOUTHWEST MONTANA AND
ALONG THE ROCKY MOUNTAIN FRONT.
- DAILY CHANCES FOR AFTERNOON SHOWERS AND THUNDERSTORMS THROUGH FRIDAY,
ESPECIALLY ALONG THE CONTINENTAL DIVIDE.
- TEMPERATURES WILL COOL OFF OVER THE WEEKEND INTO EARLY NEXT WEEK
WITH A CHANCE FOR WIDESPREAD WETTING PRECIPITATION.
DISCUSSION
- METEOROLOGICAL OVERVIEW:
SOUTHWESTERLY FLOW WILL PERSIST OVER THE REGION THROUGH FRIDAY AS
THE UPPER-LEVEL TROUGH REMAINS ALONG THE WEST COAST. THIS SETUP WILL
BRING TEMPERATURES DOWN SLIGHTLY AND ALLOW FOR DAILY CHANCES FOR
AFTERNOON SHOWERS AND THUNDERSTORMS, MAINLY IN SOUTHWEST MONTANA AND
ALONG THE CONTINENTAL DIVIDE. BREEZY SOUTHWEST WINDS WILL ALSO BE
PRESENT DURING THIS TIME ACROSS THE REGION, ALTHOUGH IT WILL BE A
FAR CRY FROM WHAT WAS OBSERVED ON WEDNESDAY.
THROUGH THE WEEKEND, THE CLOSED LOW OVER THE PACNW SHIFTS SLIGHTLY
BUT MAINTAINS SOUTH/SOUTHWESTERLY FLOW OVER THE REGION WHICH WILL
DRAW UP MORE TROPICAL MOISTURE INTO MONTANA. ON MONDAY, THE LOW
EJECTS A SHORTWAVE TROUGH OVER THE REGION WHICH HAS THE CHANCE TO
BRING MORE WIDESPREAD WETTING RAIN THROUGH TUESDAY.
- FORECAST CONFIDENCE & SCENARIOS:
WINDS ON THURSDAY AND FRIDAY:
BREEZY SOUTHWESTERLY WINDS WILL BE POSSIBLE ACROSS SOUTHWEST MONTANA
THIS AFTERNOON WITH AFTERNOON RELATIVE HUMIDITY IN THE 20S EXPECTED.
THIS WILL KEEP FIRE WEATHER CONCERNS ELEVATED FOR PORTIONS OF
SOUTHWEST MONTANA WHERE A RED FLAG WARNING REMAINS IN EFFECT THROUGH
THE EVENING. WHILE STRONGER WINDS ARE POSSIBLE ALONG NORTH-SOUTH
ORIENTED VALLEYS INCLUDING ENNIS, THERE IS LOW CONFIDENCE IN
REACHING HIGH WIND CRITERIA WITH GUSTS EXPECTED TO MAX OUT AT AROUND
45 MPH. ACROSS THE REST OF THE PLAINS AND CENTRAL MONTANA, GUSTS
BETWEEN 25 AND 35 MPH ARE LIKELY BUT MUCH STRONGER GUSTS ARE NOT
EXPECTED. A SIMILAR SETUP IS EXPECTED ON FRIDAY WITH SCATTERED
THUNDERSTORMS POSSIBLE WHICH MAY BRING LOCALLY STRONGER WIND GUSTS.
RAIN SUNDAY THROUGH TUESDAY:
BASED ON THE LATEST MODEL GUIDANCE, PRECIPITATION STARTS TO FILL IN
ACROSS THE REGION SUNDAY MORNING INTO THE AFTERNOON WITH THE
HEAVIEST MOISTURE EXPECTED ON MONDAY AS THE SHORTWAVE PASSES
THROUGH. LINGERING SHOWERS WILL CONTINUE THROUGH TUESDAY MORNING AND
TAPER OFF FROM SOUTH TO NORTH THROUGH THE AFTERNOON. THERE IS STILL
UNCERTAINTY REGARDING PRECIPITATION AMOUNTS BUT RIGHT NOW THE HI-
LINE IS THE MOST FAVORED FOR HIGHER AMOUNTS WHILE SOUTHWEST MONTANA
IS MORE FAVORED FOR THE LOW-END AMOUNTS.
OVER THE 48 HOUR PERIOD COVERING SUNDAY MORNING THROUGH TUESDAY
MORNING...
- FOR AMOUNTS GREATER THAN 0.1" THERE IS A 80% PROBABILITY OF
OCCURRENCE ACROSS THE REGION.
- FOR AMOUNTS GREATER THAN 0.5" THERE IS A 70% PROBABILITY OF
OCCURRENCE NORTH OF A LINE BETWEEN HELENA AND WHITE SULPHUR SPRINGS
AND A 50% CHANCE SOUTH OF THAT LINE.
- FOR AMOUNTS GREATER THAN 1.0" THERE IS A 50% PROBABILITY OF
OCCURRENCE NORTH OF A LINE BETWEEN HELENA AND WHITE SULPHUR SPRINGS
AND A 25% CHANCE SOUTH OF THAT LINE.
- FOR AMOUNTS GREATER THAN 1.5" THERE IS A 40% PROBABILITY OF
OCCURRENCE NORTH OF A LINE BETWEEN GREAT FALLS AND LEWISTOWN AND A
LESS THAN 15% CHANCE SOUTH OF THAT LINE.
EXACT AMOUNTS ARE LIKELY TO CHANGE BUT THERE IS INCREASING
CONFIDENCE THAT THIS SHORTWAVE WILL AT LEAST BRING MINOR RELIEF TO
SOME OF THE RECENT FIRE WEATHER CONCERNS. -THOR
AVIATION
03/06Z TAF PERIOD
HIGH CONFIDENCE IN VFR CONDITIONS ACROSS ALL TERMINALS THROUGH THE
ENTIRE TAF PERIOD. ISOLATED SHOWERS ARE POSSIBLE (30%) LEADING USE
OF PROB30 PERIODS FOR TERMINALS KWYS, AND KEKS. IF SHOWERS WERE TO
IMPACT THE TERMINAL, EXPECT BRIEFLY REDUCED CLOUD BASES AND MORE
ERRATIC WINDS WITH ANY OUTFLOW ASSOCIATED WITH THE SHOWERS. THE
REMAINING TERMINALS WILL CONTINUE THEIR TREND OF GUSTY WINDS
THURSDAY AFTERNOON, ESPECIALLY ACROSS THE SOUTHWEST TERMINALS
KWYS, KEKS, AND KBZN WHERE CONFIDENCE IS HIGH GUSTS WILL EXCEED
30KTS THURSDAY 18Z-23Z.
FOR KGTF: WINDS OVERNIGHT WILL BE LARGELY CALM AND VARIABLE BEFORE
INCREASING AS WE MOVE INTO THURSDAY AFTERNOON AND EVENING.
HEADWINDS WILL LIKELY BE IN EXCESS OF 15KT GUSTING TO 25KTS FROM
03/17Z TO 04/00Z WITH A LOW PROBABILITY (<10%) OF CROSSWINDS
EXCEEDING THE 15KT THRESHOLD. AS WINDS WEAKEN AFTER 04/00Z THEY
WILL BECOME MORE NORTHWESTERLY BRINGING A HEIGHTENED BUT STILL LOW
(20%) RISK OF CROSSWINDS EXCEEDING 15KTS. -JR
PRELIMINARY POINT TEMPS/POPS
GTF 74 49 76 48 / 0 10 0 50
CTB 66 44 66 43 / 10 30 10 60
HLN 74 47 75 48 / 0 10 20 50
BZN 75 46 79 44 / 0 0 0 10
WYS 64 36 67 37 / 0 0 0 20
DLN 72 41 74 42 / 0 10 10 20
HVR 80 50 82 48 / 0 0 0 10
LWT 77 52 82 48 / 0 0 0 10
TFX WATCHES/WARNINGS/ADVISORIES
HTTP://WWW.WEATHER.GOV/GREATFALLS
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