597
FXUS65 KTFX 090006
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
606 PM MDT TUE SEP 8 2026
AVIATION SECTION UPDATED.
KEY MESSAGES
- RAIN WILL GRADUALLY END ALONG THE HI-LINE THIS EVENING.
- IT WILL BE DRY AND BREEZY ON WEDNESDAY AND THURSDAY.
- PRECIPITATION AND COOLER TEMPERATURES RETURN FRIDAY THROUGH
THIS WEEKEND.
DISCUSSION
/ISSUED 212 PM MDT TUE SEP 8 2026/
- METEOROLOGICAL OVERVIEW:
AN UPPER-LEVEL TROUGH IS MOVING OVER NORTH-CENTRAL, CENTRAL, AND
SOUTHWESTERN MONTANA THIS AFTERNOON. AS A RESULT RAIN SHOWERS WILL
LINGER ACROSS THE HI-LINE THROUGH THIS EVENING WITH COOLER
TEMPERATURES ACROSS THE AREA. ON WEDNESDAY AN UPPER-LEVEL RIDGE
MOVES OVER NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. THIS
WILL BRING DRY AND WARM TEMPERATURES (NEAR SEASONAL AVERAGES) TO THE
AREA ON WEDNESDAY. ON WEDNESDAY THE PRESSURE GRADIENT INCREASES
WHICH WILL BRING BREEZY CONDITIONS TO THE ROCKY MOUNTAIN FRONT. ON
THURSDAY THE UPPER-LEVEL RIDGE BEGINS TO BREAK DOWN. THIS WILL KEEP
WARMER TEMPERATURES WITH MOSTLY DRY WEATHER FOR THE AREA ON
THURSDAY. THURSDAY EVENING A COLD FRONT WILL MOVE THROUGH NORTH-
CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA.
ON FRIDAY AN UPPER-LEVEL TROUGH IS OVER NORTH-CENTRAL, CENTRAL, AND
SOUTHWESTERN MONTANA. THIS COMBINED WITH THE COLD FRONT THAT MOVED
THROUGH WILL BRING COOLER TEMPERATURES (WELL-BELOW SEASONAL
AVERAGES) TO THE AREA. ON FRIDAY THERE WILL BE RAIN SHOWERS ACROSS
NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. SATURDAY THROUGH
MONDAY THERE WILL BE AN UPPER-LEVEL CLOSED LOW THAT WILL BRING
COOLER TEMPERATURES AND WIDESPREAD PRECIPITATION TO THE AREA. HIGHER
ELEVATION LOCATIONS HAVE THE POTENTIAL TO RECEIVE SNOW THIS WEEKEND.
SEE THE FORECAST CONFIDENCE & SCENARIOS SECTION FOR DETAILS. -IG
- FORECAST CONFIDENCE & SCENARIOS:
ON WEDNESDAY THERE IS A 60 - 80% CHANCE FOR WIND GUSTS OF 40 MPH OR
GREATER. ON THURSDAY THERE IS GREATER THAN A 60% CHANCE FOR WIND
GUSTS OF 40 MPH OR GREATER ACROSS THE ROCKY MOUNTAIN FRONT AND
PLAINS WEST OF 1-15, THE HI-LINE, CASCADE TO JUDITH BASIN COUNTY,
AND THE NORTH-SOUTH ORIENTATED VALLEYS OF SOUTHWESTERN MONTANA. ON
THURSDAY ALONG THE ROCKY MOUNTAIN FRONT THERE IS A 60 - 80% CHANCE
FOR WIND GUSTS OF 55 MPH OR GREATER.
SATURDAY THROUGH MONDAY DETERMINISTIC AND ENSEMBLE MODELS DIFFER ON
THE TRACK AND STRENGTH OF THE UPPER-LEVEL TROUGH/CLOSED-LOW. ON
SATURDAY TWO CLUSTERS HAVE A CLOSED UPPER-LEVEL LOW IN THE VICINITY
OF WASHINGTON/OREGON. THIS SCENARIO WOULD KEEP TEMPERATURES SIMILAR
TO FRIDAY WITH WIDESPREAD PRECIPITATION AND BREEZY CONDITIONS ACROSS
NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. ON SATURDAY ONE
CLUSTER HAS AN UPPER-LEVEL TROUGH OVER EASTERN WASHINGTON AND
OREGON. THIS SCENARIO WOULD KEEP SIMILAR WEATHER TO THE CLOSED LOW
SCENARIO BUT IT WOULD BE SLIGHTLY LESS WINDY. A THIRD CLUSTER HAS A
UPPER-LEVEL TROUGH OVER MONTANA. THIS SCENARIO WOULD BRING COOLER
TEMPERATURES AND WIDESPREAD PRECIPITATION ACROSS NORTH-CENTRAL,
CENTRAL, AND SOUTHWESTERN MONTANA. ON SUNDAY THREE OUT OF FOUR
CLUSTERS HAVE AN UPPER-LEVEL TROUGH OVER NORTH-CENTRAL, CENTRAL, AND
SOUTHWESTERN MONTANA. THIS SCENARIO WOULD BRING COOL TEMPERATURES
AND WIDESPREAD PRECIPITATION TO NORTH-CENTRAL, CENTRAL, AND
SOUTHWESTERN MONTANA. ON SUNDAY THE FOURTH CLUSTER HAS A CLOSED
UPPER-LEVEL LOW OFF THE COAST OF WASHINGTON/OREGON WITH AN UPPER-
LEVEL RIDGE OVER MONTANA. THIS WOULD BRING WARM AND MOSTLY DRY
WEATHER TO NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. THIS
ALL SHOWS THAT THIS WEEKEND THROUGH MONDAY THERE IS HIGH UNCERTAINTY
IN THE OVERALL WEATHER PATTERN. HOWEVER, IN WHICHEVER SCENARIO PANS
OUT THERE IS AT LEAST A MODERATE CHANCE FOR SNOW ACROSS THE
HIGHER PEAKS OF NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA
THIS WEEKEND. -IG
AVIATION
09/00Z TAF PERIOD
HIGH CONFIDENCE IN VFR CONDITIONS ACROSS ALL TERMINALS WITH THE
EXCEPTION OF KLWT AS WE MOVE INTO THE NIGHT. ISOLATED SHOWERS ARE
CURRENTLY SHIFTED EAST OUT OF THE REGION BUT STILL LINGERING NEAR
TERMINAL KLWT LENDING TO THE USE OF A TEMPO GROUP THROUGH
09/02Z. SHOWERS WILL BE QUICK MOVERS, BUT MAY BRIEFLY LEAD TO
DEGRADED VISIBILITY AND LOW CLOUD BASES. AS THEY SHIFT EAST AND
WEAKEN, THE TERMINAL MAY EXPERIENCE ERRATIC WINDS. BEYOND THE
09/02Z TIME FRAME, ALL TERMINAL ACROSS THE TAF PERIOD WILL REMAIN
VFR. WINDS AREA WIDE WILL RAMP UP WEDNESDAY AFTERNOON AS A RIDGE
OF HIGH PRESSURE SHIFTS ITS AXIS OVER CENTRAL MONTANA. WINDS WILL
BE GUSTY ACROSS SW MONTANA AND ALONG THE ROCKY MOUNTAIN FRONT
LARGELY OUT OF THE SOUTHWEST. -JR
FOR KGTF: VFR CONDITIONS WILL PREVAIL THROUGH THE NIGHT AND INTO
WEDNESDAY AFTERNOON. ODDS REMAIN LOW (<30%) OF CROSS WINDS
EXCEEDING THE 15KT THRESHOLD THROUGH 09/02Z BUT WORTH NOTING
SPORADIC GUSTS MAY BRIEFLY EXCEED THE THRESHOLD BEFORE DROPPING
OFF TO NEAR 0% THROUGH 09/15Z. AS WINDS BEGIN TO RAMP UP 09/15Z
AND ONWARD, DIRECTION REMAINS FAVORABLE FOR FLIGHT WITH HIGH
CONFIDENCE IN HEADWIND GUSTS EXCEEDING 15KTS AND LOW PROBABILITY
(<10%) OF CROSSWINDS APPROACHING THE 15K THRESHOLD. -JR
PRELIMINARY POINT TEMPS/POPS
GTF 63 44 76 54 / 90 10 0 0
CTB 60 44 69 50 / 90 10 0 0
HLN 68 42 76 49 / 20 0 0 0
BZN 68 39 77 45 / 30 0 0 0
WYS 63 30 70 30 / 10 0 0 0
DLN 68 37 78 41 / 0 0 0 0
HVR 63 43 75 49 / 100 40 0 0
LWT 65 41 73 50 / 30 20 0 0
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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