306
FXUS65 KTFX 090532
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1132 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 606 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
09/06Z TAF PERIOD
HIGH CONFIDENCE IN VFR CONDITION ACROSS ALL TERMINALS THROUGH THE
ENTIRETY OF THE TAF PERIOD. A RIDGE OF HIGH PRESSURE WILL CONTINUE
TO PUSH EAST INTO MONTANA BRINGING WARMER TEMPERATURES AND BREEZY
CONDITIONS. THE TIMING IS CONSISTENT ACROSS ALL TERMINAL WITH
WINDS BEGINNING TO INCREASE AND TURN MORE SOUTHWESTERLY BETWEEN
16Z AND 19Z. CONDITIONS REMAIN CLEAR WITH WIDESPREAD CLEAR TO
MOSTLY CLEAR SKY AND HIGH CLOUD BASES. WINDS ARE OF GREATEST
ACROSS NORTH CENTRAL MONTANA SPECIFICALLY TERMINALS KCTB, KHLN,
KGTF, AND KHVR WHERE GUSTS OF 25-30KTS ARE EXPECTED FROM A
WEST/SOUTHWEST DIRECTION. REGION WIDE, GUSTS FROM THE SW UP TO
20KT ARE EXPECTED.
-JR
FOR KGTF: WINDS WILL BEGIN TO INCREASE 09/14Z OFFERING A BRIEF
PERIOD OF FAVORABLE WIND DIRECTION FROM THE SOUTHWEST. WINDS WILL
QUICKLY RAMP UP TO 10G20KT WITH A LOW (30%) CHANCE OF CROSSWINDS
EXCEEDING THE 15KT THRESHOLD. BY 09/17Z WINDS BECOME MORE
WESTERLY (240-260 DEGREES) WITH HIGH CONFIDENCE (>60%) OF GUSTS
WITH A CROSSWIND COMPONENT OF 15-18KT. WINDS BECOME NEARLY DUE
WEST (270 DEGREES) BY 09/20Z INCREASING THE CROSSWIND COMPONENT OF
SUSTAINED WINDS NEAR/ABOVE THE 15KT THRESHOLD. WINDS REMAIN
CONSISTENT TILL 10/02Z WHEN THEY BEGIN TO WANE/SHIFT SOUTHWEST.
-JR
PRELIMINARY POINT TEMPS/POPS
GTF 61 44 76 54 / 90 20 0 0
CTB 62 44 69 50 / 90 10 0 0
HLN 69 42 76 49 / 20 10 0 0
BZN 66 39 77 45 / 30 0 0 0
WYS 63 30 70 30 / 10 10 0 0
DLN 68 37 78 41 / 0 0 0 0
HVR 60 43 75 49 / 100 40 10 0
LWT 64 41 73 50 / 30 20 0 0
TFX WATCHES/WARNINGS/ADVISORIES
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