255
FXUS65 KTFX 111950
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
150 PM MDT FRI SEP 11 2026
KEY MESSAGES
- ON SATURDAY IT WILL BE COOL AND MOSTLY DRY.
- ON SUNDAY THERE WILL BE SNOW ALONG THE ROCKY MOUNTAIN FRONT
WITH WINDY CONDITIONS IN THE VALLEYS OF SOUTHWESTERN MONTANA.
- ON SUNDAY THERE WILL BE SNOW ALONG THE ROCKY MOUNTAIN FRONT
WITH WINDY CONDITIONS IN THE VALLEYS OF SOUTHWESTERN MONTANA.
DISCUSSION
- METEOROLOGICAL OVERVIEW:
AN UPPER-LEVEL TROUGH ASSOCIATED WITH A SURFACE COLD FRONT IS
EXITING NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA THIS
AFTERNOON. THIS WILL BRING COOL (BELOW SEASONAL AVERAGE)
TEMPERATURES TO THE AREA WITH LINGERING RAIN SHOWERS. ON SATURDAY
AN UPPER-LEVEL RIDGE BUILDS IN BRIEFLY OVER NORTH-CENTRAL, CENTRAL,
AND SOUTHWESTERN MONTANA. THIS WILL BRING MOSTLY DRY WEATHER WITH
STATUS QUO TEMPERATURES TO THE AREA. ON SATURDAY ALONG THE ROCKY
MOUNTAIN FRONT THERE WILL BE SNOW MIXED WITH RAIN AT TIMES AND
PRIMARILY ALL RAIN AT LOWER ELEVATIONS. ON SUNDAY A CLOSED UPPER-
LEVEL LOW WILL MOVE OVER NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN
MONTANA WITH A 700MB LOW MOVING OVER SOUTHERN ALBERTA/THE HI-LINE.
THIS WILL BRING STRONG SOUTHERLY FLOW ALOFT WHICH WILL BRING
STRONG WINDS TO NORTH-SOUTH ORIENTATED VALLEYS OF SOUTHWESTERN
MONTANA. ON SUNDAY ALONG THE HIGHER PEAKS OF THE ROCKY MOUNTAIN
FRONT THERE WILL BE SNOW WITH THE REST OF THE ROCKY MOUNTAIN FRONT
SEEING RAIN AND/OR A RAIN/SNOW MIX. ON SUNDAY ACROSS THE REST OF
NORTH-CENTRAL MONTANA THERE WILL BE LIGHT RAIN SHOWERS. ON SUNDAY
WARM AIR ADVECTION WILL BRING SEASONABLE TEMPERATURES TO
SOUTHWESTERN MONTANA WITH BELOW SEASONAL AVERAGE TEMPERATURES
NORTH OF THE I-90 CORRIDOR.
ON MONDAY THE UPPER-LEVEL LOW EXITS NORTH-CENTRAL, CENTRAL, AND
SOUTHWESTERN MONTANA. PRECIPITATION WILL LINGER ACROSS NORTH-CENTRAL
MONTANA ON MONDAY. ON MONDAY LOW-LEVEL WINDS WILL INCREASE WHICH
WILL BRING AT LEAST BREEZY CONDITIONS TO NORTH-CENTRAL MONTANA. ON
MONDAY TEMPERATURES WILL REMAIN COOL. TUESDAY THROUGH THURSDAY AN
UPPER-LEVEL RIDGE GRADUALLY BUILDS IN OVER NORTH-CENTRAL,
CENTRAL, AND SOUTHWESTERN MONTANA. THIS WILL ALLOW TEMPERATURES TO
WARM BACK UP TO NEAR SEASONAL AVERAGES WITH MOSTLY DRY WEATHER. -IG
- FORECAST CONFIDENCE & SCENARIOS:
ON SUNDAY THERE IS A 40 - 80% CHANCE FOR SUSTAINED WINDS OF 40 MPH
AND A 50% CHANCE FOR WIND GUSTS OF 55 MPH OR GREATER IN THE MADISON
RIVER VALLEY. AS A RESULT A HIGH WIND WATCH WAS ISSUED FOR THE
MADISON RIVER VALLEY FROM 12 PM TO 9 PM ON SUNDAY. ON SUNDAY
THERE IS GREATER THAN A 50% CHANCE FOR 55 MPH WIND GUSTS ALONG THE
RIDGETOPS OF THE MADISON AND GALLATIN MOUNTAINS. ON MONDAY THERE
IS A 30 - 50% CHANCE FOR WIND GUSTS OF 55 MPH OR GREATER ACROSS
MOST OF NORTH-CENTRAL MONTANA.
ON SUNDAY THERE ARE DIFFERENCES IN THE 700 MB LOW TRACK BETWEEN THE
GFS AND EURO. THE EURO THE LOW TRACKING SLIGHTLY FURTHER SOUTH
WHICH WOULD BRING MORE PRECIPITATION/SNOW TO THE NORTHERN ROCKY
MOUNTAIN FRONT THAN WHAT THE GFS HAS. THERE IS A 50 - 80% CHANCE
FOR ONE INCH OF SNOW OR GREATER ALONG THE MAJORITY OF THE ROCKY
MOUNTAIN FRONT SUNDAY INTO MONDAY. THERE IS A LOW CHANCE THAT
ISOLATED MOUNTAIN PEAKS WILL RECEIVE IN EXCESS OF 6 INCHES OF
SNOWFALL SUNDAY INTO MONDAY. ON TUESDAY MORNING THERE IS A 40 -
60% CHANCE FOR LOW TEMPERATURES OF 36 DEGREES OR COLDER ACROSS THE
HI-LINE AND THE VALLEYS OF SOUTHWESTERN MONTANA. -IG
AVIATION
11/18Z TAF PERIOD
SCATTERED RAIN SHOWERS WILL GRADUALLY DISSIPATE THROUGH 21Z THIS
AFTERNOON OVER THE PLAINS OF CENTRAL AND NORTH CENTRAL MONTANA;
HOWEVER, ISOLATED RAIN SHOWERS ARE LIKELY TO PERSIST ALONG THE
CONTINENTAL DIVIDE AND ISLAND RANGES OVER THE COURSE OF THE
1118/1218 TAF PERIOD. MVFR/LOW-VFR CONDITIONS WILL PERSIST OVER
THE NEXT 24 HOURS ACROSS ALL TERMINALS, WITH THE LOWEST CIGS
OCCURRING ALONG AND NORTH OF THE US HWY 12 CORRIDOR AND IMPACTING
THE KHLN, KGTF, KLWT, KHVR, AND KCTB TERMINALS. TEMPORARY IFR
CONDITIONS CAN NOT BE RULED OUT THROUGH 20Z AT THE KLWT TERMINAL.
MOUNTAINS WILL BE OBSCURED THROUGHOUT THE PERIOD. - MOLDAN
PRELIMINARY POINT TEMPS/POPS
GTF 44 57 41 62 / 10 20 0 40
CTB 40 51 37 53 / 30 20 0 60
HLN 43 64 43 67 / 0 10 10 50
BZN 44 70 42 73 / 10 0 0 20
WYS 32 72 38 66 / 10 0 0 10
DLN 39 74 41 72 / 0 0 0 10
HVR 39 59 37 64 / 10 20 0 20
LWT 40 58 39 66 / 20 20 10 20
TFX WATCHES/WARNINGS/ADVISORIES
HIGH WIND WATCH FROM SUNDAY AFTERNOON THROUGH SUNDAY EVENING FOR
MADISON RIVER VALLEY.
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