744
FXUS65 KTFX 212321
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
521 PM MDT WED OCT 21 2026
AVIATION SECTION UPDATED.
KEY MESSAGES
- MILD AND DRY CONDITIONS WILL CONTINUE THROUGH THURSDAY.
- WIDESPREAD PRECIPITATION RETURNS LATE THURSDAY INTO FRIDAY WITH
COOLER TEMPERATURES LASTING THROUGH THE WEEKEND.
DISCUSSION
/ISSUED 303 PM MDT WED OCT 21 2026/
- METEOROLOGICAL OVERVIEW:
TODAY OVER SOUTHWESTERN MONTANA THERE REMAINS SOUTHWEST FLOW ALOFT
WITH WEAK ZONAL FLOW (WEST-EAST) OVER NORTH-CENTRAL, AND CENTRAL
MONTANA. DUE TO SLIGHTLY STRONGER WARM AIR ADVECTION TODAY
TEMPERATURES WILL REBOUND TO ABOVE SEASONAL AVERAGES. ACROSS NORTH-
CENTRAL AND CENTRAL MONTANA IT WILL BE DRY WITH A LOW CHANCE FOR
SHOWERS ACROSS SOUTHWESTERN MONTANA TODAY. SEE THE FORECAST
CONFIDENCE & SCENARIOS SECTION FOR DETAILS. ON THURSDAY THERE
REMAINS SOUTHERLY FLOW ALOFT AND AN UPPER-LEVEL TROUGH ASSOCIATED
WITH A PACIFIC COLD FRONT BEGINS TO MOVE OVER NORTH-CENTRAL,
CENTRAL, AND SOUTHWESTERN MONTANA BY THURSDAY EVENING. THIS WILL
ALLOW TEMPERATURES TO REMAIN ABOVE SEASONAL AVERAGES WITH MOSTLY DRY
WEATHER UNTIL THURSDAY EVENING. THURSDAY EVENING INTO FRIDAY MORNING
PRECIPITATION WILL GRADUALLY SPREAD OVER NORTH-CENTRAL, CENTRAL, AND
SOUTHWESTERN MONTANA.
ON FRIDAY THE UPPER-LEVEL TROUGH MERGES WITH A SHORTWAVE TROUGH
MOVING SOUTH FROM CANADA. THIS COMBINED WITH THE COLD FRONT THAT
MOVED THROUGH WILL BRING WIDESPREAD PRECIPITATION AND COOLER
TEMPERATURES (BELOW SEASONAL AVERAGES) TO THE AREA. DUE TO THE
COLD FRONT THAT MOVED THROUGH THURSDAY EVENING INTO FRIDAY MORNING
SNOW-LEVELS WILL LOWER AND THE PRECIPITATION THAT FALLS IN
MOUNTAIN AREAS ON FRIDAY WILL TRANSITION FROM RAIN TO SNOW BY
FRIDAY EVENING. ON FRIDAY THERE IS AN INCREASING PRESSURE GRADIENT
AND STRONG LOW-LEVEL AND MID-LEVEL WINDS. THIS WILL BRING WINDY
CONDITIONS TO NORTH-CENTRAL MONTANA ON FRIDAY. ON SATURDAY AN
UPPER-LEVEL RIDGE BEGINS TO BUILD IN OVER NORTH-CENTRAL, CENTRAL,
AND SOUTHWESTERN MONTANA. THIS WILL ALLOW THE AREA TO DRY OUT WITH
COOL TEMPERATURES LINGERING.
ON SUNDAY THE UPPER-LEVEL RIDGE REMAINS OVER NORTH-CENTRAL, CENTRAL,
AND SOUTHWESTERN MONTANA. THIS WILL KEEP DRY AND COOL (BELOW
SEASONAL AVERAGES) WEATHER FOR THE AREA ON SUNDAY. MONDAY THROUGH
TUESDAY AN UPPER-LEVEL TROUGH MOVES OVER NORTH-CENTRAL, CENTRAL,
AND SOUTHWESTERN MONTANA. THIS WILL BRING COOLER TEMPERATURES AND
WIDESPREAD PRECIPITATION TO THE AREA ON MONDAY AND TUESDAY. -IG
- FORECAST CONFIDENCE & SCENARIOS:
FOR TOTAL LIQUID PRECIPITATION THURSDAY NIGHT THROUGH FRIDAY NIGHT
THERE IS GREATER THAN AN 80% CHANCE FOR ONE HALF INCH OF LIQUID
PRECIPITATION OR GREATER ALONG AND SOUTH OF THE MONTANA HIGHWAY
200/US HIGHWAY 87 CORRIDOR BETWEEN GREAT FALLS AND LEWISTOWN. FOR
TOTAL LIQUID PRECIPITATION THURSDAY NIGHT THROUGH FRIDAY NIGHT THERE
IS A 30 - 60% CHANCE FOR ONE HALF INCH OF LIQUID PRECIPITATION
ACROSS NORTH-CENTRAL MONTANA NORTH OF THE MONTANA HIGHWAY 200/US
HIGHWAY 87 CORRIDOR BETWEEN GREAT FALLS AND LEWISTOWN. FOR TOTAL
LIQUID PRECIPITATION THURSDAY NIGHT THROUGH FRIDAY NIGHT THERE IS A
60 - 90% CHANCE FOR ONE INCH OF LIQUID PRECIPITATION OR GREATER
ACROSS CENTRAL AND SOUTHWESTERN MONTANA.
ACROSS MOST OF THE MOUNTAINS OF NORTH-CENTRAL, CENTRAL, AND
SOUTHWESTERN MONTANA THERE IS GREATER THAN A 60% CHANCE FOR 2
INCHES OF SNOW OR GREATER FROM THURSDAY NIGHT THROUGH FRIDAY
NIGHT. THURSDAY NIGHT THROUGH FRIDAY NIGHT THERE IS A 50 - 80%
CHANCE FOR 4 INCHES OF SNOW OR GREATER ACROSS THE MADISON AND
GALLATIN RANGES AND THE LITTLE BELTS. FRIDAY AFTERNOON INTO EARLY
SATURDAY MORNING THERE IS A HIGH CHANCE THAT AT LEAST SOME LOWER-
ELEVATION LOCATIONS ACROSS NORTH-CENTRAL, CENTRAL, AND
SOUTHWESTERN MONTANA WILL SEE A FEW FLAKES OF SNOW. THERE IS A BIT
OF UNCERTAINTY REGARDING HOW LOW SNOW LEVELS WILL GET WHICH WOULD
INFLUENCE HOW MUCH SNOW WILL BE OBSERVED AT LOWER ELEVATIONS.
RIGHT NOW THERE ARE SOME MODELS SUGGESTING 1 TO 3 INCHES IN GREAT
FALLS BUT THERE IS A LOT OF UNCERTAINTY GIVEN HOW WARM THIS SYSTEM
IS COMPARED TO WHAT WOULD BE MORE PRODUCTIVE FOR HIGHER SNOWFALL
AMOUNTS. -IG/THOR
AVIATION
22/00Z TAF PERIOD
VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD. LIGHT TO
BREEZY WINDS WILL CONTINUES ACROSS ALL TERMINALS, PEAKING DURING
PEAK HEATING HOURS AND WANING THROUGH THE NIGHTS. CLOUD COVER
SHOULD BE LIMITED TO HIGH-LEVEL CLOUDS, BUT INCREASING AND
GRADUALLY LOWERING TOWARDS THE END OF THE TAF PERIOD AS OUR NEXT
SYSTEM APPROACHES. TERMINAL KWYS WILL HAVE A BRIEF PERIOD OF
INCREASED CLOUD COVER 22/09Z TO 22/16Z WITH THE POTENTIAL FOR A
FEW LOW- LEVEL CLOUDS TO DEVELOP DOWN TO 3KFT.
-JR
PRELIMINARY POINT TEMPS/POPS
GTF 73 45 72 44 / 0 0 0 30
CTB 68 40 69 37 / 0 0 0 60
HLN 68 38 70 43 / 0 0 0 40
BZN 67 38 70 40 / 0 0 0 30
WYS 61 30 62 33 / 20 0 10 80
DLN 66 38 66 42 / 10 0 10 80
HVR 69 38 73 41 / 0 0 0 20
LWT 71 45 74 45 / 0 0 0 20
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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