543
FXUS65 KTFX 242301
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
501 PM MDT SAT OCT 24 2026
AVIATION SECTION UPDATED.
KEY MESSAGES
- ISOLATED FOG POSSIBLE SUNDAY MORNING.
- COOLER TEMPERATURES AND DRY CONDITIONS PERSIST THROUGH THE WEEKEND.
- ANOTHER PERIOD OF UNSETTLED WEATHER MOVES IN LATE MONDAY
THROUGH NEXT WEEKEND.
DISCUSSION
/ISSUED 139 PM MDT SAT OCT 24 2026/
- METEOROLOGICAL OVERVIEW:
WEAK ZONAL FLOW ALOFT WITH HIGH PRESSURE WILL CONTINUE TO DOMINATE
THE WEATHER PATTERN THROUGH SUNDAY. THIS CONTINUES TO BRING BENIGN
CONDITIONS TODAY AND SUNDAY, WITH CALMER WINDS AND COOLER
TEMPERATURES. WITH RECENT THE SNOWFALL AND SOME MELTING SNOW
TODAY, THERE WILL BE LINGERING LOW LEVEL MOISTURE ACROSS THE
REGION. ANOTHER MORNING OF CALM WINDS AND HIGH PRESSURE CAN
DEVELOP FOG AND/OR LOW STRATUS CLOUDS ACROSS THE REGION SUNDAY
MORNING.
MONDAY, A CLOSED UPPER-LEVEL LOW MOVES ONSHORE OF THE PACIFIC
NORTHWEST, WITH THE WAVE OPENING BACK UP AS IT PROPAGATES EAST. THIS
NEXT INCOMING SYSTEM BRINGS SNOW TO THE HIGHER ELEVATIONS AND
RAIN/SNOW TO THE LOWER ELEVATIONS. THERE REMAINS SOME UNCERTAINTY
IN HOW MUCH COLD AIR ALOFT THIS SYSTEM BRINGS, BUT LOW
TEMPERATURES TUESDAY MORNING BELOW FREEZING CAN ALLOW FOR LIGHT
SNOW TO MIX DOWN TO LOWER ELEVATIONS.
ENSEMBLES HINT AT AN UNSETTLED, COOLER PATTERN STICKING AROUND
THROUGH NEXT WEEKEND AS A CONTINUOUS LINE OF SHORTWAVE TROUGH
MOVE ACROSS THE NORTHWEST U.S. GENERALLY THE PATTERN SHOWS
MOUNTAIN SNOW WITH RAIN AT LOWER ELEVATIONS DURING THE DAY, AND
LIGHT SNOW AT NIGHT.
- FORECAST CONFIDENCE & SCENARIOS:
FOG SUNDAY MORNING:
BOTH FORECAST SOUNDINGS AND PROBABILISTIC GUIDANCE SUPPORTS THE
POTENTIAL FOR FOG AND STRATUS DEVELOPING FOR ISOLATED PORTIONS OF
THE REGION, WITH HIGHEST CHANCES IN CASCADE AND LEWIS & CLARK
COUNTIES. HERE, THERE'S A 20-60% CHANCE FOR FOG DEVELOPMENT, WITH A
20-30% CHANCE FOR FOG DROPPING VISIBILITY TO BELOW A MILE. ONE
CAVEAT IS THERE IS ALSO A 20-60% CHANCE FOR LOW STRATUS TO
DEVELOP, WHICH MAY LIMIT OVERALL FOG DEVELOPMENT.
STORM SYSTEM EARLY NEXT WEEK:
ENSEMBLES DON'T HINT AT THIS SYSTEM BEING A BIG SNOW PRODUCER FOR
EITHER THE MOUNTAINS OR LOWER ELEVATIONS. THIS SYSTEM TRIES TO PULL
IN COLDER AIR ALOFT, BUT IT'S NOT VERY RIGOROUS. SNOW LEVELS TRY
TO FALL TO THE LOWER ELEVATIONS OVERNIGHT MONDAY INTO TUESDAY
MORNING, WHICH WILL ALLOW FOR SOME SNOW TO REACH THE LOWER
ELEVATIONS. HOWEVER, CURRENT TRENDS HAVE THE WET BULB
TEMPERATURES RISE ABOVE FREEZING, LIMITING OVERALL IMPACTS AT
LOWER ELEVATIONS. -WILSON
AVIATION
25/00Z TAF PERIOD
THE PRIMARY CONCERN THIS TAF PERIOD WILL BE FOR FOG AND LOW CLOUDS
THROUGH SUNDAY MORNING ACROSS MOST TERMINALS. AREAS OF GREATEST
CONCERN ARE ACROSS SW MT VALLEYS AND PORTIONS OF CENTRAL MT.
CONFIDENCE IN DENSE FOG WAS TOO LOW TO INCLUDE MENTION IN ANY TAF AT
THIS TIME. MOUNTAINS WILL BECOME INCREASINGLY OBSCURED HEADING
INTO SUNDAY MORNING. -AM
PRELIMINARY POINT TEMPS/POPS
GTF 24 38 22 41 / 0 0 0 0
CTB 22 41 20 43 / 0 0 0 0
HLN 23 38 22 46 / 0 0 0 0
BZN 20 45 18 50 / 0 0 0 0
WYS 15 51 17 48 / 0 0 0 0
DLN 24 43 25 51 / 0 0 0 0
HVR 21 46 22 50 / 0 0 0 0
LWT 20 40 23 48 / 0 0 0 0
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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