439
FXUS65 KMSO 191953
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
1253 PM MST MON JAN 19 2026
DISCUSSION
KEY MESSAGES:
- FORECAST CHALLENGES WITH VALLEY FOG WILL CONTINUE.
- UNCERTAINTY IN THE PATTERN CHANGE FOR THE NEXT 10 DAYS.
THERE IS NOW SOME CONFIDENCE THAT WHILE 2 DISTINCT WAVES DROP
SOUTH OUT OF CANADA BRINGING COLDER AIR MASSES, BOTH SYSTEMS WILL
BE MOISTURE STARVED. HIGH PRESSURE AND VALLEY INVERSIONS WILL BE
THE MAIN THEME THROUGH AT LEAST THE 24-26TH AS OF CURRENT MODEL
RUNS. THE TWO WAVES, FIRST ON TUESDAY AND SECOND FRIDAY, WILL
ALLOW FOR A MINOR COOL DOWN, TEMPERATURES ACROSS THE REGION MAY
ACTUALLY DROP A COUPLE DEGREES BELOW NORMAL BY FRIDAY, ALBEIT
ONLY BRIEFLY WITH SLOW WARMING EXPECTED THROUGHOUT THE WEEKEND.
WHAT IS EXPECTED IS A CONTINUATION ON THE CURRENT PATTERN, VALLEY
FOG AND LOW STRATUS IMPROVING DURING THE AFTERNOON BUT RETURNING
OVERNIGHT. THIS PATTERN MAY PERSIST INTO THE FOLLOWING WEEK, I.E.
26 JAN.
THE MODELS, WHICH FOR WEEKS HAVE BEEN TRYING TO INSERT A PATTERN
CHANGE, HAVE COMPLETELY BACKED AWAY FROM DEMONSTRATING CHANGE AS
OF THE 12Z JAN 19 RUNS.
AVIATION
LITTLE TO NO CHANGES TO THE WEATHER CONDITIONS FOR THE NEXT 24
HOURS. FOG AND LOW STRATUS WILL CONTINUE TO IMPACT THE VALLEYS OF
NORTH CENTRAL IDAHO INTO NORTHWEST MONTANA. KGPI IS ANTICIPATED TO
HAVE A STRATUS DECK ALL DAY. KMSO COULD BE IMPACTED FOR A PERIOD
OF TIME THIS MORNING BY FOG. KSMN SHOULD EXPECTED HAZY CONDITIONS,
BUT AT THIS TIME FOG APPEARS TO HAVE FINALLY BROKEN OUT OF THE
AREA.
MSO WATCHES/WARNINGS/ADVISORIES
MT...ID...AIR STAGNATION ADVISORY UNTIL 4 PM PST TUESDAY FOR NORTHERN
CLEARWATER MOUNTAINS...OROFINO/GRANGEVILLE REGION...
SOUTHERN CLEARWATER MOUNTAINS.
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