059
FXUS65 KMSO 020652
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
1252 AM MDT FRI OCT 2 2026
DISCUSSION
KEY MESSAGES:
- WARMING AND DRYING TREND THROUGH SUNDAY; COOL/COLD VALLEY LOWS
WITH PATCHY FROST.
- WESTERLY WINDS INCREASE THIS AFTERNOON AND MONDAY WITH PASSING
DISTURBANCES.
MID- AND HIGH-LEVEL CLOUDS WILL MOVE THROUGH TODAY AS A WEAK
DISTURBANCE PASSES ALONG THE CANADIAN BORDER. A FEW LIGHT SHOWERS
OR VIRGA MAY DEVELOP THIS MORNING AS SHOWN BY HIGH-RESOLUTION
FORECAST MODELS, BUT VERY LITTLE IF ANY RAIN WILL REACH THE
SURFACE. DAYTIME TEMPERATURES WILL WARM 5 TO 10 DEGREES COMPARED
TO YESTERDAY, ACCOMPANIED BY A NOTABLE AFTERNOON WESTERLY BREEZE
GUSTING BETWEEN 15 AND 25 MPH.
OTHERWISE, HIGH PRESSURE RIDGING WILL BUILD OVER THE REGION,
BRINGING A VERY PLEASANT WEEKEND. DAYTIME TEMPERATURES WILL RUN 10
TO 20 DEGREES ABOVE NORMAL ALONGSIDE ABUNDANT DAILY SUNSHINE.
CLEAR SKIES OVERNIGHT WILL PROMOTE STRONG COOLING, DROPPING VALLEY
TEMPERATURES INTO THE 30S AND CAUSING PATCHY FROST IN COLD-PRONE
LOCATIONS. ISOLATED, SHALLOW MORNING VALLEY FOG IS POSSIBLE IN
LOW-LYING BASINS, THOUGH WIDESPREAD IMPACTS ARE UNLIKELY.
A SECOND WEAK DISTURBANCE WILL SLIDE EAST THROUGH THE REGION
MONDAY INTO TUESDAY, WEAKENING THE HIGH-PRESSURE RIDGE AND
INCREASING WESTERLY WINDS. SLIGHT ATMOSPHERIC INSTABILITY FROM
THIS SYSTEM MAY SUPPORT ISOLATED AFTERNOON SHOWERS AND GUSTIER
SURFACE WINDS. HIGH PRESSURE WILL REBUILD MID-TO-LATE NEXT WEEK,
MAINTAINING WARM AND DRY CONDITIONS. THE FIRST SIGN OF A CHANGE
APPEARS IN ENSEMBLE MODELS AROUND OCTOBER 9TH OR 10TH, WHEN A
POTENTIAL (60% CHANCE) WEAK UPPER-LEVEL TROUGH BRINGS COOLER
TEMPERATURES AND LIGHT SHOWERS; HOWEVER, CONFIDENCE IN EXACT
TIMING AND DETAILS REMAINS LOW. OVERALL, THE PRIMARY STORY OVER
THE NEXT TWO WEEKS IS PERSISTENT HIGH PRESSURE, LEADING TO WARMER
AND DRIER THAN NORMAL CONDITIONS. OCCASIONAL WEAK DISTURBANCES
WILL KNOCK DOWN THE RIDGE BUT NO SIGNIFICANT PRECIPITATION
EXPECTED.
AVIATION
VFR CONDITIONS WILL PREVAIL TODAY THROUGH THE WEEKEND,
THOUGH VERY LOCALIZED VALLEY FOG MAY BRIEFLY REDUCE VISIBILITY
EACH MORNING. A WEAK UPPER-LEVEL DISTURBANCE MOVING ALONG THE
CANADIAN BORDER WILL INCREASE WESTERLY WINDS THIS AFTERNOON,
PRODUCING VALLEY GUSTS OF 15-25 KNOTS. MID- AND HIGH-LEVEL CLOUDS
WILL PASS THROUGH THE AREA TODAY, ESPECIALLY THIS MORNING, WITH A
FEW LIGHT SHOWERS POSSIBLE ACROSS NORTHWEST MONTANA. OTHERWISE,
DRY CONDITIONS WILL PERSIST THROUGH THE WEEKEND.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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