658
FXUS65 KMSO 271900
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
100 PM MDT MON APR 27 2026
DISCUSSION
KEY MESSAGES:
-SLOW WARMING TREND WITH LINGERING SHOWERS, ESPECIALLY DURING THE
AFTERNOON AND EVENING.
NORTHWESTERLY FLOW WILL PERSIST OVER THE NORTHERN ROCKIES THROUGH
MID-WEEK. THIS FLOW PATTERN IS CONDUCIVE TO SHOWER ACTIVITY
ESPECIALLY DURING THE AFTERNOON AND EARLY EVENING HOURS. THE
INSTABILITY DURING THE AFTERNOON COULD BE EFFICIENT ENOUGH TO
SUPPORT ISOLATED THUNDERSTORMS. A FEW VERY SUBTLE DISTURBANCES
EMBEDDED IN THE FLOW WILL KEEP SOME SHOWERS LINGERING THROUGHOUT
THE OVERNIGHT HOURS, MAINLY ACROSS NORTHWEST MONTANA EACH NIGHT.
TEMPERATURES WILL BE SLOWLY WARMING EACH DAY, BUT NIGHT-TIME LOWS
WILL BE STILL DROPPING AROUND FREEZING IN MOST VALLEY LOCATIONS.
THE EXCEPTION BEING THE DEEP VALLEYS OF IDAHO AND CLEARWATER
COUNTIES, WHERE TEMPERATURES SHOULD BE IN THE UPPER 30S TO LOW
40S AT NIGHT. THIS SLOW WARMING TREND WILL CAUSE SNOW LEVELS TO
SLOWLY RISE OVER THE NEXT COUPLE OF DAYS. SNOW IMPACTS ARE
EXPECTED TO BE FAIRLY LOCALIZED MAINLY IMPACTING THE MOUNTAIN
PASSES AT TIMES ALONG THE CONTINENTAL DIVIDE AND OCCURRING DURING
THE OVERNIGHT INTO EARLY MORNING HOURS.
A RIDGE OF HIGH PRESSURE SLIDES OVER THE REGION BY THURSDAY
CAUSING A WARMING AND DRYING TREND FOR THE NORTHERN ROCKIES.
TEMPERATURES ARE EXPECTED TO CLIMB ABOVE SEASONAL AVERAGES BY
THURSDAY. A WEAK DISTURBANCE ON FRIDAY IS EXPECTED TO SLIDE ALONG
THE CANADIAN BORDER CAUSING INCREASED CLOUDS AND A FEW LIGHT
SHOWERS, BUT TEMPERATURES ARE EXPECTED TO REMAIN ABOVE NORMAL.
THE CONSENSUS OF THE LONG TERM MODELS HAVE A LOW PRESSURE SYSTEM
SLIDING SOUTHWARD ALONG THE WEST COAST THIS WEEKEND THEN MOVE
INTO THE GREAT BASIN AREA BY THE FIRST PART OF NEXT WEEK. THE
EXACT PATH OF THIS TRANSITION IS STILL UNCERTAIN, BUT THE MAJORITY
(75%) HAVE THE SYSTEM HAVING A RELATIVELY MINIMAL IMPACT TO THE
NORTHERN ROCKIES OTHER THAN INCREASED SHOWER ACTIVITY.TEMPERATURES
APPEAR TO REMAIN WARM FOR THIS TIME OF YEAR KEEPING HIGH SNOW
LEVELS.
AVIATION
NORTHWESTERLY FLOW WILL PERSIST OVER THE REGION FOR
THE NEXT 24 TO 48 HOURS. SHOWER ACTIVITY WILL INCREASE THIS
AFTERNOON INTO EARLY EVENING. THE MAJORITY OF THE SHOWER ACTIVITY
WILL BE MAINLY CONFINED TO THE HIGHER TERRAIN, BUT ALL TERMINALS
HAVE THE POTENTIAL OF VICINITY SHOWERS THROUGHOUT THE PERIOD. A
WEAK DISTURBANCE IS EXPECTED TO MOVE THROUGH NORTHWEST THIS
EVENING INTO THE OVERNIGHT HOURS WHICH HAS THE POTENTIAL TO CAUSE
SOME SHOWERS TO PASS OVER KGPI. THE PRECIPITATION TYPE ASSOCIATED
WITH THESE SHOWERS APPEAR TO BE SNOW, WHICH WILL CAUSE A REDUCTION
IN CEILINGS AND VISIBILITY FOR A PERIOD OF TIME.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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