585
FXUS65 KMSO 311953
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
153 PM MDT SUN MAY 31 2026
DISCUSSION
KEY MESSAGES:
- THROUGH MONDAY: A SLOW MOVING WEATHER SYSTEM WILL BRING
PROLONGED, MODERATE TO HEAVY RAINFALL, FOCUSED ALONG THE DIVIDE
AND IN GLACIER PARK REGION.
- RIVER, STREAM, AND CREEK RISES FROM WIDESPREAD RAIN AND SNOW
MELT, LEADING TO THE POTENTIAL MINOR FLOODING.
A WIDESPREAD RAINFALL EVENT WILL CONTINUE THROUGH TUESDAY AS A LOW
PRESSURE SYSTEM SPINS OVER CENTRAL MONTANA. THE FOCUS OF
PRECIPITATION IS NOW NORTH I-90 AND EAST OF US-93. CURRENTLY,
RADAR IS ESTIMATING LIGHT PRECIPITATION RATES BUT IT IS EXPECTED
FOR PERIODS OF MODERATE PRECIPITATION TO PULSE INTO NORTHWEST MT
THROUGH MIDNIGHT. AN ADDITIONAL 0.50 TO 1.50 INCHES OF
PRECIPITATION IS POSSIBLE FROM THE MISSION VALLEY/ MOUNTAINS AND
EASTWARD TO THE CONTINENTAL DIVIDE. SOME FLOODING CONCERNS
CONTINUE, ESPECIALLY AT FLATHEAD RIVER NEAR COLOMBIA FALLS AND
CLARK FORK ABOVE MISSOULA. THESE RIVER SYSTEMS MAY NOT PEAK UNTIL
MONDAY AFTERNOON. MOST STREAMS AND CREEKS ARE RUNNING COLD AND
FAST, EXERCISE CAUTION WHEN RECREATING IN OR AROUND ANY WATER
BODY.
SNOW LEVELS ARE ABOVE 7000 FEET, THE MAIN CONCERN NOW IS COLD,
WET, AND RAW BACK COUNTRY CONDITIONS. ANY RECREATORS SHOULD
PREPARE FOR THESE CONDITIONS.
A QUICK MID-WEEK WARMUP BRINGS US BACK TO NORMAL TEMPERATURES OR
SLIGHTLY ABOVE NORMAL. LATE WEDNESDAY INTO THURSDAY AND AGAIN
SATURDAY INTO SUNDAY, COULD BRING MORE UNSETTLED WEATHER PRODUCING
SHOWERS AND THUNDERSTORMS. MORE TO COME ON THE EVOLUTION OF THESE
SYSTEMS.
AVIATION
A LARGE UPPER LOW WILL WOBBLE AROUND EASTERN MONTANA
INTO MONDAY BRINGING PERIODS OF PRECIPITATION INTO THE NORTHERN
ROCKIES. THE HEAVIEST PRECIPITATION WILL BE NORTH OF I-90,
MOUNTAIN OBSCURATIONS WILL BE COMMON, WITH VISIBILITY AND CEILINGS
DOWN TO MVFR AT TIMES (INFREQUENTLY TO IFR) AT KGPI AND
OCCASIONALLY KMSO. OTHER TERMINAL SITES AND ACROSS NORTH-CENTRAL
IDAHO WILL SEE LOWER PRECIPITATION CHANCES AND LESSER AVIATION
IMPACTS. WEST TO NORTHWEST WINDS OF 15-20 KTS WILL BE COMMON EACH
AFTERNOON AS WELL.
MSO WATCHES/WARNINGS/ADVISORIES
MT...FLOOD WATCH THROUGH MONDAY MORNING FOR FLATHEAD/MISSION
VALLEYS...WEST GLACIER REGION.
ID...NONE.
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