373
FXUS65 KMSO 271834
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
1234 PM MDT MON JUL 27 2026
DISCUSSION
KEY MESSAGES:
- HOT, DRY, AND SMOKY CONDITIONS CONTINUE THROUGH THIS WEEK.
- ISOLATED THUNDERSTORMS REMAIN A THREAT FOR SOUTHWEST MONTANA
INCLUDING BUTTE. POTENTIALLY EXPANDING NORTHWARD LATE THIS WEEK.
- EVEN HOTTER, DRIER, AND WINDIER CONDITIONS BY SATURDAY.
ELEVATED FIRE WEATHER CONDITIONS.
- COOL DOWN TO NEAR AVERAGE TEMPERATURES SUNDAY, THOUGH IT
REMAINS DRY.
THE NORTHERN ROCKIES WILL REMAIN ALONG THE WESTERN PERIPHERY OF A
BROAD RIDGE OF HIGH PRESSURE. TOWARD THE END OF THE WORK WEEK,
THE RIDGE WILL AMPLIFY AS A DEEP, STATIONARY PACIFIC TROUGH MOVES
EAST INTO BRITISH COLUMBIA. BEGINNING AS EARLY AS FRIDAY, EMBEDDED
SHORTWAVE ENERGY EJECTING OFF THE TROUGH COULD INTERACT WITH THE
RIDGE. CURRENT GUIDANCE TARGETS LATE SATURDAY INTO EARLY SUNDAY
MORNING FOR THE RIDGE BREAKDOWN.
HOT, DRY, AND SMOKY CONDITIONS WILL BE COMMON THIS WEEK.
DEPENDING ON THE THICKNESS OF WILDFIRE SMOKE, DAYTIME TEMPERATURES
COULD BE ATTENUATED SEVERAL DEGREES FROM THE CURRENT FORECAST.
DEGRADED AIR QUALITY AND REDUCED VISIBILITY REMAIN THE PRIMARY
IMPACTS. SENSITIVE GROUPS SHOULD LIMIT OUTDOOR EXERTION.
THE ONLY HINT AT PRECIPITATION FOR THE FIRST PART OF THE WEEK IS
ISOLATED THUNDERSTORM CHANCES IN LEMHI COUNTY AND SOUTHWEST
MONTANA (MAINLY AFTERNOONS/EVENINGS) AS LIMITED MONSOONAL MOISTURE
INTERACTS WITH DAYTIME HEATING. BEGINNING WEDNESDAY AND LASTING
THROUGH FRIDAY, MODELS SHOW POTENTIAL DISTURBANCES THAT COULD
EXPAND THUNDERSTORM COVERAGE FURTHER NORTH INTO WEST-CENTRAL
MONTANA AND NORTH-CENTRAL IDAHO. IF THUNDERSTORMS DO DEVELOP, THEY
WOULD BE MOSTLY DRY WITH GUSTY OUTFLOW POTENTIAL. THERE IS A
CONCERN FOR NOCTURNAL STORMS, PARTICULARLY ON THURSDAY NIGHT BUT
OVERALL CONFIDENCE IS LOW AT THIS POINT.
THERE IS A GROWING CONSENSUS THAT A RIDGE BREAKDOWN WILL OCCUR
LATER SATURDAY INTO SUNDAY BASED ON THE LATEST ENSEMBLE CLUSTERS.
THIS TRANSITION PERIOD IS SIGNIFICANT GIVEN INCREASED WIND
POTENTIAL AND ELEVATED FIRE WEATHER CONCERNS.
AVIATION
WILDFIRE SMOKE WILL CONTINUE TO BE THE PRIMARY CONCERN THROUGH
MID WEEK, AS TERMINALS WILL OCCASIONALLY DROP TO MVFR
VISIBILITIES. OTHERWISE, RIDGING WILL DOMINATE WITH HOT AND DRY
CONDITIONS. THERE IS ONLY A SLIGHT PROBABILITY (LESS THAN 20
PERCENT) FOR THUNDERSTORM DEVELOPMENT ACROSS LEMHI COUNTY INTO
SOUTHWEST MONTANA EACH AFTERNOON. EXPECT AFTERNOON GUSTS TO 20 KTS
DIMINISHING AROUND SUNSET FOR TERMINAL SITES.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...
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