691
FXUS65 KMSO 200744
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
144 AM MDT MON JUL 20 2026
DISCUSSION
KEY MESSAGES:
- PERIODS OF SMOKE PERSIST ACROSS THE REGION TODAY. LOW RAIN
SHOWER AND STORM CHANCES.
- MONSOON MOISTURE RETURNS TODAY THROUGH THURSDAY. LOCALIZED
FLASH FLOODING IS POSSIBLE.
- HOT TEMPERATURES ARE EXPECTED THIS WEEK, WITH HIGHS REACHING
THE 90S UP TO 106 DEGREES IN THE LOWER ELEVATIONS OF IDAHO.
MOSTLY DRY CONDITIONS TODAY, WITH PERIODS OF SMOKE AND HAZE FROM REGIONAL
WILDFIRES IN OREGON AND WASHINGTON, WILL DEGRADE AIR QUALITY AND REDUCE
VISIBILITY IN ISOLATED AREAS. TODAY, WE'LL SEE THE FIRST INDICATIONS
OF THE MONSOON MOISTURE, WHICH WILL BE MOSTLY IN THE FORM OF CLOUDS,
THOUGH AN ISOLATED SHOWER, ESPECIALLY IN LEMHI COUNTY, IS POSSIBLE.
THE INCREASED CLOUD COVER WILL ALSO HELP WITH SLIGHTLY HIGHER
AFTERNOON HUMIDITY VALUES, THOUGH ELEVATED FIRE WEATHER CONCERNS
WILL REMAIN.
STARTING TUESDAY, A MORE SIGNIFICANT SURGE OF MONSOON MOISTURE WILL ARRIVE
IN THE NORTHERN ROCKIES WITH 200 TO 250 PERCENT OF NORMAL MOISTURE CONTENT.
THIS MOISTURE, ALONG WITH AN APPROACHING SHORTWAVE TROUGH, WILL BE ENOUGH
FOR MORE WIDESPREAD SHOWERS AND SCATTERED THUNDERSTORMS ACROSS WESTERN
MONTANA AND NORTH-CENTRAL IDAHO. THESE THUNDERSTORMS WILL BE CAPABLE OF
PRODUCING GUSTY, ERRATIC WINDS IN EXCESS OF 40 MPH, FREQUENT LIGHTNING, AND
BRIEF HEAVY RAINFALL. IF YOU HAVE PLANS FOR OUTDOOR ACTIVITIES, PLAN
ACCORDINGLY EACH AFTERNOON AND EVENING THROUGH THURSDAY.
WHILE WE'LL EXPERIENCE DAILY SHOWER AND THUNDERSTORM ACTIVITY THIS
WEEK, WE ARE STILL LOOKING AT ABOVE-NORMAL TEMPERATURES ACROSS
THE REGION. WESTERN MONTANA VALLEYS WILL SEE TEMPERATURES IN THE
MID-90S, WITH TEMPERATURES REACHING THE LOW 100S IN THE LOWER
HELLS CANYON AREA OF NORTH-CENTRAL IDAHO WEDNESDAY THROUGH THE
REST OF THE WEEK.
BY FRIDAY INTO THE WEEKEND, THE APEX OF THE RIDGE OF HIGH PRESSURE WILL
MOVE EAST OVER THE NORTHERN PLAINS OF THE U.S., ALLOWING FOR INCREASING
WESTERLY WINDS, DRIER AIR, AND A DECREASE IN SHOWER ACTIVITY. THIS WEATHER
PATTERN WILL ALSO REINTRODUCE NEAR-CRITICAL FIRE WEATHER CONCERNS ACROSS
WESTERN MONTANA AND NORTH-CENTRAL IDAHO.
AVIATION
MOSTLY DRY CONDITIONS TODAY, WITH PERIODS OF SMOKE
AND HAZE FROM REGIONAL WILDFIRES IN OREGON AND WASHINGTON, WILL
DEGRADE AIR QUALITY AND REDUCE VISIBILITY IN ISOLATED AREAS.
WE'LL SEE THE FIRST INDICATIONS OF MONSOON MOISTURE, WHICH WILL
BE MOSTLY IN THE FORM OF CLOUDS, THOUGH AN ISOLATED SHOWER,
ESPECIALLY IN LEMHI COUNTY, IS POSSIBLE. KGPI, KMSO, AND KBTM WILL
SEE A LIGHT EASTERLY GRADIENT THIS AFTERNOON AND EVENING, THOUGH
GUSTS WILL REMAIN BELOW 20 KTS.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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