429
FXUS65 KMSO 281922
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
122 PM MDT TUE JUL 28 2026
DISCUSSION
KEY MESSAGES:
- HOT, DRY, AND SMOKY CONDITIONS CONTINUE WITH THE PERSISTENT
WEATHER PATTERN THROUGH SATURDAY.
- DRY THUNDERSTORM POTENTIAL: THURSDAY AFTERNOON THROUGH FRIDAY
MORNING ACROSS SOUTHWEST AND WEST-CENTRAL MONTANA.
- ELEVATED WINDS AND FIRE WEATHER: SATURDAY AND SUNDAY REGION-
WIDE.
DRY SOUTHWESTERLY FLOW ON THE WESTERN PERIPHERY OF THE UPPER-LEVEL
RIDGE WILL MAINTAIN HOT, DRY, AND SMOKY CONDITIONS ACROSS THE
NORTHERN ROCKIES THROUGH THE NEXT SEVERAL DAYS. AIR QUALITY
ADVISORIES HAVE BEEN UPDATED TO REMAIN IN EFFECT FOR LEMHI COUNTY
THROUGH AT LEAST FRIDAY. EXPECT DEGRADED AIR QUALITY AND
VISIBILITY TO PERSIST.
DESPITE THE RELATIVELY OPAQUE APPEARANCE OF THE SKY DUE TO
REGIONAL WILDFIRE SMOKE, INTENSE LATE-JULY SUNSHINE HAS STILL
BEEN ABLE TO OVERCOME MOST SMOKE-SHADING EFFECTS. TEMPERATURES
HAVE STILL BEEN ABLE TO CLIMB TO WITHIN A DEGREE OR TWO OF THEIR
CLEAR-SKY POTENTIAL, KEEPING DAYTIME TEMPERATURES SEVERAL DEGREES
WARMER THAN NORMAL FOR THIS TIME OF YEAR DURING THE AFTERNOON AND
EVENING HOURS.
ISOLATED DRY THUNDERSTORM CHANCES CONTINUE IN SOUTHWEST MONTANA
EACH AFTERNOON. ATTENTION TO DETAIL IN THE FORECAST INDICATES THE
PROGRESSION OF SEVERAL WEAK SHORTWAVE TROUGHS EMBEDDED IN THIS
SOUTHWESTERLY FLOW EJECTING INTO THE REGION THURSDAY AFTERNOON
THROUGH FRIDAY MORNING . STRONG MID-LEVEL LAPSE RATES AND
SUFFICIENT SHEAR COMBINED WITH A VERY DRY SUB-CLOUD LAYER WILL
SUPPORT DRY THUNDERSTORMS CAPABLE OF PRODUCING LIGHTNING AND
STRONG ERRATIC OUTFLOW WINDS EVEN DURING THE OVERNIGHT AND EARLY
MORNING HOURS.
A BROAD LONGWAVE TROUGH OFF THE PACIFIC COAST HEADS INLAND THIS
WEEKEND BREAKING DOWN THE STUBBORN RIDGE THAT WE HAVE BEEN DEALING
WITH FOR QUITE SOME TIME. STRONG PRE-FRONTAL WARMING WILL DRIVE
TEMPERATURES NEAR THE 100 DEGREE MARK ON SATURDAY PARTICULARLY FOR
VALLEYS ALONG AND SOUTH OF I-90.
AS THE COOLER AIRMASS BEGINS TO PASS THROUGH SATURDAY INTO
SUNDAY, EXPECT WIDESPREAD WESTERLY WINDS SUSTAINING 10-25 MPH
WITH GUSTS OF 25 TO 40 MPH ACROSS THE REGION. THIS WIND/HEAT/ AND
LOW RH COMBINATION WILL SIGNIFICANTLY ELEVATE FIRE WEATHER
CONCERNS AND CREATE HAZARDOUS, CHOPPY CONDITIONS ON LAKES AND
WATERWAYS. THIS SYSTEM WILL REMAIN MOSTLY DRY WITH NO SIGNIFICANT
OR NOTABLE PRECIPITATION EXPECTED, BUT TEMPERATURES WILL DROP
10-20 DEGREES BEHIND THE FRONT FOR SUNDAY AND MONDAY BRINGING
TEMPERATURES BACK TO NEAR AND JUST BELOW NORMAL FOR THIS TIME OF
YEAR.
AVIATION
WILDFIRE SMOKE REMAINS A PERSISTENT IMPACT TO THE
REGIONAL AIRSPACE. SLANT-RANGE AND SURFACE VISIBILITIES CONTINUE
TO BOTTOM OUT NEAR 5SM AT TIMES, ESPECIALLY PRONOUNCED DURING THE
LATE AFTERNOON THROUGH SUNSET AS OPTICAL DEPTH INCREASES AND THE
DAY'S FRESH SMOKE ARRIVES FROM FIRES BURNING IN OREGON AND
SOUTHWESTERN IDAHO. ANTICIPATE CONTINUED MOUNTAIN OBSCURATIONS.
RIDGETOP WINDS WILL REMAIN OUT OF THE WEST AND SOUTHWEST AT 10-20
KNOTS THROUGH THE FORECAST PERIOD. HOT TEMPERATURES WILL CONTINUE
TO INCREASE DENSITY ALTITUDES THROUGH SATURDAY IMPACTING AIRCRAFT
PERFORMANCE PARTICULARLY AT HIGHER ELEVATION TERMINALS AND
AIRFIELDS AS TEMPERATURES CONTINUE TO CREEP INTO THE MID AND UPPER
90S EACH DAY.
NOTE: AMD NOT SKED FOR KGPI DUE TO MISSING METARS.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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