119
FXUS65 KMSO 211929
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
129 PM MDT SUN JUN 21 2026
DISCUSSION
KEY MESSAGES:
- SHOWERS AND ISOLATED THUNDERSTORMS ALONG THE CONTINENTAL DIVIDE
THIS AFTERNOON.
- WARMING AND DRYING TREND THIS WEEK, WITH A 30 TO 60 PERCENT
PROBABILITY OF MODERATE OR HIGHER HEATRISK IMPACTS.
- COOLER AND SHOWERY CONDITIONS EXPECTED THIS COMING WEEKEND,
JUNE 27-30.
A LOW-PRESSURE SYSTEM OVER ALBERTA WILL TRIGGER ISOLATED
THUNDERSTORMS AND SCATTERED SHOWERS ALONG THE CONTINENTAL DIVIDE
TODAY, PRIMARILY FOCUSING AROUND GLACIER NATIONAL PARK. AS THIS
LOW-PRESSURE CENTER SLOWLY MOVES EASTWARD, ANOTHER ROUND OF
AFTERNOON AND EVENING THUNDERSTORMS IS EXPECTED OVER THESE SAME
AREAS ON MONDAY.
A RIDGE OF HIGH PRESSURE WILL BUILD OVER THE REGION TUESDAY
THROUGH THURSDAY, BRINGING A DISTINCT WARMING AND DRYING TREND TO
THE NORTHERN ROCKIES. TEMPERATURES WILL CLIMB WELL ABOVE SEASONAL
AVERAGES BY THURSDAY, REACHING THE UPPER 80S TO LOW 90S ACROSS
MOST VALLEY LOCATIONS. LOW-ELEVATION AREAS NEAR RIGGINS, IDAHO,
ARE EXPECTED TO HIT TRIPLE DIGITS.
THERE IS A 30 TO 40 PERCENT PROBABILITY THAT MODERATE HEATRISK
IMPACTS WILL OCCUR IN WESTERN MONTANA, AND A 60 TO 70 PERCENT
PROBABILITY FOR THE VALLEYS OF NORTH-CENTRAL IDAHO. MODERATE
HEATRISK IMPACTS AFFECT ANYONE SENSITIVE TO HEAT, ESPECIALLY THOSE
WITHOUT ADEQUATE COOLING OR HYDRATION.
LONG-RANGE FORECASTS INDICATE A BROAD TROUGH OF LOW-PRESSURE WILL
MOVE INTO THE PACIFIC NORTHWEST BY THIS COMING WEEKEND, JUNE
27TH-30TH. THIS SYSTEM WILL BRING SIGNIFICANT COOLING ALONG WITH
WIDESPREAD RAINFALL. CURRENT ENSEMBLE FORECAST GUIDANCE HAS
AFTERNOON TEMPERATURES TOPPING OUT 10 TO 15 DEGREES BELOW NORMAL
ON SATURDAY.
AVIATION
A LOW-PRESSURE SYSTEM OVER ALBERTA WILL TRIGGER
ISOLATED THUNDERSTORMS AND SCATTERED SHOWERS ALONG THE CONTINENTAL
DIVIDE TODAY, PRIMARILY FOCUSING AROUND GLACIER NATIONAL PARK.
THERE IS A 30 TO 40 PERCENT PROBABILITY THAT SHOWERS WILL DEVELOP
FAR ENOUGH WEST TO IMPACT THE KGPI TERMINAL BETWEEN 21/2000Z AND
22/0200Z, BRINGING LIGHT RAINFALL, AND A 10 TO 15 PERCENT
PROBABILITY OF LIGHTNING. OTHERWISE, BREEZY AFTERNOON WINDS WITH
GUSTS UP TO 20 KNOTS WILL DEVELOP ACROSS ALL OF WESTERN MONTANA
AND NORTH-CENTRAL IDAHO.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page