884
FXUS65 KMSO 101016
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
416 AM MDT SUN MAY 10 2026
DISCUSSION
KEY MESSAGES:
- SUMMER-LIKE WARMTH BEGINS TODAY: UNSEASONABLY HOT TEMPERATURES
WITH WIDESPREAD HIGHS IN THE 80S TODAY AND LOW 90S IN THE
LOWER ELEVATIONS OF IDAHO.THIS NEAR-RECORD WARMTH WILL PERSIST
THROUGH MID-WEEK.
- SPRING THUNDERSTORMS WEDNESDAY AND THURSDAY: MEAN HAZARDS WILL
BE LIGHTNING AND ERRATIC OUTFLOW WINDS.
- WEEKEND COOL DOWN, BUT NEAR SEASONABLE LEVELS.
THE SHORT-TERM IS DOMINATED BY AN UPPER-LEVEL RIDGE THAT WILL
BRING AN IMMEDIATE TASTE OF SUMMER TO THE NORTHERN ROCKIES. A
WEAK, MOISTURE-STARVED SHORTWAVE WILL TRACK NEAR THE CANADIAN
BORDER TONIGHT WHICH WILL BRING PASSING MID TO HIGH-LEVEL CLOUDS
AND BREEZY CONDITIONS THROUGH MONDAY. IT WILL SLIGHTLY TEMPER THE
NEAR-RECORD WARMTH FOR MONDAY ACROSS MUCH OF THE REGION. THE
NOTABLE EXCEPTION WILL BE FURTHER SOUTH, SUCH AS IN THE SALMON
AREA, WHERE TEMPERATURES ARE EXPECTED TO REMAIN QUITE WARM IN THE
MID-80S.
THE RIDGE RE-AMPLIFIES ON TUESDAY, SETTING THE STAGE FOR PEAK
HEATING LASTING INTO WEDNESDAY. THERE IS A 50% CHANCE THAT SOME OF
THE LOWER VALLEYS OF WESTERN MONTANA COULD HIT 90 DEGREES.
BY WEDNESDAY AFTERNOON AND THURSDAY, THE RIDGE AXIS SHIFTS
EASTWARD, INTRODUCING SOUTHWEST FLOW AND INCREASING INSTABILITY.
THIS WILL SET THE STAGE FOR SPRING THUNDERSTORMS WITH LIGHTNING
AND GUSTY OUTFLOWS THE MAIN THREATS.
LOOKING OUT TO THE LATE WEEK PATTERN, FORECAST MODELS ARE POINTING
TO A MUCH LARGER PATTERN CHANGE, THROUGH THERE REMAINS
CONSIDERABLE UNCERTAINTY REGARDING ITS EXACT EVOLUTION. THE LATEST
ENSEMBLE CLUSTER ANALYSIS DEPICTS A SPLIT BETWEEN SOLUTIONS...ON
ONE END OF THE SPECTRUM THEY KEEP THE WARMER PATTERN GOING LONGER
WHILE ON THE OTHER END, THEY BRING A MUCH COOLER/WETTER TROUGH
OVER THE REGION.
AVIATION
VFR FLYING CONDITIONS WILL CONTINUE ACROSS THE
NORTHERN ROCKIES OVER THE NEXT SEVERAL DAYS. AN UPPER LEVEL WAVE
WILL BRING A FAIR AMOUNT OF MIDDLE TO HIGH CLOUDS THROUGH SUNDAY
NIGHT. THIS SYSTEM WILL ALSO BRING A SLIGHT INCREASE TO THE
AFTERNOON WINDS BOTH TODAY AND MONDAY. UNSEASONABLY HOT AFTERNOON
TEMPERATURES IN THE 80S TO NEAR 90 WILL RESULT IN HIGH DENSITY
ALTITUDES ACROSS THE LOWER ELEVATIONS OF IDAHO AND WESTERN MONTANA
THROUGH MID-WEEK.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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