734
FXUS65 KMSO 121827
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
1227 PM MDT SUN JUL 12 2026
DISCUSSION
KEY MESSAGES:
- THE WARMEST TEMPERATURES CONTINUE TODAY AND MONDAY. THERE IS AN
ELEVATED HEAT RISK FOR THOSE SENSITIVE TO HEAT, ESPECIALLY
THOSE WITHOUT COOLING OR HYDRATION.
- LOW RELATIVE HUMIDITY AND STRONG WINDS WILL RESULT IN ELEVATED
FIRE WEATHER CONCERNS TODAY IN SOUTHWEST MONTANA.
- A SURGE OF MONSOON MOISTURE WILL BRING CLOUDS, SHOWERS, AND
THUNDERSTORMS LATE MONDAY INTO TUESDAY.
A RIDGE OF HIGH PRESSURE POSITIONED JUST EAST OF THE NORTHERN
ROCKIES REMAINS THE DOMINANT WEATHER FEATURE THIS AFTERNOON. THE
RIDGE IS MAINTAINING DRY AND HOT CONDITIONS THROUGHOUT THE REGION.
HIGH TEMPERATURES TODAY (SUNDAY) AND MONDAY WILL CLIMB INTO THE
UPPER 80S TO MID-90S IN WESTERN MONTANA, WHILE THE LOWER VALLEYS
OF NORTH-CENTRAL IDAHO WILL APPROACH 100 DEGREES. THE POSITION OF
THE RIDGE IS KEEPING A FAST-MOVING BAND OF AIR ALOFT OVER THE
NORTHWESTERN U.S., RESULTING IN STRONG, GUSTY WINDS REACHING THE
GROUND. THE COMBINATION OF STRONG WINDS, HIGH TEMPERATURES, AND
RELATIVE HUMIDITY DROPPING INTO THE SINGLE DIGITS WILL RESULT IN
CRITICAL FIRE WEATHER CONDITIONS FOR SOUTHWEST MONTANA AND LEMHI
COUNTY.
AN INCOMING UPPER-LEVEL WEATHER DISTURBANCE, COUPLED WITH THE
LEADING EDGE OF MONSOONAL MOISTURE, WILL BRING MOSTLY CLOUDY
CONDITIONS AND A FEW SHOWERS AND ISOLATED THUNDERSTORMS MONDAY
AFTERNOON AND EVENING. CURRENTLY, MOST OF THE SHOWERS AND STORMS
ARE EXPECTED EAST OF THE HIGHWAY 93 CORRIDOR AND OVER THE
BUTTE/BLACKFOOT REGION IN SOUTHWEST MONTANA AND LEMHI COUNTY IN
IDAHO. DUE TO THE VERY DRY AIR AT THE SURFACE, THESE SHOWERS AND
THUNDERSTORMS WILL PRODUCE STRONG, ERRATIC WIND GUSTS POTENTIALLY
EXCEEDING 40 MPH.
BY TUESDAY AFTERNOON AND EVENING, THE ATMOSPHERE WILL MOISTEN
ENOUGH FOR MORE RAIN TO REACH THE GROUND. HOWEVER, THE ERRATIC
WIND GUSTS WILL REMAIN. THE SHOWER AND THUNDERSTORM COVERAGE WILL
BECOME MUCH MORE WIDESPREAD, COVERING MUCH OF WESTERN MONTANA. THE
STORM PREDICTION CENTER HAS PLACED PORTIONS OF WESTERN MONTANA,
INCLUDING LEMHI COUNTY, UNDER A MARGINAL RISK FOR SEVERE
THUNDERSTORMS DUE TO THE POTENTIAL FOR STRONG, GUSTY WINDS. AREAS
WITH THE HIGHEST RISK WILL BE LOCATIONS ALONG I-90 AND EAST OF
HIGHWAY 93 IN WEST-CENTRAL AND SOUTHWEST MONTANA, AS WELL AS LEMHI
COUNTY.
THE THREAT FOR SEVERE THUNDERSTORMS INCREASES ON WEDNESDAY AND
THURSDAY. IF YOU HAVE OUTDOOR PLANS THROUGH MID-WEEK, PLEASE PLAN
ACCORDINGLY.
AVIATION
HIGH DENSITY ALTITUDES ACROSS THE REGION WILL
CONTINUE TODAY AS TEMPERATURES REMAIN WELL ABOVE NORMAL. WINDS
WILL ALSO CONTINUE TO INCREASE THROUGH THE AFTERNOON. EXPECT
SUSTAINED SURFACE WINDS OF 15-20 KNOTS ACROSS REGIONAL TERMINALS
THROUGH 03Z, WITH LOCALIZED GUSTS UP TO 35 KNOTS AT KBTM AND KSMN.
MID AND HIGH-LEVEL CLOUD COVER WILL INCREASE ON MONDAY, WITH
ISOLATED, HIGH-BASED THUNDERSTORMS APPROACHING KSMN AND KBTM BY
LATE MONDAY AFTERNOON.
MSO WATCHES/WARNINGS/ADVISORIES
MT...RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR EAST BEAVERHEAD.
ID...HEAT ADVISORY UNTIL 9 PM MDT THIS EVENING FOR EASTERN LEMHI
COUNTY...WESTERN LEMHI COUNTY.
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