739
FXUS65 KMSO 130820
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
220 AM MDT THU AUG 13 2026
DISCUSSION
KEY MESSAGES:
- SCATTERED SHOWERS AND THUNDERSTORMS WITH GUSTY WINDS IN
WESTERN MONTANA TODAY.
- TEMPORARY RELIEF FROM SMOKE WITH EASTERLY WINDS, EXCEPT FOR
NORTH-CENTRAL IDAHO.
- A COOLER, ACTIVE SHOWER AND STORM PATTERN CONTINUES THROUGH
FRIDAY BEFORE A RIDGE OF HIGH PRESSURE SLOWLY REBUILDS THIS
WEEKEND.
ISOLATED SHOWERS AND THUNDERSTORMS WILL CONTINUE TO STREAM OVER
PORTIONS OF NORTHWEST AND WEST-CENTRAL MONTANA THROUGH MID-
MORNING, BRINGING GUSTY WINDS AND OCCASIONAL LIGHTNING. AFTERNOON
AND EVENING THUNDERSTORMS WILL RETURN AS A SECONDARY SURGE OF
MOISTURE INTERACTS WITH A PACIFIC TROUGH AND AFTERNOON HEATING.
ABUNDANT LIGHTNING AND SUDDEN WIND GUSTS EXCEEDING 40 MPH, ALONG
WITH LOCALIZED HEAVY RAIN, WILL BE POSSIBLE. THIS IS MOST
CONCERNING IN DEEP CANYONS, ACROSS BURN SCARS, AND URBAN AREAS.
THERE IS A 25 PERCENT PROBABILITY FOR RAIN RATES TO REACH 0.25
INCHES PER HOUR UNDER THE STRONGER THUNDERSTORMS. SOUTHWEST
MONTANA HAS THE HIGHEST LIKELIHOOD OF EXPERIENCING THE STRONGEST
THUNDERSTORMS THROUGH 10 PM.
AFTERNOON TEMPERATURES TODAY AND FRIDAY WILL TREND 5 TO 10 DEGREES
BELOW NORMAL, WITH HIGHS IN THE MID- TO UPPER 70S AND LOW 80S.
EAST TO NORTHEAST WINDS WILL REMAIN ELEVATED, BUT NOT AS STRONG AS
YESTERDAY EVENING.
A RIDGE OF HIGH PRESSURE WILL GRADUALLY REBUILD OVER THE NORTHERN
ROCKIES THIS WEEKEND INTO EARLY NEXT WEEK UNDER SOUTHWEST WINDS
ALOFT. WHILE AFTERNOON TEMPERATURES WILL WARM, MONSOONAL MOISTURE
DRAWN IN BY THE SOUTHWEST WINDS WILL KEEP ATMOSPHERIC MOISTURE
ELEVATED. THIS WILL SUSTAIN NEAR-DAILY AFTERNOON SHOWER AND
THUNDERSTORM CHANCES THROUGH THE WEEKEND AND INTO NEXT WEEK,
PREVENTING A RETURN TO COMPLETELY DRY CONDITIONS. WILDFIRE SMOKE
WILL REMAIN A CHALLENGE THROUGH THE FORECAST PERIOD, WITH LITTLE
IMPROVEMENT WHEN THE SOUTHWEST FLOW RETURNS THIS WEEKEND, AS THE
SOURCE REGIONS OF THE SMOKE IS LOCATED IN WASHINGTON AND OREGON.
AVIATION
ISOLATED SHOWER AND THUNDERSTORM ACTIVITY WILL CONTINUE
TO STREAM OVER PORTIONS OF NORTHWEST AND WEST-CENTRAL MONTANA
THROUGH MID-MORNING. KMSO, KHRF, AND KBTM, ALONG WITH LOCATIONS
IN-BETWEEN, WILL HAVE THE HIGHEST PROBABILITY OF SEEING SHOWERS
AND THUNDERSTORMS THIS MORNING BETWEEN 13/1200Z AND 13/1600Z.
SHOWER AND THUNDERSTORM ACTIVITY WILL INCREASE THIS AFTERNOON,
AFTER 13/2000Z, WITH A FOCUS ACROSS SOUTHWEST MONTANA AND LEMHI
COUNTY THROUGH 14/0400Z THIS EVENING. ABUNDANT LIGHTNING, SUDDEN,
GUSTY, AND ERRATIC WINDS OF 35 TO 40 KNOTS, AND LOCALIZED HEAVY
RAIN WILL REMAIN THE PRIMARY CONCERNS.
WILDFIRE SMOKE WILL REMAIN A CHALLENGE THROUGH THE FORECAST
PERIOD, WITH LITTLE IMPROVEMENT WHEN THE SOUTHWEST FLOW RETURNS
THIS WEEKEND, AS THE SOURCE REGIONS OF THE SMOKE IS LOCATED IN
WASHINGTON AND OREGON.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...
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