612
FXUS65 KBYZ 121530
AFDBYZ
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
930 AM MDT WED AUG 12 2026
KEY MESSAGES
- HAZY CONDITIONS FROM REGIONAL WILDFIRES ARE EXPECTED TO IMPROVE
THROUGH THE DAY TODAY.
- A MARGINAL RISK (1/5) EXISTS FOR SEVERE WEATHER OVER SOUTHEAST
MT TODAY. MAIN RISKS ARE LARGE HAIL, HEAVY RAIN AND STRONG
WINDS.
- MUCH COOLER WITH WIDESPREAD SHOWERS AND THUNDERSTORMS (40-100%
CHANCE) THURSDAY THROUGH FRIDAY, POSSIBLY INTO SATURDAY.
LOCALLY HEAVY DOWNPOURS ARE LIKELY WITH ANY STORMS. SEVERE
THREAT IS VERY LOW.
- WARMER WITH A DAILY CHANCE (20-50%) OF THUNDERSTORMS THIS SUNDAY
INTO MONDAY.
UPDATE
QUICK MORNING UPDATE TO PRECIPITATION CHANCES AND AMOUNTS THROUGH
TONIGHT TO REFLECT LATEST MODEL GUIDANCE. OVERALL A GOOD CHANCE
FOR SHOWERS AND THUNDERSTORMS THIS AFTERNOON OVER THE EASTERN HALF
OF THE FORECAST AREA AS A STRONG DISTURBANCE MOVES NORTHEAST OUT
OF WYOMING. LATEST HRRR SHOWS WIDESPREAD PRECIPITATION COVERAGE.
THERE IS A BRIEF PERIOD EARLY THIS AFTERNOON WHEN CAPE/SHEAR
PROFILES WILL SUPPORT AN ISOLATED SEVERE THUNDERSTORM THREAT OVER
PORTIONS OF SE MONTANA. INGREDIENTS ARE MUCH WEAKER THAN ON
TUESDAY GIVEN COOLER TEMPERATURES AND LESS FAVORABLE SHEAR AND THE
WINDOW WILL BE SHORT LIVED WITH CAPE VALUES DROPPING QUICKLY BY
LATE AFTERNOON. HRRR IS SHOWING SOME PRECIPITATION BULLSEYES OVER
AN INCH ALONG AND EAST OF A MILES CITY TO BROADUS LINE THIS
AFTERNOON. GIVEN RECENT DRYNESS THE FLASH FLOOD THREAT IS LOW WITH
1HR AND 3HR FLASH FLOOD GUIDANCE OVER 2 INCHES OVER THE EASTERN
CWA. THAT SAID, LOCALLY HEAVY RAINFALL IS EXPECTED WITH CONVECTION
TODAY. CHAMBERS
DISCUSSION
TODAY THROUGH TUESDAY...
TROUGHING OVER THE PACIFIC NW WILL GRADUALLY STRENGTHEN OVER THE
NEXT COUPLE DAYS, INCREASING SOUTHWEST FLOW OVER THE REGION. THIS
ALONG WITH PERSISTENT EASTERLY TO SOUTHEASTERLY WINDS AT THE LOW
LEVELS WILL WORK TO INCREASE ATMOSPHERIC MOISTURE VALUES AND
INCREASE CHANCES FOR SHOWERS AND THUNDERSTORMS. ENSEMBLES DEPICT
WEAK ENERGY MOVING UP UNDER SOUTHWEST FLOW THIS AFTERNOON AND
EVENING. THE MOST FAVORABLE AREA FOR STRONG TO SEVERE
THUNDERSTORMS WILL BE SOUTHEAST MT WHERE SHORT TERM ENSEMBLES
DEPICT 1000-1500 J/KG OF MUCAPE AND 30-40 KTS OF BULK SHEAR. THE
MAIN THREATS WITH ANY SEVERE THUNDERSTORMS WILL BE HEAVY RAIN,
LARGE HAIL AND STRONG WINDS. WITH PRECIPITABLE WATER VALUES
150-200% OF NORMAL AND A FEW SLOW MOVING STORMS EXPECTED, THE
THREAT FOR LOCALIZED HEAVY RAIN WILL BE A CONCERN WEDNESDAY AND
THURSDAY. INTO THURSDAY, INSTABILITY AND SHEAR LOOK TO HAVE
SLIGHTLY LESSER VALUES, BUT A FEW STRONG THUNDERSTORMS ARE
POSSIBLE ACROSS THE AREA. WITH THE MAIN THREAT BEING HEAVY RAIN,
THOSE RECREATING IN OR NEAR BURN SCARS SHOULD STAY AWARE OF
CHANGING CONDITIONS REGARDING FLASH FLOODING. SCATTERED SHOWERS
AND ISOLATED EMBEDDED THUNDERSTORMS LOOK TO KEEP LOW TO MODERATE
CHANCES FOR PRECIP FRIDAY AND SATURDAY ACROSS THE PLAINS WITH HIGH
CHANCES ACROSS AREA MOUNTAINS. THE NBM GIVES ABOUT A 60-90%
CHANCE OF A HALF AN INCH OF PRECIPITATION THURSDAY THROUGH FRIDAY
WITH ABOUT A 60-70% CHANCE FOR AN INCH FOR AREA MOUNTAINS AND
SOUTHEAST MT. ENSEMBLES THEN SHOW WEAK RIDGING STARTING TO BUILD
BACK IN BEGINNING NEXT WEEK.
TEMPERATURES WILL GRADUALLY COOL OVER THE NEXT COUPLE DAYS WITH
HIGHS FORECAST TO BE IN THE 80S TODAY THEN 70S TO LOW 80S
THURSDAY THROUGH SATURDAY. TEMPS WILL INCREASE BACK INTO THE 80S
FOR NEXT WEEK. TS
AVIATION
WILDFIRE SMOKE WILL CONTINUE TO IMPACT THE REGION THROUGH THE
PERIOD. SLANT RANGE VISIBILITY WILL BE REDUCED. REDUCTIONS IN
SURFACE VISIBILITY ARE POSSIBLE THIS MORNING, WITH PERIODS OF
MVFR REDUCTIONS POSSIBLE (20% CHANCE) NEAR KLVM. SCATTERED
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP MAINLY FROM
ROSEBUD COUNTY AND EAST THIS MORNING BEFORE INCREASING THROUGH THE
AFTERNOON. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS DEVELOP
OVER THE WEST LATE THIS AFTERNOON AND MOVE EAST IN THE EVENING.
HEAVY RAIN COULD LEAD TO MVFR CONDITIONS. STP/ARCHER
PRELIMINARY POINT TEMP/POPS
TDY THU FRI SAT SUN MON TUE
-------------------------------------------------------
BIL 085 060/077 058/073 055/076 056/083 058/086 059/085
2/W 74/T 97/T 65/T 61/B 11/B 31/B
LVM 086 050/076 048/072 045/077 045/082 048/084 049/082
1/K 66/T 99/T 87/T 72/T 22/T 42/T
HDN 087 057/082 054/075 050/078 051/085 053/088 055/087
3/T 75/T 95/T 46/T 51/U 21/B 31/B
MLS 084 057/079 057/075 052/076 053/083 056/087 058/086
4/T 56/T +5/W 13/W 32/W 21/B 32/T
4BQ 084 059/080 059/076 054/076 055/082 057/086 060/086
7/T 56/T +4/W 34/T 42/T 22/T 21/B
BHK 080 052/077 052/075 047/075 048/080 051/086 054/085
8/T 45/T +8/T 11/E 23/T 32/T 22/T
SHR 085 054/079 053/073 050/074 049/080 050/084 052/084
4/T 37/T 98/T 78/T 72/T 11/U 11/B
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
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