318
FXUS65 KBYZ 260811
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
211 AM MDT TUE AUG 26 2025
KEY MESSAGES
- SEASONABLE TEMPERATURES THIS WEEK.
- THE CHANCE OF SHOWERS AND THUNDERSTORMS RETURNS TO THE MOUNTAINS
TUESDAY AND WEDNESDAY (MODERATE CHANCE) AND THE ENTIRE AREA
THURSDAY INTO SATURDAY (MODERATE TO HIGH CHANCE).
- THUNDERSTORMS THURSDAY INTO SATURDAY COULD PRODUCE LOCALLY HEAVY
RAINFALL.
DISCUSSION
TODAY THROUGH WEDNESDAY NIGHT...
CURRENT ANALYSIS SHOWS SOUTHWEST FLOW AND MOISTURE BEGINNING TO
ADVECT INTO SOUTH CENTRAL MT, WHILE EASTERN MT REMAINS UNDER DRY
NORTHWEST FLOW. AS A RESULT, THIS WILL INCREASE PRECIP CHANCES FOR
THE BEARTOOTH/ABSAROKAS THIS AFTERNOON (30-50%). SHOWERS SHOULD
REMAIN OVER THE MOUNTAINS AND FOOTHILLS THROUGH THE PERIOD,
SPREADING ONTO THE PLAINS WEDNESDAY EVENING (15-30% CHANCE). WITH
WEAK INSTABILITY AND SHEAR PRESENT, AN ISOLATED WEAK THUNDERSTORM
CANNOT BE RULED OUT. OTHERWISE, WITH PWATS NEAR 150-200% OF
NORMAL AND THE LACK OF SHEAR, ANY SLOW MOVING STORMS WILL BE
CAPABLE OF PRODUCING HEAVY RAIN. THIS EVENT IS EXPECTED TO LINGER
INTO THE WEEKEND; SEE DISCUSSION BELOW FOR MORE DETAILS. HIGH
TEMPERATURES TODAY WILL BE IN THE UPPER 70S AND UPPER 80S.
TOMORROW, THE WEST WILL BEGIN TO SEE COOLER CONDITIONS AS THE
SHORTWAVE MOVES IN WITH HIGHS IN THE 70S WITH THE EAST REACHING
THE MID 80S. TS
THURSDAY THROUGH MONDAY...
CONFIDENCE CONTINUES TO INCREASE FOR ANOMALOUSLY HIGH PRECIPITABLE
WATERS AND SLOW-MOVING/WET THUNDERSTORM ACTIVITY THURSDAY &
FRIDAY. ENSEMBLES SUGGEST PWATS OF 1.00-1.20" (1 TO 3 STANDARD
DEVIATIONS ABOVE NORMAL) COURTESY OF DEEP MONSOON MOISTURE
SPREADING NORTHWARD. IN ADDITION TO THE MOISTURE, THERE IS A WEAK
SHORTWAVE EMERGING FROM THE SW FLOW PROVIDING ASCENT, AND MORE
ENERGY DROPPING OUT OF CANADA WHICH MAY PHASE WITH THE INITIAL
WAVE, PROLONGING THE CHANCE OF SHOWERS AND WET T-STORMS INTO
SATURDAY...THOUGH THERE IS CONSIDERABLE MODEL SPREAD HERE. WITH
SUCH WEAK FLOW ALOFT THE STORMS WON'T BE SEVERE, BUT THEY WILL
HAVE THE POTENTIAL TO PRODUCE LOCALLY HEAVY RAIN AND GUSTY OUTFLOW
WINDS. WPC HAS HIGHLIGHTED OUR AREA FOR A MARGINAL RISK OF
EXCESSIVE RAINFALL THURSDAY & FRIDAY. THE LATEST PROBABILITIES FOR
AT LEAST A HALF INCH OF RAIN RANGE FROM 20-60%, GREATEST OVER
MOUNTAINS & FOOTHILLS, BUT ACTUAL AMOUNTS WILL VARY GREATLY DUE IT
BEING CONVECTIVE. SATURDAY SEEMS TO BE THE TRANSITION DAY TO A
DRIER AIR MASS, BUT AS ALREADY MENTIONED QUITE A BIT OF
UNCERTAINTY EXISTS ON THE BACK SIDE OF THE MAIN TROF. IN ADDITION
TO THE ENHANCED PRECIP CHANCES WILL COME COOLER TEMPS, WITH HIGHS
IN THE 70S BY FRIDAY AND SATURDAY.
SUNDAY & MONDAY LOOK TO TREND WARMER & DRIER WITH ENSEMBLE
CONSENSUS SHOWING SHORTWAVE RIDGING ON THESE DAYS. WITH ABOVE
NORMAL HEIGHTS PERSISTING THIS SHOULD PUSH TEMPS BACK TO THE 80S,
WHICH WOULD BE A LITTLE WARMER THAN NORMAL AS WE MOVE INTO EARLY
SEPTEMBER.
JKL
AVIATION
VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD. EXPECT
SLANT RANGE VISIBILITY TO BE REDUCED AT TIMES DUE TO REGIONAL
WILDFIRE SMOKE, ESPECIALLY IN SOUTH-CENTRAL MONTANA AROUND THE
MOUNTAINS. LOOK FOR A FEW SHOWERS AND WEAK T-STORMS OVER THE
BEARTOOTH-ABSAROKAS THIS AFTERNOON AND TONIGHT, AS MONSOON
MOISTURE BEGINS TO INCREASE FROM THE SOUTHWEST. JKL
PRELIMINARY POINT TEMP/POPS
TDY WED THU FRI SAT SUN MON
-------------------------------------------------------
BIL 086 060/083 062/080 059/075 055/078 055/084 056/084
0/B 01/E 24/T 46/T 43/W 11/U 11/U
LVM 085 053/076 052/074 051/073 048/077 048/083 048/082
2/T 24/T 57/T 77/T 54/T 22/T 12/T
HDN 088 057/085 059/083 057/076 053/078 052/084 053/085
0/B 01/E 23/T 45/T 43/W 11/U 11/U
MLS 085 055/086 058/085 060/076 055/076 054/083 055/083
0/B 00/B 01/E 44/W 43/W 21/U 10/U
4BQ 083 059/084 060/080 059/074 055/073 054/080 056/081
0/B 00/B 12/T 55/T 63/W 21/U 11/U
BHK 082 051/084 052/083 056/075 052/074 050/078 051/081
0/U 00/B 00/B 33/T 53/W 21/U 11/U
SHR 086 055/082 055/079 053/074 050/073 049/080 050/081
1/B 12/T 35/T 67/T 65/T 22/T 11/U
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
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