421
FXUS65 KBYZ 151931
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
131 PM MDT WED OCT 15 2025
KEY MESSAGES
- LOWER ELEVATION RAIN AND MOUNTAIN SNOW THROUGH THURSDAY NIGHT;
HEAVIEST PRECIPITATION EAST OF BILLINGS; SNOW LEVELS FALL TO
AROUND 6500 FEET.
- BREEZY AND A LITTLE WARMER WITH SCATTERED SHOWERS FRIDAY AND
SATURDAY; SHOWERS MOST LIKELY FRIDAY NIGHT AND EARLY SATURDAY.
- DRY AND WARMER SUNDAY (TEMPS IN 60S TO NEAR 70F).
- TURNING COOLER AND UNSETTLED AGAIN MONDAY THROUGH WEDNESDAY;
SOME MOUNTAIN SNOW EXPECTED.
DISCUSSION
THROUGH THURSDAY NIGHT...
FIRST LET'S ADDRESS THE FOG & STRATUS, WHICH CONTINUES TO AFFECT
MUCH OF OUR FORECAST AREA TODAY. LOW LEVEL MOIST UPSLOPE FLOW
CONTINUES INTO THIS EVENING, BUT WINDS WILL SHIFT TO THE W-NW OVER
THE WEST HALF OF OUR FORECAST AREA TONIGHT. AS THIS HAPPENS THE
RISK OF DENSE FOG AND VERY LOW STRATUS WILL DIMINISH. POOR FLYING
WEATHER WILL PERSIST LONGEST (THRU MUCH OF THURSDAY NIGHT) EAST OF
BILLINGS WHERE PRECIP WILL BE HEAVIEST. BUT WE WILL FINALLY BE
EXITING THE MOIST AND SHALLOW UPSLOPE REGIME WHICH HAS PLAGUED US
SINCE MONDAY.
UPPER LOW IS LOCATED OVER EAST CENTRAL NV AND IS BEGINNING TO LIFT
TO THE NORTHEAST. A WAVE OF MID LEVEL WARM ADVECTION BROUGHT
SHOWERS AND SOME EMBEDDED T-STORMS FROM SOUTH TO NORTH LATE LAST
NIGHT AND THIS MORNING, BUT MOST ACTIVITY HAS LIFTED TO OUR NORTH
AS OF 1PM TODAY. INCREASING LARGE SCALE ASCENT/HEIGHT FALLS WILL
LEAD TO INCREASING CHANCES OF SHOWERS THIS AFTERNOON AND EVENING,
AND IN FACT WE ARE SEEING COOLING TOPS IN CENTRAL WY WHICH SEEM TO
BE THE EARLY HINTS OF THIS. FLOW ALOFT WILL BECOME STRONGLY
DIFFLUENT AS THE LOW REACHES SOUTHWEST WY TONIGHT...AND THIS IS
WHEN PRECIP WILL BECOME MOST WIDESPREAD. MODELS HAVE COME TOGETHER
IN THE LAST 12-18HRS, SHOWING A CONSOLIDATED LOW AND PERIOD OF
STRONG FORCING THURSDAY AND THURSDAY NIGHT...THE LATTER HALF OF
WHICH WILL BE DRIVEN BY THE TROWAL AS THE LOW REACHES FAR EASTERN
MT AND ND. EXPECT PRECIP TO TAPER OFF IN OUR WEST BY THURSDAY
EVENING AND FAR EAST BY EARLY FRIDAY. HEAVIEST PRECIP AMOUNTS (1+
INCHES) WILL BE OVER NORTHERN ROSEBUD, CUSTER AND FALLON COUNTIES.
CHANCE OF EXCEEDING AN INCH OF RAIN IN THIS AREA IS ABOUT 60%.
RAIN TOTALS WILL RANGE FROM 0.25-0.75" ELSEWHERE, LOWEST IN
WHEATLAND AND WESTERN FOOTHILLS PER DOWNSLOPE EFFECTS. REGARDING
MOUNTAIN SNOWFALL, THIS LOOKS LIKE A 5-10" SNOWFALL FOR THE
BEARTOOTH-ABSAROKAS, AND 3-6" FOR THE CRAZIES, PRYORS & BIGHORNS.
THE CHANCE OF REACHING 10+ INCHES IN THE BEARTOOTH-ABSAROKAS IS
ONLY 15%. AS FOR SNOW LEVELS, THEY SHOULD REMAIN ABOVE 6500 FEET.
THIS SYSTEM WILL NOT BRING WET SNOWFALL FOR RED LODGE. GIVEN IT
IS MID-OCTOBER, THAT IS SAYING SOMETHING. THIS IS A SEASONABLY
WARM SYSTEM. ONE FINAL ITEM: AS THE PRECIP TAPERS OFF IT WILL
BECOME BREEZY ALONG THE WESTERN FOOTHILLS THURSDAY NIGHT, WITH
GUSTS 30-40 MPH AT BIG TIMBER & HARLOWTON.
FRIDAY AND SATURDAY...
LIGHT PRECIP MAY LINGER IN THE FAR EAST A LITTLE PAST DAYBREAK
FRIDAY, OTHERWISE WE ARE LOOKING AT A PERIOD OF SUBSIDENCE AND
DRYING, WITH GUSTY WEST WINDS ON FRIDAY. ENSEMBLES HAVE COME INTO
BETTER AGREEMENT HERE, AND THE PROBABILITY OF GUSTS EXCEEDING 40
MPH IS 50-85%, HIGHEST IN THE NORTH AND EAST. CANNOT RULE OUT
GUSTS TO 50 MPH AT PLACES LIKE HARLOWTON AND BAKER, BUT IT DOES
LOOK AS IF THE STRONGEST 850MB WINDS ARE EARLY IN THE DAY AND
MIXING SHOULD BE LOWER THAN 700MB.
A FAIRLY POTENT BUT FAST-MOVING SHORTWAVE IN WNW FLOW ALOFT WILL
PUSH ACROSS THE AREA FRIDAY NIGHT INTO EARLY SATURDAY. THIS WAVE
WILL BRING MORE SHOWERS AT LOWER ELEVATIONS AND A FEW INCHES OF
MOUNTAIN SNOW, FOLLOWED BY ANOTHER DOSE OF BREEZY W-NW WINDS, BUT
IT'S INTERESTING TO NOTE THAT POST-FRONTAL COOLING MAY BE ENOUGH
TO BRING SOME BRIEF WET SNOW TO THE HIGHEST HILLS OF SOUTHEAST
MT. THIS BEARS WATCHING.
REGARDING TEMPS, LOOK FOR HIGHS IN THE 50S TO NEAR 60F FRIDAY, AND
UPPER 40S AND 50S SATURDAY.
SUNDAY...
THIS IS A DRY AND WARMER DAY UNDER A BRIEF PERIOD OF SHORTWAVE
RIDGING. LOOK FOR HIGHS IN THE 60S. THERE ARE SIGNS OF SOME
ENHANCED GAP FLOW SATURDAY NIGHT AND EARLY SUNDAY, AND PERHAPS
40-50 MPH GUSTS AT LIVINGSTON AND NYE (50% CHANCE). A SIGN OF THE
CHANGING SEASON, FOR SURE.
MONDAY THROUGH NEXT WEDNESDAY...
UPPER LEVEL RIDGE IS EXPECTED TO BREAK DOWN IN SOME FASHION EARLY
NEXT WEEK, BUT DETAILS ARE HIGHLY UNCERTAIN AT THIS TIME. GENERAL
EVOLUTION OF THE PATTERN SUGGESTS A PROGRESSIVE PACIFIC FLOW.
THUS, EXPECT COOLER TEMPS (50S) WITH PERIODIC CHANCES OF SHOWERS,
INCLUDING MOUNTAIN SNOW. STAY TUNED.
JKL
AVIATION
AREAS OF LOW STRATUS AND FOG WILL CONTINUE TO IMPACT MUCH OF THE
REGION THROUGH THE REMAINDER OF THE DAY AND INTO TONIGHT, WITH
REDUCTIONS TO MVFR/IFR/LIFR. AS WINDS SHIFT TO THE W-NW TONIGHT
AND INCREASE THURSDAY, THE RISK OF DENSE FOG AND VERY LOW CEILINGS
WILL DECREASE, ESPECIALLY IN THE WEST. THIS WILL BE SOMETHING TO
MONITOR. VERY POOR FLIGHT CONDITIONS WILL LAST LONGEST IN THE EAST
(KMLS & KBHK).
LOOK FOR PERIODIC SHOWERS AND A FEW EMBEDDED T-STORMS LATE THIS
AFTERNOON AND TONIGHT AS A STRONG WEATHER SYSTEM APPROACHES. A
MORE WIDESPREAD LOWER ELEVATION RAIN AND MOUNTAIN SNOW IS EXPECTED
LATE TONIGHT THROUGH THURSDAY, PRODUCING MVFR-IFR. MOUNTAINS WILL
BE FREQUENTLY OBSCURED IN RAIN/SNOW SHOWERS THRU THIS EVENING,
THEN BECOME COMPLETELY OBSCURED LATE TONIGHT AND THURSDAY. W-NW
SURFACE WINDS WILL GUST 15-25KTS TOMORROW. JKL
PRELIMINARY POINT TEMP/POPS
THU FRI SAT SUN MON TUE WED
-----------------------------------------------------------
BIL 042/048 042/062 037/056 039/067 041/054 032/054 036/056
89/R 21/N 40/U 02/W 54/W 21/U 11/B
LVM 034/047 035/059 029/054 034/063 031/049 025/053 029/053
67/R 11/N 50/U 04/W 75/W 21/B 11/B
HDN 040/047 038/062 036/055 034/068 038/055 030/056 032/057
8+/R 61/N 61/U 01/B 64/W 21/U 11/B
MLS 045/049 041/059 036/054 034/066 039/056 032/057 034/057
8+/R 81/N 30/U 01/B 32/W 11/U 01/B
4BQ 044/048 041/058 036/051 034/068 040/055 032/055 034/055
9+/R 71/N 51/B 00/U 33/W 21/U 01/B
BHK 042/048 038/058 033/053 029/065 035/056 030/056 031/056
99/R 91/N 20/N 00/U 21/N 11/U 00/B
SHR 039/047 032/062 034/052 029/070 033/054 026/055 029/055
9+/R 51/B 61/U 01/U 55/W 31/U 11/B
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
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