680
FXUS65 KBYZ 141455
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
855 AM MDT TUE OCT 14 2025
KEY MESSAGES
- AREAS OF LOW CLOUDS AND FOG CONTINUE IN THE WEST INTO WEDNESDAY,
WITH ONLY GRADUAL IMPROVEMENT THIS AFTERNOON.
- INCREASING CHANCE OF PRECIPITATION TONIGHT THROUGH THURSDAY
EVENING. HIGH ELEVATION SNOW ACCUMULATIONS EXPECTED (ABOVE
6500FT).
- BREEZY WITH SCATTERED SHOWERS FRIDAY.
- TURNING MAINLY DRY AND WARMER NEXT WEEKEND.
UPDATE
WEAK SHORTWAVE LIFTING THRU THE REGION IN SOUTHERLY FLOW ALOFT
SEEMS TO BE PRODUCING SOME LIGHT PRECIP THIS MORNING, MAINLY ALONG
THE EASTERN SLOPES OF THE WESTERN MOUNTAINS, PER CONTINUED
EASTERLY UPSLOPE WINDS. AS TEMPS EKE THRU THE LOWER 30S THE RISK
OF FREEZING PRECIP WILL END, AND THAT SHOULD BE IN THE 15-17Z TIME
FRAME. OTHERWISE, AS THE WAVE EXITS TO THE NORTH, IT WILL BE A
DRY DAY FOR MOST LOCATIONS, WITH CHILLY TEMPS IN OUR WEST. WITH
THAT IN MIND, HAVE DROPPED EXPECTED HIGHS A FEW DEGREES OVER THE
WEST HALF OF OUR CWA, WITH THE EXPECTATION OF UPSLOPE STRATUS
HOLDING THROUGH THE DAY (THOUGH THE AIR MASS ITSELF IS GRADUALLY
WARMING SO TEMPS WILL BE WARMER THAN MONDAY). STRATUS WITH
EMBEDDED FOG WILL BECOME WIDESPREAD AGAIN TONIGHT, WITH HRRR
SHOWING A BETTER CHANCE (20%) IN OUR EAST AS WELL. JKL
DISCUSSION
TODAY...
SOUTHWESTERLY FLOW ALOFT IS CONTINUING TO ADVECT IN MONSOONAL
MOISTURE. THIS FLOW THAT HAS BEEN PRESENT OVER THE PAST DAY OR SO
HAS KEPT MUCH OF THE REGION NEAR SATURATION. AS A RELATIVELY
SMALL VORTICITY MAXIMUM MOVES UP INTO SOUTHWEST MONTANA AHEAD OF
THE PARENT TROUGH THIS MORNING, CHANCES FOR PRECIPITATON WILL
INCREASE. THERE ARE MULTIPLE CHALLENGES WITH THE FORECAST PRECIP
THIS MORNING. THE FIRST BEING THAT THIS VORT MAX IS NOT SUPER
STRONG SO HOW WIDESPREAD THE PRECIPITATION IS REMAINS A QUESTION.
THE BIGGER QUESTION THOUGH IS THE PRECIPITATION TYPE.
850MB AND 700MB MESOANALYSIS SHOW IMPRESSIVE WAA MOVING IN FROM
THE PLAINS WHICH HAS WARMED THESE LEVELS UP TO 2-5C IN THE
FOOTHILLS AND EVEN AS FAR EAST AS BILLINGS. THIS COULD BRING THE
POTENTIAL FOR SOME LIGHT FREEZING RAIN DURING THE MORNING COMMUTE
IN THESE AREAS.
AN ADDITIONAL CONCERN FOR THIS MORNING IS THAT IF THE CLOUDS ARE
ABLE TO CLEAR ENOUGH TO DROP SURFACE TEMPS LOW ENOUGH FOR
FREEZING RAIN IN SOME PLACES, FOG OR FREEZING DRIZZLE COULD OCCUR
ELSEWHERE. AS MOST LOCATIONS ARE NEAR SATURATION AT THIS HOUR,
COMBINING THAT WITH THE LIGHT WINDS, FOG WOULD LIKELY DEVELOP
EASILY IN THE TRADITIONALLY PRONE AREAS AND ALONG EASTERN ASPECTS
OF TERRAIN DUE TO THE WEAK UPSLOPE FLOW. THERE IS A SATURATED
BOUNDARY LAYER BELOW A RELATIVELY DRY MID-LEVEL PRESENT ON RAP
FORECAST SOUNDINGS AROUND SUNRISE AT KLVM/KBIL/KSHR. THIS WOULD BE
CONDUCIVE FOR DRIZZLE OR FREEZING DRIZZLE IF THE SURFACE TEMP
DOES GET COLD ENOUGH.
THIS WAVE PUSHES THROUGH FAIRLY QUICKLY AND BY MIDDAY ALL PRECIP
AND FOG SHOULD NO LONGER BE AN ISSUE. SCATTERED CLOUDS THANKS TO
THE SLOW MOVING PARENT TROUGH WILL REMAIN THROUGHOUT THE DAY. WMR
WEDNESDAY AND BEYOND...
LATE TONIGHT AND INTO THE DAY WEDNESDAY THE AFOREMENTIONED HIGH
AMPLITUDE TROUGH WILL PUSH EASTWARDS BRINGING THE NEXT CHANCE FOR
WIDESPREAD PRECIPITATION.
THIS SYSTEM SHOULD BE MOSTLY STRAIGHTFORWARD IN TERMS OF
PRECIPITATION TYPE. SNOW LEVELS WEDNESDAY AM START PRETTY HIGH,
8-9KFT, BEFORE THEY GRADUALLY AND SLOWLY LOWER THROUGHOUT THE
DURATION OF THE EVENT. BY THURSDAY PM THERE IS A 30-50% CHANCE
THAT SNOW LEVELS DROP BELOW 6KFT WHICH COULD BRING SOME LIGHT,
NON-ACCUMULATING, SNOW INTO SOME AREAS OF POPULATION. SNOW TOTALS
WILL BE HIGHEST IN THE ABSAROKA/BEARTOOTH MOUNTAINS DUE TO THE
SOUTHWESTERLY FLOW FAVORING THAT REGION OF GREATEST PRECIP. THE
SOUTH/SOUTHWEST FACING ASPECTS WILL SEE THE HIGHEST TOTALS. SW
FACING ASPECTS ABOVE 9KFT HAVE A 30-50% OF SEEING A FOOT OF SNOW
OVER THIS 3 DAY PERIOD. OTHER MOUNTAINS WILL ALSO SEE SNOW BUT
MUCH LESS. THERE IS A 60% CHANCE THAT BURGESS JUNCTION IN THE
BIGHORN MOUNTAINS WILL SEE AT LEAST 6" OF SNOW WHICH WOULD IMPACT
TRAVEL ON US-14.
BEHIND THE TROUGH NORTHWESTERLY FLOW WILL ENVELOP THE REGION WHICH
COULD MAKE FOR A WINDY FRIDAY, ESPECIALLY IN THE GAP WIND PRONE
AREAS OF THE FOOTHILLS. AS OF RIGHT NOW WINDS ARE FORECAST TO BE
MANAGEABLE (REMAINING UNDER 40MPH) HOWEVER, THIS COULD QUICKLY
CHANGE AS WE GET BETTER RESOLUTION MODELS FORECASTING THE EVENT IN
THE COMING DAYS. WMR
AVIATION
A COMBINATION OF LOW STRATUS, FOG AND PATCHY DRIZZLE IS CREATING
DIFFICULT AVIATION WEATHER FOR LOCATIONS WEST OF ROSEBUD COUNTY,
ESPECIALLY ALONG THE EASTERN SLOPES OF THE MOUNTAINS. EXPECT MVFR
TO LIFR IN THESE AREAS THIS MORNING. EXPECT IMPROVEMENT TO
VFR/MVFR IN THE AFTERNOON, THEN TONIGHT STRATUS AND FOG WILL
LIKELY INCREASE IN COVERAGE AGAIN. EASTERN SLOPES OF THE MOUNTAINS
WILL REMAIN OBSCURED THROUGH THE PERIOD, WHILE TOPS ARE
PERIODICALLY OBSCURED IN LIGHT RAIN/SNOW SHOWERS. JKL
PRELIMINARY POINT TEMP/POPS
TDY WED THU FRI SAT SUN MON
-------------------------------------------------------
BIL 046 036/051 043/051 041/060 038/057 040/067 042/056
2/W 34/W 68/R 41/B 31/U 01/B 45/R
LVM 042 031/051 033/049 030/056 030/058 035/066 033/052
2/W 66/W 77/R 31/M 31/M 12/R 66/R
HDN 049 033/053 040/050 038/061 035/057 034/070 039/058
2/W 35/W 88/R 62/R 31/M 01/U 45/R
MLS 057 038/057 044/052 040/058 036/056 033/068 039/059
2/W 37/T 88/R 63/R 11/U 00/U 22/R
4BQ 061 040/060 044/052 041/057 036/053 035/068 041/060
1/U 25/T 87/R 63/R 11/U 00/U 22/R
BHK 059 038/055 041/054 038/055 032/054 029/065 036/061
2/W 26/T 87/R 63/R 10/N 00/U 11/B
SHR 052 031/057 035/050 033/060 030/055 030/071 036/059
2/B 25/W 88/R 62/R 32/R 00/U 35/R
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
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