018
FXUS65 KBYZ 140751
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
151 AM MDT TUE OCT 14 2025
KEY MESSAGES
- AREAS OF LOW CLOUDS, FOG, VERY LIGHT SNOW AND DRIZZLE CONTINUE
IN THE WEST TONIGHT INTO TUESDAY; MORE FOG AND LOW CLOUDS
EXPECTED TUESDAY NIGHT INTO WEDNESDAY.
- INCREASING CHANCE OF PRECIPITATION TUESDAY NIGHT THROUGH
THURSDAY EVENING. HIGH ELEVATION SNOW ACCUMULATIONS POSSIBLE
(ABOVE 6500FT).
- BREEZY WITH SCATTERED SHOWERS FRIDAY.
- TURNING MAINLY DRY AND WARMER NEXT WEEKEND.
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
LOW STRATUS AND AREAS OF FOG WILL PREVAIL THROUGH THIS MORNING
FOR AREAS FROM YELLOWSTONE COUNTY WESTWARD AS WELL AS EASTERN
UPSLOPE AREAS ALONG THE BIG HORN MTNS. THIS WILL IMPACT
KBIL/KSHR/KLVM/K6SO/K3HT. EXPECT MVFR/IFR CONDITIONS WITH POCKETS
OF LIFR AND EVEN OCCASIONAL VLIFR AT TIMES THROUGH 15Z. THERE IS
A 30% CHANCE OF POCKETS OF LIGHT FREEZING DRIZZLE OR SNOW AS WELL
DURING THIS TIME. IN ADDITION, THERE IS ALSO A 10% CHANCE OF
BRIEF FREEZING RAIN FROM 10Z-15Z...WITH THE MOST LIKELY TERMINAL
IMPACTED KLVM. SOME PRECIPITATION MAY SHIFT OVER TO LIGHT RAIN
BEFORE ENDING AROUND 17Z. MOUNTAIN PASSES AND FOOTHILLS WILL
LIKELY REMAIN OBSCURED THROUGH THE NIGHT WHILE MOUNTAIN TOPS
SHOULD REMAIN ABOVE THE LOW CLOUDS. ISOLATED LIGHT SNOW SHOWERS
WILL PUSH INTO THE MOUNTAIN TOPS AROUND 13Z.
LOW CLOUD DECKS ARE FORECAST TO ERODE FROM SOUTH TO NORTH AFTER
18Z WITH MOSTLY VFR PREVAILING FOR THE BULK OF THE AFTERNOON. BT
PRELIMINARY POINT TEMP/POPS
TDY WED THU FRI SAT SUN MON
-------------------------------------------------------
BIL 049 035/051 043/051 041/060 038/057 040/067 042/056
2/R 34/R 68/R 41/B 31/U 01/B 45/R
LVM 049 030/051 033/049 030/056 030/058 035/066 033/052
2/O 66/R 77/R 31/M 31/M 12/R 66/R
HDN 051 032/053 040/050 038/061 035/057 034/070 039/058
3/O 35/R 88/R 62/R 31/M 01/U 45/R
MLS 057 039/057 044/052 040/058 036/056 033/068 039/059
3/R 37/T 88/R 63/R 11/U 00/U 22/R
4BQ 062 043/060 044/052 041/057 036/053 035/068 041/060
2/B 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/R 26/T 87/R 63/R 10/N 00/U 11/B
SHR 056 030/057 035/050 033/060 030/055 030/071 036/059
2/O 25/R 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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