029
FXUS65 KBYZ 152316
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
416 PM MST SUN DEC 15 2024
KEY MESSAGES
- RAIN/SNOW SHOWERS WILL END FROM WEST TO EAST THIS EVENING.
- BREEZY CONDITIONS WITH 25-45 MPH GUSTS WILL CONTINUE THROUGH
THE EVENING. WINDS MONDAY WILL BE MUCH LIGHTER.
- ANOTHER PERIOD OF LIGHT SNOW CAN BE EXPECTED MONDAY NIGHT AND
TUESDAY, WITH LIGHT ACCUMULATIONS POSSIBLE OVER THE LOWER
ELEVATIONS AND SEVERAL INCHES OF SNOW IN THE MOUNTAINS.
UPDATE
AREAS OF RAIN/SNOW SHOWERS ARE SHIFTING EAST AS DRIER/GUSTY
DOWNSLOPE WINDS DEVELOP OVER THE WEST. THERE IS AN UPSTREAM TROF
AXIS APPROACHING W/ 500MB TEMPS OF -35C OVER NORTHWEST MT. THIS
SHOULD HELP TO KEEP SOME SNOW SHOWERS GOING OVER OUR WESTERN
MOUNTAINS AND OUR EASTERN ZONES INTO THE EVENING. HAVE MADE SOME
POP/WX AND WIND ADJUSTMENTS PER CURRENT TRENDS. WILL NOT YET MAKE
ANY CHANGES TO OUR WINTER WEATHER ADVISORY AS SNOW SHOWERS ARE
IMPACTING TRAVEL OVER THE HIGHER HILLS EAST OF BILLINGS. BILLINGS
DIDN'T SEE SNOW ACCUMULATION TODAY BUT JUST TO THE EAST AT ARROW
CREEK HILL (I-90) THE GROUND IS WHITE. TEMPS WILL FALL BELOW
FREEZING TONIGHT SO USE CAUTION IF YOU WILL BE TRAVELING. JKL
DISCUSSION
TONIGHT THROUGH MONDAY NIGHT...
TONIGHT WILL SEE PRECIPITATION EXIT THE REGION TO THE EAST. WINDS
WILL STILL BE GUSTING INTO THE 30S MPH IN FALLON AND CARTER
COUNTIES LEADING TO THE POTENTIAL FOR BLOWING SNOW. WINDS WILL
DECREASE THROUGHOUT THE OVERNIGHT. MINIMUM TEMPERATURES TONIGHT
WILL BE IN THE HIGH TEENS TO MID 20S F ACROSS THE REGION.
TOMORROW WILL BE A TRANSITION DAY BETWEEN THE WEATHER SYSTEM
EXITING AND THE ONE THAT WILL MOVE INTO THE REGION LATE TUESDAY.
TEMPERATURES WILL BE SIMILAR TO TODAY WITH HIGHS IN THE 30S F.
SHORTWAVE RIDGING WILL GIVE WAY TO UPPER LEVEL TROUGHING LATE
TUESDAY. PRECIPITATION CHANCES WILL BEGIN TO ENTER THE WESTERN
MOUNTAINS LATE TOMORROW MORNING AND SPREAD ACROSS THE LOWER
ELEVATIONS (40-60%) IN THE AFTERNOON THROUGH THE OVERNIGHT. AS
OPPOSED TO THIS WEEKENDS SYSTEM, THIS ONE APPEARS TO BE ALL SNOW.
FURTHER DETAILS ON THIS SYSTEM WILL BE IN THE LONG TERM
DISCUSSION. TORGERSON
TUESDAY THROUGH SUNDAY...
A BACK AND FORTH PERIOD FROM LIGHT RAIN/SNOW TO SLIGHT WARMING IS
THE NAME OF THE GAME THROUGH THE REST OF THE WEEK.
STARTING THE GAME OFF IS A WAVE PASSING THROUGH AND ALLOWING A
BACKDOOR COLD FRONT TO SET UP LATE MONDAY INTO TUESDAY MORNING.
THIS PERIOD WILL BE COOL ENOUGH TO SEE ITS PRECIP TYPE OF SNOW,
THOUGH AMOUNTS WITH GENERALLY BE LIGHT, WITH ONLY A 20-30% CHANCE
FOR LOWER ELEVATIONS OF SOUTH-CENTRAL MT TO GET AT LEAST AN INCH
OF SNOW (90% IN THE MOUNTAINS, MAINLY ON WEST FACING SLOPES). ONLY
MINOR WINTER IMPACTS EXPECTED FROM THIS SYSTEM.
MOVING INTO THE MIDWEEK WE SEE A RIDGE BUILD OVER THE STATE AND A
STRONG PRESSURE GRADIENT SET UP OVER SOUTH-CENTRAL MT, INCREASING
STRONG WIND POTENTIAL FROM LIVINGSTON AND NORTH THROUGH
HARLOWTON. CURRENTLY THERE IS A 50-70% CHANCE FOR WIND GUSTS TO
REACH AT LEAST 50 MPH TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. A
COLD FRONT IS THEN PROGGED TO CRASH OVER THE AREA, EXTENDING
BREEZY WINDS OUT OVER THE PLAINS THROUGH SOUTHEAST MONTANA (GUSTS
30-40 MPH). THIS FRONTAL PASSAGE HAS A VERY SMALL CHANCE TO
PRODUCE LIGHT RAIN/SNOW SHOWERS AS WELL.
THE WEEKEND SEE A MORE PROMINENT RIDGE SET UP OVER THE WESTERN
CONUS. THAT SAID, UNCERTAINLY LIES WITH HOW FAR EAST THIS RIDGE
WILL GET TO THROUGH THE WEEKEND. THE TWO EASILY SEEN OUTCOMES ARE
THE RIDGE MOVING FAR ENOUGH EAST THAT ALL OF SOUTH-CENTRAL AND
SOUTHEAST MT SEES WARM AND DRY CONDITIONS. THE OTHER OUTCOME IS
THE RIDGE STAYING FURTHER WEST, WHICH WOULD KEEP FAR EASTERN
MONTANA UNDER MORE CYCLONIC FLOW, ALLOWING A PUSH OF COOLER
TEMPERATURES AND AT LEAST SMALL CHANCES OF RAIN/SNOW TO OCCUR
THROUGH THE WEEKEND. REGARDLESS OF EITHER OUTCOME, NO HUGE WINTER
STORMS ARE EXPECTED DURING THIS PERIOD.
VERTZ
AVIATION
OVERNIGHT TONIGHT WE ARE EXPECTING THE PRECIPITATION TO EXIT TO
THE EAST. THE MAIN CONCERN IN THE SHORT TERM WILL BE SPORADIC
GUSTY WINDS INTO THE 30'S KT RANGE ACROSS THE AREA, WITH EXTRA
EMPHASIS AROUND KSHR AND KMLS. KSHR HAD A OBSERVATION OF A 49KT
GUST AT 2150Z BUT WE DO NOT EXPECT THIS TO BE THE NORMAL. ALL
PRECIP SHOULD BE CLEAR OF OUR AREA BY 6Z WITH THE WINDS DYING DOWN
SHORTLY AFTER. VFR CONDITIONS SHOULD PREVAIL WITH A CHANCE (50%)
OF A DIP DOWN TO MVFR AT SITES LIKE KSHR, KMLS, AND KBHK FOR VIS
REDUCTIONS.
TOMOROROW WE EXPECT WIDESPREAD VFR CONDITIONS AND LIGHER WINDS.
WMR
PRELIMINARY POINT TEMP/POPS
MON TUE WED THU FRI SAT SUN
-----------------------------------------------------------
BIL 025/038 023/038 023/046 030/046 028/049 029/050 031/052
01/B 42/S 10/B 10/U 00/B 00/B 00/B
LVM 022/039 026/041 028/049 033/049 031/053 033/054 033/051
04/J 73/S 11/N 10/N 00/B 00/B 11/B
HDN 024/039 023/037 020/046 027/044 021/047 023/047 025/050
20/B 53/S 10/B 10/U 00/B 00/U 00/B
MLS 024/033 020/029 014/036 021/034 015/037 016/037 021/042
20/U 32/S 11/E 10/B 00/B 00/B 00/B
4BQ 025/035 022/034 018/042 025/039 020/043 021/043 025/046
40/U 21/B 10/B 10/B 00/B 00/B 00/B
BHK 021/030 013/027 010/033 017/032 008/033 011/032 015/037
20/U 12/S 10/E 10/N 00/B 00/B 00/B
SHR 019/040 018/040 018/050 026/047 023/053 027/055 028/053
20/U 22/S 10/B 10/U 00/B 00/U 00/B
BYZ WATCHES/WARNINGS/ADVISORIES
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 11 PM MST THIS
EVENING FOR ZONES 30>33-36-37.
WY...NONE.
WEATHER.GOV/BILLINGS
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