939
FXUS65 KBYZ 211027
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
327 AM MST THU NOV 21 2024
KEY MESSAGES
- LOW CHANCE (20%) OF FREEZING RAIN ON FRIDAY FOR LOCATIONS WEST,
NORTHWEST, AND NORTH OF BILLINGS.
- NEXT ROUND OF PRECIPITATION IN THE FORM OF RAIN THEN SNOW
ARRIVES FOR MOST OF THE AREA SATURDAY NIGHT INTO SUNDAY.
- SNOW AMOUNTS WILL BE LIGHT ON THE PLAINS.
- SUNDAY AND MONDAY WILL BE COOLER.
DISCUSSION
THROUGH FRIDAY NIGHT...
OUR AREA WILL BE IN BETWEEN A 500 MB RIDGE CENTERED NEAR THE
MT/DAKOTA BORDER AND A 500 MB TROUGH OVER THE PACIFIC NORTHWEST
DURING THIS TIME. THIS PATTERN WILL RESULT IN PERIODS OF
PRECIPITATION MOVING OVER LOCATIONS MAINLY WEST AND NORTH OF
BILLINGS (15 TO 60 PERCENT CHANCE) BUT PRECIPITATION AMOUNTS WILL
BE LIGHT.
PRECIPITATION TYPE WILL MAINLY BE MOUNTAIN SNOW AND LOWER
ELEVATION RAIN OR A RAIN/SNOW MIX WITH SNOW LEVELS AROUND 7000 TO
8000 FEET. ON FRIDAY, THERE IS A LOW CHANCE (20%) OF FREEZING
RAIN FROM ABOUT BIG TIMBER-COLUMBUS NORTHWARD AND NORTHEASTWARD
TO MUSSELSHELL AND NORTHERN ROSEBUD COUNTIES, AS WARM AIR WILL BE
POSITIONED ABOVE A POSSIBLE LAYER OF COOLER AIR BELOW (MORE ON
THAT BELOW). AT THIS TIME IT LOOKS LIKE ANY ICE SHOULD OCCUR WEST
OF BILLINGS BUT WILL MONITOR. ANY SNOW IN THE CRAZY AND
BEARTOOTH/ABSAROKA MOUNTAINS WILL BE LESS THAN 3 INCHES.
IN TERMS OF WIND, THERE CAN BE GUSTY WINDS IN THE LIVINGSTON
AREA-BEARTOOTH FOOTHILLS TODAY FROM GAP FLOW AND FROM 700 MB
WINDS OF 42-46 KT MIXING DOWN TO THE SURFACE. THE GUSTY WINDS MAY
ONLY IMPACT A PORTION OF THE LIVINGSTON AREA AT A TIME (WEST SIDE
OF LIVINGSTON VS. EAST SIDE). LOOK FOR GUSTS OF 40-50 MPH TODAY.
HIGH TEMPERATURES WILL GENERALLY BE IN THE 40S TO LOWER 50S
TODAY. UNCERTAINTY INCREASES ON FRIDAY WHEN THE NBM INDICATES THAT
THE 10TH TO 90TH PERCENTILE HIGH TEMPERATURE SPREAD IS AROUND 11
TO 19 DEGREES FAHRENHEIT FOR MUCH OF THE AREA. THE REASON FOR THIS
UNCERTAINTY IS THAT A FRONTAL BOUNDARY SHOULD BE SOMEWHERE IN THE
AREA ON FRIDAY, WITH MODELS SIGNALING THAT IT COULD MOVE
SOUTHWARD AS A WEAK COLD FRONT, BUT HOW FAR SOUTH IT WILL GET
VARIES BY MODEL SOLUTION. THIS MEANS THAT HIGH TEMPERATURES ON
FRIDAY COULD BE ANYWHERE FROM THE 30S AND 40S TO THE 40S AND 50S,
WITH THE WARMEST AIR IN THE FOOTHILLS AND THE COOLEST AIR NORTH
AND NORTHEAST OF BILLINGS. RMS
SATURDAY THROUGH THURSDAY...
A COLD FRONT MOVING ACROSS THE REGION SATURDAY AND AN UPPER TROUGH
SLIDING ALONG THE CANADIAN BORDER SATURDAY INTO SUNDAY WILL BRING
RAIN AND SNOW SHOWERS INTO SUNDAY. PRECIPITATION TOTALS HAVE
DECREASED SOME FROM PREVIOUS RUNS, AND CURRENTLY, THERE IS A
60-70% CHANCE OF AT LEAST 2 INCHES OF SNOW OVER THE WESTERN
MOUNTAINS, A 20-40% CHANCE OVER THE FOOTHILLS AND BIG HORN
MOUNTAINS, AND GENERALLY A 10-20% CHANCE OVER CENTRAL LOCATIONS
WEST OF FORSYTH AND NORTH AND EAST OF BILLINGS. OVER LOWER
ELEVATIONS, A RAIN SNOW MIX IS LIKELY TO START SATURDAY MORNING,
BECOMING ALL RAIN AS DAYTIME TEMPERATURES RISE, CHANGING BACK TO A
MIX IN THE EVENING, AND FINALLY BECOMING ALL SNOW OVERNIGHT INTO
EARLY SUNDAY MORNING.
BRIEF RIDGING IS EXPECTED TO BUILD IN MONDAY, KEEPING CONDITIONS
MOSTLY DRY THROUGH THE DAYTIME, THEN, UPPER LEVEL FLOW BECOMES
NORTHWESTERLY AND BRINGS LOW DAILY SNOW CHANCES THROUGH THE END
OF THE WEEK. THE MOUNTAINS AND FOOTHILLS HAVE THE HIGHEST DAILY
CHANCE OF SNOW, AROUND 30-40%, WHILE LOWER ELEVATIONS TYPICALLY
HAVE A LESS THAN 25% CHANCE.
HIGH TEMPERATURES LOOK TO BE WARMEST ON SATURDAY, WITH HIGHS IN
THE UPPER 30S OVER THE EAST TO LOW 50S OVER THE WEST. THEN, HIGHS
WILL GENERALLY BE IN THE 20S TO 30S SUNDAY THROUGH THE REST OF THE
WEEK. LOWS WILL FREQUENTLY BE IN THE TEENS TO SINGLE DIGITS.
ARCHER
AVIATION
IN THE VICINITY OF THE WESTERN MOUNTAINS, SCATTERED RAIN/SNOW
SHOWERS WILL OCCUR TODAY INTO TONIGHT (20-30% CHANCE). THE WESTERN
MOUNTAINS HAVE A 50% CHANCE OF SNOW SHOWERS. WESTERN MOUNTAINS
WILL BE OBSCURED IN CLOUDS AND SNOW SHOWERS. OTHERWISE, VFR WILL
PREVAIL. SOUTHWEST WINDS WILL GUST TO NEAR 40-45 KT NEAR KLVM
TODAY. PRIOR TO THE WIND REACHING THE SURFACE AT KLVM, LLWS IS
EXPECTED. RMS
PRELIMINARY POINT TEMP/POPS
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 046 027/039 025/046 020/028 010/032 015/037 020/037
1/B 11/B 12/O 63/S 11/B 11/B 12/S
LVM 051 035/052 034/052 022/037 016/040 022/042 022/039
3/O 23/R 27/R 83/S 11/B 22/S 32/S
HDN 046 024/043 022/043 017/027 008/032 012/035 015/036
1/B 11/B 02/R 64/S 11/U 11/B 12/S
MLS 043 022/036 021/039 015/024 004/025 008/029 011/029
0/B 01/B 11/B 42/S 01/U 11/B 01/B
4BQ 048 024/045 023/047 018/026 008/031 013/035 016/035
0/U 00/U 00/B 22/S 10/U 00/B 01/B
BHK 041 018/038 018/037 013/025 002/025 005/031 009/032
0/U 00/B 10/B 32/S 10/B 10/B 01/B
SHR 051 027/051 026/054 018/033 009/038 015/042 018/040
0/B 00/B 00/B 44/S 20/U 11/B 12/S
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
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