005
FXUS65 KBYZ 161530
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
830 AM MST SAT NOV 16 2024
KEY MESSAGES
- AREAS OF RAIN AND WET SNOW MOVE WEST TO EAST TODAY, HEAVIEST
OVER MOUNTAINS AND ALONG FOOTHILLS, BUT THE HIGHER HILLS ACROSS
THE LOWER ELEVATIONS WILL SEE UP TO A COUPLE INCHES OF
ACCUMULATION.
- STRONG WINDS LOOK TO RETURN OVER THE WESTERN MOUNTAINS AND
FOOTHILLS LATE SATURDAY INTO SUNDAY NIGHT.
- THE FOOTHILLS HAVE AT LEAST A 30% CHANCE OF RECEIVING AT LEAST
ONE INCH OF SNOW MONDAY INTO MONDAY NIGHT, WITH TRAVEL IMPACTS
FROM LATE MONDAY AFTERNOON INTO THE NIGHT AS TEMPERATURES DROP.
- SOUTHEAST MT, EAST OF MILES CITY, HAS A 20-40% CHANCE OF ONE
INCH OF SNOW MONDAY NIGHT INTO TUESDAY.
UPDATE
AREAS OF RAIN/SNOW CONTINUE TO MOVE WEST TO EAST ACROSS OUR
FORECAST AREA, WITH SOME EMBEDDED NNW FLOW BANDING PER MODEST
INSTABILITY, AND AS OF 15Z THE FOCUS OF HEAVIEST PRECIP IS
SHIFTING EAST OF BILLINGS. DOT WEB CAMS SHOW A LITTLE ACCUMULATION
AT ROSCOE HILL, JUDITH GAP, BULL MOUNTAINS, HYSHAM HILLS, ARROW
CREEK HILL AND LAME DEER DIVIDE. A COCORAHS OBSERVER REPORTED 3.5"
OF SNOWFALL NEAR LIVINGSTON...BUT LOWER ELEVATION ACCUMULATIONS
ARE VERY LOCALIZED AND CONFINED TO THE FOOTHILLS AND HIGHER HILLS.
THE CITY OF BILLINGS HAS SEEN MAINLY LIGHT RAIN. WILL LET THE
WINTER HIGHLIGHTS CONTINUE FOR NOW (THEY RUN THRU 18Z). FORECAST
IS IN GOOD SHAPE, AND HAVE ADJUSTED MINOR ADJUSTMENTS TO POPS/WX
AND WINDS TODAY.
JKL
DISCUSSION
TODAY THROUGH SUNDAY NIGHT...
CURRENTLY, A CLOSED LOW PRESSURE SYSTEM OVER CENTRAL MT IS
BRINGING PRECIPITATION TO AREAS WEST OF ROSEBUD CO. RAIN AND SNOW
MIX IS EXPECTED FOR ELEVATIONS AROUND 3000 TO 3500 FT AND LOWER
(MAINLY AREAS OF RIVER VALLEYS). LOWER ELEVATIONS CAN EXPECT TO
SEE LIGHT SNOW ACCUMULATIONS, WITH UP TO A FEW INCHES OVER
LOCALIZED HIGHER TERRAIN. WITH THE NORTHERLY WIND COMPONENT IN THE
LOW TO MID LEVELS, UPSLOPING ALONG NORTH FACING TERRAIN WILL
RECEIVE THE HIGHER END AMOUNTS. AREAS ALONG THE FOOTHILLS WILL
SEE AN ADDITIONAL 1-3 INCHES THROUGH THE MORNING WITH SNOW
EXPECTED TO TAPER OFF LATE MORNING. THE BEARTOOTH/ABSAROKAS,
PRYORS AND NORTHERN BIGHORN MOUNTAINS ARE EXPECTED TO GET UP TO
7-10 INCHES IN THE HIGHEST PEAKS THROUGH THE MORNING. IF YOU HAVE
TRAVEL PLANS IN THE MORNING, BE CAREFUL AS ROAD CONDITIONS MAY BE
SLICK. THE WINTER WEATHER ADVISORY REMAINS IN EFFECT FOR THE
FOOTHILL AREAS THROUGH 11 AM THIS MORNING. SNOW WILL LIKELY MELT
THIS AFTERNOON AS TEMPERATURES ARE FORECASTED TO GET INTO THE
UPPER 30S TO 40S. BREEZY CONDITIONS ARE EXPECTED THROUGH THE DAY
TODAY WITH GUSTS OF 25-35 MPH EAST OF BILLINGS.
INTO TONIGHT, A GAP WIND SETUP FROM STRONG 700 MB WINDS AND
PRESSURE GRADIENT OVER THE PARADISE VALLEY WILL PRODUCE STRONG
WINDS FOR THE LIVINGSTON/NYE AREA. THE LIKELIHOOD OF REACHING 50+
MPH IS 95%, WITH A 70% CHANCE OF 60+ MPH. AS A RESULT, A WIND
ADVISORY HAS BEEN ISSUED FOR THIS AREA FOR 8 PM TONIGHT THROUGH 3
AM MONDAY.
FOLLOWING TROUGHING SUNDAY, AN ADDITIONAL WAVE OF WEAK ENERGY
BRINGS SMALL CHANCES (LESS THAN 10%) OF PRECIPITATION TO THE
REGION WITH A 20-30% CHANCE FOR THE BEARTOOTH/ABSAROKAS.
PRECIPITATION CHANCES WILL INCREASE THROUGH THE NIGHT SUNDAY AS
ENSEMBLES DEPICT A SHORTWAVE MOVING THROUGH MONDAY. HIGH
TEMPERATURES SUNDAY WILL BE IN THE 40S AND 50S. TS
MONDAY THROUGH FRIDAY...
MONDAY INTO TUESDAY, MODEL ENSEMBLE CLUSTERS AGREE ON A 500 MB
TROUGH AFFECTING OUR REGION, BUT DIFFER ON THE DETAILS.
ON MONDAY, THE TROUGH AND 700 MB FRONTOGENESIS WILL BRING LIGHT
PRECIPITATION TO THE AREA WITH SNOW IN THE WESTERN FOOTHILLS (PARK
COUNTY, BEARTOOTH AND RED LODGE FOOTHILLS) AND RAIN OR A
RAIN/SNOW MIX IN THE LOWER ELEVATIONS. THROUGH MONDAY NIGHT, NBM
SHOWS THE PROBABILITY OF AT LEAST 1 INCH OF SNOW OUTSIDE OF THE
MOUNTAINS RANGES FROM ABOUT 35-100% IN PARK COUNTY (GREATEST IN
THE PARADISE VALLEY) TO 30-100% IN THE BEARTOOTH AND RED LODGE
FOOTHILLS WITH PROBABILITY INCREASING WITH ELEVATION, 40-70% IN
THE WOLF MOUNTAINS AND 30-70% IN THE SHERIDAN FOOTHILLS. THE
PROBABILITY OF 2 INCHES OF SNOW IS LOWER FOR MOST PLACES AT 10-20%
IN LIVINGSTON, 20-60% IN THE BEARTOOTH AND RED LODGE FOOTHILLS,
30-40% IN THE WOLF MOUNTAINS AND 10-20% IN THE SHERIDAN FOOTHILLS.
IN THE HIGHER TERRAIN, PROBABILITY OF AT LEAST 5 INCHES OF SNOW
IS GREATEST IN THE BEARTOOTH/ABSAROKA MOUNTAINS AT NEARLY 90% AND
40-60% IN THE BIGHORN MOUNTAINS.
THE MAIN IMPACTS FROM THE SYSTEM ON MONDAY PROBABLY WILL OCCUR
LATE MONDAY AFTERNOON INTO MONDAY NIGHT AS TEMPERATURES DROP AND
ANY WET SURFACES FREEZE.
THEN ON TUESDAY, MODEL ENSEMBLE CLUSTERS DIVERGE WITH
SOME CLUSTERS MOVING THE 500 MB TROUGH MORE QUICKLY TO THE EAST,
WITH PRECIPITATION ENDING SOONER, AND OTHERS SLOWING DOWN THE 500
MB TROUGH AND FORMING A CLOSED LOW THAT PRODUCES ABOUT 1 INCH OF
SNOW IN FALLON/CARTER COUNTIES OR 1-3 INCHES OVER MORE OF
SOUTHEAST MT, WITH THE 3 INCHES IN FALLON COUNTY. THESE SLOWER
SCENARIOS COMPRISE ABOUT 36% OF MODEL ENSEMBLE SOLUTIONS, SO THEY
ARE WELL WITHIN THE REALM OF POSSIBILITY. IMPACTS WOULD BE
SLIPPERY ROADS AND SIDEWALKS.
ON WEDNESDAY, MODEL ENSEMBLE CLUSTERS COME BACK INTO GOOD
AGREEMENT ON 500 MB RIDGING OVER OUR REGION. CONDITIONS WILL BE
DRY OVER MUCH OF THE AREA, ASIDE FROM AN ISOLATED SNOW SHOWER IN
THE BEARTOOTH/ABSAROKA MOUNTAINS (20% CHANCE). ONE MODEL ENSEMBLE
CLUSTER FROM 27% OF MODEL ENSEMBLE SOLUTIONS DOES SHOW A PATTERN
FAVORABLE FOR GAP FLOW STRONG WINDS IN THE LIVINGSTON-NYE
CORRIDOR.
ON THURSDAY, MODEL ENSEMBLE CLUSTERS BEGIN TO DIVERGE AGAIN WITH
3/4 OF THE CLUSTERS SHOWING A MORE AMPLIFIED 500 MB RIDGE AND MORE
DRY WEATHER, BUT 1 OF THE CLUSTERS, ABOUT 26% OF THE MODEL
ENSEMBLE SOLUTIONS, SHOW A FLATTER RIDGE WITH A WEAK DISTURBANCE
MOVING THROUGH THE FLOW AND PRODUCING SOME LIGHT PRECIPITATION IN
THE FORM OF MOUNTAIN SNOW AND LOWER ELEVATION RAIN OR A RAIN/SNOW
MIX.
FOR FRIDAY, 3/4 OF THE MODEL ENSEMBLE CLUSTERS FAVOR A 500 MB
RIDGE OVER OUR AREA WITH DRY AND MILD CONDITIONS. ONE OF THE
CLUSTERS, CONSISTING OF ONLY 6% OF MODEL ENSEMBLE SOLUTIONS,
SHOWS A COOLER SCENARIO WITH A MORE AMPLIFIED 500 MB RIDGE AXIS TO
OUR WEST, WITH OUR AREA UNDER NORTH/NORTHWESTERLY FLOW IN COOLER
AIR AND PROBABLY WITH SOME LIGHT SNOW IN THE AREA.
HIGH TEMPERATURES WILL GENERALLY BE IN THE 30S AND 40S MONDAY-
WEDNESDAY, THEN UNCERTAINTY INCREASES MARKEDLY FOR THURSDAY AND
FRIDAY. HIGHS ON THURSDAY AND FRIDAY COULD BE ANYWHERE FROM THE
30S TO THE 50S, AS SUGGESTED BY THE NBM 10TH TO 90TH PERCENTILE
VALUES AT BILLINGS. RMS
AVIATION
AREAS OF RAIN AND SNOW WILL MOVE WEST TO EAST THROUGH THE REGION
TODAY, ENDING IN THE WEST BY 18Z AND THE EAST BY 00Z. EXPECT
MVFR/IFR WITH THE PRECIPITATION, AND THERE IS ALSO AN AREA OF LOW
STRATUS NEAR THE DAKOTAS BORDER. MOUNTAINS WILL BE OBSCURED THIS
MORNING. LOOK FOR A TRANSITION TO VFR REGIONWIDE THIS AFTERNOON.
BREEZY NW WINDS GUSTING 20-30 KNOTS WILL PERSIST EAST OF KBIL THRU
MUCH OF THE AFTERNOON. WINDS ALONG THE WESTERN FOOTHILLS WILL
INCREASE AFTER 00Z, WITH GUSTS EXPECTED TO REACH 50+ KNOTS AT KLVM
AFTER 06Z. JKL
PRELIMINARY POINT TEMP/POPS
TDY SUN MON TUE WED THU FRI
-------------------------------------------------------
BIL 045 030/050 035/044 023/039 019/040 027/048 028/045
3/O 00/B 17/O 21/U 00/U 11/B 22/O
LVM 040 030/047 029/040 015/035 013/042 028/050 033/051
2/S 01/N 59/S 31/B 01/B 12/R 33/R
HDN 044 024/053 030/047 022/041 016/040 022/048 024/045
6/O 00/B 18/O 32/S 01/U 11/B 22/O
MLS 039 022/051 028/047 023/039 016/037 019/045 024/038
9/O 00/U 15/O 21/U 10/U 00/B 11/E
4BQ 040 022/053 029/047 024/038 018/038 021/048 025/042
6/O 00/U 05/O 42/S 10/U 00/B 11/E
BHK 036 020/052 025/048 022/037 014/035 014/043 019/039
6/O 00/U 03/R 42/S 21/U 00/B 11/E
SHR 042 019/056 027/046 017/038 013/042 020/053 024/050
6/O 00/U 08/O 73/S 00/U 11/B 11/B
BYZ WATCHES/WARNINGS/ADVISORIES
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 11 AM MST THIS
MORNING FOR ZONES 56-63>66-172.
WIND ADVISORY IN EFFECT FROM 8 PM THIS EVENING TO 3 AM MST
MONDAY FOR ZONES 65-66.
WY...NONE.
WEATHER.GOV/BILLINGS
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