031
FXUS65 KBYZ 152018
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
118 PM MST FRI NOV 15 2024
KEY MESSAGES
- AREAS OF WET SNOW COMING TONIGHT & SATURDAY, HEAVIEST OVER
MOUNTAINS AND ALONG FOOTHILLS, BUT THE HIGHER HILLS ACROSS THE
LOWER ELEVATIONS SHOULD SEE A LITTLE ACCUMULATION AS WELL.
- STRONG WINDS LOOK TO RETURN OVER THE WESTERN MOUNTAINS AND
FOOTHILLS LATE SATURDAY INTO SUNDAY NIGHT.
- POTENTIAL WEATHER SYSTEM BRINGING COOLER AND WETTER CONDITIONS
FOR MONDAY/TUESDAY.
DISCUSSION
THROUGH SATURDAY NIGHT...
SATELLITE IMAGERY SHOWS AMPLIFIED SOUTHWEST FLOW, A SHORTWAVE
LIFTING THRU THE GREAT BASIN, AND CLEARING SKIES (I.E. DRY SLOT)
INTO THE SOUTHEAST PORTION OF OUR FORECAST AREA. THERE IS A 100KT
H3 JET LIFTING THRU EASTERN UT/WESTERN CO, WHICH WILL PROVIDE
INCREASING ASCENT AS THE DAY WEARS ON. A 700MB LOW IS ANALYZED TO
BE IN SOUTH CENTRAL ID CURRENTLY, WHICH IS FURTHER WEST THAN
IDEAL, BUT MID LEVEL WINDS ARE BACKING MORE EASTERLY OVER OUR CWA
AND WE EXPECT THE MID LEVEL LOW TO TRACK TOWARD THE ENE OVER THE
NEXT SEVERAL HOURS. A TRACK THROUGH NORTHWEST WY ON THE WAY TO
EASTERN MT WILL PUT OUR WEST IN A REGION OF HEALTHY UPPER LEVEL
DIFFLUENCE W/ EASTERLY UPSLOPE FLOW TONIGHT. AS THE LOW TRACKS
INTO MT A DEVELOPING WEAK TROWAL WILL PRODUCE EASTWARD-MOVING AREA
OF PRECIP (MAINLY SNOW) ACROSS OUR CENTRAL AND EASTERN CWA LATE
TONIGHT AND SATURDAY. OVERALL, THE FORECAST REMAINS ON TRACK FOR A
PERIOD OF WINTRY WEATHER AND HAVE MADE NO CHANGES TO THE
HIGHLIGHTS ALREADY ISSUED. IT SHOULD BE NOTED THAT TODAY'S MODEL
RUNS HAVE TRENDED DOWN A BIT WITH QPF, AND THIS IS REFLECTED IN
THE FORECAST. THAT SAID, THOUGH SURFACE TEMPS WILL BE AN ISSUE FOR
SNOW ACCUMS AT LOWER ELEVATIONS, THERE IS A BIT MORE CONFIDENCE
THAT TEMPS WILL COOL SUFFICIENTLY FOR PTYPE AS SNOW AT ALL LOWER
ELEVATIONS. 700MB TEMPS ARE ALSO EXPECTED TO FALL TO NEAR -11C,
PUTTING THE DENDRITIC LAYER MORE IN PLAY. AS A SIDE NOTE, THERE
COULD BE SOME FOG IN THE FAR EAST LATE TONIGHT & TOMORROW MORNING,
BEFORE THE SHIFT TO NW WINDS ARRIVE.
OUTSIDE OF THE HIGH ELEVATIONS, GREATEST PRECIP AMOUNTS (0.10 TO
0.20") WILL BE OVER OUR WEST AND NORTH, WHILE LOCATIONS FROM
SHERIDAN TO BROADUS AND ALZADA WILL SEE THE LEAST (0.05" OR LESS).
REGARDING SNOWFALL, WESTERN UPSLOPE AREAS WILL SEE SOMETHING LIKE
1-4", POSSIBLY A BIT MORE ON THE EAST SIDE OF THE CRAZY MOUNTAINS
NEAR MELVILLE. FURTHERMORE, DEVELOPING BREEZY NW WINDS (GUSTS
20-35 MPH) WILL PRODUCE SOME BLOWING SNOW WHERE SURFACE TEMPS ARE
COLD ENOUGH. THIS WOULD INCLUDE JUDITH GAP WHERE TRAVEL CONDITIONS
WILL LIKELY TURN DIFFICULT BY LATE THIS EVENING. OTHERWISE,
HIGHER HILLS SUCH AS THE BULL AND WOLF MOUNTAINS, AND THE HYSHAM
HILLS, SHOULD PICK UP A COUPLE INCHES OF SNOW ALONG WITH SOME
BLSN. FOR BILLINGS, WE ARE LOOKING AT 0.5" OF SNOW OR LESS IN THE
CITY (MOSTLY ON GRASS), AND UP TO 1-2" OVER THE SURROUNDING HILLS.
NO DOUBT ELEVATION WILL PLAY A BIG ROLE W/ THIS SNOW EVENT.
MOUNTAIN AREAS WILL SEE 4-8" OF SNOWFALL.
PRECIP WILL TAPER OFF EARLY TOMORROW MORNING IN THE WEST, AND
EARLY TO MID AFTERNOON IN THE EAST. DOWNSLOPE WINDS SHOULD PUSH
TEMPS TO THE UPPER 30S TO MID 40S MOST PLACES...SO EXPECT ANY SNOW
ACCUMULATION TO AT LEAST BEGIN MELTING IN THE AFTERNOON.
AS THE TROF DEPARTS TO THE NORTHEAST SATURDAY NIGHT WE BUILD
HEIGHTS FROM THE WEST AND EVOLVE QUICKLY TO WINDY CONDITIONS ALONG
THE FOOTHILLS. CURRENT INDICATIONS ARE FOR A LIKELIHOOD OF
ADVISORY LEVEL WINDS (58+ MPH) IN THE GAP LOCATIONS (LIVINGSTON &
NYE) AFTER MIDNIGHT. THE PROBABILITY OF REACHING 50+ MPH IS 95%,
WHILE FOR 60 MPH IT IS 60-70%.
HERE ARE A FEW NOTEWORTHY PROBABILITIES FOR THE UPCOMING SYSTEM.
4+ INCHES OF SNOW OVER THE BEARTOOTH-ABSAROKAS: 80%
2+ INCHES OF SNOW ALONG THE FOOTHILLS: 70%
1+ INCHES OF SNOW IN CITY OF BILLINGS: 10%
1+ INCHES OF SNOW IN THE HILLS AROUND BILLINGS: 50%
JKL
SUNDAY THROUGH FRIDAY...
EARLY NEXT WEEK A 500MB TROUGH WILL CREATE A LOW PRESSURE SYSTEM
OVER THE CANADIAN PROVINCES. A COLD FRONT WILL DRAG ACROSS THE
REGION MONDAY BRINGING PRECIPITATION CHANCES FOR MUCH OF THE
REGION. THE BEST CHANCES FOR PRECIPITATION WILL BE FOR THE
MOUNTAINS WITH NBM GIVING THEM A >70% CHANCE FOR >0.25 INCHES OF
PRECIPITATION. MOST OF THE LOWER ELEVATIONS HAVE A 30-50% CHANCE
OF GETTING >0.25 INCHES. TEMPERATURES WILL BE IN THE 40S MONDAY SO
PRECIPITATION LOOKS TO BE MOSTLY RAIN IN THE LOWER ELEVATIONS. AS
TEMPERATURES COOL IN THE EARLY EVENING DROPPING TEMPERATURES, A
RAIN SNOW MIX AND LIGHT SNOW ARE LIKELY FOR LOWER ELEVATIONS.
ANY SNOW ACCUMULATIONS FOR THE LOWER ELEVATIONS WILL REMAIN VERY
LIGHT WITH THE CHANCE FOR >1 INCH OF SNOW REMAINING BELOW 20%.
MOUNTAIN LOCATIONS WILL LIKELY (>70%) RECEIVE GREATER THAN 3
INCHES OF SNOWFALL.
STARTING SATURDAY NIGHT AND LASTING THROUGH SUNDAY, WESTERN
FOOTHILLS AREAS WILL SEE STRONG WINDS. LEE SIDE TROUGHING WILL
INCREASE THE PRESSURE GRADIENT INTO THE 15-20MB RANGE. THIS SETUP
IS FAVORABLE FOR LIVINGSTON WHICH WILL ALSO HAVE AN INVERSION
SUNDAY MORNING INCREASING STRONG GAP WIND POTENTIAL. THIS PATTERN
IS NOT AS FAVORABLE FOR LOCATIONS SUCH AS BIG TIMBER AND
HARLOWTON. THESE AREAS WILL SEE WESTERLY 700MB WINDS IN THE
40-50KT RANGE BUT WILL BE LIMITED DUE TO THE INVERSION. THIS GIVES
LIVINGSTON A VERY HIGH CHANCE (95%) OF GETTING A WIND GUST OVER
60MPH WITH LOWER CHANCES FOR BIG TIMBER (25%) AND HARLOWTON
(10%).
TEMPERATURES ON SUNDAY WILL BE NEAR 50F FOR MOST PLACES BEFORE
COOLING WITH UPPER LEVEL TROUGHING INTO THE 30S FOR TUESDAY AND
WEDNESDAY. LATE NEXT WEEK THERE IS GOOD AGREEMENT THAT SOME KIND
OF UPPER LEVEL RIDGING WILL ENTER THE REGION BRINGING
TEMPERATURES BACK INTO THE 40S TO NEAR 50. TORGERSON
AVIATION
SNOW WILL DEVELOP OVER THE WESTERN FOOTHILLS LATE THIS AFTERNOON
AND KLVM IN THE EVENING. RAIN TO WET SNOW WILL SPREAD EASTWARD
ACROSS LOWER ELEVATIONS THROUGH TONIGHT INTO EARLY SATURDAY,
IMPACTING THE ENTIRE FORECAST AREA WITH MVFR/IFR. MOUNTAINS WILL
BE OBSCURED. THERE IS A LOW (30%) RISK OF LOCALIZED FOG NEAR THE
DAKOTAS BORDER LATE TONIGHT, POSSIBLY AFFECTING KBHK. IN ADDITION
TO THE PRECIPITATION, BREEZY NW-N WINDS WILL DEVELOP BEHIND A COLD
FRONT TONIGHT. LOOK FOR 20-30 KNOT GUSTS ACROSS MOST LOWER
ELEVATIONS, WITH BRISK WINDS PERSISTING EAST OF KBIL THROUGH
TOMORROW. PRECIP WILL TAPER OFF FROM WEST TO EAST ON SATURDAY, AND
FLIGHT CONDITIONS WILL IMPROVE TO VFR. JKL
PRELIMINARY POINT TEMP/POPS
SAT SUN MON TUE WED THU FRI
-----------------------------------------------------------
BIL 032/044 028/050 035/044 023/040 020/041 028/051 032/050
+8/O 00/B 15/W 21/B 00/U 11/B 21/B
LVM 028/041 030/047 029/040 016/035 014/044 028/052 033/053
+6/S 01/N 48/J 31/B 01/B 12/W 32/W
HDN 029/044 024/052 030/046 021/041 017/042 023/051 026/048
79/O 00/B 27/W 31/B 00/U 01/B 22/W
MLS 030/039 022/051 028/047 023/039 016/039 021/046 024/043
39/O 00/U 14/W 21/B 00/U 01/B 11/B
4BQ 027/038 023/054 028/046 024/039 019/039 023/051 026/048
06/S 00/U 04/W 31/B 10/U 01/B 11/B
BHK 024/038 021/051 025/047 021/037 014/037 015/046 021/045
17/S 10/U 03/W 42/J 10/U 00/B 11/B
SHR 029/042 019/056 027/047 019/039 014/043 022/055 027/053
36/S 00/U 17/W 62/J 00/U 01/B 11/B
BYZ WATCHES/WARNINGS/ADVISORIES
MT...WINTER WEATHER ADVISORY IN EFFECT FROM 5 PM THIS AFTERNOON TO
11 AM MST SATURDAY FOR ZONES 56-63>66-172.
WY...NONE.
WEATHER.GOV/BILLINGS
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