090
FXUS65 KBYZ 172046
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
146 PM MST SUN NOV 17 2024
KEY MESSAGES
- STRONG SW WINDS WITH GUSTS UP TO 60 MPH WILL CONTINUE AT
LIVINGSTON UNTIL LATE TONIGHT.
- FRONTAL PASSAGE MONDAY EXPECTED TO BRING RAIN/SNOW SHOWERS
ACROSS THE REGION INTO MONDAY NIGHT; CHANCE OF 1" OF SNOW IS
50-70% ALONG THE FOOTHILLS AND 45% IN FAR SOUTHEAST MONTANA.
- NW WINDS GUSTING 40-50 MPH IN THE FAR EAST, TUESDAY INTO
WEDNESDAY.
- HIGH UNCERTAINTY WITH LATE WEEK PATTERN CHANGE. MODELS ARE
HINTING AT A COLD AND WET SYSTEM.
DISCUSSION
THROUGH MONDAY NIGHT...
WINDS AT LIVINGSTON AND NEAR NYE HAVE DECREASED GRADUALLY SINCE
EARLY THIS MORNING, COURTESY OF LOWER STABILITY DURING THE DAYTIME
AND A REDUCED PRESSURE GRADIENT (14MB FROM IDA-LWT AT 20Z), BUT WE
ARE STILL SEEING 50-60 MPH GUSTS. BIG TIMBER AND HARLOWTON HAVE
SEEN GUSTS OF 40-50 MPH, AS EXPECTED, BUT WINDS AT THESE LOCATIONS
WILL DECREASE BY EVENING AS FLOW ALOFT BEGINS TO BACK TO THE SW IN
ADVANCE OF AN APPROACHING PACIFIC TROF. THE BACKED FLOW AND
GRADIENT WILL FAVOR THE GAP AREAS ONLY IN THE PRE-FRONTAL PERIOD
TONIGHT. GUIDANCE OVERALL FAVORS A SLIGHT INCREASE IN GUSTS THIS
EVENING THEN A DECREASE OVERNIGHT. THE COLD FRONT IS EXPECTED
ARRIVE AROUND 12Z, ABRUPTLY ENDING THE GAP FLOW. LIVINGSTON'S GUST
PROBABILITIES FOR NOW THROUGH 3AM ARE: 100% CHANCE OF 50+ MPH, 80%
CHANCE OF 60+ MPH, AND ONLY 20% CHANCE OF REACHING 70 MPH.
SATELLITE IMAGERY SHOWS A DEEP PACIFIC TROF AND PLENTY OF CELLULAR
CLOUDS AND COLD AIR ALOFT OFF THE WA/OR COAST, WHERE MESOANALYSIS
SHOWS 500MB TEMPS OF -34C. THIS COLD AIR ALOFT WILL ASSIST WITH
THE DEVELOPMENT OF SHOWERS TOMORROW AS THE TROF ARRIVES.
TROF AND COLD FRONTAL PASSAGE WILL BRING A FAIRLY BRIEF PERIOD OF
RAIN-TO-SNOW SHOWERS TOMORROW AND TOMORROW NIGHT, BEGINNING IN OUR
WEST EARLY IN THE MORNING. THERE ACTUALLY SHOULD BE TWO AREAS OF
SHOWERS WITH THIS SYSTEM, THE FIRST ASSOCIATED WITH JET FORCING
AND THE SECOND ALONG THE TROF AXIS ITSELF. AS THE TROF PASSES WE
WILL SEE MIXED/BREEZY NW WINDS DEVELOP TOMORROW AFTERNOON AND
CONTINUE THRU THE NIGHT, ESPECIALLY IN THE EAST WHERE NIGHTTIME
GUSTS COULD REACH 40 MPH. REGARDING PRECIPITATION, MOUNTAINS WILL
SEE SEVERAL INCHES OF SNOW (70% CHANCE OF EXCEEDING 6" OVER THE
BEARTOOTH-ABSAROKAS AND BIGHORNS). CONFIDENCE IS HIGH THAT LOW
LEVEL TEMPS WILL TURN SUFFICIENTLY COLD FOR SNOW SHOWERS AS THE
TROF ARRIVES, BUT AS WITH THE PREVIOUS SYSTEM IT WILL BE DIFFICULT
TO SEE ANY ACCUMULATION OUTSIDE OF THE FOOTHILLS AND HIGHER
HILLS. RED LODGE AND LIVINGSTON HAVE A 70% CHANCE OF 1+ INCHES OF
SNOW, BUT THAT PROBABILITY LOWERS TO 25-50% IN THE SHERIDAN AREA
AND LESS THAN 20% FURTHER NORTH. WITH THE INSTABILITY THERE COULD
BE SOME BANDED SNOW SHOWERS AS WELL. AN AREA TO WATCH IS OUR FAR
EAST WHERE THERE LOOKS TO BE A PERIOD OF MID LEVEL FRONTOGENESIS
AS THE TROF ARRIVES (I.E. LATE AFTERNOON INTO THE EVENING). THERE
IS UNCERTAINTY HERE AS THE DURATION OF PRECIP IN THIS AREA WILL
DEPEND ON HOW AND WHERE THE TROF EVOLVES INTO A LOW OVER THE
NORTHERN PLAINS MONDAY NIGHT. THE PROBABILITY FOR 1+ INCHES OF
SNOW AT BAKER AND EKALAKA IS ABOUT 45%...AND THE ENSEMBLES SHOW
PLENTY OF SPREAD WITH A FEW MEMBERS SHOWING SEVERAL INCHES OF
SNOWFALL, ALONG WITH THE INCREASING NW WINDS. SOMETHING TO WATCH.
AFTER TODAY'S SEASONABLY MILD DAY, TEMPS ON MONDAY WILL COOL TO
THE UPPER 30S AND 40S.
JKL
TUESDAY THROUGH SUNDAY...
TROUGHING WILL CONTINUE TO MOVE OUT OF THE REGION, TUESDAY,
GIVING WAY TO A BUILDING RIDGE THAT IS DEPICTED BY MODELS TO LAST
INTO FRIDAY. THE CHANCE FOR PRECIPITATION WILL CONTINUE TO
DIMINISH AS WELL, THOUGH THE BEST CHANCE WILL EXIST IN THE FAR
EAST. THE LINGERING CHANCE FOR PRECIP WILL REMAIN DUE TO A
DEVELOPING TROUGH AND SFC LOW, IN THE DAKOTAS. WITH THIS LOW,
STRONG NW WINDS ON THE BACK SIDE OF THE SYSTEM WILL BRING GUSTS IN
THE 40-50 MPH RANGE FOR THE EASTERN PORTIONS OF CARTER AND FALLON
COUNTIES INTO WEDNESDAY. THE CHANCE FOR AN INCH OF SNOWFALL IN
THE FAR EAST, TUESDAY INTO WEDNESDAY, IS 10-30% (HIGHEST CHANCE
NEAR BAKER).
AS UPPER LEVEL RIDGING BUILDS THROUGH WEDNESDAY, A FAVORABLE
PRESSURE GRADIENT WILL SETUP OVER THE SW, BRINGING BREEZY WINDS TO
THE LIVINGSTON AREA. LITTLE PRECIPITATION IS EXPECTED ACROSS SE
MT AND N WY ON WEDNESDAY.
LATE WEDNESDAY INTO THE WEEKEND, MODELS AND ENSEMBLES ARE
DEPICTING A LARGE PATTERN CHANGE, WITH THE AFOREMENTIONED RIDGING
MOVING IN THE NORTHERN PLAINS/ MIDWEST AND A DEVELOPING TROUGH
OVER THE PNW. THE DETAILS OF THIS SYSTEM ARE STILL UNCERTAIN,
THOUGH COLDER AIR COULD MAKE ITS WAY DOWN FROM CANADA AS THE
TROUGH PUSHES INTO THE NORTHERN ROCKIES. THE CHANCE FOR
PRECIPITATION IS LOW TO MODERATE (20-60%), THURSDAY THROUGH NEXT
SUNDAY. AS FOR PRECIPITATION TYPE, MOUNTAIN SNOWFALL IS FORECAST
WHILE RAIN AND SNOW IS POSSIBLE IN THE LOWER ELEVATIONS. HIGH
UNCERTAINTY REMAINS WITH THIS SYSTEM, ESPECIALLY WITH
PRECIPITATION AMOUNT.
THE CURRENT FORECAST HAS HIGH TEMPERATURES IN THE 30S AND 40SF,
TUESDAY THROUGH NEXT SUNDAY. HOWEVER, THE NBM 10TH AND 90TH
PERCENTILES DEPICT TEMPERATURES IN THE 30S TO 50S DEPENDING ON THE
EVOLUTION OF THE SYSTEM, THURSDAY-SUNDAY.
MATOS
AVIATION
SW WINDS WILL CONTINUE TO GUST 45-55 KNOTS AT KLVM THRU THIS
EVENING, THEN DECREASE OVERNIGHT AS A COLD FRONT MOVES INTO THE
REGION. OTHER FOOTHILL LOCATIONS LIKE K6S0 AND KHWQ WILL GUST
35-45 KNOTS THRU LATE THIS AFTERNOON, THEN DECREASE TO 15-25 KNOTS
TONIGHT. ON MONDAY, A COLD FRONT WILL BRING A SHIFT TO NW WINDS
AND GUSTS OF 20-30 KNOTS REGIONWIDE.
VFR WILL PREVAIL LATE THIS AFTERNOON AND TONIGHT UNDER SCATTERED
TO BROKEN HIGH CLOUDS, WITH OCCASIONAL OBSCURATIONS IN LIGHT SNOW
SHOWERS OVER THE WESTERN MOUNTAINS. TOMORROW, A PACIFIC COLD FRONT
IS EXPECTED TO BRING WIDESPREAD RAIN/SNOW SHOWERS CAPABLE OF
PRODUCING LOCAL MVFR-IFR, WHILE MOUNTAINS ARE OBSCURED IN SNOW.
JKL
PRELIMINARY POINT TEMP/POPS
MON TUE WED THU FRI SAT SUN
-----------------------------------------------------------
BIL 036/044 026/039 019/040 025/047 028/042 026/040 022/034
27/W 20/N 00/U 01/B 22/W 22/W 33/J
LVM 030/039 020/035 015/043 029/051 034/051 030/049 026/042
48/J 21/U 01/B 12/W 43/W 34/W 54/J
HDN 031/045 024/041 016/040 020/046 024/043 023/041 019/034
27/W 41/U 00/U 01/B 22/W 23/W 33/J
MLS 029/044 026/039 018/036 016/041 022/038 020/036 017/032
17/W 42/J 10/U 00/B 11/E 12/W 32/J
4BQ 028/043 026/037 020/037 019/047 024/043 023/042 019/035
07/W 61/N 10/U 00/B 01/E 11/E 22/J
BHK 025/047 022/038 015/035 011/040 016/037 015/036 013/032
06/W 64/J 20/N 00/B 01/E 11/E 22/J
SHR 026/044 021/038 014/041 020/051 024/050 025/049 022/040
08/W 81/N 00/U 00/B 11/B 12/W 23/J
BYZ WATCHES/WARNINGS/ADVISORIES
MT...WIND ADVISORY IN EFFECT UNTIL 3 AM MST MONDAY FOR ZONES
65-66.
WY...NONE.
WEATHER.GOV/BILLINGS
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