177
FXUS65 KBYZ 171031
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
331 AM MST SUN NOV 17 2024
KEY MESSAGES
- STRONG SW WINDS WILL CONTINUE THROUGH LATE SUNDAY NIGHT; GUSTS
IN EXCESS OF 60 MPH EXPECTED AT LIVINGSTON.
- FRONTAL PASSAGE MONDAY EXPECTED TO BRING RAIN/SNOW SHOWERS TO
THE REGION. THE FOOTHILLS HAVE A 40-80% CHANCE OF RECEIVING AT
LEAST ONE INCH OF SNOW.
DISCUSSION
TODAY THROUGH TUESDAY EVENING...
CURRENT ANALYSIS IS SHOWING WESTERLY FLOW WITH SLIGHT RIDGING AND
LIGHT SNOW SHOWERS ENTERING OUR WEST. HI-RES MODELS DO HAVE SNOW
SHOWERS CONTINUING TO MOVE INTO THE WEST THROUGH THE MORNING.
WITH WESTERLY WINDS IN PLACE, DOWNSLOPING LOWERS CONFIDENCE IN ANY
SHOWERS MAKING IT OFF THE FOOTHILLS. WITH REGARDS TO GAP WINDS,
ONE COMPONENT THAT MAY PREVENT UPPER END WINDS IS THE ASCENT THAT
COMES WITH PRECIPITATION. HOWEVER, WITH 700 MB WINDS AT AROUND 40
KTS AND A PRESSURE GRADIENT OF AROUND 15-20MB SET UP OVER THE
PARADISE VALLEY, FORECAST IS ON TRACK FOR GUSTS OF 50-65 MPH IN
THE LIVINGSTON AND BEARTOOTH FOOTHILLS. STRONG WINDS ARE EXPECTED
TO BEGIN TO DIMINISH EARLY MORNING MONDAY AS THE PRESSURE GRADIENT
BREAKS DOWN. USE CAUTION AS STRONG WINDS MAY CREATE DIFFICULT
DRIVING CONDITIONS. FOR THE REMAINDER OF THE REGION TODAY, MOST
WILL HAVE DRY AND MILD CONDITIONS AS RIDGING BRIEFLY COMES INTO
PLACE. HIGH TEMPERATURES WILL BE IN THE 40S TO LOW 50S TODAY.
LIGHT SHOWERS AHEAD OF A FRONTAL PASSAGE (RAIN FOR LOWER
ELEVATIONS) CAN BE EXPECTED SUNDAY NIGHT. A SHORTWAVE TROUGH AND
ASSOCIATED FRONTAL PASSAGE WILL ENTER THE WEST (LIVINGSTON AREA)
AROUND 5-7 AM, REACHING CENTRAL ZONES MID DAY AND THE EAST LATE
AFTERNOON. THE HREF SHOWS HIGH PROBABILITIES (70-80%) OF SNOW FOR
THE WEST WITH A RAIN/SNOW MIX FOR LOWER ELEVATIONS. PROBABILITIES
FOR SNOW INCREASE TO AROUND 50-60% BEHIND THE FRONTAL PASSAGE
WITH THE COOLER AIR. WITH THE W/SW FLOW AT 700 MB, HIGHEST
ACCUMULATIONS FOR THE BEARTOOTH/ABSAROKAS WILL BE W/SW FACING
SLOPES. CURRENT PROBABILITIES FOR AN INCH THROUGH TUESDAY EVENING
ARE AS FOLLOWS: LIVINGSTON (45%), BILLINGS (30%), RED LODGE
(85%), SHERIDAN, WY (30%), MILES CITY (<10%) AND BAKER (30%). THE
HIGHER ELEVATIONS OF THE BEARTOOTH/ABSAROKAS AND BIGHORN
MOUNTAINS HAVE AROUND A 60% CHANCES OF GETTING AT LEAST 6 INCHES
IN THE HIGHEST PEAKS.
PRECIPITATION WILL CLEAR OUT FOR MOST TUESDAY, BUT LINGER IN THE
EAST AS ENSEMBLES DEPICT THE SHORTWAVE TRANSITIONING INTO A
CLOSED LOW OVER THE DAKOTAS. THERE IS STILL DISAGREEMENT WITH
REGARDS TO SNOW AMOUNTS, BUT BREEZY CONDITIONS WILL BE IN PLACE.
AREAS OF BLOWING SNOW COULD MAKE TRAVEL DIFFICULT, SO WATCH THE
FORECAST CLOSE AS THAT TIME APPROACHES.
HIGH TEMPERATURES MONDAY WILL BE IN THE 30S AND 40S COOLING TO THE
30S AND LOW 40S FOR TUESDAY. TS
TUESDAY NIGHT THROUGH SATURDAY...
TUESDAY NIGHT, ANY SNOW IN FAR EASTERN MT WILL BE ENDING. HOWEVER,
WINDY CONDITIONS WILL PERSIST IN FALLON AND CARTER COUNTIES WITH
GUSTS TO 30-35 MPH OVERNIGHT. OTHERWISE, 500 MB AND SURFACE
RIDGING WILL DOMINATE OUR WEATHER WITH MOSTLY CLEAR SKIES AND COOL
TEMPERATURES. LOW TEMPERATURES WILL REACH THE TEENS AND EVEN
SINGLE DIGITS IN A FEW LOCATIONS IN OUR AREA. THE COLDEST
TEMPERATURES SHOULD OCCUR IN THE SHELTERED VALLEYS WEST OF
BILLINGS.
WEDNESDAY, MODELS ARE IN GOOD AGREEMENT ON A 500 MB RIDGE OVER
THE REGION WITH DRY CONDITIONS FOR MUCH OF THE AREA. ISOLATED TO
SCATTERED SNOW SHOWERS (20-30% CHANCE) WILL BE IN THE WESTERN
MOUNTAINS.
THURSDAY INTO SATURDAY, MODELS AGREE ON THE LARGE SCALE 500 MB
PATTERN WITH A TROUGH OVER THE EASTERN PACIFIC AND A RIDGE
SOMEWHERE OVER OUR REGION OR IN THE CENTRAL US. THE FINER SCALE
DETAILS ARE WHERE THE MODELS DIVERGE. HOW AMPLIFIED THE RIDGE WILL
BE IS ONE FACTOR. IT DOES APPEAR THAT COLD AIR SHOULD BUILD IN
CANADA LATER THIS WEEK, AND THEN IT IS UNCERTAIN WHETHER THIS COLD
AIR MOVES SOUTHWARD INTO OUR AREA OR REMAINS TO THE NORTH. IF THE
COLD AIR DOES MOVE SOUTHWARD WE WOULD PROBABLY RECEIVE SOME LIGHT
SNOW. RIGHT NOW THE TIME PERIODS MOST FAVORABLE FOR COLD FRONTAL
PASSAGES AND LIGHT SNOW WOULD BE THURSDAY NIGHT-FRIDAY (20-30%
CHANCE IN SOUTH CENTRAL MT) AND SATURDAY NIGHT (20-40% CHANCE IN
SOUTH CENTRAL MT).
HIGH TEMPERATURES WILL GENERALLY BE IN THE 30S AND 40S TUESDAY AND
WEDNESDAY, THEN UNCERTAINTY INCREASES MARKEDLY FOR THURSDAY-
SATURDAY, WHEN HIGH TEMPERATURES WILL FALL SOMEWHERE IN THE 30S TO
50S RANGE, AS SUGGESTED BY THE NBM 10TH TO 90TH PERCENTILE AT
BILLINGS. RMS
AVIATION
STRONG SW WINDS AT KLVM WILL CONTINUE THROUGH EARLY MORNING MONDAY
WITH GUSTS OF 40-55 KTS POSSIBLE. THERE IS ALSO ABOUT A 25%
CHANCE OF SNOW SHOWERS BEGINNING AROUND 12Z AT KLVM AND LASTING
THROUGH THE MORNING. VFR CONDITIONS WILL PREVAIL ACROSS ALL SITES
THROUGH THE PERIOD. TS
PRELIMINARY POINT TEMP/POPS
TDY MON TUE WED THU FRI SAT
-------------------------------------------------------
BIL 051 036/044 024/039 018/039 026/048 031/046 028/045
1/B 27/W 20/U 00/U 01/B 22/R 11/E
LVM 047 029/040 015/034 012/043 028/051 034/052 032/053
2/J 49/J 21/B 01/B 12/O 32/R 12/R
HDN 053 031/045 023/041 016/040 021/048 027/046 024/045
1/B 29/W 31/U 00/U 01/B 22/O 11/E
MLS 051 029/044 024/039 017/036 017/044 025/039 022/040
0/U 17/W 21/N 10/U 00/B 11/E 11/E
4BQ 053 029/043 025/037 019/037 019/047 027/044 025/046
0/U 07/W 41/B 10/U 00/B 01/B 00/B
BHK 052 024/048 021/036 014/032 011/042 019/039 018/039
0/U 05/W 52/S 20/N 00/B 00/E 00/E
SHR 055 027/045 018/038 013/041 019/053 027/051 026/052
0/U 19/W 71/B 00/U 00/B 11/B 11/B
BYZ WATCHES/WARNINGS/ADVISORIES
MT...WIND ADVISORY IN EFFECT UNTIL 3 AM MST MONDAY FOR ZONES
65-66.
WY...NONE.
WEATHER.GOV/BILLINGS
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page