331
FXUS65 KBYZ 041117
AFDBYZ
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
517 AM MDT SUN MAY 4 2025
KEY MESSAGES
- WARM AND DRY THROUGH THIS AFTERNOON. SHOWERS AND THUNDERSTORMS
OVER THE WEST LATE TODAY AND THIS EVENING AS A COLD FRONT DROPS
INTO THE AREA.
- COOL AND WET CONDITIONS TONIGHT THROUGH TUESDAY. CHANCE OF 0.25"
OF LIQUID PRECIPITATION IS 40 TO 100 PERCENT (GREATEST CHANCE IN
THE MOUNTAINS AND FOOTHILLS). SEVERAL INCHES OF SNOW POSSIBLE IN
THE MOUNTAINS.
- DRIER AND WARMER CONDITIONS WILL RETURN FOR THE SECOND HALF OF
THE WORK WEEK.
DISCUSSION
TODAY THROUGH TUESDAY...
WARM AND DRY CONDITIONS CAN BE EXPECTED THROUGH MUCH OF THE DAY
TODAY, WITH HIGHS IN THE 70S AND 80S, BEFORE A COLD FRONT DROPS
INTO THE AREA THIS EVENING/TONIGHT BRINGING A PATTERN CHANGE TO
COOLER AND WETTER CONDITIONS THROUGH TUESDAY.
SHOWERS AND THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON AND EVENING
FOR AREAS MAINLY WEST OF BILLINGS AS SOME ENERGY ADVECTS INTO THE
AREA OUT OF THE SOUTHWEST, AHEAD OF A SHORTWAVE TROUGH AND
ASSOCIATED COLD FRONT. SMALL HAIL AND GUSTY WINDS ARE POSSIBLE
WITH THE STRONGEST THUNDERSTORMS. BEHIND THE COLD FRONT, COOLER
CONDITIONS ARE FORECAST TO MOVE INTO THE AREA WITH BREEZY
NORTHERLY WINDS MONDAY (HIGHS IN THE 40S WEST TO LOW 60S EAST. AS
THE SHORTWAVE TROUGH SLIDES SOUTH AND EAST THROUGH THE AREA
MONDAY INTO TUESDAY, IT LOOKS TO PHASE WITH THE LOW TO THE SOUTH,
BRINGING PERIODS OF SHOWERS TO WIDESPREAD PRECIPITATION AT TIMES.
PRECIPITATION CHANCES RANGE FROM 60 TO 100 PERCENT, GREATEST OVER
THE MOUNTAINS AND FOOTHILLS OVER THE SOUTH.
LIQUID PRECIPITATION TOTALS LOOK TO RANGE FROM AROUND 0.10 INCHES
IN THE NORTH, TO AROUND AN INCH OVER THE NORTHERLY UPSLOPE AREAS
OF THE SOUTHERN MOUNTAINS AND FOOTHILLS FROM TONIGHT THROUGH
TUESDAY. THE CURRENT PROBABILITY OF 0.5 INCHES OR MORE OF
PRECIPITATION RANGES FROM 20% NEAR MILES CITY AND BAKER, TO 50-70%
FOR AREAS SOUTH AND WEST OF A HARLOWTON TO BILLINGS TO SHERIDAN
LINE.
SNOW LEVELS ARE EXPECTED TO START OFF NEAR 10,000 FEET THIS
EVENING, DROPPING TO 6,000 FEET ON MONDAY, AND DROPPING TOWARDS
5,000 FEET MONDAY NIGHT INTO TUESDAY. THE MAJORITY OF THE
PRECIPITATION LOOKS TO FALL MONDAY AFTERNOON INTO TUESDAY MORNING,
WHEN SNOW LEVELS ARE FALLING. TEMPERATURES IN THE FOOTHILLS WILL
FALL INTO THE LOW 30S MONDAY NIGHT, ALLOWING FOR PRECIPITATION TO
TRANSITION TO SNOW. HIGHS ON TUESDAY WILL RANGE FROM THE 40S TO
50S. THERE IS UNCERTAINTY WITH SNOW AMOUNTS IN THE FOOTHILLS,
THOUGH THE BEST CHANCE FOR ACCUMULATIONS EXISTS FOR LOCATIONS SUCH
AS RED LODGE AND STORY. IN THE MOUNTAINS, SEVERAL INCHES OF
ACCUMULATIONS ARE FORECAST. CURRENTLY, 8 TO 12 INCHES LOOK TO FALL
ON THE NORTHERN ASPECTS OF THE BEARTOOTH/ABSAROKA MOUNTAINS, WITH
3 TO 6 INCHES IN THE BIGHORNS. WILL CONTINUE TO MONITOR FOR
POTENTIAL WINTER HIGHLIGHTS. STP
WEDNESDAY THROUGH SUNDAY...
A BIT OF AN ODD SETUP IS FORECAST FOR THE END OF THE WEEK. BY
WEDNESDAY MORNING A CUTOFF LOW WILL BE SITUATED TO OUR SOUTH OVER
THE FOUR CORNERS REGION. WHILE THIS WILL BE THE DOMINANT FEATURE
IN THE CONUS, THE BIGGER PICTURE SHOWS AN ODD REX BLOCK, OMEGA
BLOCK HYBRID WITH A WEAKER LOW OVER THE NORTHEAST US AND HIGH
PRESSURE OVER THE NORTHERN PLAINS/MIDWEST. ALL THIS TO SAY, THE
OVERALL PATTERN WILL BE VERY STALLED EVEN INTO THE END OF THE
WEEK.
ON WEDNESDAY A RELATIVELY WEAK VORT MAX WILL DISLODGE FROM THE
CUTOFF LOW IN THE SW AND MIGRATE NORTHWARD THROUGH WY/MT BEFORE
GETTING PICKED UP BY A SHORTWAVE MOVING THROUGH THE MAIN POLAR
JET. THIS WILL BE ENOUGH LIFT, IN ASSOCIATION WITH THE WAA AND
MOISTURE ADVECTION, TO GIVE THE WESTERN FOOTHILLS THE POTENTIAL
FOR SOME SHOWERS AND THUNDERSTORMS THURSDAY AFTERNOON AND EVENING
BEFORE ALL OF THE ENERGY MIGRATES EASTWARD.
THE END OF THE WEEK WILL FEATURE A DIRTY RIDGE OVER WESTERN NORTH
AMERICA. THIS WILL ALLOW OUR TEMPERATURES TO REBOUND WITH HIGHS
NEAR 80F AGAIN BY FRIDAY, BUT SOME MINOR RAIN CHANCES REMAIN. DUE
TO THE PREVIOUS WEATHER MAKER NOT EXITING CLEANLY, SOME LEFTOVER
MOISTURE AND ENERGY WILL REMAIN OVER THE NORTHERN ROCKIES. THIS
WILL ALLOW FOR DAILY CHANCES OF SHOWERS ACROSS THE CWA WITH SOME
ISOLATED THUNDERSTORMS THROUGH NEXT WEEKEND. WMR
AVIATION
12Z DISCUSSION...
VFR CONDITIONS WILL PREVAIL AREA-WIDE THROUGH AT LEAST 00Z. A
COLD FRONT WILL MOVE THROUGH FROM NW TO SE STARTING AT 01Z
TONIGHT. A WIND SHIFT TO MORE NORTHERLY WITH GUSTS BETWEEN
20-30KTS ARE EXPECTED FOR THE END OF THE TAF PERIOD. ADDITIONALLY
SOME SHRA WILL MOVE INTO THE FOOTHILLS NEAR KLVM AROUND 02-04Z.
AFTER 06Z MORE STEADY RAIN WILL SLOWLY FILL IN FROM WEST TO EAST;
STARTING AT KLVM AND REACHING KBIL BY THE END OF THE TAF PERIOD. MOUNTAINS
WILL BE PARTIALLY OBSCURED AFTER 20Z. WMR
PRELIMINARY POINT TEMP/POPS
TDY MON TUE WED THU FRI SAT
-------------------------------------------------------
BIL 083 046/049 036/053 037/074 050/082 050/076 051/081
1/U 49/R 74/W 00/U 02/W 41/U 11/B
LVM 078 040/045 032/050 034/074 045/078 045/075 047/078
4/T 79/R 62/W 00/U 03/T 32/W 12/T
HDN 085 046/052 036/053 037/074 044/082 050/078 050/082
0/U 39/R 85/W 10/U 02/W 41/U 11/B
MLS 086 050/059 038/055 040/074 050/082 052/077 051/082
0/U 26/R 63/W 20/U 01/U 31/U 11/U
4BQ 084 050/060 039/050 040/070 050/080 050/074 051/079
0/U 14/R 84/W 21/B 01/U 31/U 11/U
BHK 083 048/064 036/053 039/070 045/080 047/073 046/076
0/N 13/R 63/W 20/B 00/U 31/U 10/U
SHR 083 044/051 033/047 032/071 041/079 045/075 046/079
1/U 27/R 96/W 21/U 02/W 33/T 11/B
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
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