456
FXUS65 KBYZ 261728
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
1128 AM MDT MON MAY 26 2025
KEY MESSAGES
- MEMORIAL DAY FORECAST: MOSTLY SUNNY TODAY WITH ISOLATED (10-20%
CHANCE) LATE DAY SHOWERS/THUNDERSTORMS, MAINLY OVER AND NEAR THE
MOUNTAINS. HIGH TEMPS IN THE LOWER 60S TO MID 70S (COOLEST ALONG
MT/DK BORDER).
- BETTER CHANCE OF SHOWERS IN MOUNTAINS AND WESTERN FOOTHILLS
TUESDAY (30-70%)
- DRIER AND WARMER AFTER MIDWEEK. TEMPS PUSHING 80 DEGREES BY
THURSDAY FOR MOST LOCATIONS WITH DECREASED CHANCE OF
PRECIPITATION.
UPDATE
STRATUS IN THE EAST HAS LIFTED AND WILL SLOWLY DISSIPATE THIS
AFTERNOON. THERE ARE ALSO A FEW SHOWERS IN FAR SOUTHEAST MT PER
THE SOUTHEAST LOW LEVEL FLOW AND TROF OVER THE WESTERN DAKOTAS. BY
MID/LATE AFTERNOON, WE SHOULD SEE ISOLATED CONVECTION DEVELOP
OVER THE BEARTOOTH-ABSAROKA AND BIGHORN MOUNTAINS. THE REMAINDER
OF THE CWA WILL BE DRY W/ EASTERLY WINDS (GUSTING 30-40 MPH IN THE
FAR EAST) AND TEMPS IN THE MID 60S TO MID 70S (COOLEST EAST). A
FEW SHOWERS MAY EKE INTO OUR FAR WEST THIS EVENING AS PACIFIC
ENERGY MOVES THRU WESTERN MT, BUT ANY CHANCE OF MEASURABLE RAIN
WILL BE SPOTTY (20%). FORECAST IS IN GOOD SHAPE. HAVE ADDED PATCHY
FOG TO CARTER COUNTY AGAIN LATE TONIGHT TO EARLY TUESDAY. JKL
DISCUSSION
TODAY THROUGH TUESDAY NIGHT...
LATEST SATELLITE IMAGERY SHOWS FOG/LOW CLOUDS FORMING ACROSS OUR
EASTERN SECTIONS DOWN INTO THE SHERIDAN, WY VICINITY. EXPECT POCKETS
OF LOCALIZED FOG OR STRATUS TO BE PRESENT AGAIN OVER PARTS OF THE
CWA THIS MORNING THROUGH ABOUT 14Z.
UPPER TROUGH AXIS REMAINS ACROSS THE DAKOTAS AND CUTTING SOUTHWEST
THROUGH THE SOUTHEAST CORNER OF MT. CYCLONIC FLOW AROUND THIS
FEATURE MAY PRODUCE SOME LIGHT SHOWERS OVER THE VERY SOUTHEAST
CORNER OF MT THROUGH THE DAY WHILE LOW LEVEL MOISTURE REMAINS
SOMEWHAT ELEVATED THERE, SUSTAINED BY BRISK SOUTHEAST WINDS. HIGH
PRESSURE ALOFT OTHERWISE PREVAILS ACROSS THE AREA THROUGH THE
DAY. WE MAY SEE SOME WEAK CONVECTION DEVELOP OVER THE HIGHER
TERRAIN ALONG THE MT/WY BORDER IN THE AFTERNOON THANKS TO
DIFFERENTIAL HEATING AND MODEST INSTABILITY. BY EVENING, THE
CHANCE OF CONVECTION ACROSS OUR FAR WESTERN ZONES (BEARTOOTHS TO
JUDITH GAP) INCREASES (15-25% POPS) AS A MOIST MID LEVEL SOUTHWEST
FLOW DEVELOPS. MUCH OF THIS WILL DIMINISH WITH SUNSET.
AN UPPER TROUGH IS PROGGED TO WORK THROUGH THE DOMINANT HIGH
PRESSURE RIDGE OVER THE ROCKIES AND DROP SOUTH ACROSS OUR WESTERN
ZONES TUESDAY SYNCING UP WITH THE CYCLONIC FLOW STILL LINGERING
OVER THE UPPER MIDWEST. THIS IS EXPECTED TO PRODUCE SCATTERED TO
NUMEROUS LATE DAY SHOWERS/THUNDERSTORMS FROM ABOUT YELLOWSTONE
COUNTY WESTWARD AND SOUTH TO THE BIGHORNS REGION. THE CHANCE OF AT
LEAST 0.10 INCH OF PRECIPITATION WITH THIS SYSTEM RANGES FROM
ABOUT 15% AT BILLINGS TO 40% OVER THE BEARTOOTHS. WE DO NOT EXPECT
ANY SEVERE CELLS WITH THIS ACTIVITY AS PROGGED SHEAR AND HELICITY
ARE WEAK, BUT MUCAPE MAY REACH 500-800 J/KG, WHICH IS ADEQUATE
FOR SOME LOCALLY HEAVY RAIN AND SMALL HAIL. THE CONVECTIVE
ACTIVITY WILL END AFTER MIDNIGHT AS THE UPPER TROUGH AXIS TRACKS
INTO WYOMING.
TEMPERATURES WILL BE SEASONAL IN THE LOW TO MID 70S FOR MOST AREAS
THE NEXT COUPLE OF DAYS, WITH THE EXCEPTION BEING FAR EASTERN
MONTANA WERE TEMPERATURES WILL BE IN THE 60S. BT
WEDNESDAY THROUGH SUNDAY...
UPPER LEVEL RIDGING IS DEPICTED BY ENSEMBLES, WEDNESDAY INTO NEXT
WEEKEND. WARMER AND DRIER CONDITIONS WILL ACCOMPANY THIS PATTERN
WITH HIGH TEMPERATURES IN THE 70S AND 80S. THE GFS AND ECMWF
ENSEMBLES CURRENTLY SHOW 850MB TEMPERATURES ANOMALIES OF 5-10C.
THE RESULT OF THIS IS TEMPERATURES APPROACHING 90F BY NEXT
SUNDAY. UNCERTAINTY REMAINS HIGH AT THIS TIME, ALTHOUGH WE ARE
LOOKING AT POTENTIALLY THE WARMEST TEMPERATURES OF THE YEAR SO
FAR.
A FEW DETERMINISTIC MODELS ARE SHOWING A SHORTWAVE MOVING THROUGH
THE NORTHERN ROCKIES ON FRIDAY, BRINGING AN INCREASED CHANCE FOR
SHOWERS AND THUNDERSTORMS. THERE IS ALSO UNCERTAINTY WITH THIS, SO
CONTINUE TO MONITOR THE FORECAST GOING INTO NEXT WEEKEND.
HIGH ELEVATION SNOWMELT WILL INCREASE DURING THE EXTENDED FORECAST
PERIOD, ESPECIALLY WITH OVERNIGHT LOWS AROUND OR ABOVE FREEZING.
RIVER AND STREAM RISES WILL LIKELY OCCUR AS A RESULT OF THE
WARMER TEMPERATURES. MATOS
AVIATION
SCATTERED TO BROKEN STRATUS WITH 3.5-4.5KFT AGL BASES EAST OF
ROSEBUD COUNTY WILL SLOWLY DISSIPATE THROUGH THE AFTERNOON. AFTER
A PERIOD OF CLEARING, LOW CEILINGS MAY SPREAD BACK INTO SOUTHEAST
MT LATE TONIGHT, WITH MVFR POSSIBLE, AND LOCALIZED FOG IN CARTER
COUNTY. THIS WILL BE SOMETHING TO MONITOR TONIGHT. LOOK FOR
ISOLATED SHOWERS AND WEAK T-STORMS OVER THE ABSAROKA/BEARTOOTH AND
BIGHORN MOUNTAINS FROM 21Z TO 04Z TODAY. MOUNTAIN TOPS MAY BE
OBSCURED AT TIMES. LIGHT SHOWERS WILL SPREAD TO WESTERN LOWER
ELEVATIONS LATE TONIGHT, WITH VFR PREVAILING. JKL
PRELIMINARY POINT TEMP/POPS
TDY TUE WED THU FRI SAT SUN
-------------------------------------------------------
BIL 075 051/075 053/077 052/082 057/081 054/085 057/088
0/U 04/T 21/T 00/U 12/T 00/U 12/T
LVM 076 049/074 048/075 048/082 054/078 050/083 054/086
1/U 25/T 22/T 01/U 22/T 01/U 13/T
HDN 076 048/076 051/077 051/082 054/081 051/085 054/090
0/U 02/W 21/T 00/U 22/T 11/U 12/W
MLS 072 048/076 050/077 051/081 054/083 053/085 056/090
0/U 01/U 11/U 00/U 11/U 10/U 11/U
4BQ 068 047/074 048/073 048/077 053/081 053/082 056/088
0/B 01/U 11/U 00/U 11/U 10/U 01/U
BHK 065 044/069 044/071 044/076 048/080 050/080 052/084
0/N 00/B 11/U 00/U 01/U 10/U 11/U
SHR 072 044/072 048/073 046/077 051/077 049/080 052/086
1/U 03/T 44/T 11/U 13/T 11/U 01/T
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
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