346
FXUS65 KBYZ 271956
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
156 PM MDT TUE MAY 27 2025
KEY MESSAGES
- SCATTERED SHOWERS AND T-STORMS LATE THIS AFTERNOON AND EVENING
(30-70% POP); A FEW STORMS COULD PRODUCE BRIEF HEAVY RAIN, SMALL
HAIL AND ERRATIC WIND GUSTS; SCATTERED SHOWERS WILL LINGER
THROUGH THE NIGHT AND INTO WEDNESDAY MORNING OVER THE SOUTH AND
EAST.
- DRIER AND WARMER THURSDAY THOUGH THE WEEKEND; TEMPS PUSHING 80
DEGREES THURSDAY THROUGH SATURDAY; 90F IS POSSIBLE BY SUNDAY.
- CONFIDENCE GROWING FOR A COOLER AND VERY ACTIVE WEATHER PATTERN
NEXT WEEK, STARTING WITH A COLD FRONT LATE SUNDAY OR SUNDAY
NIGHT; SEVERE T-STORMS POSSIBLE SUNDAY AND/OR MONDAY;
SIGNIFICANT PRECIPITATION (INCLUDING HIGH ELEVATION SNOW)
POSSIBLE FROM MONDAY THROUGH THE MIDDLE OF NEXT WEEK.
DISCUSSION
THROUGH THURSDAY NIGHT...
SATELLITE IMAGERY SHOWS NORTHERLY FLOW OVER OUR REGION, WITH A
SLOWLY EVOLVING LOW OVER THE EASTERN DAKOTAS AND STRONG RIDGE OVER
THE PACNW. AS EXPECTED WITH A WEAK SHORTWAVE DROPPING THRU THE
REGION, WE ARE SEEING SCATTERED SHOWERS AND A FEW T-STORMS DEVELOP
OVER OUR WEST AS OF 1930Z. MESOANALYSIS SHOWS UP TO 500 J/KG OF
MLCAPE AND BULK SHEAR OF 20-30 KNOTS OVER OUR WEST. CONVECTION
WILL STAY SUB-SEVERE BUT COULD PRODUCE BRIEF HEAVY RAIN AND SMALL
HAIL, ALONG WITH ERRATIC WIND GUSTS UP TO 40 MPH. THE GREATEST
CHANCE OF PRECIP WILL ACTUALLY BE OVER OUR SOUTHERN UPSLOPE AREAS
(AND TO A LESSER EXTENT OUR EAST) TONIGHT AS THE MAIN VORTICITY
LOBE (NOW IN SW SASKATCHEWAN) DROPS THROUGH THE REGION. THE
PROBABILITY OF 0.25" OR MORE OF RAIN AT SHERIDAN AND OVER THE
BIGHORNS IS 35-50%. EXPECT SOME SHOWERS TO LINGER INTO THE 12-15Z
TIME FRAME IN THE SOUTH, WHILE DRIER AIR/SUBSIDENCE ARRIVES FROM
THE NORTH.
WE WILL BE UNDER CYCLONIC NORTHERLY FLOW THRU TOMORROW, BUT WITH
RISING HEIGHTS AND WARMING MID LEVELS MAKING DIURNAL INSTABILITY
MUCH MORE SHALLOW AND INCREASINGLY CAPPED. WILL KEEP ISOLATED TO
SCATTERED POPS FOR MUCH LIGHTER SHOWERS THRU WEDNESDAY AFTERNOON
IN THE SOUTH ONLY. TEMPS TOMORROW WILL REMAIN SEASONABLE WITH
HIGHS IN THE LOW-MID 70S MOST PLACES. THERE MAY BE LOCALIZED FOG
IN OUR EAST WEDNESDAY NIGHT W/ CLEARING AND PERSISTENT EASTERLY
WINDS.
PERIOD OF RIDGING WILL BRING DRY CONDITIONS THROUGH MOST OF
THURSDAY. RIDGE AXIS SHIFTING EAST (FINALLY) WILL YIELD SOME
MODEST DOWNSLOPE WARMING, PUSHING TEMPS TO THE UPPER 70S AND LOWER
80S. NEXT PACIFIC WAVE WILL SWING ACROSS NORTHERN MT AND SOUTHERN
AB/SK, BRINGING A WEAK COLD FRONTAL PASSAGE AND SLIGHT CHANCE
(10-20%) OF SHOWERS FROM LATE THURSDAY AFTERNOON THRU THURSDAY
NIGHT. NOT MUCH MOISTURE OR INSTABILITY WITH THIS SHORTWAVE THUS
PRECIP WILL BE SPOTTY.
JKL
FRIDAY THROUGH TUESDAY...
SHORTWAVE PASSAGE THROUGH NORTHERN MT AND A SURFACE COLD FRONT
WILL BRING A LOW (10-20%) CHANCE OF SHOWERS, ALONG WITH BREEZY
POST-FRONTAL CONDITIONS, ON FRIDAY. ANY PRECIP WILL BE SPOTTY AND
LIGHT, AND THE BIGGER IMPACT WILL PROBABLY BE THE 25-35 MPH MIXED
W-NW WIND GUSTS. TEMPS ON FRIDAY WILL REMAIN ABOVE NORMAL DESPITE
THE FRONTAL PASSAGE. RIDGE REBUILDS FOR WARMER/DRY WEATHER
SATURDAY AND MOST OF SUNDAY. LOOK FOR HIGHS IN THE 80S SATURDAY
AND 80S TO LOWER 90S SUNDAY...THE LATTER OF WHICH SHOULD BE
WARMEST IN THE EAST. DEPENDING ON THE TIMING OF THE NEXT COLD
FRONT, SUNDAY COULD BE THE WARMEST DAY YET OF 2025. IF PRE-FRONTAL
TIMING IS PERFECT, SOME LOCATIONS COULD PUSH THE MID 90S (W/
700MB TEMP PLUME NEAR +14C).
THINGS GET MUCH MORE INTERESTING WITH THE LATE SUNDAY OR SUNDAY
NIGHT FRONTAL PASSAGE...AND THERE REMAINS PLENTY OF UNCERTAINTY
WITH THE FRONT'S TIMING, THOUGH THERE SEEMS TO BE A GROWING
CONSENSUS FOR THE FRONT TO ARRIVE BEFORE MONDAY. NOT ONLY WILL A
DEEP TROF EMERGING FROM THE NORTH PACIFIC DROP OVER THE WESTERN
CONUS EARLY NEXT WEEK, A WEAK LOW OVER BAJA IS EXPECTED TO EJECT
NORTHEASTWARD AT THE SAME TIME. FURTHERMORE, WE WILL SEE MOISTURE
ADVECTION UP THE HIGH PLAINS, TO THE POINT THAT PWATS MAY REACH AN
INCH (2 STANDARD DEVIATIONS ABOVE NORMAL). OVERALL IN A SYNOPTIC
SENSE, WE ARE LOOKING AT PERIODS OF STRONG ASCENT IN A RATHER
MOIST ENVIRONMENT, IN EARLY JUNE. SPECIFICS ARE IMPOSSIBLE AT THIS
TIME, BUT THERE IS POTENTIAL FOR SEVERE T-STORMS LATE SUNDAY
AND/OR MONDAY, STORMS CAPABLE OF PRODUCING HEAVY RAIN WHICH COULD
ADD TO ALREADY HIGH RIVERS AND STREAMS, AND EVEN HIGH ELEVATION
SNOW OVER BEARTOOTH PASS AS SNOW LEVELS FALL TO 9-10KFT MSL.
A QUICK LOOK AT 72-HOUR PROBABILITIES FOR SUNDAY NIGHT THROUGH
WEDNESDAY SHOW A 50-70% CHANCE OF 1+ INCHES OF PRECIP WEST OF
ROSEBUD COUNTY, AND A 20-40% CHANCE OF 2+ INCHES WEST OF ROSEBUD
COUNTY AND SOUTH OF THE MUSSELSHELL RIVER. EVEN THE PROBS FOR 3+
INCHES ARE NON-ZERO (5-15%) ALONG THE SOUTHERN FOOTHILLS. PLEASE
MONITOR THE FORECAST OVER THE COMING DAYS AS THESE DETAILS BECOME
CLEARER.
AS FOR TEMPERATURES, AFTER A HOT WEEKEND, WE ARE LOOKING AT SHARP
COOLING WITH HIGHS IN THE 60S TO MID 70S MONDAY, THEN UPPER 50S
AND 60S TUESDAY.
JKL
AVIATION
A DISTURBANCE TRACKING FROM THE NORTH WILL PRODUCE SCATTERED
SHOWERS & T-STORMS THIS AFTERNOON AND EVENING...INITIALLY WEST OF
KMLS & K00F, BUT SOME ACTIVITY WILL SPREAD FURTHER EAST AFTER 00Z.
THESE STORMS MAY PRODUCE BRIEF MVFR IN HEAVY RAIN, SMALL HAIL AND
ERRATIC WIND GUSTS. SHOWERS WITH LOCAL MVFR WILL PERSIST THROUGH
THE NIGHT SOUTH AND EAST OF KBIL. MOUNTAINS (ESPECIALLY THE
BIGHORNS) WILL BE OCCASIONALLY OBSCURED. LOOKING TO WEDNESDAY,
MOST OF THE AREA WILL BE DRY BUT SCATTERED SHOWERS WILL LINGER
OVER THE SOUTH. VFR WILL PREVAIL TOMORROW. JKL
PRELIMINARY POINT TEMP/POPS
WED THU FRI SAT SUN MON TUE
-----------------------------------------------------------
BIL 054/076 050/081 057/079 053/085 057/087 055/066 049/061
41/B 00/U 22/W 00/U 02/T 56/T 87/W
LVM 049/074 045/082 054/077 049/085 055/084 050/063 044/057
21/U 01/U 21/U 00/U 03/T 68/T 88/T
HDN 054/076 049/081 054/079 050/085 055/090 055/068 049/064
51/B 00/U 22/W 00/U 02/T 56/T 87/W
MLS 054/076 049/080 052/082 052/084 057/090 058/074 051/067
31/U 00/U 01/U 10/U 01/U 44/T 75/W
4BQ 052/071 047/077 052/079 052/081 055/089 057/074 050/065
42/W 00/U 01/U 10/U 01/U 33/T 75/W
BHK 046/070 043/075 047/079 048/079 051/085 055/075 047/065
21/B 00/U 00/U 10/U 00/U 33/T 64/W
SHR 050/071 043/079 052/076 048/082 052/089 052/069 045/063
75/T 00/U 02/W 10/U 01/U 36/T 87/T
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
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