408
FXUS65 KBYZ 040246
AFDBYZ

Area Forecast Discussion...Updated
National Weather Service Billings MT
846 PM MDT Tue Jun 3 2025

.KEY MESSAGES...

- Winter Weather Advisory in effect for the Beartooth Highway
  through tonight, with snow showers bringing an additional 1 to 2
  inches of accumulation generally above 8,000 feet.

- Scattered showers and isolated weak thunderstorms will continue
  into tonight. Additional chances of precipitation Wednesday and
  Thursday this week.

- Warming trend through the remainder of the week, with above
  normal temps returning Friday and the weekend.

- Rivers are running high and fast, but cooler temperatures will
  slow mountain snowmelt and result in decreasing flows through
  the middle of the week.

&&

.UPDATE...

Shower activity is gradually increasing over the forecast area
this evening. Look for these showers to continue into tonight as
the associated upper wave progresses through the region. With this
activity, lightning has been minimal. However, an occasional
strike or two remains possible into tonight. Over the mountains,
precipitation is still expected to fall as snow with this activity
mainly above 7,500 feet, with accumulations possible mainly above
8,000 feet. Therefore, the Winter Weather Advisory for the
Beartooth Highway remains in effect through tonight. The rest of
the forecast is in good shape. Arends

&&

.DISCUSSION...

Through Wednesday night...

Satellite imagery shows a cyclonic NW flow over the region with an
upstream shortwave in far northwest MT. Most of our forecast area
has been dry thru the morning, but as of 19z we are starting to
see some weak convection develop over the mountains. Mesoanalysis
shows some low sbcape values emerging as temps reach the upper 50s
and low 60s. This modest instability along with some synoptic
ascent will yield an increase in shower coverage over the next few
hours, with the highest chances of actual precip at lower
elevations likely to hold off til close to 00z and tonight w/ the
passage of the wave. There will be a few weak t-storms as well.
Forecast soundings show some mid level moistening and steep lapse
rates tonight, so there should be some activity persisting for
most of the night, while in general tracking from NW to SE. Precip
will be spotty and may avoid the northeast portion of our cwa
entirely.

After a brief break tomorrow morning and early afternoon, expect
another round of scattered showers and isolated non-severe
t-storms Wednesday afternoon and evening, with an additional
shortwave in the NW flow. A bit warmer temps should yield a bit
higher instability tomorrow, so shower coverage looks to be a
little greater than today. Over the next 36 hours, the chance of
exceeding 0.10" of rain is only 10-15% at lower elevations and
20-50% over/near the mountains & foothills.

Temperatures will remain cooler than normal. Expect lows in the
upper 30s and 40s, and highs Wednesday in the mid 60s to around
70F. Winds will remain light through the period, but could be
briefly gusty near any shower activity.

Finally, today`s hazy sky is brought to you by the numerous
Canadian wildfires well to our north. The NW flow will bring waves
of lofted smoke to our east (and especially northeast MT) over the
next couple days but the risk of surface impacts seems to be low.

JKL

Thursday through Tuesday...

Northwest flow will remain in place with higher heights also
building in allowing for temperatures to increase into the
weekend. Ensembles keep a small to moderate chances for precip in
the forecast for Thursday (mainly along the MT/WY border), but any
accumulations will be light. A low to our east in North
Dakota/Minnesota will allow for breezy conditions in eastern MT
Sunday afternoon with gusts 30-40 mph possible. As ridging
transitions east Monday and Tuesday, the region will be under
southwest flow, enhancing the chances of unsettled weather which
the ensembles do depict.

Overall, warm and mostly dry conditions with slightly above
temperatures expected for early next week. High temperatures will
be in the 70s Friday, warming into the 80s and potentially low
90s by early next week. TS

&&

.AVIATION...

Scattered showers will roam across the forecast area overnight
before tapering off early Wednesday. Another round of scattered
showers and isolated t-storms is expected Wednesday afternoon and
evening. VFR will prevail over the next 24 hours, but any
moderate showers could produce brief MVFR. Also, mountains will be
frequently obscured in snow showers. BT/JKL

&&

.PRELIMINARY POINT TEMP/POPS...

    Wed     Thu     Fri     Sat     Sun     Mon     Tue
-----------------------------------------------------------
BIL 047/068 048/072 048/081 054/084 057/083 057/089 060/085
    22/T    21/U    00/U    10/U    00/U    01/U    23/T
LVM 038/065 039/070 042/077 049/081 051/083 053/086 055/081
    32/T    22/T    01/U    10/U    00/U    11/U    24/T
HDN 043/070 047/073 045/081 053/084 055/083 054/089 058/087
    22/T    22/T    00/U    11/B    10/U    01/U    23/T
MLS 045/071 047/073 047/080 055/085 057/083 054/089 057/086
    13/T    12/W    10/U    11/B    10/B    10/U    22/T
4BQ 043/068 046/068 047/077 054/081 056/080 054/086 057/086
    12/T    13/T    10/U    11/B    10/B    00/U    22/T
BHK 040/069 043/070 044/076 051/081 050/078 048/083 052/084
    02/T    12/W    10/U    01/B    10/U    00/U    12/T
SHR 039/066 042/067 042/075 049/079 050/079 051/084 053/084
    33/T    35/T    11/U    11/B    11/U    01/U    24/T

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory in effect until 6 AM MDT Wednesday
      FOR ZONE 67.
WY...None.

&&

$$
weather.gov/billings