063
FXUS65 KBYZ 230905
AFDBYZ

Area Forecast Discussion...Corrected
National Weather Service Billings MT
305 AM MDT Fri May 23 2025

.KEY MESSAGES...

- Periodic showers, a few afternoon and evening thunderstorms, and
  seasonable temps through Sunday.

- Memorial Day Forecast: Mostly sunny with a slight (20%) chance
  of showers/thunderstorms in the afternoon and evening; high
  temps in the lower 60s to mid 70s (coolest east).

- Temps back to near 80 degrees toward the middle of next week.

&&

.DISCUSSION...
Through Saturday Night...

Weak upper trough was lifting northeastward overnight across
Montana, pushing an area of showers and embedded thunder with it.
This area of shower activity is progged to lift out of our CWA by
morning, with a few showers possibly lingering over Fallon County
through mid morning before exiting into the Dakotas.

Another weak trough in an otherwise benign westerly flow will
produce isolated/sct showers this afternoon into the evening. Most
of this will be over the Beartooth/Absaroka Ranges aided by
differential heating in the afternoon. The trough energy gradually
shifts across our area through the night and into Saturday as a
somewhat amplified upper ridge builds over the Pacific NW. SO
isol/sct showers may very well linger over the southern half of
our CWA tonight. SE low level flow will increase and bring some
additional moisture into the area by Saturday, increasing
instability with MUCAPE progged to be over 500 J/kg over portions
of the area. Best chance of showers/Thunder will be Sheridan
Countyand the Big Horns region on Saturday with a 50-60% chance of
0.25 inches of precip.

Drier air moves into western and central Montana by Saturday night
ending most of the convection.

High temperatures will be in the 60s for most of southeast
Montana with some 50s along the Dakotas border. BT


Sunday through Thursday...

Spring showers will continue in the long term, along with a
warming trend early next week. No severe thunderstorms are
expected at this time throughout the extended period.

Trough axis will extend from eastern MT to the Great Basin Sunday,
with a ridge over the northern Rockies. This will leave a chance
of showers/thunder over SE MT and north central WY through the day
and into the evening...possibly lingering across that area
through Monday morning. Precipitation should be on the light
side...under two tenths even for the stronger cells. Ensembles
are not in very good agreement just yet regarding another trough
poised to cut across the west and into the Rockies by mid week. So
there will remain a chance of late day showers/thunder, mainly
over the mountains Monday through Thursday. If that next trough
moves in quicker like some ensemble members suggest, we will need
to increase the chance of showers/thunder by midweek. As it
stands now, look for a warming trend with highs in the 60s to near
70 Sunday, mostly lower 70s for Monday (Memorial Day), and
pushing 80s by midweek which is about 10 degrees above seasonal
norms. We should see increased snowmelt and thus runoff by middle
of next week as well. So use caution if you are near rivers and
streams as flows pick up. BT
&&

.AVIATION...

Widely scattered light showers and some thunder will linger over
east central MT and in the SE corner of MT through 14Z, possibly
affecting KMLS and KBHK. MVFR/IFR cloud decks are possible across
eastern routes after 15Z (KMLS, KBHK). Another round of isolated
to widely scattered showers and isolated thunderstorms will
develop over mountains after 19Z, with a few thunderstorms also
possible over east central MT. Areal mountain tops may be obscured
at times. Local gusts over 30 kts are possible with stronger
storm cells. BT
&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Sat     Sun     Mon     Tue     Wed     Thu
-------------------------------------------------------
BIL 067 045/066 047/069 047/073 049/075 051/077 051/080
    2/T 24/T    22/W    01/U    13/T    22/W    13/W
LVM 066 042/066 042/068 043/073 047/073 047/076 048/079
    3/T 34/T    11/U    02/T    35/T    22/W    13/T
HDN 068 045/066 046/070 047/073 046/075 048/077 049/081
    2/W 24/T    23/T    12/W    12/T    22/W    13/W
MLS 061 045/066 047/067 047/067 046/071 048/076 049/079
    2/W 24/W    23/T    12/W    11/U    11/U    12/W
4BQ 066 045/061 047/063 048/064 046/069 046/072 048/075
    1/U 25/T    34/T    22/T    12/W    22/W    12/W
BHK 053 040/058 042/061 043/061 041/064 042/069 044/072
    6/W 23/W    23/T    22/W    11/B    12/W    12/W
SHR 067 042/060 041/064 042/069 043/071 045/073 045/076
    2/T 26/T    36/T    23/T    14/T    23/T    23/T

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.

&&

$$
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