806
FXUS65 KBYZ 151734
AFDBYZ

Area Forecast Discussion...Updated
National Weather Service Billings MT
1034 AM MST Sat Nov 15 2025

.KEY MESSAGES...

- Weather system late Sunday into Monday will lower temperatures
  to near normal with an increased chance of precipitation.

- Further cooling and unsettled conditions middle part of next
  week.

&&

Upadated 18z Aviation Discussion.

.DISCUSSION...

Today through Friday...

Current analysis and satellite imagery indicated broad low
amplitude trough axis was sliding east into the Dakotas overnight.
Associated upper dynamics were also moving east of Montana
bringing shower activity to an end.

For today...a frontal boundary will sag across east central
Montana under NW flow aloft. A weak perturbation in the flow will
track NW to SE across our eastern zones this morning and models
have trended toward producing some light precip under this
feature, so have increased coverage of low PoPs (15-30%) and
lingered the activity into the afternoon near the Dakota border.
Look for decreasing clouds from west to east this afternoon. Highs
will be in the lower 60s west to near 50 far east. Ridging will
build back in tonight and Sunday for mild dry conditions. Highs
Sunday will be in the 50s to around 60 degrees.

Late Sunday through Monday night...A slow moving upper trough
will track across Wyoming for the latter part of the weekend and
into Monday. Models generally push some moisture up from the south
into our forecast area, but are in a little better agreement
about keeping the bulk of the energy to our south before it tracks
into SD/Nebr. Therefore, we anticipate a low impact event for us
with about 2-5 inches of snow possible in the Beartooths (mainly
above 7500 ft), and scattered rain showers over the lower
elevations through Monday. There is a 25-60% chance of at least
0.25 ins of liquid precip, highest over our western mountains.
Highs will be in the 50s Monday, and again Tuesday.

Wednesday through Friday...a split flow pattern to our west will
shift east across the Rockies. This is likely to lead to temps
cooling down to around seasonal norms (highs 40s) with a chance
of showers and mountains snow. It does not currently appear to
result in a big precip event for us, but cluster analysis of
ensembles suggest a good deal of uncertainty yet. BT

.AVIATION...

18z Discussion...

Weak Gap Flow setup continues in the Livingston area with
southwest gusts in the 40kt range localized there. This pattern
should relax over the next few hours with gusts decreasing into
the 30kt range then 20kts by late afternoon.

Weak backdoor cold air push into northeast zones has low stratus
covering areas from Rosebud county and much of SE Montana this
morning. Models want to keep this layer around for another few
hours with erosion occuring through the late afternoon/early
evening. Given weak flow and some lighter winds in the lower
boundary layer can`t rule out IFR ceilings holding on through the
afternoon and into tonight, possibly evolving into broader fog
development by late evening. For now going with the model
consensus for KMLS and eroding the stratus to scattered by 20z or
so.

Central zones stay west of the cooler air today and will see
mixed westerly winds in the 20 to 30kt range for a few hours this
afternoon, quickly diminishing with the late afternoon sunset.
Winds look fairly weak tonight allowing that cooler high pressure
over NE Montana to sag westward overnight, possibly making it into
the western foothills by sunrise tomorrow morning. Will have to
keep an eye out for patchy fog/stratus development to follow this
shallow airmass into the area tonight. Chambers

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Sun     Mon     Tue     Wed     Thu     Fri
-------------------------------------------------------
BIL 064 038/055 038/056 038/055 035/049 029/049 031/049
    1/U 00/E    13/W    32/W    23/W    10/B    11/B
LVM 061 035/057 037/055 036/053 032/049 029/050 027/048
    0/N 01/E    24/W    33/W    33/W    11/B    21/U
HDN 063 035/059 036/054 036/055 032/049 026/049 027/049
    2/W 00/E    14/W    42/W    34/W    21/B    11/B
MLS 054 031/056 036/051 034/052 033/049 029/048 028/048
    2/W 00/B    02/W    31/B    22/W    10/B    00/B
4BQ 059 035/059 038/051 037/053 034/049 030/048 029/047
    0/U 00/B    13/W    21/B    12/W    20/B    01/B
BHK 050 029/055 033/047 030/050 029/049 026/047 026/046
    2/W 00/B    13/W    31/B    12/W    20/B    00/B
SHR 061 033/059 034/052 031/054 031/049 026/050 025/048
    0/U 00/B    25/W    32/W    23/W    21/B    11/B

&&

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

&&

$$
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