Decker, Montana Weather Forecast Discussion

723
FXUS65 KBYZ 140730
AFDBYZ
Area Forecast Discussion
National Weather Service Billings MT
130 AM MDT Sun Sep 14 2025
.KEY MESSAGES...
- Mainly dry and warmer today.
- Unsettled and cooler Monday and Tuesday.
- Drying out with seasonal temperatures Wednesday through Friday.
&&
.DISCUSSION...
Through Tuesday night...
A few changes to the short term forecast tonight. Upper level
ridge over the eastern US evolves into a High over Low blocking
pattern which pushes the northern extent of the ridge further
north and strengthens it. This feature cuts off the west to east
flow over the northern US and bottles up the upper trof over the
Northern Rockies. Energy with this trof was previously forecast to
push eastward with ridging aloft bringing dry and warmer
conditions today and Monday. However with this east coast pattern
change the energy that would have flowed eastward is now diving
southward deepening the trof over our area and opening the door
for the next upstream wave to flow on into our area.
Today still looks mainly dry however the approaching wave to the
west could push isolated showers/tstms into our western mountains
by late afternoon/early evening and another piece of energy
moving south to north out of NE Colorado could bring a few
thunderstorms to far eastern portions of the forecast area this
afternoon into tonight. The UKMET solution actually brings the
wave fully into SE Montana producing a significant amount of
convection today, though the EC/GFS solution stay further east
just skirting our area. Still looking at more sun today which will
push temperatures into the 75 to 85 degree range this afternoon.
By tonight the next Pacific system is already moving into the area
pushed by a jet streak that moves across southern Idaho and into
NW Wyoming, with a bit of a northeastward curl on its nose. This
energy aloft buckles the trof into a negatively tilted
configuration through the day Monday as it progresses eastward and
sets up a deformation zone over SC Montana resulting in a
significant increase in precipitation chances (40-70%) from
Monday into Tuesday. While precipitation chances are fairly high
during this period, QPF amounts are a bit muted as plains moisture
is largely cut-off with this system, so only residual moisture
from recent precipitation and mid level Pacific moisture brought
along by the upper low will be available, with PWATS mainly under
0.75 inches for central and western zones, and under an inch over
SE Montana. With the increased precipitation and cloud cover,
high temperatures will be mainly in the 70s Monday, and lower 70s
Tuesday.
East coast blocking pattern weakens Tuesday allowing the upper
trof to begin shifting eastward once again, and this will allow
precipitation chances to diminish heading into Tuesday night.
Chambers
Wednesday through Saturday...
Wednesday looks to be a transition day as the early-week weather
system shifts east and low amplitude ridging begins to build over
western Montana. With that said, models do suggest an additional
piece of energy will bring a backdoor cold front through eastern
Montana Wednesday, subsequently keeping cooler temperatures and a
slight chance of precipitation in the forecast for areas east of
Billings during the day. On Thursday into Friday, the
aforementioned low amplitude ridge looks to move east through our
region. This will bring drier conditions across the area, but
temperatures have trended a bit cooler to normal values through
this time (70s). While the National Blend of Models (NBM) begins
to increase the chance of precipitation across the region late
Friday into Saturday, the upper level pattern remains very
uncertain. At this time, troughing of some fashion looks to move
over the western United States Friday into Saturday, but how this
pattern moves through our region is where the uncertainty remains.
Will have to see how the upper level pattern trends through the
week.
Temperatures look to remain season through the long-term
forecast. Arends
&&
.AVIATION...
While the chance is low, cannot rule out patchy fog early this
morning over eastern Montana, mainly around KMLS and KBHK.
Otherwise, VFR conditions will prevail today. As far as
precipitation goes, scattered showers and isolated thunderstorms
are forecast over south-central Montana late this afternoon into
tonight. With this activity, gusty and erratic winds are possible.
Over far eastern Montana, a few showers and embedded storms are
possible today as well, but uncertainty remains on the westward
extent of this activity over the Dakotas into Montana. Arends
&&
.PRELIMINARY POINT TEMP/POPS...
Tdy Mon     Tue     Wed     Thu     Fri     Sat
-------------------------------------------------------
BIL 081 057/074 055/070 052/075 049/077 050/076 051/076
    0/U 05/T    66/T    21/U    00/U    01/U    22/W
LVM 077 045/065 044/068 043/076 043/079 043/076 045/075
    1/U 26/T    44/T    10/U    00/U    01/B    33/T
HDN 081 052/077 052/071 049/074 046/077 045/078 048/077
    0/U 14/T    66/T    31/B    10/U    00/U    22/W
MLS 080 055/081 055/073 051/074 049/074 048/075 050/075
    1/U 11/B    56/T    42/W    10/U    00/U    11/B
4BQ 077 054/079 054/069 052/070 048/072 048/073 050/073
    1/B 01/U    66/T    52/T    11/U    00/U    11/B
BHK 074 052/080 051/072 048/073 046/072 045/070 045/072
    1/E 11/B    45/T    42/W    11/B    10/B    11/B
SHR 078 048/074 046/068 044/071 043/074 043/077 045/076
    0/U 04/T    68/T    42/T    10/U    00/U    22/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings

NWS BYZ Office Area Forecast Discussion