Area Forecast Discussion
Issued by NWS Billings, MT

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879
FXUS65 KBYZ 251526
AFDBYZ

Area Forecast Discussion...Updated
National Weather Service Billings MT
926 AM MDT Mon Sep 25 2017

.UPDATE...

Morning fog is already lifting in many areas and should continue
to diminish over the next hour or so. Weakening upper low
currently located near Riverton, Wyoming and moving slowly to the
northeast this morning. Moisture and weak energy wrapping around
this feature is producing areas of light precipitation and/or
cloud cover along and east of a Forsyth to Hardin to Pryor line
this morning. Best areas for precipitation are in and near the
Bighorn mountains and over Carter/Fallon counties. Increased pops
in these areas to high chance/likely category for this morning
based on latest model/radar trends. Total accumulations should be
a tenth of an inch or less from this activity, which will
diminish as we get into the afternoon hours. Could see an
additional inch of snow in the Bighorn mountains above 7000 feet
today. Highs in the 50s to around 60 degrees look good. May see a
few instability showers over western mountains move into the
adjacent lower elevations west this afternoon/early evening, but
any of this activity will be very light. Chambers

&&

.SHORT TERM...valid for Tdy and Tue...

Upper level low over southwest Wyoming will drift northeastward
today, crossing into the Dakotas by Tuesday. This system is
filling and becoming weaker with time and most of the associated
dynamics will remain south of our CWA. Model dprog/dt indicate
this through a significant trend of decreasing QPF for this
morning over our region. Thus, we continue to trend PoP`s down,
especially over areas further north in our CWA. We are looking for
just a chance of showers, basically from the Big Horns to Custer
County and eastward. Precipitation should be on the light side as
well with most locations that do see rain picking up a few
hundredths.

Upper trof axis shifts east tonight with warming and drying trend
expected into Tuesday. Highs Tuesday back into the 60s with
partly cloudy skies. BT

.LONG TERM...valid for Wed...Thu...Fri...Sat...Sun...

An upper level ridge will dominate our weather Wednesday through
Saturday morning with dry conditions and near-seasonal
temperatures. High temperatures should be in the upper 60s to
the middle 70s Wed.-Sat.

During the day on Saturday, an upper shortwave trough and
associated cold front should approach Montana from the west. This
upper trough and surface front can bring a round of showers and
thunderstorms to the area Saturday afternoon into Saturday night.
Rainfall amounts should be light /generally 0.25 inches or less/
given the swift motion of the shortwave and lack of upslope flow.
Some snow can mix in over the mountains Saturday night.

As the upper trough and cold front move eastward, some morning
showers are possible on Sunday mainly east of Billings...otherwise
Sunday should be a dry day with an upper ridge progged to build
over the Northern Rockies. In addition, the pressure gradient
behind the cold front should produce breezy conditions over the
area Saturday night into Sunday. The wind will bring in cooler air
from the northwest, lowering high temperatures on Sunday to the
lower to middle 60s. RMS

&&

.AVIATION...

Areas of scattered low clouds will lift during the afternoon,
however MVFR or lower conditions are possible around KSHR due to
numerous showers, as well as over SE MT. Otherwise scattered
showers E and S of KBIL will decrease during the afternoon.
Showers may be associated with MVFR conditions. Expect widespread
obscurations over the NE Bighorns. VFR will return to the entire
area tonight. Arthur

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Tue     Wed     Thu     Fri     Sat     Sun
-------------------------------------------------------
BIL 059 041/065 042/068 044/068 044/072 047/072 046/063
    1/B 00/B    01/U    00/U    00/U    02/T    33/W
LVM 059 037/062 037/067 036/068 038/072 041/069 040/062
    0/B 11/B    11/U    00/U    00/U    02/T    21/B
HDN 060 038/067 040/070 042/071 044/074 045/074 044/065
    1/B 00/B    01/U    11/U    00/U    01/U    33/W
MLS 056 037/066 042/071 044/070 045/074 047/074 047/065
    1/E 00/B    01/U    11/U    00/U    01/U    22/W
4BQ 055 037/064 040/069 041/069 044/071 046/072 045/064
    5/W 10/B    01/U    11/U    00/U    11/U    33/W
BHK 053 037/063 040/070 043/068 043/070 045/072 045/064
    4/W 10/B    01/U    11/U    10/U    01/U    22/W
SHR 054 035/063 037/066 038/068 040/071 042/071 043/061
    6/W 10/U    01/U    00/U    00/U    01/U    44/W

&&

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

&&

$$
weather.gov/billings



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