Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 121550

Area Forecast Discussion
National Weather Service Billings MT
950 AM MDT Thu Oct 12 2017


A band of rain and snow showers from the Absarokas through
Yellowstone County has continued to dissipate and push eastward
this morning into Rosebud County. Clouds and cooler weather today
behind departing cold front with temperatures in the upper 40s to
mid 50s. Bumped up winds in the western gap zones from Livingston
to Big Timber this afternoon to account for 30 mph gusts. Walsh


.SHORT TERM...valid for Tdy and Fri...

Weakening trough axis moving through western Montana with
unsettled southwesterly flow over southern Montana and northern
Wyoming this morning. Radar trend over the past 2 hours is to show
a band of showers over southwest Montana extending into Livingston
and the Crazy Mountains is moving east slowly. This activity is
periodically producing intense snow showers with visibility
occasionally at Livingston near 1 mile and web cam showing
accumulation of snow on the grass at Bozeman Pass. Suspect most of
this activity will be weaker by daybreak but latest RUC wants to
produce precipitation through the morning hours. Will maintain
scattered pops as activity is moving pretty quickly and should not
remained over a given location for an extended period of time
though orographic effects may produce a few favored areas near the
Crazy and Snowy mountains.

Wave does fill by this afternoon reducing shower activity but
temperatures are cooler behind yesterdays cold front and winds
will be maintained which will make it fell much more fall like
than the previous couple of days.

Shortwave ridging overnight dries the airmass out ahead of another
area of troughiness moving through the Pacific Northwest. Similar
to the system ejecting this morning...this trough will be
weakening as it moves into central Montana Friday afternoon and
evening. It will bring increased moisture which will bring back
shower activity to western areas Friday afternoon spreading
eastward in the evening. The period from 06z-12z could produce
light snowfall across south central Montana as temperatures will
be cold enough and the trough experiences some stretching allowing
a baroclinic band to intensify a bit over the area. Did increase
pops in this time frame and increase precipitation amounts a bit
but if through is projected to move slower in later runs it could
produce some minor accumulations. borsum

.LONG TERM...valid for Sat...Sun...Mon...Tue...Wed...

Only relatively minor changes to the extended forecast period,
with building heights and shallow ridging aloft in control
through the bulk of the period.

The upper level trof will complete passage across the region
Saturday. The orientation or the trof, and associated energy,
indicate improved precip potential, especially Saturday morning,
with expanded region of snow in the western zones. System also
appear to be moving a little more slowly, and hangs in the east
into the afternoon period. have increased pops across the west in
the morning, and the east in the afternoon. Cloudy conditions and
more pronounced cold air advection through the day will keep temps
in the mid to upper 40s.

Northwest flow aloft takes over Sunday before transitioning to
general westerly flow aloft under the influence of a broad upper
level ridge through the remainder of the period. Temps in the 50s
can be expected Sunday as we transition to ridgy pattern. Low to
mid 60s can be expected through the remainder of the period. will
be warm and above average through much of the work week and mainly
in the low to mid 60s.

No significant weather systems are anticipated through next week.
That said, generally breezy conditions can be expected, as a lee-
side sfc trof sets up over the lower elevations. Nothing appears
highlight worth at this time. AAG



A passing upper disturbance will bring a few mainly light showers
to areas west of KBHK-KSHR today. Local MVFR is possible, and
mountains will be occasionally obscured, but otherwise VFR flight
conditions will prevail. Expect dry/VFR across the area tonight.
West winds will gust to 20-25 kts across the western foothills
including KLVM today. JKL



    Tdy Fri     Sat     Sun     Mon     Tue     Wed
BIL 052 034/054 033/049 033/058 038/065 040/065 043/065
    4/W 01/B    34/J    10/U    00/U    00/U    00/B
LVM 047 031/047 027/044 029/055 035/061 037/064 038/061
    5/W 15/W    53/J    00/N    00/N    00/N    11/N
HDN 055 031/058 032/050 030/059 034/067 036/067 039/066
    4/W 01/B    24/W    10/U    00/U    00/U    00/B
MLS 053 033/057 033/048 031/057 036/066 038/067 041/063
    3/W 11/B    23/W    11/U    00/U    00/U    00/B
4BQ 055 031/058 033/046 030/056 035/066 037/068 040/064
    0/B 01/B    14/W    10/U    00/U    00/U    01/U
BHK 053 033/057 032/045 030/054 035/064 037/066 040/063
    1/B 01/B    13/W    11/U    00/U    00/U    01/U
SHR 053 030/056 029/045 025/057 031/066 033/067 037/064
    2/W 00/B    14/W    10/U    00/U    00/U    00/B




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