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Area forecast discussion...updated 
National Weather Service Billings Montana
835 PM MST Wednesday Dec 17 2014

Update...

Radar echoes both from Roundup to Colstrip and around Baker are on
a downward trend as of middle evening...and it seems not much reached
the ground under them to begin with. We thus dropped probability of precipitation for this
evening and instead went with a scattered flurry mention in south-
eastern Montana. We also extended it through the night...and right into
Thursday morning around Baker as a weak shortwave trough continues
to move from eastern Montana into ND. We kept patchy fog in play across
far southeastern Montana tonight as well with some support for it still
in recent hrrr runs. Low-level winds are almost 10 knots though as of
03 UTC and if that trend continues then near-surface flow might be
too turbulent for visibility to lower very far or for very long.

We also increased lows a bit tonight given clouds across southeast
Montana and modest southwest winds tied to weak Lee-side troughing over
south central Montana. Schultz

&&

Short term...valid for Thursday and Friday...

Weak upper low pressure system will move across northern Montana
tonight and will bring areas of light snow this evening across our
northeast zones. Snow is expected to be very light with no
accumulations. As the low moves to our east tonight...some
clearing is expected across our western and central zones. This
will allow for cooler overnight low temperatures with teens to
lower 20s. Hrrr is indicating fog to redevelop over southern
Powder River and Carter counties tonight as low level moisture
remains pooled over these areas. Did included patchy fog for
portions of southeast Montana tonight. Weak short wave to move
through Thursday which which will bring scattered snow showers to
our Southwest Mountains. Dry weather and slowly warming
temperatures will continue into Friday as short wave ridging moves
in over the region. High temperatures will be in the upper 30s to
lower 40s both Thursday and Friday. Richmond

Long term...valid for Sat...sun...Mon...Tue...Wed...

Guidance continues to be in good agreement into early next week.
While the finer details may differ...the overall unsettled
pattern in the extended continues. After the ridging Friday...a
weak shortwave will cross the state...bringing another chance for
light precipitation to the mountains. Upper level flow begins to increase
Saturday night as a Pacific jet starts moving into the state. Lee
side troughing develops...with a surface low developing over
southern Alberta. In response...the pressure gradient tightens
over southern Montana...resulting in stronger winds developing
first in The Gap areas...then spreading out to around Billings.
Mex MOS for Livingston has winds increasing into 30 miles per hour to near 40
miles per hour range Sunday afternoon. Still keeping grids sub advisory given
this is still four days out...but if current trends hold...looking
at another wind event during the day Sunday.

As the low tracks out of Canada into the northern plains
Monday...a cold front moves through the area. With ample moisture
still bring transported into the area...probability of precipitation continue Monday into
Tuesday. Temperatures will remain relatively warm...so much of the
central zones still look to get rain. Farther east wards Miles
City and Baker...where temperatures are a bit cooler...may see
some freezing rain. Winds will also be more north westerly...so
not as much of an up slope flow event. Things begin to tapper
off...with temperatures cooling back into the 30s for highs.

Looking ahead to Christmas evening and Christmas...another low
develops and tracks across Montana...giving the area a shot at
more precipitation. With the system...the air mass in place will be
colder...with 850mb temperatures below freezing. The the GFS and
European model (ecmwf) are suggesting a shot at a white Christmas...will continue
to watch this. Reimer

&&

Aviation...

Flight conditions remain mainly VFR/MVFR overnight and into
tomorrow....however some patchy fog is possible from kmls south
and east. Occasional mountain obscuration will continue
overnight...with middle level clouds crossing the region. Aag

&&

Preliminary point temp/pops...

Thursday Friday Sat sun Monday Tuesday Wednesday
-----------------------------------------------------------
bil 023/038 023/038 027/041 027/046 033/045 026/038 022/033
00/b 00/b 11/b 13/west 32/west 21/north 23/j
lvm 024/042 024/040 027/043 028/046 035/045 022/039 023/035
01/north 11/north 21/b 24/west 43/west 21/north 33/j
hdn 018/037 015/037 020/040 021/044 029/043 021/037 020/034
10/b 00/b 01/b 13/west 33/west 21/b 22/j
mls 018/038 019/037 021/040 022/042 029/040 025/036 020/031
10/b 00/b 11/b 13/west 22/west 11/b 11/east
4bq 017/041 017/040 019/041 022/044 030/042 024/037 019/033
10/b 00/b 11/b 12/west 23/west 21/b 22/j
bhk 016/036 019/037 019/040 021/042 026/037 021/033 017/027
11/M 10/b 01/b 02/west 22/west 11/north 11/b
shr 012/041 015/038 020/040 019/043 030/042 022/037 019/033
10/b 10/b 11/b 13/west 34/west 32/j 22/j

&&

Byz watches/warnings/advisories...
Montana...none.
Wyoming...none.

&&

$$
Weather.Gov/Billings

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