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Area forecast discussion...updated 
National Weather Service Billings Montana
631 am MST sun Nov 29 2015

updated southern zones where radar and surface observation are indicating
some decent light snow has picked up. Increased probability of precipitation and nudged
up snow amounts. Bt


Short term...valid for today and Monday...

Upper low that has been spinning its wheels over the Great Basin
and central rockies will continue to gradually eject out of the
mountains to the plains over the next couple of days. This system
will continue to produce generally low impact weather over our
southern zones. Models agree that the best chance of light snow
will be over the big horns and southeast Montana today...shifting
to mainly the big horns and around the beartooths for Monday. I
anticipate another couple of inches in the higher terrain and
perhaps another inch over portions of southeast Montana over the
next 24 to 36 hours.

One feature that has been problematic for our forecast area
is the cold air drainage out of the Big Horn basin. This has kept
Logan Airport in Billings with very brisk wind and temperatures
from reaching their potential. The orientation of the pressure
gradient with surface low over Billings and the surface high back
over southern Idaho would be the pattern generating this feature.
This may continue through the morning and possibly well into the
afternoon again. As such...have undercut guidance numbers again
for Billings and nearby well as locations in valleys or
with poor mixing. There does appear to be a change in the gradient
developing late today into tonight as stronger surface troughing
digs south and increases the westerly component of the wind while
decreasing the southerly component. This has ME thinking we have
very good chance of finally reaching those warmer temperatures Monday
that the guidance has been trying to show. Bt

Long term...valid for Tuesday...Wed...Thu...Fri...Sat...

Long term period begins with a ridge axis extending through the
western Continental U.S.. this ridge will allow quiet conditions to prevail
across the area Tuesday and early Wednesday before several low
precipitation Pacific disturbances move into the area through the
latter part of next week. Ahead of these disturbances downslope
conditions and warmer temperatures aloft will allow temperatures
to climb into the upper 40s through the week with temperatures
reaching near 50 by the weekend. Most precipitation with these
systems should remain west of Roundup...Billings...and the Pryor

The biggest update with this forecast package involved upping the
winds in the latter part of next week as these Pacific systems
help set up good pressure gradients across the western terrain
near Livingston...Big Timber...and Nye. First Pacific system
rounds the ridge and quickly drops in from the northwest with 40
to 50 knots winds aloft at 850mb Wednesday afternoon. Most of the
stronger winds will be to our north but we could see stronger gap
winds develop once the sun sets. Pressure gradient relaxs early
Thursday morning lessening the winds. Stronger disturbance moves
in early Friday quickly followed by another early Saturday. Should
see another period of winds with these two systems though too
early to pin down details of strength so just upped the winds a
little bit above our normal blend. Dobbs


Mostly VFR conditions will prevail across the region through the
period...though MVFR/IFR conditions are possible near kmls where
patchy fog could occur from 10z though 16z. Mountain obscurations
are possible over the beartooths and absarokas with overcast skies. Dobbs

Preliminary point temp/pops...

Today Monday Tuesday Wednesday Thursday Friday Sat
bil 029 014/033 019/039 021/042 026/045 031/047 029/045
0/b 11/b 00/north 00/u 00/b 01/b 11/u
lvm 027 012/033 016/036 019/038 023/044 032/043 026/041
0/u 11/north 10/north 00/north 10/north 11/north 11/north
hdn 029 008/032 014/039 014/041 017/046 025/046 027/045
1/b 11/b 10/b 00/u 00/u 00/b 11/u
mls 025 008/028 011/034 015/041 020/044 024/047 025/043
0/b 00/b 10/b 00/u 00/u 00/b 11/u
4bq 029 011/029 014/036 014/041 020/044 027/049 026/045
4/S 11/b 11/b 00/u 00/u 00/b 11/b
bhk 027 009/027 012/032 015/041 020/044 026/047 024/043
2/S 11/b 11/b 00/u 00/u 00/b 11/b
shr 029 011/032 013/039 016/043 018/046 025/046 024/043
8/S 22/S 10/b 00/u 00/u 01/b 11/b


Byz watches/warnings/advisories...



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