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Area forecast discussion 
National Weather Service Billings Montana
945 am MST Wednesday Feb 10 2016

shortwave dropping into the northern plains has allowed for a push
of pressure rises from Canada into eastern Montana. These Lee side
pressure rises has resulted in a modest decrease in winds along
the foothills...with cool advection for our east... and eventually
some lower cloud and perhaps fog in our far east by tonight as
seen on latest visible imagery to our northeast. There still seems
to be a slight risk of light snow or light freezing drizzle in our
far east late tonight into early Thursday. We will also see
another period of Lee side pressure falls along the foothills
tonight which should allow for gap flow to increase again at
Livingston and Nye. 12z models suggest advisory level gusts will
be approached. Will adjust hazardous weather outlook and weather story to
account for the expected increase in winds in our west tonight.
Pressure gradient will relax through the day on Thursday as
Canadian shortwave exits to our east. Jkl


Short term...valid for today and Thursday...

Ridge axis responsible for our mild weather has slid a tad
further east and now is lined up over Idaho. We expect another
warm day across our region. However...we do have a couple of
forecast issues to deal with for this short term package.

First is the potential for hitting Wind Advisory criteria in The
Gap locations of Livingston and Nye. Livingston is gusting to just
under 55 miles per hour early this morning. Surface low is sliding rather
quickly from NE Montana into northwest South Dakota this morning...and
may briefly tighten the pressure gradient a bit more toward
sunrise. Counter to this argument...isobars are lined up a little
to vertical for good gap flow...and gradient weakens after 8 am.
We have some web and social media content already covering this
marginal gap wind will hold off on any highlight at
this time as simply do not feel this will be a very solid or
lengthy episode.

The other issue is the slight possibility of freezing
precipitation in the Fallon County vicinity tonight/Thursday
morning. There is a weak short wave /currently near the British
Columbia coastline/ that will race around the ridge and drop down
into eastern Montana and the western Dakotas late tonight into
Thursday. This feature is preceded by some other weak
perturbations today which will allow some colder air into far
eastern Montana late today. This sets the stage for some
isentropic lift over low level cold air...and thus the possibility
of some freezing precipitation. WRF soundings support a slight
risk of this...but GFS soundings keep the column to cold. Probably
to much thought into this considering we only have chance probability of precipitation
anyway...but will simply carry a chance of light snow or freezing
drizzle late tonight into Thursday morning. Bt

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

A fast flow aloft will prevail during the extended period making it
difficult to pinpoint the timing and strength of the various
systems that will affect the area. Overall...conditions will be
wetter than they have been...but temperatures will remain above

The upper ridge that has been anchored west of the forecast area will
slide east over the region on Friday and continue moving east Friday night as
a Pacific shortwave approaches the area. The European model (ecmwf) was weaker with
the wave than the GFS. Weak isentropic lift will precede the wave
on Friday with some moisture bringing a low chance of rain and snow
showers to parts of the area. The weak lift/moisture continues Friday
night with slight chances for precipitation over much of the
area. A cold front will work its way through the region on Sat
associated the Pacific wave. Model disagreement in strength and
timing of the wave created differences in quantitative precipitation forecast placement between
the models so went with a model blend for probability of precipitation which resulted in
at least a low chance of showers over the entire area. The quantitative precipitation forecast
differences continued Sat night so continued with a chance of
precipitation for the entire region.

Unsettled northwest flow/anticyclonic flow will be over the area sun
through Monday and the GFS/gefs showed an atmospheric river nudging
into the region. Continued with chances of precipitation for the
entire area with poor model agreement with the quantitative precipitation forecast. Synoptic
ridging returns to the area for late in the period with drier

Monday through Tuesday looked like possible windy periods over the plains
but will have to watch model trends regarding the winds given the
uncertainty in the forecast. Arthur


VFR conditions will prevail over the area today and tonight.
Gusty west-southwest surface winds will affect Big Timber and klvm with gusts
of 45 to 50 knots expected at klvm. Arthur/reimer


Preliminary point temp/pops...

Today Thursday Friday Sat sun Monday Tuesday
bil 064 039/063 036/055 035/056 034/052 036/060 038/057
0/north 01/north 12/west 22/west 32/west 22/west 21/north
lvm 059 039/055 038/055 038/052 033/047 038/054 039/053
0/north 01/north 22/west 24/west 32/west 22/west 21/north
hdn 066 031/063 030/054 031/055 032/051 031/059 033/057
0/u 01/b 12/west 22/west 33/west 22/west 21/north
mls 055 029/052 028/044 029/051 031/049 032/056 037/054
0/b 11/b 11/east 22/west 32/west 22/west 21/north
4bq 060 028/058 027/047 028/052 030/049 030/056 033/056
0/u 01/b 11/east 22/west 32/west 22/west 21/north
bhk 050 026/040 025/036 022/043 029/045 029/050 033/050
0/b 13/o 11/east 33/j 32/west 12/west 21/north
shr 063 030/059 030/052 031/054 029/046 028/054 032/054
0/u 00/b 12/j 12/west 32/west 22/west 11/b


Byz watches/warnings/advisories...



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