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Area forecast discussion...updated 
National Weather Service Billings Montana
926 am MDT Tuesday Oct 21 2014

Update...

Forecast looks to be in good shape but did make a few adjustments
with this update. Upper low currently moving across southern Idaho
is providing for a southerly flow aloft across our area. Satellite
showing plenty of clouds moving from south to north across our
western counties with a slow movement eastward. Have tweaked sky
cover to represent more partly cloudy skies than sunny from
Billings westward. In addition...winds are a bit higher than
previously forecasted from Billings to Livingston so have
increased winds for those areas into the 15 to 25 miles per hour range today.
As the upper low moves east...it will sweep a cold front through
our western zones this afternoon and central areas late afternoon
or early evening and toward the Dakota border by late evening.
Winds will become gusty along and behind the front with some gusts
around 4o to 50 miles per hour.

A slight chance for showers still looks good for this afternoon
for the same locations...Billings westward with best chances
across the beartooth/Absaroka Mountains north through park and
Wheatland counties. Soundings do show a little bit of cape this
afternoon ahead of the front so can't rule out an isolated
thunderstorm given the fact there are currently a few
thunderstorms along the Idaho/Wyoming border. Hooley

&&

Short term...valid for today and Wednesday...

Short term forecast appears in good shape. Models remaining
consistent...bringing a strong disturbance across the
region...with greatest impacts this evening and overnight.

Southwest flow aloft ahead of the approaching system will begin increasing
moisture availability in the area and possible isolated to
scattered showers in the high terrain early in the day. The
shortwave is not expected to impact western mountains until this
afternoon...with improved shower potential. This system will
combin with an advancing cold front as it cross the
region...which will create additional lift and increased chance of
precipitation. Front should move through Billings around 00z and exit
into the western Dakotas after midnight. The weather system will
bring isolated to scattered showers and possible thunderstorms as
it crosses the region. Strong and gusty northwest winds are also
expected behind the front...with gusts to of 35 to 45 miles per hour across
the region.

Showers will complete passage through the area through Wednesday
morning...with ridging building back into the region through the
day.

As for temperatures...although we do expect to see increasing clouds
through the day today...the timing of the weather system will
allow for a significant warm up for much of the area. Western
zones will only reach 60s with persistent cloud cover and possible
showers throughout the day. Central and eastern zones however
will see highs approach around 80 in most locations. Cold airmass
behind the front will keep temperatures much cooler Wednesday...but
still expect above average temperatures in most areas...as temperatures
climb into low to middle 60s under the redeveloping ridge.

Fire weather will be of some concern today. Relative humidity values will fall
to teens and 20 percent range as temperatures rise in a
prefrontal environment this afternoon. Relative humidity values are expected to recover
some before stronger winds move in...but will need to keep a
close eye developing situation. Aag

Long term...valid for Thursday...Fri...Sat...sun...Mon...

Above normal temperatures and mostly dry weather will continue
Thursday through Saturday but with a couple of wrinkles. Pacific
moisture plume which will impact the Pacific northwest during this time
period may sag enough to bring the beartooth absarokas and crazies
some light precipitation Thursday night into Friday. Have made slight
adjustments to probability of precipitation to account for this. Also...shortwave moving
across southern Alberta/Saskatchewan looks to allow for a weak
backdoor front to drop into our area reducing temperatures a bit for
Friday. Ridge will re-assert itself late Friday into Saturday
bringing another very warm day to start the weekend. Though it is
several days off yet...prefrontal conditions on Saturday may allow
temperatures to approach some record highs.

Models in good agreement showing a Pacific frontal passage by
Saturday night as upper trough is kicked across the northern
rockies. Though models are differing in the details...lower
heights with cyclonic flow/colder air aloft will bring US the
potential for some showers Sunday and Monday...with temperatures cold
enough for snow over the mountains. Lower elevations will keep
downslope winds and temperatures warm enough to keep any precipitation as rain.
Expect temperatures to be near late October normals each of these
days...or perhaps a bit below normal by next Monday.
Remarkably...Billings has not experienced a cooler than normal
day since October 3rd.

Jkl
&&

Aviation...

VFR conditions will prevail at all flight terminals today...with
an increase in middle and high cloud through the day. A cold front
will push west to east across the area late this afternoon and
evening...bringing a shift to gusty west winds and isolated to
scattered shower activity. Gusts of 25 to 35 kts will follow the
cold front. VFR should prevail tonight but occasional mountain
obscurations can be expected with some rain and snow showers
behind the frontal passage. Jkl
&&

Preliminary point temp/pops...

Today Wednesday Thursday Friday Sat sun Monday
-------------------------------------------------------
bil 076 045/065 043/071 048/067 043/072 044/059 037/055
2/T 31/north 00/u 00/b 00/u 12/west 22/west
lvm 069 040/061 040/067 044/065 042/070 042/056 034/053
3/T 50/north 00/north 01/b 11/north 22/west 22/west
hdn 079 043/067 038/073 043/069 039/074 039/061 035/057
0/b 32/west 00/u 00/b 00/u 12/west 22/west
mls 078 045/065 038/072 044/068 041/070 041/060 035/053
0/u 32/west 00/u 00/b 00/u 11/north 22/west
4bq 081 044/065 037/071 042/069 039/072 042/060 035/054
0/u 22/west 00/u 00/b 00/u 11/b 22/west
bhk 078 044/062 036/069 041/067 038/066 039/058 033/049
0/u 12/west 00/u 00/b 00/u 11/b 22/west
shr 080 040/065 034/073 039/072 037/075 038/060 032/055
0/b 22/west 00/u 00/b 00/u 02/west 22/west

&&

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

&&

$$
Weather.Gov/Billings

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