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fxus65 kbyz 182146 
afdbyz

Area forecast discussion
National Weather Service Billings Montana
346 PM MDT Wed Oct 18 2017

Short term...valid for Thu and Fri...

Lee troughing developing over central Montana has tightened the
surface pressure gradients, leading to increased winds along the
western foothills this afternoon. Gusty winds are expected to
continue through the evening and overnight from Livingston east to
the Nye area. Still thinking we will not need wind advisories for
the foothill locations, although winds in excess of 50 mph will
be possible. This will need to be monitored. As we head into
Thursday, dry conditions look to continue with ridging
intensifying over the central US, causing southwest flow to
develop over the area. This will allow winds to remain breezy
along the western foothills with temperatures warming into the 70s
to near 80 degrees across much of the area. Gap flow winds will
continue along the western foothills Thursday night.

On Friday, models continue to prog a strong cold front moving
through the area. Latest model runs have slowed the frontal
passage, with the front moving through Livingston around midday,
making it east through the area by 03z Saturday. Guidance
continues to indicate strong pressure rises behind the front with
a sharp gradient from southwest winds ahead of the front, to
northwest winds behind it. Wind gusts of 40 to 60 mph are possible
along and behind the front as it passes through the area. At the
same time, scattered showers look to develop along and behind the
front with enough instability warranting a mention of thunder as
well. Best precipitation chances continue to be over the Southwest
Mountains. Conditions out ahead of the front are expected to be
warm and dry, with areas east of Billings potentially seeing
temperatures reach the 70s to near 80 degrees with relative humidity values down
into the teens before the frontal passage. Will likely need fire
weather highlites for Friday across portions of the area, but have
held off on issuing any watches with this forecast package with
the uncertainty in the timing of the front. Winds look to
diminish Friday night, but will still be gusty at times. Stp

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

While mostly dry through the long term forecast, the beginning of
this forecast period will be quite active with wind being the
main concerns.

Mid-level flow will be elevated through much of the weekend so
expect breezy conditions across the plains Saturday through
Monday. Wind gusts will likely reach at least 30 to 40 in the
afternoon as we mix into these winds aloft. It looks like Sunday
will be the stronger day for winds as the strongest mid level
winds and greatest mixing don't look to arrive into the region
until then. Expecting our foothill regions to see the strongest
winds as the westerly flow will induce a persistent Lee-side
trough on the east sides of the Rocky Mountain front. This will
tighten the pressure gradient across our foothill regions leading
to the potential for 60-70mph gusts in locations such as
Livingston and Nye overnight Saturday into Sunday morning. While
conditions will be cooler through the weekend, drier air will be
moving into the region so this will offset the cooler air and
still allow relative humidities to drop into the 20s over the
week. With the strong winds in place this could allow some fires
to easily spread.

Models keep the winds elevated through Monday morning but better
lift moving into the region due to a weak disturbance could limit
the strongest winds from reaching the surface so only increased
winds slightly for Monday. Isolated mountain snow showers and low
elevation rain showers are possible on Monday. Models in good
agreement that the region will remain dry Tuesday and Wednesday,
but the upper level flow pattern varies significantly from model
to model. The ec is noticeably cooler, and less windy, while the
GFS and Canadian models keep conditions warm and breezy. Dobbs

&&

Aviation...

Current wind gusts of 35 to 45 kts along the mountain foothills
will continue through the evening and overnight hours. Off the
foothills, southwest winds around 10 to 20 kts are expected at
kbil with even lighter winds anticipated at kmls and kshr. VFR
conditions will prevail through the taf. Dobbs

&&

Preliminary point temp/pops...

Thu Fri Sat sun Mon Tue Wed
-----------------------------------------------------------
bil 047/076 047/066 039/059 042/069 047/064 039/064 041/067
00/u 03/T 21/north 11/north 33/west 10/u 00/u
lvm 045/077 047/059 035/053 045/066 049/061 038/062 039/063
00/north 05/T 31/north 22/west 33/west 10/north 00/north
hdn 043/079 043/072 037/061 038/071 044/065 036/064 036/068
00/u 03/T 31/b 12/west 23/west 10/u 00/u
mls 041/079 042/075 039/058 037/070 045/063 035/062 035/066
00/u 01/u 30/north 02/west 22/west 10/u 00/u
4bq 041/078 042/077 039/057 036/070 043/061 034/061 036/066
00/u 01/u 20/north 01/north 23/west 10/u 00/u
bhk 040/079 042/079 040/056 034/067 042/058 033/059 034/063
00/u 00/u 21/north 01/north 22/west 10/u 00/u
shr 039/079 041/076 033/057 032/070 042/062 034/062 034/068
00/u 02/T 20/b 11/b 23/west 10/u 00/u

&&

Byz watches/warnings/advisories...
Montana...red flag warning in effect from 11 am to 7 PM MDT Thursday
for zone 117.
Wyoming...none.

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