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Area forecast discussion 
National Weather Service Billings Montana
247 PM MDT Tuesday Oct 6 2015

Short term...valid for Wednesday and Thursday...

After a very nice fall day today will see changes coming for
Wednesday and Thursday as a Pacific trough moves through.

Moisture being pushed north across Wyoming could bring an
isolated shower or thunderstorm to southern mountains and Sheridan
County this evening before any convective activity dissipates
around Sunset. Ridge aloft over the state this afternoon will
begin to break down tonight as Pacific trough moves onshore
Washington/British Columbia. This will increase boundary layer
westerly winds as Lee side trough intensifies and bring warmer
temperatures to the region compared to the past few nights.
Stronger winds will also prevent a third night of fog across
eastern zones...though a bit of low stratus development is
possible for areas east of a Miles City to Broadus line.

Cloud cover will be on the increase Wednesday morning as Pacific
trough approaches and will see a fast moving cold front push through
during the afternoon hours. Temperatures should push into the low
to middle 70s ahead of the front thanks to fairly warm start to the
day. Moisture and cooler air build in behind the system and will
see shower activity develop over western zones late afternoon and
shift east during the evening. Ensembles show well above average
atmospheric moisture profiles from Wednesday afternoon through
Thursday night. As a result have increased precipitation chances
for this period. Best location for precipitation will be along and
south of a Harlowton to Billings to Broadus line Wednesday night
into Thursday. Temperatures Thursday will be hampered by cloud
cover and residual shower activity during the afternoon. Currently
advertising middle to upper 60s but that could be a bit warm and may
need to adjust downward a bit more with subsequent forecast.

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

Long term forecast looks breezy and warm headed into the weekend
with a Pacific cold front for Sunday.

Faster flow aloft develops over the northwest U.S. Friday into
Saturday resulting in enhanced Lee side trofing along the Front
Range. This will induce windy conditions at times along the Front
Range with breezy conditions spreading out into the plains.
Downslope winds will bring dry conditions and warm temperatures
with highs Friday and Saturday around 80 degrees. There will be a
good deal of middle and high level cloud cover in the foothills and
adjacent plains as cirrus/altocumulus standing lenticularus develop off area mountains.

Another Pacific trough drops into the area with a cold front on
Sunday to drop temperatures back into the lower 70s heading into
next week. This system will tap a sub-tropical moisture feed that
stretches back to Hawaii /pineapple express/ so expect to see
some precipitation develop with it. However the current wind
forecast is strong enough that downslope drying could eat most of
the precipitation before it makes it to the ground despite the
strong moisture advection. Added in some low probability of precipitation to get foot in
the door Sunday and will have to see how the winds develop because
there is certainly enough Pacific moisture to support more
precipitation if wind speeds decrease just a bit. High clouds and
breezy conditions will continue behind the front for the start of
next week as strong zonal jet stream persists across northern
Montana. Chambers



VFR conditions are expected through the taf period though some
reduced visibilities and low level IFR fog is possible again
tonight near kshr and kmls. An approaching frontal system and
elevated winds will reduce fog probabilities compared to last
night so mentioned vcfg at kshr and only 3 miles visible near kmls
from 07z to 16z tonight. Wind shift from southeast to a westerly
direction will occur early tomorrow morning at most terminals
after 07z. Dobbs


Preliminary point temp/pops...

Wednesday Thursday Friday Sat sun Monday Tuesday
bil 048/073 047/069 051/079 054/082 056/075 048/074 048/069
01/b 22/west 11/b 00/u 02/west 11/b 21/b
lvm 044/070 044/069 049/078 052/081 053/071 047/071 044/068
02/west 32/west 11/north 00/north 02/west 21/north 21/b
hdn 046/076 046/070 049/081 052/083 056/077 047/074 048/069
00/b 22/west 11/b 00/u 01/b 11/b 11/b
mls 047/074 046/069 050/079 054/084 055/075 048/073 046/067
00/b 11/b 01/b 00/u 01/b 11/b 21/b
4bq 048/075 047/068 049/079 052/084 053/078 046/074 045/066
00/b 22/west 01/b 00/u 01/u 11/b 11/b
bhk 046/072 044/065 045/075 052/081 052/074 045/072 045/065
01/b 11/b 01/b 00/u 01/north 11/north 21/north
shr 044/075 044/067 046/077 048/083 050/077 045/074 044/067
00/b 32/west 11/b 00/u 01/b 10/b 10/b


Byz watches/warnings/advisories...



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