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Area forecast discussion...updated 
National Weather Service Billings Montana
800 PM MDT Tuesday Oct 6 2015


Only major update to this forecast package was to take out the
slight chance for isolated precipitation over the higher terrain for the
rest of the evening. Rest of the forecast is in great shape...with
some moisture moving into the region by tomorrow afternoon. Singer


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 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

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 from fog are possible again tonight/early
morning near kmls. An approaching frontal system and elevated
winds will reduce fog probabilities compared to last night...have
thus opted for only vcfg in kmls and to remove fog potential from
kshr given weak model signal/agreement. Wind shift to a westerly
direction will occur at most terminals as per timing in taf.


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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