Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 201028

Area Forecast Discussion
National Weather Service Billings MT
328 AM MST Tue Feb 20 2018

.SHORT TERM...valid for Tdy and Wed...

Still seeing a few areas of light snow/flurries over far eastern
zones, otherwise its been drying out across the forecast area from
west to east overnight. Cloud cover has been thinning out and
shifting east as well with the main area of cloud cover now along
a Forsyth to Sheridan line and pressing eastward. Where clouds
have cleared out have seen temperatures in the -15 to -25 degree
range. Billings airport so far has reached -13, here at the
office -15, while the airport in Laurel was -18. Harlowton so far
is the cold spot at -23 while Reed Point sits at -22 at 230am.
Drainage winds ranging from 5 to 12 mph are producing wind chills
of -15 to -40 across the area. Laurel has been hitting -35 to -39
wind chills over the past few hours as those drainage winds off
the foothills push in from the southwest.
Expect skies to continue to clear out this morning so should see
temperatures in eastern areas drop significantly around sunrise.
Mostly sunny skies and mainly dry conditions expected today. Some
weak moisture advection into the Cooke City area could bring a few
snow showers, especially late in the day. Temperatures will only
climb into the single digits in most areas today as area remains
under the cold trof aloft and surface winds remain light with cold
high pressure underneath.

Reinforcing trof pushes into the area tonight with enough moisture
to squeeze out a few snow showers for western mountain locations,
an maybe into the lower valleys. Winds associated with this
system, while not gusty, along with more cloud cover should be
enough to keep temperatures 5 to 10 degrees warmer than this
morning for areas west of Columbus. For areas further east
Wednesday morning should be colder than this morning.

A few snow showers continue in the western mountains and foothills
Wednesday, diminishing by morning. Could see some light
accumulations for the Beartooth/Absaroka and Crazy mountains.
Otherwise dry conditions with temperatures slowly working into the
teens. Looks like the Clarks Fork drainage will kick in bringing
breezy conditions from Belfry to Park City and Billings, and maybe
some areas of blowing/drifting snow if wind speeds tick up just a
bit more than currently forecast. Clearing skies and light winds
Wednesday night will allow for subzero lows once again for
Thursday morning. May need a few wind chill advisories overnight.

Surface high keeps dry conditions in place Thursday. Yet another
weak trof aloft moves in from the northwest for additional
mountain and western valley snow shower chances, though nothing
looks significant for the lower elevations while the mountains
could pick up a few inches. One more night of subzero lows appears
likely Thursday night. Temps probably reach lows in the evening
then rise overnight as the upper trof moves through stirring up
the atmosphere a bit and increasing cloud cover. Chambers

.LONG TERM...valid for Thu...Fri...Sat...Sun...Mon...

Northwest flow finally shifts to a zonal direction late Friday,
allowing downslope winds to increase and begin to scour out the
Arctic air thats been in place for the better part of a week.
Moisture advection on this flow should bring a good shot of snow
to the higher elevations on west facing slopes. Temperatures hit
the 20s west and teens east on Friday, then wind aided 20s and 30s
on Saturday and Sunday. May need a few wind highlites for gap wind
areas from Friday night into Sunday. Sunday afternoon cold front
will calm winds down and increase lower elevation snow chances
through Monday. Doesn`t look like an impactful snow event at this
point due to a quick progression of the upper forcing through the
region, but upslope areas could see some accumulating snow.

Keeping an eye on a system for mid to late next week. This is a
large storm system that takes up much of the western U.S. in the
past several GFS runs, and the latest ECMWF is trending closer the
GFS solution. This type of system is a one of the northern
rockies heavy snow patterns so will need to keep close tabs on it
as it develops over the next week or so. Chambers



Light snow shifting off to the east early this morning will
produce occasional MVFR conditions from KMLS and areas east.
Otherwise, expect mainly VFR conditions to prevail today, with a
mid level cloud deck across eastern areas diminishing into the
afternoon. Snow showers will become possible over the
Beartooth/Absaroka mountains by this evening, with mountain
obscurations possible. STP



    Tdy Wed     Thu     Fri     Sat     Sun     Mon
BIL 007 911/014 906/017 907/023 007/029 013/028 013/031
    1/U 00/B    00/U    11/B    11/B    22/J    21/B
LVM 010 906/017 000/023 000/026 013/031 017/031 016/032
    1/U 12/J    12/J    21/B    12/J    33/J    23/J
HDN 008 914/014 908/017 910/022 002/028 011/027 009/029
    1/U 00/B    00/U    11/B    11/B    22/J    21/B
MLS 002 914/009 912/011 912/014 001/023 010/022 006/022
    1/B 10/U    00/U    00/B    01/B    12/J    21/B
4BQ 005 913/011 909/014 909/017 002/025 011/026 009/028
    1/B 00/U    00/U    11/B    01/B    11/B    21/B
BHK 002 913/009 910/015 909/014 001/023 008/024 004/023
    1/B 10/U    00/U    00/B    01/U    11/B    21/B
SHR 007 915/013 904/020 905/023 003/029 011/029 010/030
    1/U 00/U    00/U    11/B    01/B    12/J    21/B


MT...Wind Chill Advisory in effect until noon MST today FOR ZONES


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