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fxus65 kbyz 181639 
afdbyz

Area forecast discussion
National Weather Service Billings Montana
939 am MST sun Feb 18 2018

Update...
approaching upper trough is providing light lift and despite cold
air deepening over the region enough ascent in place to generate
snowfall across the region. Winds are combining with the snow to
cause areas of more significant conditions in particular over
Carter and Sheridan counties. Updating as different information
comes into the office but still many winter highlights in effect
and poor travel across the region. Borsum

&&

Short term...valid for tdy and Mon...

Snow had spread south overnight as isentropic ascent and an area
of frontogenesis moved through the area. Many places saw a few
inches of snow overnight, with the mountains outside Cooke City
receiving upwards of a foot of new snow. Models struggled greatly
with the area of snow overnight, and now prog snow to linger
along our southern areas this morning, gradually spreading back
north by the afternoon as the Arctic air deepens and isentropic
ascent increases again, leading to a period of overrunning
precipitation. Snowfall is expected to persist through much of
Monday, before an upper trough moves overhead causing snow to
slide east of the area. Have gone ahead and issued winter storm
warnings for the beartooth and Red Lodge foothills, as well as
expanded winter weather advisories currently in effect for
portions of the area to include the rest of the area, and taken
them through Monday. Have also extended the Winter Storm Warning
for the crazy and beartooth/Absaroka Mountains through Monday.
Additional snowfall from today through Monday will range from 3 to
6 inches across much of the lower elevations (lesser totals
towards Miles City and baker), to 4 to 8 inches for the beartooth
and Red Lodge foothills, to 6 to 14 inches for the mountains.

Highs today will be in the lower teens for many areas, with
temperatures struggling to make it above zero on Monday as the
Arctic air deepens. Low temperatures tonight are expected to range
from the single digits to teens below zero, with teens to twenties
below zero Monday night. Livingston, Billings, and Sheridan may
break their low temperature records Monday night. Stp

Long term...valid for Tue...Wed...Thu...Fri...Sat...



Colder than normal with unsettled conditions but no big system
remains the theme of the extended period. Temperatures will be
slow to warm up from the deep freeze as there is not a ton of wind
to scour it out and some periods of clearing during the nighttime
hours followed by cloud cover during the day work to hold
temperatures down given the deep snowpack currently in place.
Pacific moisture will work into the area but mainly produces
mountain precipitation, occasionally spilling into the plains but
any accumulations outside of the mountains will be very light.
Chambers
&&

Aviation...

Periods of snow will impact the area today, with more persistent
snow mid afternoon into tonight. Heavier bands of snow will
produce LIFR conditions. Expect mountain obscuration through
tonight. Gusty east surface winds will persist in klvm into tonight.
Arthur
&&

Preliminary point temp/pops...

Tdy Mon Tue Wed Thu Fri Sat
-------------------------------------------------------
bil 013 906/001 918/005 909/015 001/026 003/028 010/031
8/S 96/S 21/b 11/b 11/b 12/j 12/j
lvm 020 910/002 917/010 906/017 007/027 009/031 014/033
9/S 94/S 21/b 12/j 12/j 22/j 22/j
hdn 014 905/002 921/006 912/016 904/023 901/026 006/028
8/S 96/S 21/b 10/u 01/b 11/b 11/b
mls 012 906/000 915/002 915/010 908/016 905/019 002/022
4/S 76/S 31/b 00/u 01/b 11/b 11/b
4bq 018 903/003 916/002 914/014 905/022 901/025 005/027
8/S 98/S 31/b 00/u 00/u 01/b 11/b
bhk 012 905/002 914/002 914/010 906/019 904/020 001/023
2/S 66/S 31/east 00/u 00/b 11/b 11/b
shr 022 906/003 919/008 914/016 907/024 000/027 005/031
9/S 97/S 31/b 10/u 00/u 11/b 11/b

&&

Byz watches/warnings/advisories...
Montana...Winter Weather Advisory in effect until 5 PM MST Monday for
zones 28-29-34-35-39>42-63>65.
Winter Weather Advisory in effect until 11 PM MST Monday for
zones 30-31-36>38-57-58.
Winter Storm Warning in effect until 5 PM MST Monday for
zones 56-66>68.
Wyoming...Winter Weather Advisory in effect until 11 PM MST Monday for
zone 98.
Winter Storm Warning in effect until 11 PM MST Monday for
zone 99.

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