Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Billings Montana
233 PM MST Mon Dec 5 2016
Short term...valid for Tue and Wed...
Arctic air continues to push into the area from the north this
afternoon. Isolated to scattered snow showers continue across the
region, but are not likely to create any additional issues for
travelers. Therefore have chosen to drop all winter weather
advisories that are still active at this time. Mainly dry
conditions will persist through the short term period over most of
the region once cold air becomes entrenched tonight. The exception
is a weak Pacific wave sliding across the west and southwest on
Tuesday that brings snow to western high terrain...and nearby
foothills and plains.
Made several other changes to inherited short term forecast this
afternoon. Primarily centered around increasing wind speeds across
central and eastern zones through the bulk of the period, as this
Arctic system exits the region. Winds finally taper off in the
east Wednesday night. Stronger winds point toward very cold wind
chills each night...especially Tuesday night. Currently grids
indicate Wind Chill Advisory type conditions Tuesday night...but
will hold off on highlights at this time given variable snow
cover...and slow upward trend of temps through the period.
Certainly something for later shift to watch for Tuesday
night...especially in easternmost zones.
Given the slower and more easterly Arctic intrusion...as well as
local snow cover...continued to trend temps slightly warmer
Tuesday and Wednesday...especially around Billings and north. Aag
Long term...valid for Thu...Fri...Sat...sun...Mon...
Challenging forecast into the extended period for forecast
temperatures and precipitation. Main player will be the Arctic
boundary as it meandors across the region throughout the period
with fluctuating temperatures and overunning snow in the colder
airmass. This is resulting in quite a bit of uncertainty once we
get into next weekend and early next week. The model spread for
temperatures right now for early next week is 15 to 20 degrees in
some cases with 30s south of front and barely teens to the north.
Weak ridging builds into the region for Thursday for dry
conditions. At that point, we'll likely be still struggling to
back the Arctic airmass out of the region and highs expected to
remain in the teens and single digits. Ridge shifts east on
Friday and a strong westerly upper flow begins to dominate with an
attempt to push the Arctic airmass north and east. As it does,
some overunning precipitation is expected to increase. Difficult
to time this far out as fast moving waves move through the westerly
flow. Could begin as early as Thursday night, but right now the
best chance for snow appears to be during the Saturday through
Saturday night time frame. Into early next week, we'll still be
watching the position of the boundary. Any little shift in the
upper flow to the north or northwest will push the cold air back
into the region with an increase threat for overunning
precipitation. A forecast to monitor closely day to day.
VFR conditions will prevail into Tuesday with mostly mid level
ceilings. There will be some lingering light snow showers in the
cyclonic flow producing some localized MVFR conditions with
lowered visibility and ceilings, mainly east and south of kbil.
Expect mountain obsurations to persist through the overnight.
Preliminary point temp/pops...
Tue Wed Thu Fri Sat sun Mon
bil 009/011 902/006 904/013 009/029 018/032 021/034 018/029
32/j 21/b 10/u 12/S 33/S 21/b 12/S
lvm 004/011 907/007 906/015 015/035 024/034 023/033 021/031
22/j 21/b 11/b 33/S 43/S 22/S 12/S
hdn 009/012 903/005 904/016 008/026 016/031 017/035 015/029
32/j 11/b 00/u 12/S 33/S 21/b 12/S
mls 005/011 902/005 908/008 000/017 008/022 008/026 008/023
11/east 11/east 00/u 02/S 33/S 21/b 22/S
4bq 005/011 904/005 911/012 001/024 012/029 009/032 009/026
11/b 11/b 00/u 01/b 23/S 21/b 12/S
bhk 003/008 903/004 910/004 904/013 005/020 004/021 005/020
31/north 11/north 00/b 02/S 23/S 21/b 12/S
shr 004/014 904/009 908/014 005/031 016/032 014/033 013/029
21/b 21/b 00/u 11/b 23/S 31/b 12/S