Area Forecast Discussion
Issued by NWS Great Falls, MT
FXUS65 KTFX 091137
Area Forecast Discussion
National Weather Service Great Falls MT
436 AM MST Fri Dec 9 2016
Aviation Section Updated.
Today through Sunday...Gentle lift associated with weak warm
advection over southwest/central Montana has produced a band of
light snowfall across the middle portion of our forecast area.
This area of snow is expected to dissipate while moving north
into at least southern portions of North-central MT. In general
only a trace to 0.01 inches of liquid equivalent precipitation is
expected, but with high snow ratios could produce a few tenths to
one-half inch of new snow today. Temperatures are expected to
warm into the upper 20s today for southwest valleys, but the
Arctic airmass remains locked in place for north-central MT.
Shortwave ridging aloft moves quickly through the region this
afternoon. A stronger shortwave arrives later tonight. Light snow
is expected once again, developing from southwest to northeast
across the area. The winter weather advisory over SW MT remains in
effect even as snow tapers somewhat this afternoon and then
resumes tonight. A second segment to the winter weather advisory
begins 00Z tonight as snowfall spreads north into central Montana.
Snowfall amounts tonight into Saturday will generally be around 1
inch at lower elevations with 2-4 inches in the mountains. Areas
of snow continue through Saturday before ending Saturday night. A
new surge of Arctic air pushes into Montana Sunday morning as
mountain snowfall continues. PN
Sunday night through Friday...Northwest flow aloft over the Northern
Rockies will bring a continuing chance for snow Sunday night.
Another Canadian cold front pushes southward through North Central
Montana by Monday morning with high temperatures expected to drop
back into the single digits above zero while Southwest Montana
remains in the 20s. By Tuesday, a deep upper level closed low is
expected to be centered over central Manitoba with continued
northerly flow aloft continuing to push the surface cold front
through Southwest Montana along with areas of light snow and gusty
northerly winds. The closed low gradually drifts eastward across
Canada with flow over Montana becoming northwesterly once again and
allowing a very slight moderation in temperatures and slightly drier
conditions for Wednesday and Thursday. Medium range model consensus
falls apart late in the week but indications point toward another
surge of colder air and snow so have trended the forecast in this
A band of light snow extends across MT from the NW to the SE.
Snow will continue falling for a few hours this morning as the area
of snow drifts further north. MVFR/IFR conditions will gradually
improve back to MVFR/VFR conditions as the this first of wave of
snow tapers off from south to north Fri aftn/early eve. But second
trough with more extensive moisture plume is right on heels of first
system, with widespread -SN and IFR conditions re-developing
around 00-03Z near KEKS/KBZN and expanding northward Fri night.
Surface winds remaining generally less than 10 kts across the region
through tonight and tomorrow. PN
.PRELIMINARY POINT TEMPS/POPS...
GTF 0 -3 15 10 / 70 90 40 10
CTB -4 -9 6 -1 / 60 60 20 10
HLN 14 9 33 16 / 70 60 20 10
BZN 23 19 35 16 / 50 70 20 30
WEY 25 17 31 8 / 80 90 40 40
DLN 31 20 36 15 / 50 50 20 30
HVR 0 -4 5 -5 / 30 70 40 20
LWT 5 -1 20 7 / 50 60 40 20
Winter Weather Advisory from 5 PM this afternoon to 5 PM MST
Saturday Broadwater...Cascade...Central and Southern Lewis and
Winter Weather Advisory until 5 PM MST Saturday Beaverhead...