Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Missoula Montana
216 PM MST sun Dec 28 2014
..travel difficulties expected along The Divide due to blowing
..bitterly cold temperatures tonight through Wednesday...
Discussion...a strong band of snow has developed over Missoula
and along I-90 from Missoula east to Drummond. This band has been
producing snow rates of 1-2 inches per hour, and could continue
for the next couple hours. Up to a total of 4 inches could fall
before the band dissipates. Lookout Pass is seeing similar
conditions until around 5pm this afternoon.
Other locations across western Montana are seeing off and on
light snow showers this afternoon. A strong Arctic front has been
making its way through northwestern Montana this afternoon.
Strong east-northeast winds will continue through the night. With
all the snow they received in those areas reduced visibility due
to blowing and drifting snow will be a great concern. The Arctic
front will begin to affect the Missoula area later this afternoon
and evening. Same conditions with the blowing snow will be a
concern here as well, especially along the Hellgate Canyon
downtown. Bitterly cold wind chills will be likely by Monday
morning. Given all of the impacts the winter weather advisories
and warnings will continue into Monday afternoon.
As the surface low tracks to the southeast this evening, a
northwest flow will setup over the Camas Prairie. This is a good pattern
for several inches of snow to fall in these locations.
Particularly over whitebird hill and Greer grade, where up to 6
inches of snow is possible. Because of this the current Winter
Weather Advisory may need to be extended into Monday morning.
A surface high pressure will build over the northern rockies
behind the Arctic front Monday, which will allow things to dry
out. Though due to all the snow currently on the ground and the
cold airmass, morning valley temperatures in western Montana
will be well below zero. High temperatures will remain in the
single digits for most through Wednesday. Central Idaho will see
similar temperatures, though not as cold as to western Montana. Toward
the end of the week valley inversions will develop allowing
temperatures in the mid and upper slopes in the terrain to
moderate slightly, though the valley cold pools will keep
temperatures in the teens.
The general trend in the long range is for a snowy and cold
pattern for western Montana and central Idaho. Confidence however
has begun to decrease as the long forecast models have started to
differ with the overall pattern. Stay tuned as the details begin
to come more clear.
Aviation...a strong snow band has developed over kmso the past
couple hours. This band has been producing 1-2 inch per hour snow
rates and reducing visibility from 1/4-1/2sm. This is expected to
continue for the next couple hours. Snow has for the most part
ended for kgpi, however the Arctic front has began to impact the
terminal. East winds are expected to become even stronger
potentially gusting up to 35kts or slightly higher this evening.
These winds will begin to create blowing snow reducing the
visibility. Kmso will also begin to see these winds by 28/2300z
this evening, and blowing snow will again be an issue here. These
winds are expected too continue into the midday on Monday.
Montana...Winter Weather Advisory until 11 am MST Monday
Winter Weather Advisory until 5 PM MST this afternoon for I-90
Lookout Pass to Haugan in the Lower Clark Fork region.
Winter Storm Warning until 11 am MST Monday Flathead/mission
valleys...West Glacier region.
Winter Storm Warning until 11 am MST Monday Potomac/Seeley Lake
Winter Weather Advisory until 11 am MST Monday Butte/Blackfoot
Idaho...Winter Weather Advisory until 4 PM PST this afternoon