Scientific Forecaster Discussion
fxus65 kmso 231217
Area forecast discussion...updated
National Weather Service Missoula Montana
517 am MST Thu Feb 23 2017
Discussion...the combination of light snow and moisture freezing
on roadways has created slick conditions for the morning commute
through the Seeley/Swan and Missoula/Bitterroot valleys. Winter
weather advisories have been issued as roads have become a mix of
snow covered and icy. Conditions should improve later this
morning as warming temperatures allow roads to melt.
Aviation...snow showers will continue over the northern rockies
today, particularly across southwest Montana and into central
Idaho. Fairly widespread obscurations of the terrain should be
anticipated, generally south of the Interstate 90 corridor due to
low ceilings. Kbtm is expected to see the best potential for
snowfall, producing periods of decreased ceilings and visibility
between roughly 23/1100z through 23/1800z. Kmso and ksmn will
experience periodic reductions due to snow, but these should not
be long lived. Kgpi will have the most benign weather today as
moisture should remain well south of the terminal.
Previous discussion... /issued 345 am MST Thu Feb 23 2017/
Discussion...a low pressure system passing through southern Idaho
will continue to wrap moisture into mainly southwest Montana and
central Idaho, generally south of the Interstate 90 corridor.
Periods of light snow showers will persist through the day in
these areas. Snow accumulations will be light, but could cause
some localized slick roadways.
Generally showery and cooler conditions will persist across the
region into early this weekend as a large scale trough remains
over the region. Periods of light snow showers will cause
localized impacts to roadways, but issues should not be long
lived or widespread. More noticeable will be the general drop in
temperatures, back to below normal for this time of year.
A more robust system will move into the area beginning Sunday
into Tuesday, which will bring enhanced moisture and continued
snow across the area. Northwest Montana, the Montana/Idaho border, and
north-central Idaho could see several inches of widespread
accumulating snow during this period which would result in winter
driving conditions and the return to shoveling for all elevations.
The rest of Tuesday into late next week, a cold northwest flow
will continue to stream snow showers across the area, enhancing in
the afternoons during peak instability hours. Though confidence
still remains low due to model variability, there is a possibility
of Arctic cold air intrusion and breezy winds influencing the
pattern Tuesday and Wednesday.
Montana...Winter Weather Advisory until 11 am MST this morning
Missoula/Bitterroot valleys...Potomac/Seeley Lake region.