Area Forecast Discussion
Issued by NWS Missoula, MT
FXUS65 KMSO 191016
Area Forecast Discussion
National Weather Service Missoula MT
316 AM MST Thu Jan 19 2017
.DISCUSSION...A strong north flow to the west over Washington and
south flow over the area today will continue to bring rain to many
valleys, with some locations like Missoula and Columbia Falls
seeing some freezing rain this morning. As the boundary between
the north and south flow continues to move eastward slowly, rain
and snow will continue especially over the mountains and in
central Idaho today, though showers will decrease throughout the
day. Missoula should mix out today, removing the valley inversion
and reaching the upper 30s to low 40s for temperatures this
afternoon. Winter weather advisories remain out through about noon
today for the continued freezing rain and snow.
Friday, a weak cold front will cause the snow levels to quickly
drop along with the amount of precipitation. Some showers will
remain, especially over the mountains, but all the precipitation
will return to snow on Friday. Very little new snow accumulation
is expected behind the front.
A large trough that forms along the Pacific Northwest coast will
eject a few waves of showers across the Northern Rockies over the
weekend. The first wave of precip will be fairly light Saturday
night with only light snow amounts expected. By Sunday night into
Monday, a stronger wave of precipitation is forecast to track
across north central Idaho and into western Montana. Additional
snowfall can be expected above 1500-2000 feet, including Lookout,
Lolo, Lost Trail Passes. However, this disturbance will quickly
lose its energy as the bulk of the parent trough diverts south and
eastward. The Northern Rockies will be left in a cold, northerly
flow with scattered snow showers in the area by Tuesday.
Confidence for a drier ridge pattern is fairly high by mid to
late week, supporting cold valley inversions and air stagnation to
settle back into place.
.AVIATION...Overall precipitation is decreasing today over the
region. A slight chance of freezing rain remains for KGPI and
especially KMSO this morning with some light showers in the area.
Overall accumulations will be low and periods of freezing rain
will be intermittent. Inversions will likely mix out of the valley
today for KMSO and KGPI, though KSMN will remain inverted today.
MT...Winter Weather Advisory until 11 AM MST this morning
Freezing Rain Advisory until 6 AM MST early this morning
Potomac/Seeley Lake Region...West Glacier Region.
Winter Weather Advisory until 11 AM MST this morning
Winter Weather Advisory until 11 AM MST this morning Lower Clark
ID...Winter Weather Advisory until 10 AM PST this morning Lower Hells
Canyon/Salmon River Region.
Winter Weather Advisory until 10 AM PST this morning Northern
Clearwater Mountains...Orofino/Grangeville Region.
Winter Weather Advisory until 10 AM PST this morning Southern