Flood in Idaho, February 6 to 10, 2015

Area Forecast Discussion
National Weather Service Missoula MT
225 PM MST FRI FEB 6 2015

.DISCUSSION...

The very warm weather system currently passing through the
Pacific Northwest is resulting in very high snow levels (above
7000 feet), high amounts of moisture in central Idaho and
northwest Montana, and record high temperatures mainly south of
I-90 today. The next significant plume of moisture has just
arrived to north central Idaho and northwest Montana and is
expected to produce moderate to heavy rain through the evening,
while central and southwest Montana will mainly stay dry with
increased wind. Gusty winds will also continue in
Grangeville/Camas Prairie and in the high terrain through tonight.

Precipitation will decrease in northern Idaho and northwest
Montana early Saturday morning but another warm front will quickly
follow and spread rain from south to north through the day.
Places like Missoula that have been mostly rain shadowed stand a
really high chance to see steady rain through Saturday morning.
This warm front will be in northern Idaho and northwest Montana
Saturday afternoon with rain expected into Saturday night. Rain
will linger into early Sunday, but in general Sunday will be a
drier day before the next weather system for late Sunday. This
weather system will pass as a trough on Monday through early
Tuesday and an associated cold front will cool temperatures
briefly.

Next week the pattern transitions to a ridge that will bring
warmer weather. This is a very warm ridge with temperatures much
above normal expected, especially for the mountains. The big
question for the long term forecast is fog. While the pattern is
good for fog, especially after such a wet period leading up to it,
the air mass dries out considerable by Thursday and Friday of next
week. This combined with a lack of snow in many of the area
valleys will allow many valley locations to warm up and dry out
well, especially in central Idaho. The most likely exception to
this scenario is up in the Flathead and Mission valleys where
there has been a lot of snow and the most moisture recently.

&&

.AVIATION...The warm and moist southwesterly flow over the region
will maintain the concern for obscured terrain, lowered ceilings,
rain, and gusty winds in north central Idaho and western Montana
for the rest of today and tonight. Another warm front within this
flow pattern will pass through the region on Saturday that will
continue the threat of low cloud cover, gusty winds, and rain.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WIND ADVISORY until 8 PM MST this evening Missoula/Bitterroot
     Valleys.

ID...None.
&&