Area Forecast Discussion
Issued by NWS Boise, ID

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FXUS65 KBOI 170406
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
906 PM MST Tue Jan 16 2018

.DISCUSSION...Seeing dry conditions in the wake of an exiting
trough that brought rain and snow to the region today. Lingering
moisture is supporting a persistent mid-level cloud deck across
much of southwest Idaho, while an upper ridge and high clouds work
into southeast Oregon. Expect the mid-level clouds to gradually
erode as the ridge builds into Idaho overnight and drier air works
toward the surface. As skies clear from the west, the possibility
for fog development increases in sheltered valleys/basins of
southeast Oregon and far southwest Idaho. Have updated forecast
to increase cloud cover overnight, otherwise it`s on track.

&&

.AVIATION...Fog and stratus tonight into early Wednesday in the
lower valleys especially around KBKE and KMYL. Remaining areas will
see broken to overcast skies through Wednesday. Light surface winds.
Winds aloft to 10k feet MSL: SW 10-25 kts through 06z then SW 10-20

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Thursday...A few residual showers
associated with a weakening trough in central Idaho will shift to
our east this afternoon. Moisture left behind in the wake of the
trough, along with a weak short wave ridge building in tonight,
will lead to patchy valley fog. A warm front will move through on
Wednesday, accompanied by partly to mostly cloudy skies along with
a slight chance of snow in the higher elevations of Baker County.
Southwest flow will follow the warm front Wednesday night and
Thursday. A moist frontal system will bring widespread
precipitation into southeast Oregon and portions of southwest
Idaho (dry south and east of Mountain Home) on Thursday. Snow
levels will rise considerably ahead of the front - around 6500
feet in the north to around 8500 feet near the Nevada border.
Winds will increase as the front approaches, becoming breezy in
the Treasure and Western Magic Valley, most of southeast Oregon,
and the higher terrain of southwest Idaho from Wednesday afternoon
through Thursday. Temperatures will remain above normal.

LONG TERM...Thursday night through Sunday...Active weather
pattern for the length of the long term forecast and beyond.
Widespread precipitation as we head into Friday as the upper level
trough continues to press through the region. Rain for valley
locations beginning Friday then a transition into a wintry mix by
Friday afternoon as the cold boundary pushes through. Snow levels
drop to valley floors by Friday evening, but as has been the case
for much of this winter, by this time precipitation is mostly in
the mountains. Some differences in models on Sunday with
precipitation placement leaves confidence low, but that looks to
be the best opportunity to see some valley snow.

Sunday night through Tuesday...Wet and windy are the main weather
features showcased during this extended forecast period as a
tightly packed trough quickly moves across the CWA. Widespread
snow is expected in the mountains with mixed rain and snow in most
lower valleys. Slightly drier by Tuesday as a weak ridge rushes
in behind the exiting trough. Strong gusty southwesterly winds
will lead off in southwest section of the CWA early Monday morning
but diminishes to breezy by the late afternoon as the ridge
begins to transition in. Wind directions in the Treasure valley
will be lesser in speed and predominately from the southeast with
a short period of westerly during Monday afternoon. Temperatures
fluctuating a few degrees around normal.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.
OR...None.

&&

$$

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DISCUSSION...DG
AVIATION.....JS
PREV SHORT TERM...BW
PREV LONG TERM....JC/WH



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