Area Forecast Discussion
Issued by NWS Boise, ID

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000
FXUS65 KBOI 191534
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
934 AM MDT Tue Sep 19 2017

.DISCUSSION...Showers noted across the area today. Wind concerns
remain through Wednesday. Based on trends, increased wind across
the West Central Mountains of Idaho for this afternoon and
evening. The remainder of the forecast looks on track, with some
threat for thunderstorm activity this afternoon. A cold front
moving through the area tomorrow afternoon remains similar in
recent model analysis. Pre-frontal winds should be breezy to
strong for areas of southeastern Oregon through the afternoon
hours, with winds relaxing with the frontal passage during the
late afternoon/early evening hours.


&&

.AVIATION...VFR except local brief MVFR conditions in heavier and
more widespread showers this afternoon. Snow levels around 6500
feet. Isolated thunderstorms north of a Burns to Magic Valley line
after 19/18Z, shrinking north after 20/00Z. Surface winds west to
northwest 10-20 kts decreasing by 20/03Z. Winds aloft at 10k ft MSL
west 20-30 kts.


&&

.PREV DISCUSSION...
SHORT TERM...Today through Wednesday...Northwest flow aloft will
continue into tonight, before backing to zonal by sunrise Wed.
Cold air aloft and sufficient moisture will bring another day of
showers and isolated thunderstorms. Precipitation will be most
prevalent in the north. Snow levels today will range from near
6000 feet in the north to 7000 in the south. Tonight, as the flow
backs ahead of a shortwave moving down the backside of the
longwave trough, snow levels will rise to a range of 6000 feet in
the north to near 8000 feet in the south. Showers will continue,
with more in the north than in the south once again. Wed,
precipitation chances increase further. There`s a slight chance
once again for thunderstorms, mainly in the north. Temps will
remain 15 to 20 degrees below normal. Winds will increase this
afternoon and even more-so Wed afternoon, especially across
southeast Oregon. West winds will gust 35 to 45 mph over much of
Harney and Malheur counties, as well as Owyhee county in southwest
Idaho Wed afternoon. These winds will occur both ahead of and
behind a cold front that will enter southeast Oregon during the
day. It will likely not make it through southwest Idaho until
evening.

LONG TERM...Wednesday night through Monday...Upper level trough
remains over the region through the weekend bringing below normal
temperatures and precipitation. The upper level trough will be
directly over the region Wednesday night through Friday. This will
bring widespread showers, mainly in the afternoon, to the
forecast area. Snow levels remain around 5500 feet at their lowest
Thursday through Friday before beginning to climb back up above
6000 feet by Saturday evening. Saturday afternoon an upper level
ridge begins to press inland from offshore causing a steady
decrease in precipitation from west to east. Temperatures start to
climb back towards normal as the ridge shifts inland next week.

&&

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

&&

$$

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DISCUSSION...KB
AVIATION.....AB
PREV SHORT TERM...SP
PREV LONG TERM....JS


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