Area Forecast Discussion
Issued by NWS Pendleton, OR

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FXUS66 KPDT 221620

Area Forecast Discussion
National Weather Service Pendleton OR
920 AM PDT SAT OCT 22 2016

.UPDATE...A shortwave that is crossing the area has moved into
Central Oregon and the Eastern Oregon mountains this morning.
Showers have come to an end except for perhaps a shower or two
lingering in Wallowa County. Skies have cleared from North Central
Oregon and the Columbia Basin northward. The clear skies, light
winds and abundant low level moisture from recent rain have
allowed fog to develop in some areas, mainly the Yakima Valley,
the Washington Columbia Basin north of the Tri-Cities and along
Interstate 90 near Snoqualmie Pass. Expect that the fog will lift
in the next couple of hours. Have updated the forecast to lower
cloud cover today. Winds will be light through the day but made a
few minor adjustments. Temperatures will be in the upper 50s to
mid 60s with mainly 50s in the mountains. Tonight another system
will approach the coast with increasing clouds though any showers
will be confined to the Cascade Crest. Temperatures will be up a
degree or two tonight due to the increased cloud cover. Forecast
update already out. Perry


.PREV DISCUSSION... /issued 444 AM PDT SAT OCT 22 2016/

SHORT TERM...Today through Monday Night...A shortwave is moving
across eastern WA/OR early this morning...with radar/obs showing
scattered to numerous showers mainly from the Blue Mountains
eastward. Activity further west continues to diminish as shortwave
ridging begins to enter the region. Some patchy light fog is
beginning to develop across the WA Columbia Basin...and with
conditions continuing to stabilize...think fog may thicken a bit
and expand in coverage to portions of the OR Columbia Basin by
sunrise...but do not expect dense fog. Residual showers across
the eastern mountains will end by sunrise/shortly thereafter
as the shortwave ridge moves overhead...with partly cloudy skies
generally prevailing today. With less cloud cover...expect
temperatures to be warmer than yesterday...with highs this
afternoon in the upper 50s/lower 60s for the lower elevations
with mainly 50s for the mountains.

For tonight into Monday...The region will be in between amplifying
ridging to the east...and the next system approaching from the
west. With the ridge progged to move very slowly east...this will
result in the trough to the west remaining offshore. Initial
shortwave energy will try to push onshore by Sunday
think the east slopes of the Cascades will see some precip Sunday
afternoon through Monday...but there will not be a significant
push to the will leave most areas from a Yakima Valley
to Central Oregon line eastward dry. Surface pressure gradients
will tighten as the low approaches...with breezy/windy conditions
developing mainly across Central Oregon. Expect temperatures
slightly above seasonal norms.

Monday Night...Models in general agreement pushing the trough
onshore...with a more significant shortwave and deeper moisture
in southerly flow. Will increase PoPs to high end chance/likely
as the shortwave crosses the area. Seasonably mild temperatures
will continue with significant cloud cover and south flow.

LONG TERM...Tuesday through Friday. Upper low remains centered
offshore next week with several short waves moving through it. These
short waves will spin up surface lows which will also remain off the
coast. The flow aloft will be southwesterly and will maintain mild
temperatures with fairly high snow levels at 6-8k feet. Skies will
be mostly cloudy through the extended time frame with periods of
rain. GFS and EURO have some significant differences on timing and
placement of rainfall so have used a blend for now. Temperatures
will continue to be above normal with highs in the 50s to mid 60s.
Lows in the upper 30s and 40s. Could have some breezy to windy
conditions Tue night into Wed as models all showing a fairly deep
surface low off the Oregon coast with stronger winds aloft.
Otherwise no significant winds expected through the period. 94

AVIATION...12z tafs. Patchy fog in the Columbia basin will impact
PSC YKM this morning. Otherwise sct 050-080 with increasing cirrus
later this morning and afternoon becoming bkn200. Patchy fog is
possible again tonight after 08z in the Columbia basin. Winds


PDT  60  41  60  44 /   0   0   0  10
ALW  62  47  63  50 /   0   0   0  10
PSC  61  45  60  46 /   0   0   0  10
YKM  62  41  61  41 /   0   0  10  20
HRI  62  42  61  45 /   0   0   0  10
ELN  58  40  58  41 /   0  10  20  20
RDM  62  34  63  38 /   0   0  10  10
LGD  59  40  66  43 /   0   0   0  10
GCD  59  42  64  45 /   0   0   0  10
DLS  64  45  63  46 /  10  10  20  20


.PDT Watches/Warnings/Advisories...


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