Wildfire in Washington, September 1 to 3, 2018

Area Forecast Discussion
National Weather Service Pendleton OR
849 AM PDT Sat Sep 1 2018

updated the aviation discussion

.UPDATE...A quiet weather day is underway with a dry northwest
flow over the area. A weak disturbance is brushing the area with a
few cirrus clouds crossing the far northeast fringe of the area
around Washington Blue Mountain Foothills, the northern Blue
Mountains and Wallowa county. Otherwise clear skies will remain
over the region through tonight. Winds will be generally light
today except for the Columbia Gorge and Kittitas Valley. Have
bumped winds up some those areas today to 10 to 20 mph in the
Columbia Gorge and 15 to 25 mph in the Kittitas Valley.
Temperatures look to be a couple of degrees warmer than yesterday
and have made a few adjustments. Temperatures this morning were
quite cool this morning in the higher mountain valleys with
several locations at or below freezing. The airmass looks a few
degrees warmer tonight but still made a few adjustments downward
to the mid 30s for places like Meacham, Ukiah and Seneca. Forecast
update already out. Perry

.AVIATION...vfr conditions will persist at all taf sites for the
next 24 hours.

&&

.PREV DISCUSSION... /issued 404 AM PDT Sat Sep 1 2018/

SHORT TERM...Today through Monday...The weather pattern will be
rather benign during the short term period. A dry northwest flow
will keep dry and cool conditions with slightly below normal
temperatures over the forecast area. There will be a weak cold front
on Sunday and then another one on Monday afternoon. These will have
very little moisture. However the one for Monday afternoon will have
enough moisture and an upslope low level flow for warranting the
mention of a slight chance of showers in the Blue Mountains, Elkhorn
Mountains and the Wallowa Mountains/high plateau. Elsewhere it will
just be partly to mostly cloudy. There will be mostly diurnally
driven local breezy conditions in the afternoons and early evenings,
mainly in the vegetation free terrain such as the eastern Columbia
River Gorge, the Oregon Lower Columbia Basin and the Blue Mountain
Foothills. There will be good mixing through the short term and am
not expecting any smoke or air quality issues through Monday due to
the northwest flow and frequent cold fronts. 88

LONG TERM...Monday Night through Friday...Dry northwest flow will
be over WA and OR Monday night through Tuesday. Tuesday night a
deepening offshore trough will shift the upper level flow to the
southwest. The GFS shows monsoonal moisture moving north from AZ and
CA to provide enough moisture and instability for a few showers
Wednesday afternoon while the ECMWF indicates very limited moisture
and instability that will keep eastern OR and WA dry. A blend of the
SuperBlend and GFS MOS kept the pops too low for showers. Thursday
and Friday an upper level low will move from the Gulf of Alaska to
Vancouver Island as the upper level trough moves toward the coast. A
few showers may develop along the WA Cascades Friday. There may be
some afternoon buildups in the OR mountains, but there is not enough
confidence to add any precipitation with the bulk of the energy
remaining in Canada.

Temperatures will be at or a few degrees below normal with highs in
the mid 70s to mid 80s Tuesday through Thursday then cooling Friday
to the upper 70s in the lower elevations and in the upper 60s and
70s elsewhere. Lows through the period will be cool with upper 40s
to mid 50s in the lower elevations and in the mid 30s to mid 40s
elsewhere.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  77  50  81  54 /   0   0   0   0
ALW  79  53  82  56 /   0   0   0   0
PSC  81  50  85  54 /   0   0   0   0
YKM  80  49  84  53 /   0   0   0   0
HRI  80  51  84  55 /   0   0   0   0
ELN  76  50  82  53 /   0   0   0   0
RDM  79  40  83  44 /   0   0   0   0
LGD  76  42  80  47 /   0   0   0   0
GCD  77  47  81  49 /   0   0   0   0
DLS  79  54  85  57 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
&&

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