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000 
FXUS66 KPDT 230927
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
227 AM PDT Sat Jun 23 2018

.SHORT TERM...Today through Monday...A northwest flow aloft today 
will keep cooler and dry conditions over the forecast area through 
tonight. There may be a few light rain showers along the central 
Washington Cascade east slopes this morning due to an upslope flow 
into the Cascades with some spill over. But it will be dry over the 
rest of the CWA. A building and amplifying upper ridge will move 
into the Pacific Northwest on Sunday with the ridge axis reaching 
the Cascade range by 12Z (5 AM PDT) Sunday morning. This ridge will 
bring a sharp warming trend on Sunday from temperatures today. Highs 
on Sunday in the lower elevations will be into the lower 90s with a 
few locations possibly reaching the mid 90s. In the mountains 
temperatures will be mostly in the 70s to lower 80s. The next 
weather system and its upper trough will begin to move into the 
region Sunday night into Monday. This will bring cooler temperatures 
with a marine push and increasing winds...especially along the 
Cascade east slopes, the eastern Columbia River Gorge, the Lower 
Columbia Basin, the Blue Mountain Foothills and the Kittitas Valley. 
However, the winds will not be as strong as they were on Friday. 
This system will have very limited moisture and can expect only some 
light rain showers over the Washington Cascade east slopes on 
Monday. Temperatures on Monday will cool back down to the lower to 
mid 80s in the lower elevations with 60s to mid 70s mountains. 88

.LONG TERM...Monday night through Saturday...Winds will taper off 
Monday evening as pressure gradients equalize across the Cascades 
behind a departing cold front. High zonal flow becomes established 
behind the departing system Tuesday through Thursday morning with 
dry westerly flow and near zero precipitation chances. Weak onshore 
flow will keep westerly afternoon winds in the 10-15 mph range 
during this period which may aggravate any continuing wildfire 
suppression efforts. Models have come into a little better agreement 
with deepening longwave trough Thursday into the weekend. Main 
impacts from this system will be breezy winds during the day 
Thursday with strengthening onshore flow and a slight chance of 
showers into Friday and Saturday as an upper level low becomes 
established over the forecast area. Given rather meager mid-level 
lapses even with upper low overhead have kept any mention of 
thunderstorms out of the forecast for now. Peck

&&

.AVIATION...12Z TAFS...The pressure gradient across the Cascades 
will continue to relax through this afternoon as upper level ridging 
builds into the region with winds trending down for RDM/BDN/DLS/PDT 
through late this afternoon. SCT-BKN mid-level cigs in the vicinity 
of PDT/ALW this morning associated with marine influenced air 
ridging up into the Blues will dissipate through the afternoon as 
mixing increases. North-northwest transport winds should keep most 
smoke from central Oregon fires away from the TAF sites this 
morning. Peck

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  80  55  90  59 /   0   0   0   0 
ALW  81  58  91  62 /   0   0   0   0 
PSC  85  57  92  63 /   0   0   0  10 
YKM  82  54  89  58 /   0   0   0  10 
HRI  84  57  93  62 /   0   0   0   0 
ELN  77  54  88  56 /   0   0   0  10 
RDM  78  46  92  51 /   0   0   0   0 
LGD  73  49  85  54 /  10  10   0   0 
GCD  73  49  85  54 /  10   0   0   0 
DLS  80  57  92  60 /   0   0   0   0 

&&

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

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