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000
FXUS66 KPQR 260918
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
218 AM PDT Fri May 26 2017

.SYNOPSIS...Upper level high pressure builds over the region on
today, with dry and warmer conditions developing. High pressure
aloft will hold over the region through the Memorial Day holiday
weekend, and afternoon temperatures will remain well above normal.
High pressure shifts eastward early next week ahead of the next
approaching disturbance. Temperatures trend gradually cooler with a
return of rain chances during the second half of next week as a
disturbance tracks across the Pacific Northwest.

&&

.SHORT TERM...Today through Sunday...An upper level ridge currently
offshore will continue to gradually shift eastward today, with the
ridge axis near the coast by this evening and squarely over the
Pacific Northwest and Great Basin over the weekend. The upper low
which helped some showers to develop over the Cascades Thursday
afternoon will continue to move east of the area today and it looks
like any related forcing will stay east of the Cascades, so have
continued a dry forecast for today within the local forecast area.

With 500 mb heights rising steadily through the holiday weekend with
the high pressure taking hold, and 850 mb temperatures likewise
warming, afternoon temperatures will respond accordingly with
increasing warmth over the next few days. High temperatures in the
Willamette Valley will be in the lower 80s today, and generally in
the mid to upper 80s over the weekend. However, models continue to
suggest a weak surge of marine stratus due to a southerly wind
reversal along the coast tonight, starting in south and pushing north
to around Pacific City. This may keep Saturday`s temperatures a
little bit cooler along the central coast than the pattern might
otherwise suggest. If the surge spills over into the southern
Willamette Valley, areas around Eugene and possibly even Corvallis
could end up seeing significant cloud cover Saturday morning, leading
to cooler afternoon temperatures. Bowen/Cullen

.LONG TERM...Sunday night through Thursday. Little change to the
overall pattern for the Memorial Day holiday, with the upper level
high pressure still squarely positioned over western U.S. and
temperatures remaining around 20 degrees above seasonal normals, at
least inland. However, by Monday night into Tuesday, heights begin to
lower ahead of the next approaching disturbance. Some discrepancies
among the models with respect to timing and strength of this feature,
so for now have trended the forecast in line with a blend of models
for Tuesday and Wednesday. However, confidence in the forecast during
the breakdown of the ridge is a bit lower than average. Nonetheless,
expect a cooling trend back to near or perhaps slightly below normals
for the start of June. Tweaked the forecast in the extended period,
but overall the trend has remain consistent, even with the model
discrepancies. Bowen/Cullen

&&

.AVIATION...VFR conditions are expected for the entire area
today and tonight. We could see some patchy IFR with low stratus
or fog along the coast this morning and also locally inland, but
anything should be brief.

KPDX AND APPROACHES...VFR today and tonight. pt

&&

.MARINE...Winds will remain below Small Craft Advisory criteria
well into next week, but there may be a few times with gusts
near 20 kt in parts of the coastal waters such as this afternoon
and evening, late Sunday, and again Monday afternoon and
evening.

Seas were very slow to come down below 10 ft, and have been
running around 2 ft above wave model guidance since early
Thursday. Seas are finally below 10 ft and are expected to
continue to subside a couple more feet as they remain below 10
ft well into next week. We do have very strong ebbs right now and
this will push the Columbia River Bar to require a Small Craft
Advisory for a rough bar during those times. pt

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory for hazardous seas until 3 AM PDT early
     this morning for Coastal Waters from Cape Shoalwater WA to
     Florence OR out 60 nm.

     Small Craft Advisory for Rough Columbia River Bar until 8 AM
     PDT this morning.

     Small Craft Advisory for Rough Columbia River Bar from 4 AM to
     9 AM PDT Saturday.

&&

$$

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This discussion is for Northwest Oregon and Southwest Washington
from the Cascade crest to 60 nautical miles offshore. The area is
commonly referred to as the forecast area.