Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 281547
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
845 AM PDT Thu Jul 28 2016

.SYNOPSIS...Weak upper ridging will lead to the warmest temperatures
we`ve seen this July to inland locations today and Friday. An upper
level trough will increase night and morning clouds and cooler
temperatures this weekend. Brief high pressure will move over the
area Monday before another upper low impacts the clouds and
temperatures Tuesday and Wednesday.

&&

.SHORT TERM...(Today through Sunday)...Clouds never made it into the
valley this morning and have already started to retreat towards the
coast. This will allow temperatures to warm quickly today. PDX 840AM
temp is already at 66F and SLE 756AM temp was already at 68F. This is
setting up for a warm day with highs in the low 90s most inland
locations and mid 90s in valley locations from SLE south. Did not
make any changes to ongoing forecast as morning analysis of KSLE
sounding yielded high temperatures very near our current forecast.

There will be little change in the weather tonight and Friday as
marine clouds will sock in the coast tonight, with little inland
intrusion Friday morning. Inland temperatures will again warm into
the 90s.

An upper trough over the gulf of Alaska will drop south towards the
Pacific NW Friday night and 500mb heights over the area will lower.
This will deepen the marine layer for marine clouds returning to
parts of the Willamette Valley (mostly northern Valley) Saturday
morning. Inland afternoon temperatures will cool closer to the
seasonal normal Saturday afternoon, especially in the central and
northern areas. Lane County will remain slightly above normal.

The marine clouds will move much further inland Saturday night and
likely extend from the coast to the Cascades Sunday morning. There
may be some patchy drizzle along the Washington and north Oregon
coast in the morning. The daytime temperatures will cool a few
degrees with most inland areas remaining just below 80 degrees.
TJ/Bentley

.LONG TERM...(Sunday Night through Thursday)...There will be brief
ridging over the area Sunday night and Monday with marine clouds
having a weaker impact on inland areas. Inland temperature may warm
a few degrees but another upper low will move over the area Monday
afternoon and limit the warming. THe upper low will result in
increased cloudiness and cooler temperatures Monday night and
Tuesday. Upper level heights will build Tuesday and flatten Wednesday
for a return of near normal temperatures. TJ

&&

.AVIATION...IFR stratus confined to the coastline and some of the
major coast valley drainages as of 15Z. Stratus pushed up the
Columbia River to KKLS. Expect coastal valleys to clear by 18Z,
but the coastal TAF sites, especially KAST, will likely hold on to
IFR cigs through early afternoon. Guidance suggests IFR marine
stratus returns to the coastline this evening.

KPDX AND APPROACHES...Satellite imagery at 15Z showed a small
stratus patch near KTTD, otherwise clear skies. There is a chance
for brief IFR cigs at KTTD, but believe it will not impact the
KPDX terminal. VFR to prevail at the terminal through Fri morning.
Weishaar

&&

.MARINE...Current forecast in good shape. Surface high pres remains
over the NE Pac with a thermal trough along the N Calif and S
Oregon coast. This will continue the typical summertime pattern of
gusty north wind over the coastal waters. The strongest winds
will continue to be over the southern portion of PZZ255 and
PZZ275, where gusts to 30 kt are possible during the afternoon and
evening hours today and Fri. A small craft advisory for wind is
in effect for all zones except PZZ250 through 12Z Fri. Winds will
also pick up over PZZ250 this afternoon, where a small craft
advisory goes into effect at 20Z. Wind speeds will begin to
gradually subside over the weekend as the NE Pac surface high
weakens. However, small craft advisories will likely be needed
into Sat.

Choppy and wind-wave dominated seas will also continue through
the rest of the week. A small craft advisory for hazardous seas is
in effect for zones PZZ255 and PZZ275, in the area of strongest
wind. Expect seas to run at 7 to 9 ft with a dominant period of 7
to 8 seconds. Seas will be a bit lower in PZZ250 where wind speeds
and resultant wind waves are lower. Locally driven wind waves will
start to subside Sat as wind speeds diminish, but a fresh swell
from the nnw will keep seas steep. Weishaar

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory for winds until 5 AM PDT Friday for
     Coastal waters from Cascade Head to Florence OR out 10 nm-
     Waters from Cape Shoalwater WA to Florence OR from 10 to
     60 nm.

     Small Craft Advisory for hazardous seas until 5 AM PDT Friday
     for Coastal waters from Cascade Head to Florence OR out 10
     nm-Waters from Cape Shoalwater WA to Florence OR from 10
     to 60 nm.

     Small Craft Advisory for winds from 1 PM this afternoon to 11
     PM PDT this evening for Coastal waters from Cape
     Shoalwater WA to Cascade Head OR out 10 nm.

&&

$$

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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.



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