Weather Service Report


272 
FXUS66 KPQR 202208
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR 
304 PM PDT Fri Jul 20 2018

.SYNOPSIS...Hot weather return to the interior starting Sunday
through early next week.  The warm weather will likely continue
through the week.      

&&

.SHORT TERM...Tonight through Monday. Seasonal temperatures will be
with us one more day. Then a warm-up follows early next week with
temperatures well above normal.  Skies will be clear this evening
with clouds returning to the coast overnight as a field of marine
stratus well offshore moves to the coast.  A shortwave trough arrives
early Saturday morning that could extract some
drizzle out of the marine stratus.  SREF, NAM-nest shows 20-30
percent PoPs so have added drizzle to the north coast zones for early
Sat morning.  By Sunday morning the upper trough has moved on
allowing a strong upper ridge over the Desert Southwest to expand
into the region. Below about 700 mb, high pressure builds into
eastern OR/WA resulting in east to northeast flow across the CWA.  If
there is significant smoke from fires east of the Cascades, it could
advect into our area.  The upper ridge strengthens on Monday and
should be the hottest day this week with inland highs in the upper
90s.  The coast will be cooler with highs in the 70s. 

.LONG TERM...Monday night through Friday...Dry weather and much above
normal temperatures will remain with us.  Monday looks to be the 
hottest day inland which will set up for a warm night for the 
interior lowlands with the warmest spots in urban areas.  Not a 
whole lot of change for the remainder of the long term. Global 
models are in good agreement through Tue where the region will 
remain under the influence of the strong upper high centered over 
the Desert Southwest. The GFS and a majority of its ensemble members 
depress the ridge slightly as a shortwave trough moves into the 
region Wed-Thu. It is not much of a trough though, 500 mb heights 
remain above 585 DAM. The ECMWF however is weaker with this feature. 
This means the GFS would bring slight cooling with onshore flow, 
while the ECMWF would maintain the very warm conditions inland. 
Coastal areas remain cooler with light onshore flow. The GFS shows 
some moisture and instability nearing the SE portion of the forecast 
area Tue. The ECMWF does not.  Will have to see how later model runs 
handle this feature. /mh

&& 

.AVIATION...Weak onshore flow over the northern half of the
forecast area will bring predominately MVFR conditions to KAST 
later this evening and mostly VFR conditions to the Portland 
Metro TAF sites for the next 24 hours. There could be a few hours
of MVFR cigs Sat morning for metro sites, but confidence is low.
Dry northerly flow over the southern half of the will result in 
mostly VFR conditions for the remaining TAF sites. The exception 
to this may be KONP which could see a few hours of lower cigs 
early Sat morning, but suspect winds will remain slightly 
offshore and prevent lower cigs from developing.

KPDX AND APPROACHES...Mostly VFR the next 24 hours. There could
be a few hours of MVFR cigs Sat morning, but confidence is low.
/64

&&

.MARINE...High pressure over the northeast Pacific and thermal low 
pressure over southwestern Oregon will result in a fairly typical
summer-time northerly wind pattern. The surface ridge axis is a
bit further north today which could bring a few stronger gusts to
25 kt for areas south of Cape Meares this afternoon and evening,
but probably not enough to warrant an advisory. Otherwise, wind 
gusts near 25 kt should be fairly widespread across the central 
Oregon waters each afternoon and evening through Saturday.

Seas will continue to flirt with steep and hazardous criteria as
combined seas climb into the 6 to 8 ft range with dominant periods
between 7 to 8 seconds. Still think the best chance of widespread 
square seas have passed so will not reissue an advisory for it.
Nonetheless, seas will remain very step.

Winds and seas should ease a bit Sunday through Tuesday as 
thermal low pressure over southern Oregon shifts north and 
inland. A return to a stronger northerly wind pattern looks to 
arrive towards the middle of next week. /64

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory for winds until 3 AM PDT Saturday for 
     Coastal Waters from Cascade Head OR to Florence OR out 60 
     NM.

&&

$$

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

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Western Regional Climate Center, wrcc@dri.edu