National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS66 KPQR 190452 AAA
AFDPQR

Area Forecast Discussion...UPDATED
National Weather Service Portland OR
952 PM PDT Thu Apr 18 2024

Updated aviation discussion...

.SYNOPSIS...
High pressure over the region will remain through
Friday, maintaining mild sunny days and cool clear nights.
Offshore flow continues, with breezy easterly winds on the west
slopes of the Cascades and to some degree, the Coast Range.
Will return to cooler conditions this weekend, as a front pushes
across the region. Unsettled weather continues into early next
week.

&&

.SHORT TERM...TODAY THROUGH SATURDAY...High pressure continues
in the region, with sunny and warm conditions. Temperatures
today are on track to reach right about to 70 or just barely
into the low 70s throughout the Willamette Valley, while the
coast will be just a bit cooler, peaking in the upper 60s.
Offshore flow continues, with generally NE winds curling N in
the central and southern Willamette Valley. Generally pleasant
spring conditions expected today and tomorrow.

Breezy east winds through the Gorge are currently gusting to
around 25mph, but this is expected to continue increasing
through tonight and Friday as the thermal trough continues
building. High temperatures Friday will be just a degree or two
warmer, and east wind through the Gorge will increase late
Thursday night/early Friday morning. Exposed upper elevation
areas could see gusts potentially up to 35-50mph throughout most
of Friday, gradually weakening over Friday night. The rest of
the region should see NE or E breezy winds up to 10-20 mph. Will see
wind-reversal along the coast in the afternoon, with east to
northeast winds becoming southerly to south of Florence in the
afternoon, and as far north as Newport by sunset as the thermal
trough shifts inland over the Coast Range. This will allow for
cooler ocean air to spread back across the coastal zones at that
time. But, offshore flow persists on to the north overnight,
such as at Astoria. Likely be one of those afternoons where
Newport is 59 with light south wind and Astoria is around 70
with an east wind in the late afternoon.

Changes gradually arrive Fri night into early Sat, as a front well
offshore approaches. Will see offshore flow gradually weaken Fri
night, with increasing clouds later Fri night into Sat am. Timing
still suggest showers or pockets of light rain spreading to the coast
by midday Sat, and pushing inland during the afternoon. Again, not a
strong front, as rainfall expected on Sat being 0.10 to 0.25 inch
along the coast/coastal mountains, and 0.02 to 0.10 for
lowlands form Cowlitz Valley through the Willamette Valley. Will
be much cooler on Saturday, thanks to clouds and onshore flow.
Highs only in the 50s along the coast, and lower to middle 60s
inland. /Rockey/JLiu

.LONG TERM...SUNDAY THROUGH WEDNESDAY...Onshore flow begins
developing Saturday night into Sunday. Cooler conditions are
expected Sunday as a result, with coastal highs in the mid 50s,
and right around 60 inland. Ensemble guidance points towards a
brief shortwave ridge impacting the area on Monday and Tuesday
morning, allowing for warmer temperatures potentially back into
the 70s. Tuesday and Wednesday see potential for another front,
allowing for light showers and cooler temperatures again. /JLiu

&&

.AVIATION...VFR thresholds with clear skies prevail at all
terminals through the entire TAF period as high pressure remains
aloft. Winds tonight will generally be easterly and around 5-10
kt, except in the central/south Willamette Valley where winds
will be more northerly. Inland locations could see isolated gusts
up to 18-20 kt through 15-16z Fri.

Easterly/northeasterly winds continue Friday as surface high
pressure remains settled east of the Cascades. East winds will
strengthen after 15-16z Fri as KTTD-KDLS pressure gradients
tighten slightly. The strongest winds will be through the
Columbia River Gorge into the Portland Metro Area, where east
winds could gust up to 25-30 kt through 00-02z Sat. Friday
evening, winds will begin to weaken.

PDX AND APPROACHES...VFR thresholds under clear skies through the
entire TAF period. East winds will be around 12-15 kt tonight,
strengthening after 15-17z Fri to around 18-22 kt with gusts up
to 25-30 kt through 00-02z Sat. Winds begin to weaken in the
evening.-Alviz


&&

.MARINE...A thermal trough continues to build over the western
Oregon coast this afternoon with high pressure off the WA/B.C.
coast. This has caused a tightening of surface pressure gradients,
which will bring elevated wind gusts to 25-30 mph through this
evening, resulting in choppy waters. A Small Craft Advisory
remains in effect through this evening. Pressure gradients will
weaken tonight as the thermal trough continues to build north
along the Oregon Coast, causing winds to weaken. This pattern will
continue through Friday until a Pacific front approaches the
waters Friday night, breaking down the thermal trough and turning
winds southerly. Southerly winds increase through the day Saturday
as the front moves through the waters, with Small Craft winds
likely into Sunday.

General seas through Saturday afternoon of 4 to 7 feet at 15 to
17 seconds, consisting of a long period southwest swell. Swell
becomes westerly Saturday evening into Sunday, increasing general
seas to 9 to 11 feet at 9 to 11 seconds. -HEC

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...Small Craft Advisory until 11 PM PDT this evening for PZZ252-253-
     272-273.
&&

$$

www.weather.gov/portland

Interact with us via social media:
www.facebook.com/NWSPortland
www.twitter.com/NWSPortland