Oak Grove, Oregon 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

650
FXUS66 KPQR 260904
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
204 AM PDT Thu Mar 26 2026

.SYNOPSIS...Isolated showers taper off this morning. Otherwise,
dry weather returns today, continuing through the weekend, along
with temperatures in the 60s Friday into the weekend. Rain is
expected to return sometime early next week, though the exact
details remain uncertain at this time.

&&

.DISCUSSION...Thursday through Wednesday...Radar imagery early
Thursday morning shows very isolated showers continuing across
NW OR and SW WA as the upper level shortwave moves into eastern
OR and ID. These showers should taper off by around 5-8 AM.
Outside of these showers, satellite imagery indicates that skies
are mostly clear. This is allowing for radiative cooling, which
combined with the colder airmass behind today`s cold front, is
causing a much cooler temperatures early this morning. Current
observations show temperatures across the interior lowlands and
the coast have already fallen to the mid to upper 30s, and low
temperatures this morning are forecast to drop to the low to mid
30s with pockets of upper 20s in rural areas. Widespread frost
is likely, which could cause impacts to sensitive outdoor
vegetation. Additionally, this pattern could lead to a period of
low stratus or fog development around the sunrise hours due to
lingering moisture from the recent rains. Motorists should be
cautious of sudden changes in visibilities, especially in more
rural areas.

Zonal flow will take shape over the PacNW today behind the
shortwave, and ensembles are in good agreement that this pattern
will continue through at least Saturday with increasing chances
into Sunday. The colder airmass behind yesterday`s cold front
will keep high temperatures today in the mid to upper 50s
across the interior lowlands, but daytime temperatures will warm
quickly into the 60s for Friday into Sunday. Clear skies will
allow for a similar overnight pattern as today with chances of
frost and fog. However, these chances decrease each day as
overnight temperatures increase slightly each night and surface
conditions become more dry. A weak thermal trough will develop
over the Oregon coast this afternoon continuing through Friday
afternoon. This will tighten surface pressure gradients, causing
weak offshore flow along the western Cascades and Coast Range,
especially tonight into Friday morning.

Ensemble guidance is coming into better agreement in pushing
back the next round of precipitation into late Sunday at the
earliest with better chances sometime on Monday. Ensemble
members in latest runs have better have resolved the upper
level pattern for Sunday into Monday, indicating that instead
of one long trough moving through the eastern Pacific, there
will be two separate features: a closed low moving southeast
through the central Pacific and a low off of western Canada
pushing south through the northeastern Pacific. The majority of
ensemble members suggest these will meet over the eastern
Pacific late Sunday and continue moving east towards the West
Coast into Monday. This meeting is where uncertainty increases
as some members essentially indicate the two features will
merge into one longwave trough while other members keep them
mainly separate and moving east at different speeds. The
dynamics can be very different with these solutions, but either
way, guidance shows the portion that will affect NW OR and SW WA
weakening as it reaches the coast late Sunday/Monday, leading
to not much precipitation. Another feature is evident Tuesday
into Wednesday that could lead to higher chances of another
round of precipitation, though details are still uncertain. -03

&&

.AVIATION...Predominately VFR conditions expected over the next
24 hours as upper level flow becomes zonal with westerly winds
aloft. Mostly clear skies and calm winds will support
temperatures in the low to mid 30s through 14-16z Thu, leading to
potential frost development over metal surfaces. Though frost is
more likely due to cold temperatures, can`t rule out fog or low
stratus development either (5-15% chance) after 10-12Z Thu,
especially for our typical foggy sites like KHIO and KEUG. Any
lowered flight conditions will improve to VFR by 16-18z Thu.
Winds become northerly after 18Z Thu which will promote increased
winds around 8-12 kts along the coastal terminals and those from
KUAO south, decreasing by 03-06z Fri.

KPDX AND APPROACHES...VFR conditions through the TAF period.
Clear skies and calm winds will support frost development over
metal surfaces through 16z Thu. Light and variable winds become
northerly after 18-20z Thu, though remaining below 10 kts. -03

&&

.MARINE...High pressure is building over the waters with winds
turning northerly throughout today. A surface thermal trough then
develops tonight into Friday morning, tightening pressure
gradients and strengthening these northerly winds. Breezy
northerly winds initially remain south of Cape Falcon and beyond
20 NM offshore, however by Friday afternoon there is a 80-90%
chance for widespread northerly wind gusts of 21 kt or greater
across all waters south of Cape Falcon. For now, a Small Craft
Advisory remains for the waters south of Cape Foulweather and
beyond 10 NM offshore between 5 PM Thu through 5 AM Fri, but this
advisory will likely be extended in areal coverage and duration
with upcoming forecast packages. The thermal trough breaks down
Saturday with high pressure continuing over the waters through the
weekend. North winds will continue through the weekend, just not
as gusty. Seas will generally remain between 7-9 ft at 10-11 sec
through the weekend. -03/10

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...Small Craft Advisory from 5 PM this afternoon to 5 PM PDT Friday
     for PZZ272-273.

&&

$$

www.weather.gov/portland

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