Oregon City, Oregon 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

167
FXUS66 KPQR 061043 AAA
AFDPQR

Area Forecast Discussion...UPDATED
National Weather Service Portland OR
343 AM PDT Sun Oct 6 2024

Updated PQR WATCHES/WARNINGS/ADVISORIES.

.SYNOPSIS...High pressure will result in areas of patchy morning fog
in valleys with mostly sunny afternoons and pleasant temperatures for
the next several days. A series of weakening fronts will bring
increasing chance for light rain later this work week, with the
highest chance for widespread rain on Friday.

&&

.DISCUSSION...Now through Saturday night...Clear skies and calm winds
will result in another round of fog development early Sunday morning,
albeit less widespread and less dense than what was observed across
much of the interior lowlands early Saturday morning. Aside from
early morning patchy fog, Sunday will be another sunny day with temps
warming into the mid 70s over the Willamette Valley and Clark County
lowlands, except upper 70s in the Eugene-Springfield area and near 80
degrees around Oakridge and Creswell. Winds will be light, making for
a beautiful fall day.

Even warmer temps are in store on Monday. Models and their ensembles
remain honed in on high pressure over the area and another day of
sunshine, with high temps warming into the upper 70s to lower 80s
from Kelso to Portland to Eugene. The coast will be a bit cooler with
highs in the mid 60s to lower 70s.

Models continue showing southwest flow aloft Tuesday through Thursday
with a gradual cooling trend and mainly dry conditions, aside from a
round of light rain at the coast with a decaying Pacific cold front
that is set to move inland Monday night into Tuesday morning. Models
show another decaying front moving inland on Wednesday with slighter
higher chances for at least some light rain inland (NBM PoPs are at
25-45%, except 50-60% in Astoria and on the Long Beach Peninsula).
PoPs increase close to 50% on Friday across all of northwest OR and
southwest WA, as this is when most ensemble guidance is showing at
least some rain over the area. That being said, there are still some
ensemble members from the GEFS/ENS/GEPS showing no rain at all and
overall model spread remains high. The NBM is showing a 35-50% chance
for 24-hr rain amounts in excess of 0.25" from 5am Friday-5am
Saturday. -TK

&&

.AVIATION...VFR conditions prevailing as of 09Z Sun, but IFR/LIFR
stratus at the coast as far north as KONP. Fog/stratus forecast
to spread north to around KTMK by 12Z Sun then dissipate over
land area 18-20Z Sun, but could linger just offshore through the
afternoon. North of KTMK there is lower chances 30-40% for IFR
conditions to reach KAST 12-18Z Sun.

Under clear skies and light winds comes the potential for low
stratus and fog for the Willamette Valley. As of 09Z Sun RH values
in the 85-95%, and there is already fog at KCVO & K775. Satellite
fog products not picking the fog yet (too small an area.) HREF
forecasting up to 20% chance for IFR between KUAO and KEUG
through 18Z Sun. Overall pattern suggests higher chances for fog
this morning and current forecast looks reasonable with fog at
most sites through 18Z Sun. Surface winds are generally variable
less than 5 kts, becoming north to northwest after 18z.

Similar fog potential inland late tonight into Monday morning
with HREF showing up to 20% chance for low stratus/fog. Coastal
fog/low stratus chances are lower tonight as weak offshore
component to the low level flow should keep mainly VFR conditions.
With that said fog/stratus may lurk just offshore.

PDX APPROACHES...Light winds and clear skies 10-15% probability
of fog development 12-18z Sunday. Winds mainly less than 5 kts,
variable then turning northwesterly after 18z. /mh

&&

.MARINE...Weak high pressure resides over the coastal waters with
a thermal low pressure along the south Oregon coast and a trough
offshore for the next couple days. By Tuesday the trough offshore
nudges to the coastal waters, followed by a stronger system
Wednesday. Right now winds look to remain below 20 kt through at
least mid-week. Seas 4 to 5 feet will increase to around 6 to 7
feet on Monday as a system moves well to our north. Seas subside a
foot or two into the latter part of next week. /mh
-Batz

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...Dense Fog Advisory until 9 AM PDT this morning for ORZ103.

WA...None.

PZ...Dense Fog Advisory until 11 AM PDT this morning for PZZ252-253.

&&

$$

www.weather.gov/portland

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