Newberg, Oregon 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

828
FXUS66 KPQR 112223
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
323 PM PDT Fri Apr 11 2025

.SYNOPSIS...Overall, the next week will be encompassed by high
pressure leading to clearing skies and low overnight
temperatures. Frost and near freezing temperatures expected
each night through Monday morning. Significant warming mid-week.

&&

.SHORT TERM...Now through Monday...High pressure will be the
overall synoptic patten that will dominate for the next few
days. The shortwave trough that passed through overnight has
exited the region with a few lingering showers along southwest
Washington. These showers have not been impactful, and have had
minimal accumulation. They do signify mixing though which will
aid in setting the stage for the next trough that is sitting
offshore. Satellite shows the next shortwave trough draped over
Vancouver Island to around -130W. This system will bring another
round of light rain and breezier winds. Conditions will continue
to be showery and scattered with large breaks between periods of
precipitation. This system will make landfall later this evening
into the morning. This system will bring some cloud cover to the
area which will insulate the surface and inhibit radiational
cooling. This will help keep frost at bay over most of the
forecast area. The one region that will not be immune will be in
the Upper Hood River Valley. When looking for frost forecasting,
we specifically look for temperatures less than 36 degrees F,
light winds, and no mixing in the lower atmosphere. We also need
to have enough moisture available, but not too much where it
keeps conditions too warm. For those in the Upper Hood River
Valley, take precautions with outdoor plants that are vulnerable
to frost.

Behind the shortwave a broad area of high pressure will move in
and will remain anchored over the Pacific and along the coast.
This high will keep conditions generally settled, and clear.
Before we get to the warmer temperatures from Monday on, we have
to make it through one more evening of near or below freezing
temperatures. Overnight, skies are forecast to be clearer than
on the previous night which will allow for more cooling. This
combined with northerly winds and 850 temperatures around
freezing will aid in keeping the column cool enough to inhibit
any warmer air from mixing down. In addition, due to the
stagnant position of the ridge, winds are not expected to be an
issue and therefore more widespread frost is possible,
especially in the rural portions of the southern Willamette
Valley, Coast Range valleys, and the valleys of the Cascade
Foothills will be the most at risk of frost development. Areas
that are shaded will maintain frost longer through the morning.
The Upper Hood River Valley will see at or below freezing
temperatures. The challenge here is just how low in elevation
these temperatures will go. For right now, the highest
probability of temperatures at or below 32 deg F is from
Parkdale south, and at the higher elevations. However, there is
around a 40% chance for below freezing temperatures around
Odell. Near the river in Hood River proper chances are low
(less than 5%). Given the beginning of growing season and the
higher probability, have issued a Freeze Warning for Sunday
morning. If skies become cloudy, or if temperatures aloft warm a
bit more, overall surface temperatures may become warmer.
However if that does occur, frost would still be possible.

Sunny skies on Sunday will lead to a warmer Monday. South to
southeasterly flow will become dominate and usher in warmer air
from the desert southwest. Ensembles are in excellent agreement
shortwave ridging continues the warming trend into Monday.
Confidence is extremely high for 70s to materialize on Monday
with the probability of them occurring at 80-90%+ at most sites
in the Willamette Valley and other inland valleys per the NBM.
With the axis of a weak thermal trough passing overhead on
Monday in addition to weak warm advection aloft, high
temperatures were adjusted a couple degrees higher than the
deterministic NBM - it has a habit of slightly under forecasting
springtime high temperatures in these scenarios. Ended up
trending towards the 75th percentile for the Greater Portland-
Vancouver Metro, the outskirts in Washington County, and
more urban areas of the central Willamette Valley.  -Muessle


.LONG TERM...Monday Night through Friday...Ensemble models are
beginning to come into better agreement in the long term with
all showing the ridging continuing through at least mid-week.
500 mb ensembles show the ridge intensifying on Friday with a
nearly stationary low sitting over southern California.
Previously, there was a low digging over the inner mountain
west, but that trough has wained a bit. Therefore the impacts
will be felt less. Still looking at breezy conditions from the
east, but no strong winds are expected necessarily on Tuesday.
If we see increased gusts, they would occur around KAST, and the
Columbia River Gorge. However, the GFS ensembles are weaker than
that of the ECMWF ensembles. The NBM has trended with a high
bias in the Columbia River Gorge over the last several weeks so
have used that to our advantage and maintained those elevated
winds east of Troutdale. Temperatures will stay stagnant during
this time with the mean high temperatures around 70-75 deg F
and lows in the mid 40s. No rain expected until after this
forecast time frame. -Muessle


&&

.AVIATION...VFR conditions expected to through the period as upper
level flow pivots from southwest to northwest with the passage of
a weak upper level trough. Winds increasing to 8-12 kt out of the
NW at most sites 21-00z this afternoon, decreasing to 5 kt or
less after 07z Sat. Stronger gusts expected along the immediate
coast, with gusts up to 20 kt at KONP. Hi-res model guidance
depicts a 20-40% chance for MVFR cigs at inland terminals after
12z Sat, with the highest probs across the north.

PDX AND APPROACHES...VFR through the period in onshore flow. Winds
increase to around 10 kt out of the NW 21-23z this afternoon, then
subside after 07z Sat. Around a 40% chance for MVFR cigs after 12z
Sat, but generally expect prevailing cigs above FL040 through the
period. /CB


&&

.MARINE...Conditions begin to ease as the front from the last
several days exits to the east. Winds have slowed with
widespread northwest winds of 5-10 kt with gusts up to 15 kt.
This will be the trend for the next several days with little
change. Seas have remained slightly elevated hovering in the
8-10 ft range at 10 seconds. Given the steepness of the seas,
have extended the small craft advisory for the waters for a few
more hours. As the thermal trough begins to develop on Sunday
afternoon will see northerly winds with increasing speeds,
especially south of Tillamook Bay. Gusts up to 25 kt likely from
Sunday evening through mid week.

Seas will not significantly build until Tuesdsay night as a
northerly wind wave enters the picture. That will be short lived
as it eases early Thursday morning. -Muessle

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...Frost Advisory from midnight Saturday night to 8 AM PDT Sunday
     for ORZ104>110-113>119-123>125.
     Frost Advisory from midnight tonight to 8 AM PDT Saturday for
     ORZ121.
     Freeze Warning from midnight Saturday night to 8 AM PDT Sunday
     for ORZ121.
WA...Frost Advisory from midnight Saturday night to 8 AM PDT Sunday
     for WAZ202>205-208.
PZ...Small Craft Advisory until 5 PM PDT this afternoon for PZZ210.
     Small Craft Advisory until 11 PM PDT this evening for
     PZZ251>253-271>273.
&&

$$

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