Carver, Oregon Weather Forecast Discussion

158
FXUS66 KPQR 241007
AFDPQR
Area Forecast Discussion
National Weather Service Portland OR
307 AM PDT Wed Sep 24 2025
.SYNOPSIS...High pressure will maintain warm and dry conditions
across the Pacific Northwest through today. A thermal trough
remains in place, supporting offshore flow and continues low
relative humidity, particularly across the Cascades and interior
valleys. Conditions moderate Thursday as onshore flow returns,
bringing slightly cooler temperatures and higher humidity.
Another warming trend is expected over the weekend ahead of an
approaching frontal system, which looks increasingly likely to
bring rain to the region Sunday into Monday.
&&
.SHORT TERM...Now through Friday Night...High pressure over the
region is keeping summer like conditions in place with above
normal temperatures, clear skies, and offshore flow. A strong
upper-level ridge dominates the region. The ridge has been
amplified in part by surrounding upper-level troughs over the
Gulf of Alaska, the Rockies, and southern California. This
pattern has reinforced the warm, dry airmass in place across the
Pacific Northwest.
Offshore flow remains today, but not nearly as strong as
Tuesday. Will still see gusty winds within the typical areas
like the Columbia River Gorge and some of the Cascade Passes
through the early afternoon. The ridge begins to break down
today though which will cause winds to shift to an onshore flow
pattern. This transition will occur later in the day so will
have minimal impact on temperatures and humidity. Still
expecting above normal highs today, especially in the Willamette
Valley where the thermal trough will set up. Have trended
towards a "persistence" high temperature forecast incorporating
some of the local effects from Tuesday`s observations.
If you`re more in the mood for more typical early fall
weather, you will be pleased with Thursday and Friday. The
ridge continues to break down becoming more zonal into Friday
which will promote onshore flow, and a cooler air mass. Winds
will be elevated within the Columbia River Gorge - especially
near the Upper Hood River Valley. 850 mb temperatures will
settle in at 7 deg C on Thursday, and around 12 deg C on Friday.
This will bring highs into the mid 70s inland, and the 60s
along the coast. There is fairly good agreement in ensembles in
the temperature forecast on both Thursday and Friday with only a
5 deg F spread between the 25th-75th percentile. One caveat to
this forecast though is where the upper level low over
California ends up. There continues to be strong consistency in
the low tracking further south. However, if it takes a
northerly shift, the ridge is less likely to break down and thus
temperatures will be more consistent to what is expected today.
This is a low probability scenario though. -Muessle
.LONG TERM...Saturday through Tuesday...The trend of a pattern
shift over the weekend is still on track though maybe a bit less
of a pendulum as what was previously forecast. The zonal flow
will be maintained through Saturday which will keep conditions a
bit more seasonable and mild. Through the day though, a long
wave trough will advect over the northeast Pacific bringing with
it precipitation and much cooler temperatures. This cold front
is not expected to make landfall until Sunday afternoon. Rain
will initially start over the north Oregon and south Washington
Coast, then shift southeastward through the day. There is still
some uncertainty though in the rain onset time. While a majority
of models show rain starting either late Saturday (northern
coastal locations) or Sunday afternoon (southern portions of the
area), there is a 10% chance that the northern coast could see
rain as early as Friday night. In contrast, there is equal
probability of rain not arriving until late Sunday night or even
early Monday morning. This uncertainty is due to the speed of
the front, the strength, and how it will overcome the lingering
impacts of the ridge. There is some concern that this first
system - yes first - could act as a sacrifice and therefore
preparing the environment for another weather system.
Models are beginning to show a secondary trough and an almost
separate cold front moving in directly behind the first. This
is likely where some of the discontinuity in models is stemming
from. This frontal system appears to be slightly stronger with
more rainfall potential. At this point it is too early to tell
what the impacts of this front will be but if it does behave
like a typical cold air wrapped low, will see an increase of
southerly flow and potential for more convective weather.
-Muessle
&&
.AVIATION...High pressure will maintain VFR conditions for most of
the area. Satellite shows some areas of very patchy cloud cover
but that has been concentrated along the coast and the central
Willamette Valley. Even with this cloud cover, only coastal
terminals are experiencing IFR CIGS. Winds through the Columbia
River Gorge and east- west oriented Cascade gaps remain easterly
but gradually shift onshore after 00Z Wednesday. Winds less than
10 kts expected through the period. Along the coast and inland
through the Willamette Valley winds will be more northerly. While
they will start off light (less than 5 kt), they will increase in
the afternoon with daytime heating. Will see gusts up to 20 kt
with the gustiest conditions from KTMK south, and KSLE south
inland.
After 06Z Thursday winds will become offshore which will bring in
added moisture and increase the probability for areas of fog.
KPDX AND APPROACHES...Northerly winds through the period. For
eastern approaches, will see more of an offshore wind above 1000
ft AGL, but not expected to exceed 15 kt. Vertical wind profile
will shift northerly after 03Z Thursday.-Muessle
&&
.MARINE...Surface high pressure offshore will continue to yield
northerly flow into the weekend. A tightening coastal pressure
gradient will see winds increase this morning. Winds of 15-20 kt
with gusts of 25 kt will be widespread in the outer waters until
this afternoon when they increase further with gusts up to 30 kt.
The highest wind speeds will be from Cape Falcon southward. This
trend rings true for the inner waters as well though they will
maintain more of a widespread gust up to 25 kt. Seas of 6-9 ft
build to 7-10 ft as winds strengthen. Small Craft Advisories
therefore remain in effect beyond 10 NM, and will go into effect
at 11 AM PDT Wednesday closer to shore, continuing through early
Thursday morning. Conditions will ease Thursday and Friday before
building again ahead of an approaching frontal system this
weekend. -Muessle/Picard
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory from 11 AM this morning to 5 AM PDT
     Thursday for PZZ251>253.
     Small Craft Advisory until 5 AM PDT Thursday for PZZ271>273.
&&
$$
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NWS PQR Office Area Forecast Discussion