333
FXUS66 KPQR 062256
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
256 PM PST Thu Mar 6 2025

.SYNOPSIS...
Mostly dry conditions expected through the end of
the week. Expect warmer temps above normal over the weekend.
The next weather system will bring increasing chances for light
rain late Sunday into early next week, with potentially more
active weather returning later in the week.

&&

.DISCUSSION...Now through Wednesday...An upper level ridge
continues to move over the region today, resulting in high
pressure giving way to dry northerly flow throughout the region.
With mostly clear to partly cloudy skies today, expect afternoon
temps to reach the mid to upper 50s in the lowland valleys and
low to mid 50s along the coast. Additionally, could see patchy
fog develop tonight into Friday morning, specifically after
midnight.

Saturday into Sunday, a weak frontal system will move eastward
through our coastal waters, shifting winds southerly. This
front will pivot, with the north part of the front stalling
around Vancouver Island and the southern part swinging toward
our coast. As a result, expect light rain to arrive at the coast
(from north to south) Saturday night and spread inland by late
Sunday. Specifically, should receive under 0.25 inches of rain
along the coast and under 0.10 inches of rain inland between 10
PM Saturday and 10 PM Sunday. With current guidance suggesting a
split flow pattern beginning Sunday, there is moderate
confidence in receiving much less precipitation. With models
trending towards dry and southerly flow persisting over the
weekend, expect afternoon temps in the low 60s Saturday and
Sunday.

Monday and onward, there is generally less agreement between
models. Recent cluster analysis suggests a 50-70% probability
for a split-flow pattern to develop with an upper level cut-off
low off of California by late Sunday into early Monday. This
split flow would result in the front weakening as it moves
through our waters and inland, resulting in relatively drier
weather on Monday. NBM members show some uncertainty in the
pattern given the split between wet and dry members Sunday into
Monday. Around 10-30% of members suggest precip to begin inland
during Sunday afternoon and around 50-70% of members suggest
precip beginning late Sunday night / early Monday morning. With
all considered, there is low to moderate confidence for timing
and strength of this weakening frontal system during Sunday
night into Monday morning. Will have to wait for models/clusters
to come into better agreement to have higher confidence, but
currently there is little to no impacts expected.

More active weather possible for the middle of next week as
guidance suggests a shortwave trough arriving early Tuesday,
and then an approaching low pressure system that digs south as
it approaches the region by late Tuesday through Wednesday.
While there is uncertainty this far out, clusters have decent
agreement for an upper level trough to persist. This would
result in temps at or slightly below normal, as well as
increased rainfall in the lowland valleys and more snow in the
mountains. The digging low pressure system on Tuesday night
into Wednesday is the next system we will be keeping a close eye
on, as current guidance suggests a 10-20% chance for impactful
winds on Wednesday. The closer the low develops near the Oregon
coast, the higher chances for impactful winds. As more ensemble
members come into better agreement, there will be high
confidence regarding how strong the winds will be and what
impacts to expect.                                     ~Hall

&&

.AVIATION...High pressure will maintain VFR thresholds under clear
skies through late Thursday night. Expect northerly to northwesterly
winds at all terminals through this evening, generally under 10 kt
across the Willamette Valley. Along the coast, expect gusts up to
20 kt this afternoon, but easing pressure gradients should
support weakening winds after 01-03z Fri.

Tonight, the low level atmosphere will moisten and likely support
a return of MVFR stratus along the coast after 12z Fri. Valley
terminals also have a 20-40% chance of MVFR CIGs or lower after
12z Fri. Do have moderate to high confidence that Valley terminals
could at least see FEW/SCT low-level clouds early Friday morning.
Expect variable winds under 5 kt tonight across the area.

PDX AND APPROACHES...Predominately VFR thresholds through the TAF
period. 30-40% chance of MVFR CIGs or lower after 12z Fri.
Northwest winds 6-9 kt this afternoon becoming variable under 5
kt tonight.       -Alviz

&&

.MARINE...High pressure over the waters will maintain breezy
northerly/northwesterly winds through this evening with gusts up
to 25 kt and seas 8-10 ft at 12 seconds. The Small Craft Advisory
remains in effect across the waters through 10 PM Thursday.
Pressure gradients ease tonight, resulting in winds weakening
below 10 kt. Seas will also subside to 6-7 ft at 11 seconds by
Friday morning as the westerly swell diminishes.

The next front is forecast to approach the waters late Friday
into Saturday, returning breezy southerly winds with gusts up to
30 kt. Another westerly swell will push through the waters,
building seas to 10-13 ft at 14-15 seconds. There is increasing
confidence that this westerly swell could produce a high sneaker
wave threat this weekend, which may warrant a beach hazards
headline with future updates.         -Alviz

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...Small Craft Advisory until 10 PM PST this evening for PZZ251>253-
     271>273.
&&

$$

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