423
FXUS66 KPQR 222240
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
240 PM PST Wed Jan 22 2025

.SYNOPSIS...High pressure persists, bringing clear skies and
another chilly, frost night. We`ll see increasing clouds as a
shortwave trough drops south from Canada, but little to no
precipitation is expected for our area. Dry weather with chilly
nights continue through early next week. At this point, no
winter weather concerns.

&&

.SHORT TERM...Now through Friday...High pressure over the West
Coast U.S. continues to dominate the area and bring dry weather
and sunny skies. Tonight will be chilly again as clear
conditions leads to efficient radiational cooling. Lows are
forecast in the mid to upper 20s for most interior lowland areas
west of the Cascades. Will note that the low temperature
forecast was nudged toward the 10th percentile NBM since models
have been running warmer than actual observations the previous
few nights. Since "feels-like" temperatures are forecast between
20 to 25 degrees for many places, a Cold Weather Advisory has
been issued again west of the high Cascades from 10 PM Wednesday
to 10 AM Thursday. Frost also continues to be a possibility,
especially on exposed metal surfaces and shaded areas.

Pressure gradients between KTTD and the KDLS will tighten again
tonight, strengthening easterly winds through the Columbia River
Gorge. Easterly wind gusts are forecast around 35 to 45 mph
through the Gorge, and 25 to 35 mph across the eastern
Portland/Vancouver Metro Area. Although winds will provide more
mixing to keep overnight temperatures in the low 30s in the
east metro, wind chills could fall as low as 20 to 25 degrees.

Tomorrow (Thursday), the upper level ridge over the area will
begin to flatten as a shortwave trough dips down from western
Canada. This will bring increasing cloud cover over the area,
but we`ll most likely remain dry. The ridge is so strong that
it just degrades the trough. There remains a 15-30% chance of
light snow Thursday night into Friday over the Cascades, but
little to no accumulation expected.       -Alviz

&&

.LONG TERM...Friday night through Tuesday...The shortwave trough
will drop southward and out of the area early Saturday morning
causing winds aloft to return to the east and surface winds to
the north. There is another hint of breezy easterly winds on
Saturday during this transition but confidence is low. Rinse and
repeat of this week is expected Saturday night through Sunday.
Will see a steady decline in temperatures as high pressure once
again builds. Coldest overnight temperatures expected Sunday
morning with lows ranging from near freezing along the Coast, to
near 25 degrees F in the Willamette Valley. Ultimately, these
temperatures are similar to what we have seen over the last
week. Minimal change through early in the week.      -Muessle

&&

.AVIATION... Widespread VFR conditions persist as high pressure
remains anchored over the Pacific Northwest. Clear skies, along
with sub-freezing temperatures during the overnight hours will
likely result in frost developing on exposed surfaces. Currently,
not expecting significant frost accretion at this time. There
could be some very isolated areas of freezing fog, but am not
expecting any to impact the terminals.

PDX AND APPROACHES...VFR conditions to persist with light and
variable winds. Clear skies, along with sub-freezing temperatures
during the overnight hours will likely result in frost developing
on exposed surfaces. Minimal frost accumulation expected at this
time.     /42

&&

.MARINE...A ridge of high pressure overhead will maintain calm
conditions and produce northeasterly winds with gusts up to 30 kt
for zones PZZ272 and PZZ273 on Thursday into Friday due to a weak
weather disturbance clipping the region from British Columbia.
Seas around 4-7 ft before building towards 8-10 ft on Friday. with
the highest seas expected in the outer waters. Seas ease 5-8 ft
range for the weekend as the ridge of high pressure strengthens,
along with breezy north/northeast winds Saturday and into the
start of the upcoming week. Highest winds are expected over the
southern outer waters where small craft wind gusts up to 30 kt
are likely to occur (60-80% probability). Overall it appears
this rather benign winter-time weather pattern likely persists
into at least the early to middle portion of next week.
                                                 /42-Schuldt

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...Cold Weather Advisory from 10 PM this evening to 10 AM PST
     Thursday for ORZ104>118-123>125.

WA...Cold Weather Advisory from 10 PM this evening to 10 AM PST
     Thursday for WAZ203>208.

PZ...Small Craft Advisory from 10 AM Thursday to midnight PST
     Thursday night for PZZ272-273.
&&

$$

www.weather.gov/portland

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