318
FXUS66 KPQR 022223
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
221 PM PST Thu Jan 2 2025

.SYNOPSIS...Rain continues overnight, as cold front offshore
approaches. Meanwhile, snow and areas of freezing rain will continue
in the Hood River Valley and across low valleys of Skamania County
where chilly air persists overnight. Front will push across region
early Friday, with rain transitioning to showers. Snow levels will
briefing go above passes tonight, then drop back to 3500 feet on
Friday, with more snow in the Cascades. Unsettled weather continues
through Sunday. But, dry weather awaits us for next week. We hope.
&&

.SHORT TERM...(Thursday afternoon through Saturday)...
What a drippy day it has been. This as warm front has been slowly
pushing across the region. Light rain and drizzle continues, through
will ease up for a brief time later this afternoon into this evening
as the warm front lifts across the region and we await a cold front.

Offshore flow continues in/around the Columbia River Gorge, where
chilly air and temperatures in the 30s persist. Hood River still at
32 deg, with occasional snow. Have had reports of sticking snow down
as low as 500 feet in the Hood River Valley and lower valleys into
southeast Skamania County. Did push up the start of the Winter
Weather Advisory to noon today to cover the earlier arrival this. As
the warm lifts across the region this evening, will see snow levels
rise, likely to 6000 feet or higher by midnight. That will bring an
end to the snow for those lowlands. But, the chilly air will remain.
As such, the rain will be falling into an air mass with temperatures
at/just below freezing. So, will have area of freezing rain between
500 and 2000 ft across the Hood River Valley, and into the low
valleys of southeast Skamania County. When all said and done, think
snow accumulations across this area will be 1 to 4 inches, with 0.10
to 0.33 inch of ice accumulations. Temperatures will warm a bit
Friday, but mainly precipitation becoming more showery, any ice
accumulations will not be all that impactful after mid-morning.
Bottom line, be prepared for icy conditions through 9 am Fri.

For rest of the region, rain will increase overnight as the cold
front well offshore approaches. Still breezy in/near the Columbia
River Gorge, with east winds gusting 30 to 35 mph in east
Portland/Vancouver metro, and gusts 35 to 50 mph at more exposed
spots in the west Gorge. Gradients tighten up a bit more this
evening, and give an uptick in the winds (gusts 30 to 40 mph east
metro, and 45 to 60 mph in western Gorge).

Cold front will push onshore late tonight, then lift inland across
region early Fri am. Will see rain transition to showers at that
time. Could be rather breezy along the coast as well, as south winds
return, with gusts to 35 to 50 mph, with highest on the usual
headlands. Showery day on tap across the region Friday, with snow
levels dropping, generally 4000 to 4500 feet by mid-afternoon.

Pattern such that will see another fast moving weather system push
across region later Friday night into early Saturday, with a period
of rain and mountain snow. Showery for a time on Saturday, but
another system arriving late in the day will bring rain back to the
region, along with more snow for the Cascades. Total snowfall for the
Cascades:  6 to 12 inches on the passes, with 1 to 2 feet for the
higher elevations (above 6000 ft).      /Rockey

.LONG TERM...Sunday through Wednesday...Showers will persist
through Saturday morning then high pressure builds in. Cluster
analysis shows an amplified pattern developing early to middle
of next week with ridging across the West Coast. Could have a
stretch of mild and dryish conditions which is supported by the
Climate Prediction Center (CPC) projecting a tad warmer than normal,
and dry for next week. Highs for inland valleys ranging from upper
40s to low 50s expected with overnight lows in the upper 30s to lower
40s.      /Batz

&&

.AVIATION...Front is currently passing through, with steady rain
at all terminals. Conditions still generally a mix of VFR/MVFR,
but stronger bands of moisture will briefly drop visibilities to
IFR at times. Offshore winds continue during frontal passage,
with northeasterly flow under 10 kts everywhere but the Columbia
River Gorge (easterly gusts to 30 kt at KTTD). Frontal passage
continues until 16-20z Fri, and a transition to more showery
post-frontal rain is expected then. Cigs remain generally MVFR
afterwards, and winds pick up from the south. Southerly gusts up
to 20-25 kt will be possible then.

PDX AND APPROACHES...Mixed VFR/MVFR cigs throughout the frontal
passage, with high res ensemble guidance showing a 30-40% chance
for MVFR ceilings through 05z Fri. After this time, better
agreement on MVFR ceilings as a second, slightly stronger wave of
rain arrives. At this time, winds will shift southerly and
increase to gusts up to 25 kt. /JLiu

&&

.MARINE...Relatively quiet marine conditions today (Thursday) as a
weak surface low brings rain and non-impactful winds. As the low
tracks to our south, southerly winds over the waters will turn
more easterly this afternoon. Pressure gradients are not looking
tight today, so winds are forecast around 10-15 kt. Seas will be
around 8-9 ft at 14 sec today, but a westerly swell will move in
and build seas to 10-11 ft by this evening.

A more robust low pressure system approaches the region tonight
into Friday, but remains offshore as it moves north toward
Vancouver Island. It will push a front across the waters on
Friday, tightening pressure gradients and returning southerly to
southeasterly winds with wind gusts up to 30 kt. Occasional gusts
up to 35 kt are possible across the waters (15-20% chance). Seas
will also build to around 12-14 ft at 16 seconds. Another
disturbance arrives Saturday morning, and elevated winds up to 30
kt will be possible through Saturday evening. As a result, the
Small Craft Advisory has been extended through Saturday 10pm. High
pressure begins to build on Sunday, and more benign conditions are
expected through early next week.
-Alviz/JLiu

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...Winter Weather Advisory through 4 PM FRI for ORZ121-126.

WA...Winter Weather Advisory through 4 PM PST for WAZ211.

PZ...Small Craft Advisory until 4 PM FRI for
 PZZ210-251>253-271>273.
&&



$$

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