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000
FXUS66 KPQR 150429 AAA
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
930 PM PDT Sun Apr 14 2024

Updated Aviation discussion

.SYNOPSIS...
Weak showers over the Willamette National Forest and the
foothills end Sunday afternoon/evening. Another upper level
trough passes through central Washington into the Rocky
Mountains, clipping us with some insubstantial showers Monday
and Tuesday. High pressure will build back in afterwards,
keeping things generally dry and warmer until the weekend.
Possibly more rain over next weekend, but confidence is low.

&&

.SHORT TERM...THROUGH TUESDAY NIGHT...A few weak showers in the
central and southern Oregon Cascades have all but ended, and all
other areas are just dry with intermittent cloud cover. Today
will be the last day of slightly elevated temperatures, with
highs pushing up into the mid to 60s for most of the Willamette
Valley, closer to 60 south of Corvallis and at the coast. No
impactful weather is expected Monday night.

Late Sunday night, we begin to see a few very insubstantial rain
showers in the northern part of the region as onshore flow
develops and a weak trough passes north of us, with the southern
edges of moisture barely clipping us. QPF looks little-to-none,
but the northern Oregon Cascades could see maybe some slightly
more substantial accumulations due to orographic lift. Snow
levels will begin around 3000 ft Monday, dropping to 1500-2000
Tuesday night. Regardless, with such weak moisture, a dusting of
snow is all that could be expected above. Daytime temperatures
in the mid to upper 50s are expected for most lowland areas
during this time. /JLiu

.LONG TERM...WEDNESDAY THROUGH SATURDAY...The ridging pattern
continues through the rest of the next workweek, with warmer
temperatures and dry conditions. Temperatures on Thursday and
Friday look to become warm again, with With a shift to offshore
flow beginning Thursday, breezy winds through the Columbia
Gorge will be possible; gusts up to 25-30mph will be possible
Thursday midday through Saturday morning.

On Saturday, while ensemble guidance is still pointing mostly
towards ridging continuing, there does appear to be the
possibily of another trough developing off west in the Pacific
Ocean. There`s a 20% chance this trough approaching close
enough to begin developing some light rain showers and cooler
temperatures. On Sunday, chance of a trough being in place
increases to around 30%. /JLiu

&&

..AVIATION...Northwest flow aloft tonight as weak upper level ridge
shifts over the region. Low level onshore flow will maintain
marine stratus at the coast through Monday morning, while MVFR
CIGS around 2000-3000 ft are likely through at least 12Z Monday.
Low stratus also expected to backbuild across the Willamette
Valley tonight but likely remain VFR, with a 20-40% chance of
MVFR conditions through 18Z. A weak front moves across the area
Monday morning with very light showers possible. CIGS expected to
lift through Monday afternoon with predominately VFR conditions
expected after 18Z Monday. Northwest winds again increase along
the coast with gusts up to 20 kt after 18Z Monday.

PDX AND APPROACHES...Predominately VFR expected through the TAF
period with stratus building across the area tonight. CIGS likely
remain around 3500-5000 ft, although there is a 20-30% chance of
MVFR conditions between 10-18Z Monday. Northwest winds around 5-10
kt through the period, strongest during afternoon and evening
hours. /DH

&&

.MARINE...Weak ridging slowly builds through the overnight hours
as a cut-off low continues to push into the Great Basin. This will
result in the northerly winds to slacken and become more
northwesterly/westerly into Monday. Persistent NNW-NW winds will
remain with gusts up to 25 knots across all waters Also, a NW
swell at 7-9 feet with a period of 8-10 seconds will cause 8 to 10
ft seas through at least Monday morning. As a result, will
maintain the Small Craft Advisories for all waters through at
least late tonight.

As the aforementioned high pressure builds over the region expect
winds and seas to subside from south to north. Have tried to time
out the Small Craft Advisories to represent this. Late Monday
night/early Tuesday, benign conditions will have settled in
resulting in NW winds with gusts around 20 kt and seas of 6-8 ft.
Wednesday, there will be a small pattern change as an upper level
system moves southeastward from Canada. This will bring NE winds
to all waters, with a 50-60% probability of Small Craft wind
gusts for the outer waters. Towards the end of the week, models
are showing a ridging pattern developing which in turn could lead
towards offshore flow. /42

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...Small Craft Advisory until 11 AM PDT Monday for PZZ210-251-271.

     Small Craft Advisory until 3 AM PDT Monday for PZZ252-253.

     Small Craft Advisory until midnight PDT tonight for PZZ272-273.
&&

$$

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