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882
FXUS66 KPQR 182122
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
222 PM PDT Wed Sep 18 2024

.SYNOPSIS...
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High pressure returns, bringing dry weather with
near to slightly below normal temperatures through the end of
the week. Another front will bring a chance of showers Sunday
into Monday. Warmer and drier conditions possible next week,
however some uncertainty remains with the weather pattern.
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.SHORT TERM...
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Now through Friday Night...Satellite imagery and
surface weather observations as of early Wednesday afternoon
depict dry conditions with lingering scattered/broken clouds as
yesterday`s upper level trough exits the region. As high pressure
re-builds over the NE Pacific and Pacific Northwest, expect
decreasing clouds through the early evening. Winds will be out
of the north/northwest with the strongest gusts (up to 20 mph)
through the Columbia River Gorge. High temps this afternoon will
re-bound into the low to mid 70s for interior lowland valleys
(slightly below normal) and mid to upper 60s along the coast.

Expect dry weather with mostly sunny skies Thursday to Friday
as high pressure remains over the area. Light to moderate
onshore flow continues, with the strongest gusts again through
the Gorge and Upper Hood River Valley area. Each night, could
see some patchy fog development along with low clouds overnight
into the early morning hours. Low temperatures are forecast in
the 40s to mid 50s, with afternoon high temps similar to today.
Overall, we`ll have pleasant days to end the week.     -Alviz
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.LONG TERM...
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Saturday through Wednesday...Lingering uncertainty
this weekend into the early part of next week as medium and long
range guidance continues to diverge with respect to how the
pattern will evolve beyond Friday. That said, ensemble clusters
have started to slightly favor a warmer and drier pattern for
Saturday and beyond, with about two thirds of solutions now
indicating a ridgier pattern while the other third still depict
troughing or more zonal flow. As a result, NBM interquartile
ranges for temperatures have narrowed to show inland high
temperatures most likely residing in the mid to upper 70s
Saturday through Monday. Precipitation chances have also gone
down as models hint at upper level ridging, but NBM mean
guidance still carries chance to slight chance PoPs across
mainly the northern half of the area late Sunday into early
Monday, which reflects the below normal forecast confidence.
Model agreement actually increases towards the beginning of next
week as ensemble clusters show about 90 percent of solutions
favoring some degree of upper level ridging over the Pacific
Northwest for Monday and Tuesday. As such, Tuesday looks to be
the warmest day in the next week with highs possibly reaching
into the mid 80s in the interior valleys. Models start to
diverge again beyond Tuesday as guidance is split between
another trough and a more gradual breakdown of the ridge.   /CB
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.AVIATION...
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Northeast flow aloft as upper ridge of high pressure
gradually builds over the region today. As of 21z Wednesday, skies
are becoming predominately VFR with some lingering higher-end
MVFR CIGs. Stratus is expected to develop again at the coast
around 03-05z Thursday with conditions likely (60-80%)
deteriorating to IFR tonight. Stratus also likely (60-80%)
builds across inland terminals after 12z Thursday with MVFR CIGs
trending toward 1500-2000 ft. Generally expect north to
northwest winds, increasing to around 10 kt this afternoon.

PDX APPROACHES...Predominately VFR expected through this evening
as broken stratus has lifted to around FL040-050. MVFR stratus
likely (60-70% chance) to redevelop after 12z Thursday. Expect
northwest winds to around 6-8 kt through this evening.    /DH
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&&

.MARINE...
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High pressure has returned to the coastal waters,
resulting in increased northerly winds today, likely continuing
through the week. Winds may gust up to 20-25 kt at times tonight,
especially over the outer coastal waters. Wind gusts to 25 kt
becomes more likely by Thursday afternoon as the thermal trough
strengthens over the southern Oregon coast. Have issued a Small
Craft Advisory to cover the increased winds and choppy seas
expected through Thursday night. Pressure gradients across the
coastal waters weaken somewhat over the weekend, likely resulting
in a decrease in north to northwest wind speeds.

A persistent northwest swell around 5 to 7 ft is expected to
continue through late week. Seas around 5 to 6 ft today likely
increase to around 7 to 8 ft Thursday through Friday, with a
dominant period of around 8 to 9 seconds. Seas then expected to
subside back to around 5 to 6 ft for the weekend.    /DH
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&&

.PQR WATCHES/WARNINGS/ADVISORIES...

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OR...None.
WA...None.
PZ...Small Craft Advisory until 9 PM PDT this evening for PZZ210.

     Small Craft Advisory from noon to 11 PM PDT Thursday for PZZ253.

     Small Craft Advisory from noon Thursday to 5 AM PDT Friday for
     PZZ271>273.
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&&

$$

www.weather.gov/portland

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