257
FXUS66 KPQR 281032
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
332 AM PDT Fri Jun 28 2024

.SYNOPSIS...Warm and dry conditions return today, with
temperatures warming into the upper 70s and low 80s for interior
valleys and upper 60s along the coast. Another shortwave trough
returns Saturday night into Sunday, bringing a 15-25% chance of
showers, mainly for the coast and higher terrain. Consistently
warm and dry conditions continue through next week.
Temperatures begin to rise Thursday, but uncertainty remains
with how warm we will get.

&&

.SHORT TERM...Friday through Sunday...Dry weather has returned
to NW Oregon and SW Washington as fairly zonal upper level flow
takes shape over the region into tomorrow. Winds aloft and at
the surface have shifted northerly and will remain in this
light offshore pattern today. Daytime temperatures will warm
nearly 10 degrees inland from yesterday`s temperatures under
sunny skies and with the warming north winds. Expect 60s along
the coast and upper 70s to low 80s across the inland valleys.
NBM indicates a 60-70% probability of temperatures exceeding 80
degrees for the Willamette Valley and a 15-30% for reaching 85
degrees.

Saturday remains warm with temperatures rising a couple
degrees. NBM probabilities for exceeding 80 degrees and 85
degrees in the Willamette Valley increase to 70-80% and 35-50%
respectively. Temperatures along the coast will remain fairly
steady in the 60s as winds will turn more westerly from a broad
trough deepening into the eastern Pacific and approaching the
region. Clouds will begin spreading over the region through the
day, which could potentially keep temperatures from rising as
much as expected depending on how thick the cloud cover is.

The upper trough moves inland Sunday, though ensemble guidance
continues weakening the forcing and shower chances. Latest
guidance indicates only a 10-25% chance of showers for the
northern Cascades and Coast Range due to orographic forcing,
though some drizzle is possible along the coast. Any
accumulation will be very limited. Temperatures will fall a few
degrees back to near normal with upper 70s in the inland valleys
and upper 50s to 60s along the coast. -HEC

.LONG TERM...Monday through Friday...As the trough passes to
the east on Monday, WPC clusters are in very good agreement of
upper ridging building over the Eastern Pacific Monday into
Wednesday with mostly zonal flow continuing over the PacNW.
This is expected to keep temperatures pretty steady with 60s
along the coast and upper 70s to low 80s inland. Beyond
Wednesday, uncertainty remains on whether the ridging will
spread east inland or remain out over the ocean. Nearly all
clusters show the ridging moving east at some point into
Friday, but strength of the ridge as well as timing varies
drastically. As such, NBM high temperature spreads for inland
areas range anywhere from around 80 degrees for the 25th
percentile to the low 90s for the 75th percentile for the 4th of
July holiday and the following Friday. Current deterministic
NBM forecast hedges temperatures to the upper 80s which. -HEC

&&

.AVIATION...Conditions across the area should remain mainly VFR
through the day. Broken stratus can be seen below some of the
midlevel clouds on satellite imagery, mainly along the northern
Oregon and southwest Washington coasts/coast range and lesser so
over the cascades. This bit of stratus is around 3000 ft
according to the KAST observations from the past 6 hours. HREF
guidance suggests this sticking around until around 18-20Z. HREF
guidance also suggests a chance (30-50%) for a short period of
MVFR CIGs inland between 12-17Z. High pressure offshore will build
toward the PNW coast through the day, supporting northwest winds
at 10-15 kts along the coast and northerly winds inland around 10
kts.

PDX AND APPROACHES...Mainly VFR conditions are expected, though
HREF guidance does suggest a chance (30-50%) for MVFR CIGs around
12-17Z, with the highest probabilities around PDX and TTD. Light
and variable winds will become northerly around 5-10 kts today as
high pressure builds. -Batz

&&

.MARINE...High pressure offshore will continue to build towards
the PNW coast today, supporting N/NW winds at 10-15 kts. At same
time, thermal low pressure will remain over far southwest Oregon
into northwest California. As such, will get back into some
northerly winds, with gusts up to 20 kt Friday afternoon, mainly
south of Tillamook. Overall, seas staying in the 4 to 5 ft range.

Yet another weak low pressure arrives later Sat, with winds
flipping back to the west or southwest. Gradients weaker, so winds
not expected above 15 kt, while seas stay at 4 to 6 ft. Next
week, will see high pressure offshore build, along with the
potential for a stronger thermal low along the south Oregon coast,
possible reaching to the north. This would tighten the pressure
gradient, possibly enough for wind gusts to reach 25-30 kts,
warranting a small Craft Advisory. Time frame to keep in mind is
next Wednesday and beyond. -Batz

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...None.

&&

$$

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