008
FXUS66 KPQR 130439
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
939 PM PDT Wed Jun 12 2024

UPDATED AVIATION DISCUSSION

.SYNOPSIS...
High pressure offshore maintains seasonably warm and
dry conditions through Thursday. Low pressure then brings cool
and showery weather Friday into the early part of next week,
with a slight chance of thunderstorms Saturday into Sunday.
Temperatures look to rebound near or above seasonal normals by
the middle of next week.

&&

.SHORT TERM...Now through Friday Night...
Now through Friday Night...Plenty of sunshine
across the area today as morning cloud cover has been scoured
out by dry northerly flow with high pressure anchored offshore
as of early Wednesday afternoon. This has allowed temperatures
to climb well into the 70s across the interior lowlands. Not
much change expected through Thursday as high pressure remains
offshore and maintains warm and dry weather. Continued drying of
the air mass will result in less cloud cover tonight into
Thursday morning, which will in turn allow temperatures to climb
a couple degrees higher on Thursday afternoon. Generally expect
highs to top out in the upper 70s away from the coast, with
probabilistic guidance showing a 25-30 percent chance to reach
80s degrees across the Portland metro for Thursday.

Expect a pattern shift back towards cooler and cloudier weather
on Friday as an upper level trough currently over the Gulf of
Alaska descends upon the Pacific Northwest. This will drop
temperatures back near or slightly below seasonal norms with
highs in the upper 60s or low 70s and also bring a chance of
showers as a weak front moves through the area. Shower chances
look to be generally confined to areas along and north of a
Lincoln City-Portland-Mt St Helens line through Friday evening
before more widespread shower activity spreads across the area
Friday night. Model QPF remains on the light side, ranging from
0.25-0.50" in the higher terrain but generally closer to a
tenth of an inch or less for all other locations through
Saturday morning. /CB

.LONG TERM...Saturday through Wednesday...WPC ensemble clusters
remain in strong agreement on maintaining upper level troughing
and a resulting cool, cloudy and showery pattern over the
Pacific Northwest this weekend through the early part of next
week. This is reflected in ensemble temperature forecasts which
keep the area below normal with highs in the 60s through at
least Monday. Cold air aloft will maintain showery conditions
into Tuesday, though these look to be mainly spotty in nature
with model QPF amounts remaining light through the period.
Guidance indicates a 15-25 percent chance for a few rumbles of
thunder across the north both Saturday and Sunday afternoon,
which will largely be dependent on if there are enough sun
breaks to allow for adequate destabilization. Temperatures look
to rebound into the 70s next Tuesday and Wednesday as the
majority of ensemble clusters depict the trough starting to
shift east of the region by midweek. /CB

&&

.AVIATION...High pressure will remain in control of the area,
which is expected to maintain VFR conditions through the TAF
period. Winds along the coast will remain N/NW at 10-15 kts and
gusts around 20 kts late this evening and early tonight. Winds
will relax after 8-10Z to around 10 knots through the remainder of
the night. Winds within the Willamette Valley will also remain
N/NW at 5-10 knots, becoming light and variable after 8Z.

HREF guidance indicates possible development of marine stratus,
mainly in the vicinity of KONP at 30-50% after 8-9Z. There are
also lower chances of 10-20% around KAST and some development
along the foothills in the western Willamette Valley with a 20-30%
chance near KTTD from 12-16Z. Will hold off on adding any stratus
at the inland TAF sites and KAST but will add in a broken stratus
deck at KONP after 10Z based on guidance.


PDX AND APPROACHES...Predominantly VFR and clear skies throughout
the TAF period. N/NW winds will become light and variable
overnight. A few wind gusts around 20 kts will be possible at PDX
early on. -Batz

&&

.MARINE...
A Small Craft Advisory for the Columbia Bar will remain
in effect until midnight tonight, with winds gusting to 20 to 25
kt. Wind-driven Small Craft Advisory will be maintained until
Thursday night for the inner and outer waters. Seas are currently
around 7-9 feet at 10 seconds, with northerly winds gusting up to
25 kt, increasing to near 30 kt this evening into tonight.
Thursday, winds will gust up to 25 kt, then decrease below Small
Craft Advisory criteria by Thursday night. Seas will have settled
to 5 to 7 ft around this time, but may remain choppy. Next front
will arrive late Friday, shifting winds back to westerly at 10 to
15 kt for late Friday into early Sunday.
-JH

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory until midnight PDT tonight for PZZ210.
     Small Craft Advisory until 11 PM PDT Thursday for PZZ251>253-
     271>273.
&&

$$

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