571
FXUS66 KPQR 100438
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
938 PM PDT Wed Jul 9 2025

Updated aviation discussion.

.SYNOPSIS...A weak front will bring clouds and chances for
showers along the north Oregon and south Washington coast this
afternoon. Dry with seasonable temperatures for interior
valleys this afternoon and Thursday. High pressure builds Friday
into the weekend, leading to much warmer temperatures. Hotter
temperatures possible early next week with light offshore flow.

&&

.SHORT TERM...Now through Friday night...Satellite imagery as of
early Wednesday afternoon depicts a weak cold front moving
through the north Oregon and south Washington coast from the
northeast Pacific. So far, there have been some observations of
rainfall along the coast, but amounts have been minimal (around
0.05" or less). A 15-30% chance for showers along the north
Oregon and south Washington coast remain through the afternoon,
with conditions drying up in the evening as the front further
weakens. Not expecting any precipitation for inland locations;
just mostly sunny skies mainly south of Salem, and partly cloudy
conditions Salem northward due to the front. Temperatures are
forecast to be near or slightly below seasonal norms, generally
in the upper 70s to low 80s for interior valleys of Oregon, and
low to mid 70s across the southwest Washington lowlands due to
cloud cover. Mild conditions persist along the coast with
onshore flow.

Thursday remains dry and warm as high pressure begins to re-
build. Could see some morning clouds, but those clouds should
beginning dissipating throughout the day as daytime heating
ramps up. High temperatures are forecast similar to today,
though temps along the coast are forecast few degrees warmer
since there will be no front passing through. Friday, high
pressure amplifies further, leading to much warmer temperatures
with highs forecast in the upper 80s to low 90s heading into the
weekend.       -Alviz

&&

.LONG TERM...Saturday through Tuesday...For the weekend, the
heat is  on. WPC 500 mb cluster guidance continues to show very
good agreement as a ridge of high pressure building and
strengthening over the Eastern Pacific and Pac NW through at
least early next week. There are some slight variations in exact
strength and placement of the ridge over the region, but a
prolonged period of upper 80s to low 90s throughout the
Willamette Valley look good. It should also be noted that as
next week progresses, there is a very high probability of areas
within the Willamette Valley reaching the first day(s) with
triple digits daytime highs.

Probabilities for highs to reach 95 or greater from Salem to
Eugene  on Saturday are 35-60%, on Sunday it is 65-85% and on
Monday it is 30-50%. Probabilities around the Portland/Vancouver
Metro on Saturday are 10-30%, on Sunday 30-50% and Monday to
10-20%. At this time, HeatRisk is expected to remain moderate
through Monday.

As for 100 degrees or greater, there is a chance that some areas
within the Willamette Valley could see those temperatures. Salem
to Eugene has a 20-30% probability, while the Portland/Vancouver
Metro area has a less than 5% probability at this time.
However, the hottest day so far for next week looks to be on
Tuesday. There is a more detailed breakdown of Tuesday below.

Probabilities for highs to reach 100 or greater for various
locations in our Forecast Area on Tuesday (7/15/2025):

Portland/Vancouver Metro: 30-50%
Salem: 60-80%
Eugene: 45-65%
Battle Ground: 15-30%
Kelso/Longview: less than 10%
Astoria: less than 1%
Hood River: 5-10%
Newport: less than 1%
Oakridge: less than 5%

If temps trend toward the 75th percentile or greater then we may
see HeatRisk for these days jump into the Major category.

In addition to the upper level high pressure, models are also
showing the development of a thermally induced trough slowly
spreading northward into the Willamette Valley towards the start
of next week. If this solution within the models does manifest,
then will likely result in offshore flow. Lastly, expect most of
the area to remain dry through the end of the long term IE no
precipitation in the forecast at this time. However, models are
hinting at a possible pattern change come Wednesday/Thursday and
that could bring some very light precipitation into the
forecast, but model probabilities are too low to warrant
inclusion of any precipitation in the forecast for now, but will
continue to monitor as models start to better resolve this
feature in the coming days.      /42

&&

.AVIATION...Westerly flow continues across NW Oregon and SW
Washington, becoming northerly after 16z Thu. IFR/LIFR conditions
expected along the coast with cigs around FL003-FL009 and vsbys
bouncing between 1/4 SM and 2 SM. Conditions are expected to improve
to MVFR/VFR north of KTMK between 07-10z Thu and south of KTMK
between 10-14z Thu. For inland locations, the onshore flow is
causing stratus to form on the western banks of the Cascades as of
04z Thu. This stratus is expected to slowly backfill west into the
Willamette Valley, though guidance is uncertain on how far stratus
could spread. Most terminals could see a couple of hours of MVFR
cigs at some point, though terminals in the central Willamette
Valley such as KUAO and KSLE have higher probabilities (70-80%) of
MVFR cigs. Expect inland locations to recover to VFR by 16-19z Thu.

PDX AND APPROACHES...VFR conditions through the majority of the TAF
period. There`s a 30-60% chance of MVFR cigs between 10-15z Thu.
Winds out of the north/northwest at less than 10 kt. -HEC

&&

.MARINE...A weak front will continue to move across the waters
through the evening. Overnight, fog is likely to manifest again
tonight because of upwelling. This will result in visibilities
across all waters likely falling below 1 NM or less tonight
through tomorrow morning. Timing remains difficult, but will
monitor conditions and issue a Dense Fog Advisory if warranted.

Southerly winds will briefly become north/northwest this evening.
However, a weak frontal passage late tonight/early Thursday will
bring about a brief southerly wind shift. North/northwest winds
will return across all waters by late Thursday morning and persist
through the weekend as a broad area of high pressure and a
thermally induced trough spreads northward. As the high
pressure and associated thermally induced trough mature, expect
gusty northerly winds and choppier wind driven seas,
particularly south of Cape Falcon. Winds and seas will be
strongest off the central coast of Oregon and will typically
peak in the afternoon and evening hours over the inner waters
each day through the weekend.      /42

&&

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

&&

$$

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