485
FXUS66 KPQR 090945
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
245 AM PDT Fri May 9 2025

.SYNOPSIS...Benign weather conditions through the end of the
week with daytime highs in the 60s-70s through the weekend and
into next week. Today is expected to be the warmest, but as a
broad area of low pressure starts to push eastward, temperatures
are expect to slowly cool towards the 50s along the coast and
60s for inland locations. Wetter weather is also expected to
make a return on Sunday into early next week.

&&

.SHORT TERM...Today through Sunday Night...Dry conditions with
mostly clear skies persist today as a ridge of high pressure
remains the dominant synoptic feature. However, this will slowly
change as a broad area of low pressure will bring about a
pattern change for the region towards the start of next week.
Daytime highs today will be in the 60s along the coast and 70s
for inland locations. Generally northerly winds today, with
gusts peaking up to 20 mph. Winds decrease going into the late
afternoon/evening, and will be fairly light and variable
throughout tonight. Tonight through Sunday, cloud cover begins
to increase as the ridge begins to slowly acquiesce to an
incoming low from the eastern Pacific. This will start a slow
cooling trend across the CWA pushing out of the region,
resulting in slightly cooler temperatures. Daytime highs on
Saturday look to be in the upper 60s to low 70s inland and into
the 50s to 60s along the coast. Sunday will be even cooler with
daytime highs in the low to mid 60s inland and upper 40s to mid
50s along the coast. Models are even showing a frontal passage
late Saturday/early Sunday with most of the rainfall arriving
Sunday; 30-60% probability of light rainfall starting late
Saturday night and the probability of rainfall increasing
through Sunday. Current storm total rainfall starting late
Saturday night through Sunday light will be around 0.15 inches
to 0.50 inches, highest rainfall totals look to be along the
Central Oregon Coast range. /42

.LONG TERM...Monday through Thursday...A more robust front is
expected with the system by the start of next week.
Precipitation totals with the second front looks to be around
0.10 to 0.25 inches for Monday. NBM probabilities for 24 hour
liquid precipitation exceeding 0.25 inches ending 5 PM Monday
are around 30-60% along the coast and high terrain, and 25-60%
for interior valleys. Also, this trough will advect more cold
air aloft which may help create a more unstable atmosphere. NBM
guidance currently pointing towards a 5-10% probability of
thunderstorms Monday afternoon. However, this will be heavily
dependent on whether or not sufficient clearing in cloud cover
occurs as well as the path of the incoming low. If the low moves
more northward towards our CWA, the probability of
thunderstorms will increase, while if the low tracks more
towards the OR/CA border the probability will be lower. Showery
conditions with light precipitation remain in the forecast
through Friday as WPC 500mb Cluster guidance shows strong
agreement in troughing continuing through at least Thursday. /42

&&

.AVIATION...VFR over the area through the next 24 hours. Along the
coast, clear skies and lowering temperatures will promote the
development of IFR conditions. Areas that will be the most at risk
will be around KONP and KTMK. Some models are suggesting a weak
easterly wind which would keep any fog or low stratus at bay.
After sunrise, conditions will improve. With the high pressure
in place, winds will transition to the north through the afternoon
and amplify along the coast.

Towards the end of the TAF package, 40-60% chance of MVFR/IFR
conditions redeveloping.

PDX AND APPROACHES...VFR CIGS/VIS through the next 24 hours.
-Muessle
&&

.MARINE...High pressure will maintain steady conditions through at
least Sunday. Seas will be 5-7 ft at 10 seconds. Winds will be
northerly 5-10 kt through Saturday morning before transitioning to
the south in the evening as a low pressure system moves towards
the northeast Pacific. On Sunday, winds will be 10-15 kt with
gusts up to 20 kt. There is around a 50% chance of gusts up to 25
kt in the southern portions of PZZ273 late Sunday into Monday.

The next pattern shift occurs on Monday. A strengthening low
pressure system will move over the coastal waters causing winds
and seas to increase. There is still a lot of inconsistency in
modeled location of the low. However, with the colder air filling
in behind the low, cannot rule out a few thunderstorms embedded
within the precipitation. -Muessle

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...None.

&&


$$

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