Mc Kenzie Bridge, Oregon Weather Forecast Discussion

931
FXUS66 KPQR 190437 AAA
AFDPQR
Area Forecast Discussion...UPDATED
National Weather Service Portland OR
937 PM PDT Thu Sep 18 2025
Updated aviation discussion.
.SYNOPSIS...Persistent onshore flow will maintain seasonable
conditions through the remainder of the week. A deeper trough
moving in from the Gulf of Alaska this weekend will bring a more
pronounced cool-down and an increasing chance for rain,
especially along the coast and across southwest Washington.
There is also a low potential for isolated thunderstorms in the
Cascades Friday through Sunday.
&&
.SHORT TERM...Now through Saturday...Tranquil conditions are expected
to prevail across the area through Saturday. A weak disturbance
continues to lift northeast while high pressure builds in from
the west. Skies remain mostly clear today through winds are
expected to be gusty through the evening as the pressure
gradient tightens. Northerly to northwesterly winds 8-15 mph
with gusts to 20 mph are possible throughout the Willamette
Valley, slightly higher along the coast with sustained winds
15-20 mph and gusts closer to 30 mph possible. Winds become
light and variable overnight. Mostly clear skies are expected
overnight for most locations as high pressure builds in from the
west. Cloud cover across the southern Willamette Valley into
eastern Lane and Linn counties will increase as a weak surface
low across northern California drifts northward tonight into
tomorrow. Lows close to average in the upper 40s along the coast
and low 50s inland are expected.
Conditions are expected to remain dry Friday with an uptick in high
temps as a short wave ridge moves overhead. Highs in the low to mid
80s are expected inland and 60s along the coast. Northerly winds
will return as surface high pressure remains in place. An area of
moisture associated with the northern California low moving
northward will come into central OR. Confidence remains low,
around 10% or less, for a shower or stray storm to develop
across far eastern Lane and Linn counties tomorrow afternoon and
evening. Saturday will remain dry with highs around average.
Winds turn westerly, then southwesterly late in the day as a
cold front approaches the area. -Batz
.LONG TERM...Saturday night through Wednesday...Rain chances
increase this weekend as a strong shortwave trough digs
southeast from the Gulf of Alaska. A cold front associated with
this system will approach late Saturday into Sunday, bringing
probabilities of measurable precipitation to 30-60% across most
of northwest Oregon and southwest Washington. Lower
probabilities (as low as 10-25%) are favored for the southern
Willamette Valley and the Lane/Linn County Cascades and
foothills. The highest chances, in the 50-80% range, are
expected north and west of a line from Willapa Hills to
Tillamook, including the southwest Washington coast and Astoria.
Temperatures will trend cooler under cloud cover and frontal
passage, with highs Sunday in the low 70s inland and 60s along
the coast. Heading into early next week, conditions remain
seasonable with inland highs in the mid to upper 70s and coastal
highs in the 60s. Guidance suggests another round of
precipitation Tuesday into Wednesday as low pressure off
northern California lifts northward into a broader trough over
the northeast Pacific. Probabilities of measurable precipitation
at this time are around 20-30%, but timing and coverage remain
uncertain. ~Hall/Batz
&&
.AVIATION...VFR conditions prevail across the region as high
pressure remains in place. Expecting skies to stay mostly clear
tonight into tomorrow. That said, cannot completely rule out LIFR
to IFR cigs at the coast towards 12-15z Friday (25% chance at
KAST, 40% chance at KONP).
Otherwise expect breezy north to northwest winds to gradually
weaken after 06-08z before increasing again Friday afternoon with
daytime heating. However, winds most likely won`t be as strong as
what was observed Thursday afternoon.
KPDX AND APPROACHES...VFR conditions with mostly clear skies
through the TAF period. Expect northwest winds around 5-10 kt
throughout the TAF period, strongest during the afternoon and
evening hours. -TK
&&
.MARINE...Surface high pressure across the waters will maintain
breezy northerly winds through tonight. Buoy observations as of
early Thursday afternoon are showing wind gusts to 20-25 kt with
seas around 8-9 ft at 11-12 seconds. Small Craft Advisories remain
in effect for all marine zones including the Columbia River Bar
through tonight for northerly wind gusts to 25-30 kt. Northerly
winds will gradually weaken on Friday as pressure gradients ease,
with gusts falling below 20 kt. Seas will also gradually subside
to around 5-7 ft at 9-10 seconds by Friday afternoon.
The next frontal system arrives this weekend from the north,
returning southerly winds on Saturday. The front is expected to
push through Saturday night into Sunday, potentially leading to a
brief coastal jet across the Columbia River Bar and inner waters
north of Cape Falcon. Guidance suggests a 30-50% chance for
southerly wind gusts greater than 21 kt (small craft advisory
level) for these locations Saturday night, while chances are
around 5-10% or less everywhere else. -Alviz
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory until 11 PM PDT this evening for PZZ210.
Small Craft Advisory until 5 AM PDT Friday for PZZ251>253-
     271>273.
&&
$$
www.weather.gov/portland
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NWS PQR Office Area Forecast Discussion