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000
FXUS66 KPQR 141059
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
359 AM PDT Sun Apr 14 2024

.SYNOPSIS...Showers continue over the Willamette National Forest
and the foothills this morning. These showers will persist
through the day as low pressure moves inland over Nevada. High
pressure will build back in through this week keeping things
generally dry and warmer.

&&

.SHORT TERM...Now through Wednesday...No major changes over the
next few days as an area of low pressure will shift inland and
weaken through early this week. Showers will linger through
today as we sit on the back side of the low and northeasterly
flow pushes the airmass up and over the Cascades. The orographic
lift of the Cascades will enhance the chances for showers.
While thunderstorms were present last evening, there is a lower
probability for thunderstorms again today due to a lack of CAPE
and convective enhancing parameters. Generally will see showers
from Detroit southward.

Moving into Monday and Tuesday, onshore flow will take over as
high pressure builds over the northeast Pacific. There is a band
of cooler air present at 850 mb (around -5 deg Celsius) which
will aid in cooling down the area. Looking at the spread, there
is fairly good agreement that temperatures will lower. However,
cloud cover will be a major determining factor in just how warm
things will be. If there are more clouds (similar to Saturday),
then highs will be lower and lows will be warmer. High pressure
intensifies with warmer conditions each day. We will also see
relative humidity slowly drop through the day. -Muessle


.LONG TERM...Thursday through Saturday..There is higher and
higher confidence in a ridging pattern persisting through the
end of the week. While there are some differences depending on
the models, of the 500 mb clusters, all show a riding pattern on
Friday with the GFS and ECMWS showing the strongest trend. By
day 6 (Saturday) there is even more consensus. Temperatures will
rise with solid agreement through Thursday. This riding pattern
will increase easterly winds so have added more of a local
effect through the Columbia River Gorge to bring higher gusts to
terrain above 1000 ft. Long term ensembles are showing a range
of highs between 72-78 deg Fahrenheit (25th-75th percentile) on
Friday. But, by Saturday the spread is much larger at 61-75 deg
Fahrenheit. Ultimately minimal weather based impacts from
Thursday through Saturday. -Muessle


&&

.AVIATION...An upper-level low over central California will
continue to move eastward today as mid to high levels clouds and
isolated showers rotate into the region, albeit generally
decreasing as the day progresses. Predominately VFR conditions are
expected through the period at inland sites, except at the
coastal sites where marine stratus keeps low MVFR to IFR
conditions in place tonight through much of the forecast period,
especially at KONP. That said, there`s still a chance(30-50%) for
briefly lowered CIGS to MVFR at inland sites between 12-17z,
highest probs for this reduction across the southern Willamette
Valley. Higher confidence in prevailing VFR conditions after this
morning period and at KPDX/KTTD.

PDX AND APPROACHES...Expect VFR conditions with mid to high
clouds through the period. Winds stay out of the NW at 5-10 knots
through the forecast period. -Schuldt

&&

.MARINE...Expect weak ridging to build in aloft today as a cut-off
low currently over California progresses into the Great Basin and
surface pressure gradients responsible for the northerly winds
the last several days slowly weaken headed into Monday. That said,
persistent NNW-NW winds will remain in place through this evening
with high confidence in gusts around 20-25 knots over the inner
and outer waters in addition to a NW swell at 7-10 feet with a
period of 9-10 seconds. Thus, the Small Craft Advisory will stay
in effect for winds and seas through at least Sunday evening for
all zones. Going forward, a surface high pressure over the eastern
Pacific strengthens and meanders eastward Monday into midweek
with widespread winds decreasing below Small Craft conditions
(gusts greater than 21 kts) and seas decreasing to 4-6 ft with
period of 9-10 second by Wednesday. Guidance suggests Thursday
into Friday an upper-level ridge builds over the eastern Pacific
accompanied by a thermal trough over northern California into
southern Oregon which could bring elevated N-NE winds to the
waters. -Schuldt/HEC

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory until 11 PM PDT this evening for PZZ210-
     251>253-271>273.
&&

$$

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