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000
FXUS66 KPQR 171016
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
315 AM PDT Wed Apr 17 2024

.SYNOPSIS...High pressure over the region will remain through Friday,
maintaining mild sunny days and cool clear nights. Offshore flow
increases a bit for Thu and Fri, with uptick of easterly winds. Back
to cooler conditions this weekend, as a front pushes across the
region on Sat.
&&

.SHORT TERM...(TODAY THROUGH FRIDAY)...
After a cool start, and frosty in spots, will see a rather pleasant
April day, with sunshine and light north winds. Overall, will see
temperatures will climb back to the upper 50s along the coast, and
lower 60s for most of the interior lowlands.

Rather nice weather expected for Thu and Fri, as high pressure
offshore drives the local weather patterns. High pressure will
remain anchored just offshore today into Thursday. This high
pressure ridge offshore will lead to development of low level
offshore flow across the region, as thermal trough develops along
the coast. As such, will maintain mostly clear skies into Thu, with
another cool night on tap. But, should not be as cool as this am.

On Thu, will see high pressure build east of the Cascades, thanks to
high pressure sliding southeast out of Alberta into the northern
Plains. As such, will see a boost to the offshore pressure gradients,
enough to push east winds of 5 to 15 mph over much of the region Thu
into Fri. Models mostly suggest about 4 to 6 mb of cross-Gorge
gradient, enough to support gusts of 25 to 35 mph near Troutdale and
for more common east wind favored spots of the Portland/Vancouver
metro for Thu through Fri. Even the coast will have touch of east to
northeast winds as well, with gusts 10 to 20 mph in spots. This
offshore flow will help to boost afternoon temperatures, with highs
(mainly Fri) in the upper 60s to lower 70s along the coast, and lower
to middle 70s for interior lowlands. /Rockey

.LONG TERM...(SATURDAY THROUGH TUESDAY)...
Models have been consistent, and persistent, in showing a weakening
front arriving on Saturday. As such, will be cooler day, with
increasing clouds. Difficult to say how much precipitation will be
around, but will follow guidance and keep PoPs (prob of
precipitation) at likely along the coast in the morning, spreading
inland and northward for mid-day into the afternoon. With system
falling part as it moves inland, will transition high PoPs over
Washington and lower as move southward towards Lane County. ONshore
flow, with clouds and few showers around for Sat night into Sun. But,
GFS and ECMWF still show gradual improvement on Sun. Likely to be
mostly dry for Sun afternoon, and will trend forecasts as such. But,
not confident to go all dry, so will keep some small chance of
showers in the forecasts for Sun.

High pressure will build for early next week, with return of dry and
mild weather for Mon into Tue.             /Rockey
&&

.AVIATION...VFR expected to prevail through 12Z Thu as high
pressure aloft dominates the weather. Clear skies, calm winds,
and near freezing temperatures may result in frost build-up on
exposed and elevated surfaces early this morning. Northerly winds
along the coast and Willamette Valley increase this afternoon to
around 10-15 kt, with gusts up to 20-25 kt. Winds strongest at the
coast.


PDX AND APPROACHES...VFR conditions expected through 12Z Thu. Winds
turn more northerly and strengthen to around 08-13 kt after 21z
Wed through 05Z Thu. /mh
&&

.MARINE...High pressure off the WA/B.C. coast with a thermal
trough along the south Oregon coast will persist through Thursday
night. The high pressure shifts inland by Friday shifting winds
front northerly to easterly. This configuration breaks down Friday
night as a Pacific front approaches and moves through the waters
Saturday. Northerly wind gusting to 25 kt expected today for most
of the waters, so a Small Craft Advisory remains in effect for
PZZ252, 253, 272, 273 through tonight. May need to extend the
Small Craft Advisory into Thursday but will see what next model
runs show.

General seas through the weekend of 4 to 6 feet at 11 to 17
seconds, consisting of a long period southwest swell or a shorter
period west to northwest swell. /mh

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...Frost Advisory until 9 AM PDT this morning for ORZ101>105-
     108>115-119-120-122.

     Freeze Warning until 9 AM PDT this morning for ORZ106-107-
     116>118-121-123>125.

WA...Frost Advisory until 9 AM PDT this morning for WAZ201-202-
     204>207-209-210.

     Freeze Warning until 9 AM PDT this morning for WAZ203-208.

PZ...Small Craft Advisory from 2 PM this afternoon to 11 PM PDT this
     evening for PZZ252-253.

     Small Craft Advisory from 2 PM this afternoon to 5 AM PDT
     Thursday for PZZ272-273.
&&


$$

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