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fxus66 kpqr 240426 rra 
afdpqr

Area forecast discussion
National Weather Service Portland or
925 PM PDT sun Apr 23 2017

Synopsis...an upper level trough swinging through the Pacific
northwest tonight will continue showers across the forecast area,
this will be followed quickly by the first in a series of systems
riding a strong Pacific jet stream for rain and Cascade snow on
Monday, with breezy conditions in the afternoon. This will be
followed by another wet and cool system Tuesday and Tuesday night.
Moist onshore flow will continue the threat of showers
Wednesday through Friday.

&&

Short term...tonight through Wednesday...an upper low currently
offshore the North Washington coast will move across SW Washington
and northwest Oregon tonight and Monday morning for continued showers. Snow
levels are just above the Cascade passes this evening, but should
lower to near or just below the Cascade passes overnight. A surface
low will drag a cold front across the area Monday morning for more
steady rain and Cascade snow. Rain totals of 1-2 inches is expected
for the Cascades, Coast Range, and the coast, with 0.5-0.75
inch in the valleys from tonight through Monday afternoon. Snow
totals up to a foot is possible above 5000 feet, with around 4 inches
near the Cascade passes, and made no changes to the current Wind
Advisory.

Gusty winds will accompany this front with possible gusts around 40
mph for the coast and 30-35 mph for the interior valleys (mainly
Salem and southward). Suspect that these winds may pose some problems
for the weakened or fully blossomed trees due to the saturated grounds
and recent tree blossoms. However, think that the most weakened trees
were already removed from the last wind storm and that tree damage
from the winds will not warrant an advisory. If the low pressure
deepens more than currently forecasted, then there will be an
increase in forecasted winds and a heightened concern for potential
damage. ~Tj

Previous discussion (from 258 PM sunday)...
showers ease up overnight Monday night before the next system arrives
during the day Tuesday. Snow levels may rise a bit with the Tuesday
system, rising above pass levels during the day. But look for
increasing rain again. The track of the associated surface low is
farther north, but we should see some breezy south winds again along
the coast and inland Tuesday afternoon and evening.

Onshore flow will keep a considerable amount of showers across the
forecast area Tuesday night and Wednesday. Snow levels are expected
to lower back down to near the Cascade passes later Tuesday night and
Wednesday. It appears there will be a wave moving through Wednesday
that would bump up the shower coverage during the day Wednesday.
Tolleson

Long term...no changes. Previous discussion follows...Wednesday
night through Sunday...showers will continue across the forecast area
Wednesday night into Friday as a couple of more disturbances ride
through on a jet stream that turns more northwesterly through through
Friday. The models are now in better agreement that enough of an
upper ridge will build early in the weekend for some drying. The next
system is expected about Sunday. Tolleson

&&

Aviation...conditions along the coast are predominately MVFR
south of ktmk, with VFR conditions to the north. The interior
remains predominately VFR this evening, with occasional MVFR
under heavier showers. A stronger front approaches the coast
later tonight, which will bring winds up along the central coast
overnight. The front will also bring some gusty winds to portions
of the Interior Valley south of kuao Monday morning. Expect
conditions to become predominately MVFR as the front moves across
the forecast area Monday, with some MVFR cigs persisting into the
afternoon/evening.

Kpdx and approaches...mainly VFR this evening, with occasional
MVFR under heavier showers. Conditions are expected to become
predominately MVFR later tonight, with reduced flight conditions
possible through Monday afternoon/evening. /64

&&

Marine...a stronger low, around 1000 mb, will move across the
waters late tonight into Monday morning and is expected to make
landfall between Tillamook and Cascade Head. Models continue to
suggest some marginal gales to 35 kt with this system. However,
based on the latest guidance, the gales will likely not be
widespread nor frequent enough to warrant a Gale Warning, but
would not be surprised to see a few gusts to 35 kt early Monday
morning. Beyond Monday there is another system on Tuesday that
could bring high-end Small Craft Advisory or low-end gales on
Tuesday. The active pattern continues through the end of the
week.

Seas are currently hovering around 9 to 10 ft this evening. Seas
south of Cascade Head will build to around 10 to 12 ft later
tonight as winds ramp up with the approaching low. Seas start
to come back down Monday afternoon as this system moves inland.
Tuesday seas look to remain around 7 to 9 ft. Next time seas get
up above 10 ft looks to be Thursday with a fetch developing from
a low off the coast of British Columbia. With this system models
have backed off, now only bringing seas up to 10 to 12 ft. Seas
start to fall late Friday and look to stay below 10 ft through
next weekend. /64/McCoy

&&

Pqr watches/warnings/advisories...
or...Winter Weather Advisory until 8 PM PDT Monday for Cascades in
Lane County-northern Oregon Cascades.

Washington...Winter Weather Advisory until 8 PM PDT Monday for South
Washington Cascades.

Pz...Small Craft Advisory for winds until 2 PM PDT Monday for
coastal waters from Cape Shoalwater Washington to Cascade Head or
out 60 nm.

Small Craft Advisory for hazardous seas until 11 PM PDT this
evening for coastal waters from Cape Shoalwater Washington to
Cascade Head or out 60 nm.

Small Craft Advisory for winds until 2 PM PDT Monday for
coastal waters from Cascade Head or to Florence or out 60
nm.

Small Craft Advisory for hazardous seas until 5 PM PDT Monday
for coastal waters from Cascade Head or to Florence or out
60 nm.

Small Craft Advisory for rough Columbia River bar from 2 am to
6 am PDT Monday.

Small Craft Advisory for rough Columbia River bar from 2 PM to
6 PM PDT Monday.

&&

$$

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