Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 300955

Area Forecast Discussion
National Weather Service Portland OR
255 am PDT Mon May 30 2016

.SYNOPSIS...An upper level ridge will build into the Pacific
Northwest today in the wake of a departing weather system, bringing
clearing skies and drying weather to southwest Washington and
northwest Oregon. The ridge will produce warming temps over the
nextcouple of days with light offshore flow pushing inland temps
close to 90 on Tuesday. Onshore flow will start to develop Wednesday
to take the edge off the heat. Though daytime temperatures will be
slightly cooler the latter half of next week, they will remain well
above normal.

.SHORT TERM...(Tonight through Wednesday)...The upper ridge of high
pressure seen in water vapor pictures along 130W early this morning
is expected to shift east to the coast by the end of the day, and
then inland over the Pacific NW by Tue. The classic cycle of a
thermal trough is the result, with models showing the trough of
thermally induced low pres along the S Oregon coast building n up
the coast today and tonight, before shifting inland into the Coast
Range during the day Tue. With the resulting turn to offshore flow,
a return to dry and mostly sunny weather is expected for the region
today and Tue. Temps will quickly warm well above normal during the
next two days, with models continuing to show h8 temps climbing to
around 18 deg C by Tue afternoon, which coupled with the offshore
flow would pugh inland high temps near 90 Tue. Temps along the coast
by Tue will likely peak in the 70s early in the day, but as flow
turns onshore in the afternoon marine air would cut off heating for
the rest of the day.

As the upper ridge continues to move further inland Tue night and
Wed and begins to flatten, the low level flow turns onshore as the
surface trough moves east of the Cascades. Low stratus and fog
appears likely to develop along the coast Wed resulting in a return
to cool marine air. Inland temps will also modify some as well, but
still should remain well above normal with model h8 temps still on
the order of 15 deg C Wed afternoon.

.LONG TERM...No Changes. Previous discussion follows...(Wednesday
night through Sunday)...Remnants of a weak shortwave could bring some
light showers to the far northern portions of the forecast area on
Thursday as it rides over the top of the upper level ridge.
Otherwise, the models have come to the consensus that upper level
ridging will persist through at least Saturday. This will keep dry
weather and warm temperatures over the region, with afternoon highs
at the coast in the upper 60s to lower 70s. The interior will likely
see highs stay in the 80s. With overnight lows in the upper 50s to
mid 60s and light winds expected late next week we could be in for
some unpleasant nights. However, a slight onshore gradient should
keep temperatures from getting out of hand. Another weak shortwave on
Sunday could bring a slight chance of thunderstorms to the Oregon
Cascades, but confidence remains low. /64

.AVIATION...VFR conditions expected at all through Monday night.
There may be patchy stratus around 1000 feet between kcvo to keug
from 13Z to 16Z. But do not expect it to affect KEUG.

PDX AND APPROACHES...VFR conditions expected through Monday night.


.MARINE...High pressure in the northern Pacific will shift
northward Monday with a thermally induced low developing across
northern California and southern Oregon. This combination will
lead to gusty north winds this afternoon through Tuesday then
weakening on Wednesday. A small craft advisory in effect for all
waters through 12Z Tuesday and continues for the outer waters
through Tuesday evening. There will probably be small craft
advisory winds for the nearshore waters Tuesday afternoon and

Seas between 4 and 5 feet today and should become choppy
especially during the afternoon and evening with the stronger
diurnal winds. Seas will increase slightly due to a gusty
northerly fetch for the first half of the week, do not expect
this rise to be more than a couple of feet. /Bentley


PZ...Small Craft Advisory for winds from 2 PM this afternoon to 11
     PM PDT Tuesday for Waters from Cape Shoalwater WA to
     Florence OR from 10 to 60 nm.

     Small Craft Advisory for winds from 2 PM this afternoon to 5 AM
     PDT Tuesday for Coastal Waters from Cape Shoalwater WA to
     Florence OR out 10 nm.



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This discussion is for Northwest Oregon and Southwest Washington
from the Cascade crest to 60 nautical miles offshore. The area is
commonly referred to as the forecast area. is the U.S. government's official web portal to all federal, state and local government web resources and services.