Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 230952

Area Forecast Discussion
National Weather Service Portland OR
252 AM PDT Sat Sep 23 2017

.SYNOPSIS...Mix of sun and clouds today and Sunday. Weak front
offshore may bring spotty light rain or sprinkles this am, mainly to
the coast. Next front arrives Mon, with increasing chance of light
rain. High pressure builds later Tue, and remains over the region
through end of next week. This will allow for dry weather, with above
normal temperatures under some offshore flow.


.SHORT TERM...Today through Monday...Westerly flow aloft allowing
weak system in the flow over the Gulf of Alaska to drift into the Pac
NW, with bulk of the energy heading into Washington. This system will
will maintain plenty of mid and high clouds over the region today.
Can not rule out some spotty light rain along the the coast, and
occasional sprinkles inland this am. But, will see threat of
precipitation decreasing this afternoon as clouds break up a bit
more. Will keep threat of morning patchy fog, through will be quite
patchy if forms due to more clouds around the region this am.

Dry tonight and Sunday, with mix of mid and high clouds over the
region, with thicker and more extensive clouds to the north over
Washington. With less in way of clouds on Sunday, should see highs
back in the 60s along the coast, and lower 70s inland.

Next system over the Gulf of Alaska will arrive on Monday, with
increasing clouds early in the day. Will maintain threat of some
light rain spreading inland through the day. But, not confident will
see all that much in way of rainfall, so will keep only 40 to 50 pct
chance of rain for later Mon and Mon night. Again, highest threat of
rain would be over Washington, and the north Oregon Coast Range and
coastal areas. Highs stay in the mid to upper 60s.Rockey.

.LONG TERM...No Changes. Previous discussion follows...Monday night
through Saturday...Ridge of high pressure will continue to build into
the area from the NE Pacific. This will bring warmer temperatures
into the area. Offshore winds are looking to start around Tuesday
night. Which will prevent nighttime clouds and fog from forming.
There is uncertainty in when the offshore winds will end, which makes
the temperature forecast for the end of next week more uncertain.


.AVIATION...Much less IFR out there this morning than this time
yesterday. IFR fog can be seen in the Coast Range and Cascade
valleys with some MVFR cigs near Kelso and along the north
Cascade foothills. Expect these MVFR cigs to expand over the next
few hours and impact at least KPDX and KTTD. Along the coast,
MVFR cigs have been in and out. Based on webcams, it appears
there is some fog near KONP, therefore, have trended the TAF
towards that possibility within the next few hours. Expect all
locations to improve to VFR by this afternoon.

KPDX AND APPROACHES...MVFR conditions are expected to develop at
the terminal within the next few hours. This MVFR stratus is
expected to continue through the morning before clearing around
mid day. /Bentley


.MARINE...Not much marine weather to talk about for the next 5
days with winds less than 15 knots and seas 5 feet or less. As
the thermal trough builds north along the coast early next week,
small craft advisory northerlies are possible by Tuesday night.




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