821 
FXUS66 KPQR 141640
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
939 AM PDT Sat Oct 14 2017

.SYNOPSIS...Dry weather will continue through Monday as high pressure
remains over the Pacific Northwest. The next chance for rain comes
Tuesday as the tail end of a cold front moves across the Pacific
Northwest. Stronger, wetter systems are expected for the second half
of next week.

&&

.SHORT TERM...Today through Monday...Clear skies under a cool, moist,
and stable airmass overnight last night allowed thick radiational fog
to develop this morning.  Fog has become dense in areas Salem
southward along the I-5 corridor and out near Hillsboro. This fog may
hang on for another hour or two before it starts to break up. 

A broad ridge will keep us dry through the rest of this weekend into
early next week. Only exception may be this afternoon a weak system
hitting B.C. will brush western WA bringing some clouds to the south
WA coast. Will see offshore winds increase a bit this evening as the
thermal trough currently over the northern CA coast builds northward
onto the south OR coast. This should mean less fog Sunday morning,
however have left a chance for patchy fog Sunday for those areas that
are more protected from easterly winds. The thermal trough moves off
to the east Sunday afternoon, cutting back on winds Sunday night for
a better chance of morning fog on Monday. Nighttime temperatures over
the next few days will be flirting around or just below freezing in
many locations, similar to this morning. Sunday and Monday should be
the warmest days this week, due to an approaching system bringing
rain back midweek. -McCoy

.LONG TERM...Monday night through Friday...No changes. Previous
discussion follows...A more active pattern takes hold across the
region next week. Several embedded shortwave troughs pass across the
Pacific Northwest as the general storm track shifts south from
Canada. There continue to be timing differences among forecast models
with respect to when these impulses track across the area, as would
be expected in this pattern featuring a rather strong Pacific jet. At
this point, sometime in the Wed-Thur time frame looks to be a fairly
wet period as a slug of moistures slowly tracks across the area. 
Model precipitable water amounts forecast to be around 1.3" to 1.4"
which is about 200 percent of seasonal averages.  Of course models
are likely to change between now and then but the the overall message
is expect rainy period for the second half of next week with
significant rises on rivers likely especially coastal ones.  Rain
total estimates for next week vary widely. 3 to 5 inches in the
coastal mountains and north Cascades/foothills, with 2 to 3 inches in
the valley locations and remaining Cascades/foothills is a reasonable
estimate at this time. Snow levels would be above 6,000 ft for the
first half of the week, then potentially drop to around Cascade pass
level later next week. /mh

&&

.AVIATION...High pres over the region through the weekend. Clear
skies overnight allowed surface temps to cool considerably,
resulting in areas of IFR fog and low stratus over the interior
lowlands. There is enough offshore flow at the coast that
conditions are generally VFR at this time. The remaining fog and
low clouds will gradually dissipate over the next couple of
hours, giving way VFR conditions and mostly sunny skies this
afternoon and tonight. 

KPDX AND APPROACHES...IFR fog and stratus to clear by 18Z-19Z.
Then expect VFR conditions with clear skies this afternoon and
tonight. Pyle

&&

.MARINE...There will be very little change to the overall weather
pattern through Mon. Surface high pres will remain in place over
the NE Pac, with a thermally induced surface trough over northern
Calif. This will bring persistent northerly winds. The latest
fcst models suggest gusts of 20 to 25 kt with develop over
PZZ275 this afternoon and tonight, so have issued a small craft
advisory for winds during this time. Winds will generally remain
20 kt or less on Sun and Mon. Seas will remain 5 to 7 ft through
Mon. 

A significant pattern change will begin on Tue, bringing periodic
strong fronts through the waters through the end of next week.
Southerly
winds will increase, especially Wed and Thu with strong 
southerly gales expected. Will also see building seas, possibly 
reaching near 20 ft later Wed and Thu. Pyle/Rockey 

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory for winds from 3 PM this afternoon to 5 AM 
     PDT Sunday for Waters from Cascade Head to Florence OR 
     from 10 to 60 NM.

&&

$$

Interact with us via social media: 
www.facebook.com/NWSPortland 
www.twitter.com/NWSPortland    

This discussion is for Northwest Oregon and Southwest Washington 
from the Cascade crest to 60 nautical miles offshore. This area is 
commonly referred to as the forecast area.