982 
FXUS66 KPQR 151729
AFDPQR

Area Forecast Discussion 
National Weather Service Portland OR 
1030 AM PDT Sat Apr 15 2017

.SYNOPSIS...High pressure will bring an end to the shower activity 
over the nw part of the forecast area today, and will bring clearing 
skies for much of the forecast are today and tonight. High pressure 
will shift east of the Cascades tonight and Sunday, bringing dry and 
mild offshore flow to much of the district. Meanwhile, low pressure 
off the Northern California coast Sunday morning will start to lift 
northward, eventually spreading rain south to north across the 
forecast area Sunday evening. Unsettled weather will continue 
through midweek as a series of Pacific systems move onshore into the 
Pac NW. Drier weather is possible Friday as an upper level ridge 
moves across the region.

&&

.SHORT TERM...Today through Monday...Showers seen on radar this 
morning mainly relegated to areas from the south WA coast to down 
off the north OR coast. A weak shortwave weas moving onshore over nw 
WA this morning as seen in water vapor imagery, and will cross WA 
during the day today. Will hang on to a small chance for showers 
across the northern part of the forecast area today, before 
subsidence ends all chance for showers this evening. There are a few 
areas of valley stratus and fog this morning in the stable low level 
air mass, but the areas were not extensive and should burn off 
this morning with the April sun. 

A northerly offshore flow will strengthen tonight asnd turn 
easterly, provind further drying of the low level air mass. The 
offshore flow will warm temps above normal Sun, something we haven't 
seen a lot of this Spring. With h8 temps expected around 6 deg C, 
could see high temps reach into the upper 60s in the interior 
valleys, although high clouds ahead of the next approaching low may 
knock a few degs off the potential highs. The offshore flow should 
also allow the coast to warm into the 60s. Models continue to 
suggest a small chance for showers by late Sun as a southerly flow 
spreads moisture up from the south ahead of the incoming low. 

Remainder of short term discussion unchanged...The previously 
mentioned low pressure system will not be all that strong at the 
surface, likely staying above 1000 mb. The upper level portion of 
this system is a little more impressive, and may result in a bit 
more of a convective nature to this system Sun night/Mon. On the 
flip side, if the associated upper low opens up and lifts NE through 
Oregon like the 00z GFS/ECMWF suggest, there may be a band of more 
stratiform deformation-related precip somewhere over our forecast 
area. Either way, Sunday night and Monday will likely turn 
increasingly wet...especially as the next Pacific frontal system 
follows and brings a chance for more organized rain late Monday or 
Monday night. None of these systems appear particularly strong, but 
these and a couple additional systems will likely keep the weather 
unsettled for much of the upcoming week after our relatively dry and 
mild Easter Sunday.  Weagle

.LONG TERM...No Changes. Previous discussion follows...
Monday night through Friday...Another rather progressive pattern will
bring several periods of rain to the region next week. An initial
shortwave will continued precipitation Monday night into early
Tuesday, while the main upper low will advance and an associated
front will slide through the region Wednesday. A brief break in the
precipitation is possible late Thursday into early Friday as heights
rise in between systems, with clearing skies and a drier air mass
pushing temperatures up into at least the mid 60s. However, at this
point, it seems that a 70 degree reading will continue to be elusive
for yet another week. Clouds return late Friday night as the next
front approaches, with precipitation possible again Saturday.  Cullen

&&

.AVIATION...Ribbons of IFR/LIFR with spotty VLIFR cigs along the
interior valleys this morning, also with fog reported at KEUG.
Expect most area will see the low stratus break up by 18z
however, northerly flow up the Willamette Valley could prove
problematic at KEUG today. Climatology for KEUG suggests Vsby
will improve into IFR around 17z while Cigs may last more toward
19z. There's a fair amount of low level clouds and fog stretching
north toward KSLE, however, so fell climatology may be a bit too 
optimistic today. Otherwise, just some showers with BKN MVFR Cigs
at KAST while the rest of the area remains VFR through the 
evening. Coastal terminals and KEUG look to drop back under a low
cloud/fog regime late overnight tonight through tomorrow 
morning.

KPDX AND APPROACHES...Thin LIFR cigs at KPDX should break by 17z.
Then VFR will remain through tomorrow morning. /JBonk

&&

.MARINE...High pressure building across the Pacific Northwest and
will produce increasing northeasterly winds across the waters 
late Saturday and Sunday. High resolution models are showing
a fairly solid threat for north/northeasterly wind gusts around 
25 kt beginning late this afternoon starting first across the
central Oregon waters. Winds will then veer to east overnight 
with the primary threat shifting to the northern waters through
Sunday morning. Have issued a SCA for winds to address.

More active weather will return next week. The first front will
likely spread southerly winds of 20 to 30 kt across the waters
during the second half of Monday with some gusty winds lingering
into Tuesday. The next frontal storm system appears likely to
arrive Wednesday before quieter weather returns for a day or two
towards the end of next week. There is a chance the Monday and/or
Wednesday storm system could push winds into low end Gale 
gust criteria of 35 kt, but for now kept this out of the 
official forecast given confidence is relatively low in this 
actually occurring at this point. JBonk/Neuman

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory for winds from 6 PM this evening to noon 
     PDT Sunday for Coastal Waters from Cape Shoalwater WA to 
     Cascade Head OR out 60 nm.

     Small Craft Advisory for winds from 4 PM this afternoon to 4 AM 
     PDT Sunday for Coastal Waters from Cascade Head OR to 
     Florence OR out 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. The area is
commonly referred to as the forecast area.