Rip Current in Washington, September 7, 2016

Area Forecast Discussion
National Weather Service Portland OR
817 PM PDT Wed Sep  7 2016

.SYNOPSIS...Mostly clear skies across much of the region will
allow for patches of fog to develop in the area valleys tonight.
Another weak front will pass over the region late tonight, possibly
brushing southwest Washington and far northwest Oregon with light
rain Thu morning. Expect better clearing Thursday afternoon with
temperatures a bit warmer still. Friday will be the warmest day of
the week as high pressure moves over the Pac NW. Expect a brief
cooldown Sunday as another relatively dry front moves inland. Longer
range forecast for next week brings dry and warmer conditions, along
with light offshore winds.

&&

.update...Mostly cosmetic changes to the previous forecast package
for this evening to account for less cloud cover across most of the
region. The clearer skies and decreasing winds will allow for patchy
fog to develop in the valleys later tonight. Don't have much
confidence as to the nature of it nor precise locations so will
continue to keep the broader mention across most of the Central and
South Willamette Valley and adjoining drainages. Also added some
patchy fog to the central coast. Additionally, vertical moisture
profiles are rather shallow across out northern tier despite the
frontal passage slowly developing. Am finding very little moisture
above 4000 feet. Thus suspect we may get another drizzly morning
east of the north coast range and Willapa Hills where the terrain may
end up providing more of a gradual lift to the stratus field instead
of the sharper frontal lift. Regardless, feel the morning
dreariness will give way to a rather pleasant afternoon for most of
the area aside from the north coast where stratus will tend to hold
on a while longer into the afternoon. Text and grid updates will be
available shortly. /JBonk
&&

.AVIATION...VFR conditions across the region early this evening.
Around 05z tonight a front moving in will bring a mix of MVFR and
IFR conditions with light rain to the north part of the OR coast
that will last through around 13z Thu morning. On the central OR
coast fog developing will likely bring areas of IFR conditions
between 05z and 18z. Conditions improving on the coast after 18z.
Inland mainly VFR conditions will continue tonight and Thu, except
for some areas of MVFR cigs and light rain in the far north mainly
north of KSLE between 10z and 19z.

KPDX AND APPROACHES...VFR conditions early tonight are likely to
give way to marginally MVFR cigs between 10z and 19z Thu as a
weak front moves across. Some patchy light rain or drizzle may
accompany the front Thu morning. Conditions return to VFR midday Thu
after 19z.
&&

.MARINE...A weak front will brush east across the northern waters
tonight. High pressure will rebuild across the northern waters Thu
and Fri, while a trough of low pres strengthens on the south OR
coast. This will bring strengthening north winds to the southern
waters late Thu that will continue into Fri, bringing Small Craft
Advisory conditions. Another weak front will brush across the
northern waters Sat continuing gusty north winds into the
weekend.

Seas generally remaining in the 5 to 8 ft range through Sat,
dominated by a choppy fresh swell and wind waves.
&&

.PREV DISCUSSION... /issued 259 pM PDT WED SEP 7 2016/

SHORT TERM...(Today through Saturday)...An longwave upper level
trough remains over the Rockies for the next several days with a
strong ridge over the NE Pac. The Pac NW will remain in generally
northwesterly flow aloft between these two features.

It was a mostly cloudy start to the day today, with some patchy
drizzle over the northern Willamette Valley and over the higher
terrain of the south Washington and far north Oregon Cascades and
Coast Range. However, visible satellite shows the cloud cover
scattering out this afternoon. Expect a mix of sun and clouds through
the rest of the day with high temps recovering a bit compared to
yesterday.  A moist frontal system is moving onto the B.C. coast
today, with a trailing cold front apparent on satellite extending
west from Vancouver Island. This front will be approach the Pac NW
overnight, bringing mid and high clouds in from the northwest
starting this evening. The front will be dissipating considerably
between now and then, but the fcst models continue to indicate that
our northern zones may be brushed by light rain late tonight or Thu
morning. Otherwise expect little impact from this system.

Expect plenty of clouds to start out Thu, along with the possibility
for light rain up north. Further south, there should be less in the
way of high clouds moving in overnight, which may allow patchy fog or
low stratus to form early Thu. Clouds should clear a little earlier
in the day Thu, allowing inland temps to warm up into the mid 70s,
with near 80 possible down near Eugene.

Fri should be the warmest day of the week as a shortwave upper level
ridge moves over the Pac NW. Expect mostly clear skies and light
winds Thu night, with fcst model soundings indicating that there may
be some fog to start the day over the interior lowlands. But light
offshore flow may develop, which should ensure that any fog or low
clouds clear fairly quickly. High temps Fri will finally be back
above normal, with 80s over the interior lowlands and 60s and low 70s
at the coast. Sat looks similar to Fri. Then an upper level trough
swings down Sat night into Sun. This system brings a weak cold
front through as well, but at this time it looks to be mostly dry.
However, we do expect a better marine push and cooler temps Sun with
highs into the 70s again over the interior. Pyle

LONG TERM...Sun night through Tuesday...An upper level trough is
modeled move through the Pac NW late in the weekend, then split. The
northern stream energy races off into the Great Basin and then the
Rockies, while the southern piece appears likely to close off over
California and Nevada next week. This may open the door for the NE
Pac ridge to build into the Pac NW. The first half of next week
looks mainly dry with temps above average, especially toward
midweek. There is also potential for a light offshore flow pattern
to set up. Pyle

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory for winds from 2 PM Thursday to 5 AM PDT
     Friday 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.