Rip Current in Oregon, June 6, 2018

Area Forecast Discussion
National Weather Service Portland OR
1100 AM PDT Wed Jun 6 2018

.SYNOPSIS...High pressure builds over the region today for
drier and slightly warmer conditions. Clouds increase Thursday ahead
of a front that will result in unseasonably cool and wet weather
Friday through the weekend. Some thunderstorms may develop Saturday
afternoon as an upper level trough moves over the region. Warmer and
drier weather is expected early next week.

&&

.SHORT TERM...Minor update this morning, taking clouds off the coast.
 Otherwise, no additional changes.  Previous discussion follows.
-McCoy

.Today through Saturday...High thin clouds associated with an upper
level trough over N. CA are streaming over the forecast area. Upper
level heights will build over the Pacific NW today as the California
upper trough moves inland. This will cause the offshore front to lift
north this morning and reduce the chance for rain along the South
Washington coast.  This afternoon will be warmer than the past few
days with inland temperatures peaking close to 80 degrees. Light
onshore winds will keep seasonal high temperatures for the coast (low
60s).

Marine clouds will likely return to the coast tonight as an
upper trough returns to the region with a deepening marine layer
possibly resulting in low clouds moving through the coastal gaps into
parts of the north Willamette Valley Thursday morning at least
along the lower Columbia River. However, the onshore gradient
remains rather weak, so it seems unlikely that clouds will cover the
entire Willamette Valley. Clouds increase on Thursday as the next
front approaches and the inland temperatures will be closer to the
seasonal normals (low 70s).

The cold front will likely produce light rain along the coast late
Thursday night and Friday morning before moving inland Friday
afternoon and evening. Widespread rain will continue Saturday as a
sharp upper trough moves over the area. Rainfall totals of 0.5 to
0.75 inch of rain are expected from Friday morning to Saturday
evening. Decent modeled Cape and negative LI's Saturday afternoon
and evening suggest the potential for thunderstorms over the area as
the upper trough tilts negatively and moves inland. The models
indicate the best instability is over the Willamette Valley, but
expect the terrain will enhance instability as well, and have
forecasted a slight chance for thunderstorms from the coastal
mountains to the Cascades of NW Oregon and SW Washington. ~TJ

.LONG TERM...No Changes. Previous discussion follows...Saturday night
through Wednesday. Not much change to the long term period, with
models in fairly good agreement through the weekend. The upper level
trough responsible for the cool and wet conditions early in the
weekend will slowly migrate eastward into Sunday, but showers will
likely continue much of the day before tapering off late. A gradual
warming trend will start Monday and last through mid next week as an
upper level ridge returns. Models hint that weak surface systems may
continue periods of light rain on Monday. Then a drying trend will
join the warming trend for Tuesday and Wednesday. Cullen/TJ

&&

.AVIATION...VFR across the area today aside from some patchy MVFR
stratocumulus at the coast. That deck could bring brief periods
of MVFR cigs 020-030 at times during daylight today. Expect a
shallow stratocu deck will invade the coast around 08z tonight
then push inland reaching the inland terminals around 12-14z.
The cigs should remain in the 030-035 range and not much more
than 500 feet thick. Cigs will likely clear after 07/16z.

KPDX AND APPROACHES...VFR until about 12z when a shallow 030-035
cig will arrive. Expect the deck will affect visual approaches
through the bulk of the morning arrivals. /JBonk

&&

.MARINE...Made an abrupt update to the swell and resultant seas
today as a long distance swell arrived at buoy 89 this morning
and pushed east across the waters. Steep seas quickly built
reaching 11-13 ft and were 3-4 ft above all available model data.
Issued SCA for seas across all waters earlier and also issued a
Rough Bar Advisory to cover. Expect conditions to ease this
evening and remain mild for most of Thursday.

A cold front Thu night into Fri may bring small craft winds
advisory. The higher resolution NAM is indicating stronger winds
than ECMWF and GFS with this front. Winds then ease again for
the weekend. However something to watch - the 00Z GFS indicating
a low approaching the Oregon coast late Sun into Mon. Other
models are weaker and further offshore with this feature.

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory for hazardous seas until 10 PM PDT this
     evening for Coastal Waters from Cape Shoalwater WA to
     Florence OR out 60 NM.

     Small Craft Advisory for Rough Columbia River Bar until 11 AM
     PDT this morning.

     Small Craft Advisory for Rough Columbia River Bar from 11 PM
     this evening to 3 AM PDT Thursday.

&&

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 CWA or forecast area.