850 
FXUS66 KPQR 041630 AAA
AFDPQR

Area Forecast Discussion
Weather Service Portland OR
930 AM PDT Tue Jun 4 2019

Updated aviation discussion

.SYNOPSIS...Dry weather continues Tuesday, with another day of
seasonable afternoon temperatures. A cold front will move onshore
Wednesday, possibly bringing some light rain or drizzle to the
coastal areas. Cool and unsettled weather will follow, likely lasting
into the weekend. Snow levels may occasionally lower to the Cascade
passes later this week.

&&

.SHORT TERM...Today through Thursday. A cool start to Tuesday across
the region as skies remain clear for most of the area. Some scattered
lower clouds may still reform along the coastal areas and can't
entirely rule out a few patches of fog in the coastal valleys toward
daybreak.  Any lower clouds that form won't last long, though, and
expect a mostly sunny day across the region today. Afternoon high
temperatures will again be near seasonal normals along the coast with
continued onshore flow, but temperatures inland will again be a few
degrees above normal.

This will begin to change late today, however, as a pattern shift
begins to take place.  Increasing mid-level clouds begin to reach the
northern coastal portions of the forecast area late in the afternoon
or evening, ahead of an approaching cold front. Meanwhile, lower
marine stratus likely also reforms along the coast tonight and pushes
into portions of the interior by early Wednesday morning. The cold
front will reach the coast early Wednesday and push across the region
through the day. Some light rain or drizzle may develop along the
coastal areas as the front pushes onshore. Some showers may also
develop in the higher terrain Wednesday afternoon, but moisture will
be somewhat limited per latest model guidance, so these will likely
be scattered at best and have maintained a very low QPF. 

The trailing upper level trough moves into the region late Wednesday
and into Thursday, with a much cooler air mass settling overhead.
This will aid in increasing instability, but models still not too
supportive of lightning on Thursday so will continue to not include
in the forecast. Despite some daytime heating, enough mid-level
moisture/cloud cover may be enough to mitigate sufficient warming for
surface based storms to develop. Snow levels fall to around 5,000
feet on Thursday, bringing some potential light snow accumulation in
the higher Cascades, but no significant impacts expected down at the
passes.    Cullen

.LONG TERM...Thursday night through Monday. The long term period will
be a tale of two patterns. Showers will continue Thursday night, and
have slightly expanded the mention of thunderstorm chances late
Thursday night for parts of the coast (generally Lincoln City and
south) and adjacent coastal waters. A better chance for lightning
will be into the day Friday across most of the area as some diurnal
heating could further enhance the instability. The degree to which
cloud cover may mitigate daytime heating, however, remains uncertain.
Regardless, will need to monitor the potential in the next few days
for Friday, and expect that the area where thunderstorms are a
possibility may shift slightly in future forecast updates. Meanwhile,
snow levels down to 4,500 feet Thursday night may bring light
accumulation of slushy, wet snow down to the higher Cascade passes. 

Some showers will continue to linger into Saturday, but flow aloft
becomes more northerly as the upper trough shifts eastward. This will
limit moisture through the day and bring precipitation to an end
early in the day to most of the area, though some showers may linger
in the south WA and north OR Cascades into the afternoon.
Temperatures will be a bit warmer but still several degrees below
normals. Heights will rise more significantly on Sunday, as high
pressure aloft will build into the Pacific Northwest. Expect
decreasing clouds and warmer temperatures for the start of next week.
Forecast models continue to indicate a more significant warming trend
early next week as developing offshore flow and rising heights may
push afternoon temperatures into the mid 80s in the interior lowlands
and even into the 70s along the coast.	 Cullen

&&

.AVIATION...VFR through this evening, with variable mid to high 
clouds through the day. Onshore flow increasing tonight, with 
MVFR stratus spreading along the coast. Could see some drizzle 
developing along the coast overnight. Expect the stratus to work 
its way to the interior lowlands after 08Z, but still expecting 
VFR conditions.

KPDX AND APPROACHES...VFR today through this evening, with just 
variable thin mid to high clouds. /42

&&

.MARINE...Northerly pres gradients still strong enough to keep
northerly winds gusting around 20 kt, with gusts up to 25 kt
south of Cascade Head. Will maintain Small Craft Advisory for
such winds until 5 am today. Gradients will weaken this am, with
generally 10 to 15 kt for later this am through rest of the day. 

Seas holding at 5 to 7 ft, though do have band of 7 to 8 ft swell
that is pushing across the Washington and far northern Oregon
waters. This will subside a bit, with 5 to 7 ft seas for rest of
the day. 

A weak front will push into the region Wed, with winds becoming W
to SW, but still under 15 kt for the most part. Another front
arrives on Thu, but still looks as though winds stay under 20 kt.
Seas too will stay in the 5 to 7 ft range.		Rockey. 

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory for winds until 5 AM PDT early this 
     morning for Coastal Waters from Cascade Head OR to 
     Florence OR out 60 NM.

     Small Craft Advisory for Rough Columbia River Bar until 8 AM 
     PDT this morning.

&&

$$

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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 
commonly referred to as the forecast area.