Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 280952
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
252 AM PDT Thu Jul 28 2016

.SYNOPSIS...Weak upper ridging will lead to the warmest temperatures
we`ve seen this July to inland locations today and Friday. An upper
level trough will increase night and morning clouds and cooler
temperatures this weekend. Brief high pressure will move over the
area Monday before another upper low impacts the clouds and
temperatures Tuesday and Wednesday.

&&

.SHORT TERM...(Today through Sunday)...A building upper ridge of high
pressure is limiting the inland intrusion of marine clouds this
morning. Marine clouds have socked in the coast and some of the
coastal valley, and along the lower Columbia River.  The clouds will
expand a little further inland this morning, but should not make it
far into the Willamette Valley. ANy clouds that do form in the
interior valleys this morning will be shallow and clear rapidly. This
will result in warmer inland temperatures today with many locations
peaking in the 90s. Onshore winds will persist and limit clearing and
warming along the coast.

There will be little chance in the weather tonight and Friday as
marine clouds will sock in the coast tonight, with little inland
intrusion Friday morning. Inland temperatures will again warm into
the 90s.

An upper trough over the gulf of Alaska will drop south towards the
Pacific NW Friday night and 500mb heights over the area will lower.
His will deepen the marine layer for marine clouds returning to parts
of the Willamette Valley (mostly northern Valley) Saturday morning.
Inland afternoon temperatures will cool closer to the seasonal normal
Saturday afternoon, especially in the central and northern areas.
Lane County will remain slightly above normal.

The marine clouds will move much further inland Saturday night and
likely extend from the coast to the Cascades Sunday morning. There
may be some patchy drizzle along the Washington and north Oregon
coast in the morning. The daytime temperatures will cool a few
degrees with most inland areas remaining just below 80 degrees. TJ

.LONG TERM...(Sunday Night through Thursday)...There will be brief
ridging over the area Sunday night and Monday with marine clouds
having a weaker impact on inland areas. Inland temperature may warm
a few degrees but another upper low will move over the area Monday
afternoon and limit the warming. THe upper low will result in
increased cloudiness and cooler temperatures Monday night and
Tuesday. Upper level heights will build Tuesday and flatten Wednesday
for a return of near normal temperatures. TJ

&&

.AVIATION...IFR marine stratus along the coast and in the coastal
gaps this morning. The stratus is also pushing slowly up the lower
Columbia, reaching as far as Kelso as of 09Z. The stratus is more
shallow that the past couple of mornings, so think the inland
progression will be slightly less. That being said, there is
a chance for a few hours of broken low-MVFR or IFR cigs for KPDX
and KTTD between 13Z and 17Z. Otherwise, conditions will be VFR
over the interior today. The stratus should burn back offshore by
around 21Z. VFR conditions then likely at the coast through around
03Z Fri, then IFR stratus to push back onshore.

KPDX AND APPROACHES...There is a chance of low-MVFR or IFR stratus
around the terminal from around 13Z-17Z. Otherwise, VFR conditions
expected today and tonight. Pyle

&&

.MARINE...Not much change in the overall weather pattern through
the end of the week. Surface high pres remains over the NE Pac
with a thermal trough along the N Calif and S Oregon coast. This
will continue the gusty northerly winds over the coastal waters.
The strongest winds will continue to be over the southern portion
of PZZ255 and PZZ275, where gusts to 30 kt are possible during the
afternoon and evening hours today and Fri. A small craft advisory
for winds is in effect for all zones except PZZ250 through 12Z
Fri. Winds will also pick up over PZZ250 this afternoon, where a
small craft advisory goes into effect at 20Z. Winds will begin to
gradually subside over the weekend as the NE Pac surface high
weakens. However, small craft advisories will likely be needed
into Sat.

Choppy and wind-wave dominated seas will also continue through
the rest of the week. A small craft advisory for hazardous seas is
in effect for zones PZZ255 and PZZ275, where the strongest winds
will be. Expect seas to run at 7 to 9 ft with a dominant period of
7 to 8 seconds. Seas will be a bit lower further north. For now,
will leave the northern zones out of the small craft advisory, but
they may be bordering on square seas at times as well. As winds
subside some over the weekend, locally driven wind waves will also
subside, but a fresh swell from the nnw will keep seas steep. Pyle

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory for winds until 5 AM PDT Friday for
     Coastal waters from Cascade Head to Florence OR out 10 nm-
     Waters from Cape Shoalwater WA to Florence OR from 10 to
     60 nm.

     Small Craft Advisory for hazardous seas until 5 AM PDT Friday
     for Coastal waters from Cascade Head to Florence OR out 10
     nm-Waters from Cape Shoalwater WA to Florence OR from 10
     to 60 nm.

     Small Craft Advisory for winds from 1 PM this afternoon to 11
     PM PDT this evening for Coastal waters from Cape
     Shoalwater WA to Cascade Head OR out 10 nm.

&&
$$

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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.


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