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Area forecast discussion 
National Weather Service Portland or
146 am PDT Wednesday Jul 1 2015

Synopsis...high pressure will dominate the weather the next several
days. Marine stratus will keep the coastal temperatures in the 60s to
low 70s...but hot weather will continue inland with afternoon
temperatures reaching into the 90s. An upper low north of the area
will flatten the upper ridge this weekend resulting in slight cooling
for the beginning of the week.


Short upper ridge of high pressure will result in hot and
dry weather this week. 500mb heights will rise to around 590 dams
today with 850mb temperatures around 21 degree c...and hold through
Thursday. This will result in inland temperatures peaking in the middle
90s with local areas in the upper 90s to low 100s. The Heights will
begin to lower Friday as an upper low over northwest Canada deepens and
moves SW...and there will be slightly cooler temperatures for
Friday. Since these temperatures are running around 15 degree f above
the seasonal normals and my push into the upper 90s...decided to
issue a heat advisory for most inland areas today through Friday

Marine stratus will be mostly confined to the immediate coast in the
nights and mornings...keeping cooler temperatures for the coast and
parts of the Coast Range. The stratus may move further up the coastal
valleys and the lower Columbia River Thursday night...and may briefly
move over the Vancouver and Portland metropolitan areas. These low clouds
stratus will be shallow though and clear quickly...with only
marginal cooling to the inland temperatures.

Models are a bit on how much the Canadian low will impact The
Heights...and temperatures over the area Saturday. The 500mb heights
will lower and expect temperatures to cool some...but am uncertain of
how much cooling there will be. With the current model runs expect
the inland temperatures on Saturday to be 2 to 6 degree f cooler. Tj

Long term...Saturday night through Tuesday...upper level ridge of
high pressure will rebuild westward and maintain over the region
through the weekend. This will maintain temperatures well above
seasonal normals...namely in the low to middle 90s inland and near 70
at the coast. Upper low pressure passes well to the north of the
area over the weekend...but will flatten the ridge slightly and may
increase onshore flow. This would bring increased marine stratus
along the immediate coast and keep temperatures slightly cooler than
currently indicated. Maintained a slight chance of afternoon/evening
thunderstorms near the crest of the Cascades for Sunday with a
fair amount of instability depicted by forecast models...especially
in the Lane County Cascades. Models begin to diverge early next
week...but likely remaining generally dry and warmer than normal.

Aviation...VFR clear for the next 24 hours...except along the
coastline. Satellite fog product as of 08z showed a very shallow
marine layer...but it has been shrinking during the past couple of
hours. Localized IFR ceilings along the S Washington and far north Oregon coast
through about 12z then VFR. Central Oregon coast fog and stratus
getting pushed further to the S...thus konp may remain VFR through
this evening. Models indicate another weak upper disturbance
moving across northern Washington Wednesday night. Expect IFR ceilings to return
to the coastline after 06z Thursday.

Kpdx and approaches...VFR clear through 12z Thursday. Wind speeds to
pick up late this afternoon...but not as strong as Tuesday. Weishaar

Marine...pretty persistent pattern for the next few days. High
pressure to remain anchored over the NE Pacific through Sat then gradually
weaken. Thermally-induced surface trough will persist along the north
cal and S Oregon coast for the next couple of days...which will
maintain Small Craft Advisory wind speeds over the majority of the
waters. Strongest wind will continue to be south of Cascade Head
with gusts up to 30 knots during from the afternoon to early evening
hours. Wind will ease late in the week and over the weekend as
gradients diminish. Models in general agreement showing a switch
to a fairly light south to southwest wind late sun.

Generally wind-wave driven seas for the next few days...with steep
and choppy conditions. A building northwest swell looks to arrive late
Friday and Sat...possibly reaching 10 feet. This will be short-lived
as models indicate seas falling back to around 5 feet by Sun night
or Monday. Weishaar

Pqr watches/warnings/advisories...
or...heat advisory from 1 PM this afternoon to 9 PM PDT Friday for
Cascade foothills in Lane County-central Coast Range of
western Oregon-central Columbia River gorge-central
Willamette Valley-greater Portland metropolitan area-lower
Columbia-northern Oregon Cascade foothills-south Willamette
Valley-Upper Hood River Valley-western Columbia River gorge.

Washington...heat advisory from 1 PM this afternoon to 9 PM PDT Friday for
central Columbia River gorge-Greater Vancouver area-I-5
corridor in Cowlitz County-South Washington Cascade
foothills-western Columbia River gorge.

Pz...Small Craft Advisory for winds until 6 am PDT Thursday for
coastal waters from Cape Shoalwater Washington to Florence or out
60 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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