High Wind in Washington, October 6 to 7, 2016

Area Forecast Discussion
National Weather Service Portland Oregon
306 PM PDT Thu Oct  6 2016

.SYNOPSIS...A fast moving front will push rain and breezy south winds
into the region tonight. Upper level disturbance will lift north on
Friday, but lift north on Saturday, which will maintain dry and mild
conditions for much of the weekend with weak high pressure building
aloft. The next disturbance approaches the region early next week for
a return of rain to the area.

&&

.SHORT TERM...(Today through Sunday)...Widespread overcast skies
across the forecast area this afternoon as a deepening surface low
pressure continues to track eastward across 130W towards southern
Vancouver Island. As the low tracks east, the surface pressure
gradient will increase, resulting in windy conditions across the
region. Gusts to 50 mph on the southern Washington coast and 40 mph
for the northern Oregon coast will be likely this evening through
early Friday. Meanwhile, southerly gusts to 30 mph are possible later
tonight and particularly early Friday morning across the interior.
The leading edge of the precipitation shield, associated with a warm
front, has reached the Oregon coastline this afternoon as expected,
and this rain will continue to spread inland into the evening, as the
system is pushed forward by a 110 kt upper level jet. Forecast models
continue to push the front inland late this evening through early
Friday, with the mid/upper level boundary clear of the Cascades by
daybreak Friday.  As a result,	the heaviest rain will likely be late
this evening into early Friday morning.. Plenty of low level moisture
behind the front, so will likely see lighter rain continuing,
especially inland.

Rainfall amounts should be fairly decent, despite the fast movement
of the front. This mainly due to relatively moist air mass, as stream
of 1.40 to 1.50-inch precipitable water aimed at northwest Oregon and
western Washington tonight. Generally 1 to 1.5 inches for the Coast
Range, Willapa Hills, and Cascades of south Washington and north
Oregon. Inland, expect around one half inch north of Salem, but less
to the south. Snow levels will be on the climb, up to 7500 feet by
early Friday and up to 9000 feet later Friday, so little to nothing
in terms of new snow for the mountains.

A shortwave with a good bit of associated moisture with then move
towards the region, but remain generally focused on the north and
central Washington coast. Therefore, have maintained some lower end
PoPs across the far northern portion of the forecast area, with the
best chance north of the the Columbia River and a slight chance as
far as Lincoln City to Mt Hood line. Rain threat will end for the
rest of the area this weekend, as heights begin to rise. Some
uncertainty with respect to sky cover for Saturday, but some
scattering of lower clouds possible by the afternoon. Sunday looks to
be another dry day for most south of the Columbia River. Temperatures
this weekend will also be warmer, with temperatures inland climbing
into the lower 70s.   Cullen

.LONG TERM...(Sunday night through Thursday)...Models continue to
show the upper level ridge weakening early next week. Conditions
across the forecast area will likely remain warm and dry through
late Monday. A weak frontal system then looks to brush by the region
on Tuesday which could bring a chance of rain, but confidence is not
high. The active weather pattern looks to continue through the end
of the forecast period as a deep upper level low swings a series of
frontal systems across the Pac NW, with the potential for a potent
early season atmospheric river unfolding next week. There are still
a lot of uncertainty with the details as the storm track could
shift, but as of now it looks like next week could turn out to be
extremely wet. /64
&&

.AVIATION...As the warm front approaches, expect MVFR conditions
to continue along the North Coast this afternoon, with a mix of
MVFR and IFR conditions overnight. Rain will spread inland after
00Z, and bring cigs down to MVFR inland around 06-10Z Friday. The
front will bring southerly winds along the Coast with gusts to 30
to 40 kt between 03Z and 10Z Friday. Winds above 1500 feet near
KAST may gust to 40 to 50 kt during the same period. Inland will
see southerly gusts to 20 to 30 kt, generally KSLE northward from
06Z to 15Z Friday. Winds will ramp down behind the front, with a
mix of VFR and MVFR conditions through Friday morning. Conditions
should improve to primarily VFR inland by around 21Z, while the
Coast may hold on to at least MVFR cigs through Friday.

KPDX AND APPROACHES...VFR conditions with a scattered to broken
deck around 3500 feet this afternoon. Rain should start at the
terminal around 00Z Friday with cigs lowering to MVFR by 06Z to
08Z Friday. MVFR conditions continue until around 18Z to 21Z
Friday. -McCoy

&&

.MARINE...Warm front expected to move through the waters this
evening through late tonight, bringing southerly Gales to our
northern zones, with gusts to 40 kt for PZZ250 and PZZ270. Models
are showing the potential for a Coastal Jet over the nearshore
waters occasional gusts to 40-50 kt from about 10 pm tonight to
3 am Friday. For the waters off of Oregon's Central Coast, looks
like more of a high-end small craft advisory event. Higher pres
builds in over the weekend, for a period of lighter winds.

Seas are starting to build ahead of this warm front and will
continue to build to around 12 to 15 ft in the northern waters
and 9 to 11 ft in the waters off of Oregon's Central Coast. Seas
should peak with the winds around midnight tonight then slowly
fall through the day Friday to around 7 to 8 ft by Friday night.

Weather remains fairly benign through early next week, with an
active Fall pattern setting up for late next week. -McCoy

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Gale Warning from 2 PM this afternoon to 5 AM PDT Friday for
     Waters from Cape Shoalwater WA to Cascade Head OR from 10
     to 60 nm.

     Gale Warning from 7 PM this evening to 5 AM PDT Friday for
     Coastal waters from Cape Shoalwater WA to Cascade Head OR
     out 10 nm.

     Small Craft Advisory for winds from 2 PM this afternoon to 8 AM
     PDT Friday for Waters from Cascade Head to Florence OR
     from 10 to 60 nm.

     Small Craft Advisory for hazardous seas from 4 PM this
     afternoon to 3 PM PDT Friday for Coastal Waters from
     Cascade Head OR to Florence OR out 60 nm.

     Small Craft Advisory for winds from 5 PM this afternoon to 8 AM
     PDT Friday for Coastal waters from Cascade Head to
     Florence OR out 10 nm.

     Small Craft Advisory for Rough Columbia River Bar from 10 PM
     this evening to 4 AM PDT Friday.

     Small Craft Advisory for Rough Columbia River Bar from 7 AM to
     11 AM PDT Friday.

&&

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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.