Gale Warning 9, NWS Portland, OR

Area Forecast Discussion
National Weather Service Portland OR
859 AM PST Thu Feb  9 2017

.SYNOPSIS...A very moist frontal boundary will slowly move inland
today. Offshore low-level flow will persist through at least
mid-afternoon, which will maintain cold air in the Columbia
Gorge, Hood River Valley and parts of east Skamania County in SW
Washington. A secondary trough swings into the area late tonight
and Friday morning, which could will bring another burst of wind to
the South Washington and North Oregon coast. High pressure begins to
build Saturday, but a couple weak disturbances in northwest flow
aloft will maintain some shower activity across much of the area. The
ridge strengthens Saturday night and Sunday for dry conditions.

&&

.SHORT TERM...Today through Saturday...Morning water vapor and
satellite imagery show an surface low moving by buoy 46004 at 16Z.
The cold front was along the coast. Offshore low-level flow continues
through the Gorge, despite the warming across much of the area. At
16Z the KTTD-KDLS gradient was -7 mb. Cold air remains trapped in the
Central Gorge, Hood River Valley and east Skamania County. At 16Z
temps were still near freezing across these areas. Have had several
reports of sleet and freezing rain. Believe cold air will remain in
these areas through at least mid-afternoon, and may linger into the
most stubborn valleys until the evening. The cold front moves across
the Central Gorge and Hood River Valley mid to late afternoon. Will
hold on to the Winter Storm Warning through 00Z Fri, although the
worst of the event has already occurred.

Coastal wind speeds have diminished, but will likely increase over
the next couple hours until the surface low moves well north of the
area. The air mass this afternoon becomes more showery in nature, as
model forecast soundings indicate decent amount of instability. A low
level southwest flow will favor SW facing terrain with orographic
lift for most persistent showers. The next issue is the secondary low
that swings across the area late tonight and Fri. Models in general
agreement with this feature. 12Z NAM shows 50-55 kt 900 mb wind along
the coast 12Z Fri. Given the more unstable nature of the air mass,
these wind speeds will be more able to mix to the surface. For now
will cap wind gusts to 55 mph for the South Washington and North
Oregon coast, but high wind criteria is not out of the question. GFS
and NAM indicate 25 to 40 kt 850 mb WSW flow Fri, for decent
orographic enhancement. Expect up to around .50 inches QPF for the
Cascades, which would translate to about 6 inches of snow. May need
an advisory and will look at this for the afternoon forecast.

Northwest flow aloft prevails Fri night and Sat. Models imply a few
disturbances moving through in the northwest flow. Will need to keep
some shower chances across much of the area through Sat afternoon,
primarily focused on the north half of the forecast area. Weishaar

.LONG TERM...Saturday Night through Wednesday...Upper level ridging
moves in for the first half of the long term period which will usher
in a period of quiet, dry weather into the beginning of next week.
ECMWF and GEM keep weather dry into Wednesday morning, however the
GFS brings a shot of rain into the area Monday Night/Tuesday. All 3
models are consistent cutting off an upper low underneath the ridge
and swinging it through on Tuesday, but the GFS brings better
moisture with it and actually pushes the wave inland. Have added
slight chance PoPs to the Monday night/Tuesday timeframe, but most
likely solution is still the dry ECMWF/GEM. Otherwise, freezing
levels look like they will push up to the 7000 to 9000 ft range
towards the middle of next week which won't be great for ski
resorts, although it is possible the Portland area could see its
first week with multiple 50 degree days since November. /Bentley
&&

.AVIATION...A cold front is pushing onshore this morning,
bringing widespread moderate rain. Conditions at the coast are a
mix of IFR and MVFR, while the interior is predominantly VFR.
There will be some MVFR over the interior as well this morning
during periods of heavier rain. Expect conditions to generally be
improving this afternoon as we transition from rain to showers
behind the departing cold front. Expect conditions to become
mainly VFR, with occasional MVFR in heavier showers. Gusty
southerly winds will also ease this afternoon behind the front,
and the easterly winds near the gorge will switch to southerly.

KPDX AND APPROACHES...Steady rain continues this morning as a
cold front pushes onshore. Expect mainly VFR conditions, but a
period of MVFR is possible as the front moves through. Rain will
transition to shower behind the front around 18Z-19Z. Easterly
surface winds will also shift to southerly behind the front,
ending the low-level wind shear concerns. Expect mainly VFR in
showers this afternoon and tonight, with occasional MVFR possible
in heavier showers. Pyle

&&

.MARINE...A cold front pushing onshore this morning is bringing
one more burst of strong southerly winds. Will maintain the
storm warning over the waters through 18Z. Expect winds to
subside gradually through the rest of the day behind the front.
However, the post-frontal winds will still still be fairly gusty,
with gusts to 35 to 40 kt likely to continue through much of the
afternoon. Winds should drop below gale criteria by early this
evening. The main surface low associated with this frontal system
will toward the coast overnight into Fri morning, then push
onshore near the tip of the Olympic Peninsula by mid-morning Fri.
This will bring another burst of strong SW winds. At this time,
think winds will remain at high-end gale speeds with gusts of 40
to 45 kt.

Winds have climbed in the upper teens to low 20s with the strong
southerly winds this morning. They will be peaking this morning,
then will gradually subside this afternoon and tonight, reaching
the mid teens. However, they will likely come quickly back into
the upper teens and low 20s again Fri morning with the approach
of the main surface low. Think the best chances for seas
exceeding 20 ft will be over the WA and far N OR waters, which is
where the strongest winds will be.

High pres should then build across the waters Saturday through
at least Monday, which will bring substantially quieter weather
and seas to the waters. However, an active weather pattern looks
to resume towards the middle of next week. Pyle

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...Winter Storm Warning until 4 PM PST this afternoon for Central
     Columbia River Gorge-Upper Hood River Valley.

     Flood Watch through late Friday night for Cascade Foothills in
     Lane County-Central Coast Range of Western Oregon-Central
     Oregon Coast-Central Willamette Valley-Coast Range of
     Northwest Oregon-Greater Portland Metro Area-Lower
     Columbia-North Oregon Coast-Northern Oregon Cascade
     Foothills-South Willamette Valley.

     High Wind Warning until 10 AM PST this morning for Central
     Oregon Coast-North Oregon Coast.

     Coastal Flood Advisory until 2 PM PST this afternoon for North
     Oregon Coast.

WA...Winter Storm Warning until 4 PM PST this afternoon for Central
     Columbia River Gorge-South Washington Cascades.

     Flood Watch through late Friday night for Greater Vancouver
     Area-I-5 Corridor in Cowlitz County-South Washington
     Cascade Foothills-South Washington Coast-Willapa Hills.

     High Wind Warning until 10 AM PST this morning for South
     Washington Coast.

     Coastal Flood Advisory until 2 PM PST this afternoon for South
     Washington Coast.

PZ...Storm Warning until 10 AM PST this morning for Coastal Waters
     from Cape Shoalwater WA to Florence OR out 60 nm.

     Small Craft Advisory for Rough Columbia River Bar until 7 AM
     PST 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.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PORTLAND OR
428 AM PST THU FEB 09 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0335 AM     FREEZING RAIN    HOOD RIVER              45.71N 121.52W
02/09/2017  E1.00 INCH       HOOD RIVER         OR   PUBLIC

            TOTAL ICE ACCUMULATION ESTIMATED AS 1.0 INCH.

&&

DELSON

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PORTLAND OR
728 AM PST THU FEB 09 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0400 AM     DEBRIS FLOW      10 SSW PORTLAND AIRPORT 45.46N 122.68W
02/06/2017                   MULTNOMAH          OR   BROADCAST MEDIA

            HEAVY RAIN CAUSED A LANDSLIDE NEAR SKYLINE BOULEVARD AND
            BURNSIDE. APROXIMATELY 600 CUBIC YARDS OF DEBRIS SLID
            ONTO THE ROADWAY.

0600 AM     DEBRIS FLOW      8 SSW PORTLAND AIRPORT  45.48N 122.66W
02/08/2017                   MULTNOMAH          OR   BROADCAST MEDIA

            HEAVY RAIN CAUSED A LANDSLIDE ON US HIGHWAY 26 NEAR THE
            VISTA RIDGE TUNNEL THAT BLOCKED TWO EASTBOUND LANES.

0400 AM     DEBRIS FLOW      12 SW PORTLAND AIRPORT  45.47N 122.78W
02/09/2017                   WASHINGTON         OR   BROADCAST MEDIA

            HEAVY RAIN CAUSED A LANDSLIDE NEAR NORTHWEST THOMPSON
            ROAD AND CORNELL ROAD THAT BLOCKED LANES IN BOTH
            DIRECTIONS.

&&

TW

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PORTLAND OR
733 AM PST THU FEB 09 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0945 PM     ICE STORM        UNDERWOOD               45.72N 121.54W
02/08/2017                   SKAMANIA           WA   TRAINED SPOTTER

            WEATHER SPOTTER REPORTED 0.5 INCH ICE ACCUMULATION.

&&

TW