High Wind and Strong Wind in Oregon, November 4, 2021

Area Forecast Discussion...UPDATED
National Weather Service Portland OR
957 PM PDT Wed Nov 3 2021

Updated aviation discussion

.SYNOPSIS...The active weather across the Pacific will continue
into next week. Some of the storms will affect the Pacific NW with
rain and wind. The next storm will bring gusty south to southwest
winds to the coast and inland valleys later tonight into Thursday.
More Pacific storm systems affect the area over the weekend into
early next week and push their associated fronts through the Pac NW,
bringing periods of rain, Cascades snow, and gusty winds to the
region.

&&

.SHORT TERM...Tonight through Saturday...Satellite loop shows cold
front approaching the coast this afternoon with embedded convection.
So far lightning remains west of the coastal waters, but is forecast
to move to near the coast by this evening. Further west on satellite,
the cold front wraps up into an occluded front around a double low,
one near 46N 132W and to a tightly wrapped low center near 40N 134W.
The development of the system is supported by a strong jet
(100-120kt) along 40N across the north Pacific into northern CA.
Buoy 46006 reported msl pressure of 994 MB as the second low passed
nearby, it is now gusting to 49 kt in the northwest winds in the bent
back occlusion. Models are in decent agreement on the location and
strength of the low, but 12Z GFS/ECMWF appear to have a good grasp on
the details by having a closed low at the satellite location.  The
whole system will swing northeast overnight but the second low is the
one to watch as it swings closer to the Oregon coast overnight
increasing winds over the waters, then eventually land Thu. Winds at
the coast will become breezy this evening, but due to offshore
component to the wind will have to wait until the overnight hours
into Thu morning before southerly winds kick in. That should happen
from south to north early Thu morning with peak gusts to around 60
mph at the beaches and gusts 40 to 50 mph for coastal communities. A
high wind warning is in effect for the Oregon coast.  Winds at the
south WA coast is expected to become windy but not quite reaching high
wind criteria.	As the associated front moves inland will see
pressure gradients and isobar orientation become favorable for gusty
winds for the interior valley. It will become breezy early Thu
morning most every where, but the valley likely to have the most wind
impacts as the strongest winds from mid morning through mid
afternoon.  Model wind forecast at the 975 and 925 mb level have
25-35 kt and 40-50 kt respectively during that time, when it can be
more efficiently be mixed to the surface. Wind east fairly quickly in
the afternoon, but next front will bring breezy conditions to the
coast Thu night.

Will see decent amount of rain for the OR coast range per hires
models but will not be prolonged, so not expecting hydro issues. Rain
rates may reach 0.3 to 0.4" per hour in the OR coast range for a
short period tonight and early Thu as mean IVT values around 650-700
kg/m/s.  Snow level will be above most of the Cascades tonight, then
descend to near pass levels after the front moves through Fri, but by
then pcpn amounts are waning.

Friday evening will be relatively quiet as showers continue. But the
still active and similar weather pattern continues into the weekend
as Pacific lows approach the region. Current deterministic models
are not in good agreement on the strength, position and timing of
the lows. Right now looks at least windy at the coast and breezy
inland Sat. But one solution like the 12Z GFS is indicating
potential for high winds at the coast. But the air mass will be
cooler Sat so we'll likely see accumulating snow at the Cascade
passes. /mh

&&

.LONG TERM...Saturday night through Wednesday...Model and ensemble
guidance is in good agreement an active weather pattern will persist
into the middle of next week and make November feel like it's really
November (unlike some recent Novembers) across southwest Washington
and northwest Oregon. Temperatures should start off relatively cool
with snow levels generally hovering in the 2500-3500 ft range
Saturday night into Sunday with our first substantial round of snow
likely in the Cascades. Snow levels should then rise into early next
week, but confidence in details remains relatively low. Rain chances
appear more likely than not each day, but are highest over the
weekend and then again towards next Tuesday and Wednesday.
Specifically, we appear likely to be in a showery weather pattern
Saturday night into Sunday and more likely in a pattern conducive
for a longer duration steadier rain next Tuesday and Wednesday. It
should be noted that 10-20% of model guidance suggests a moderate to
strong atmospheric river oriented from west-to-east will impact the
region late Tuesday or Wednesday, which would result in hydrology
issues given the wet weather of late. For now, this still looks like
a low probability event, but something worth monitoring. /Neuman

&&

.AVIATION...06Z Tafs: Cold front is nearing the southern Oregon
coast as of 0430Z. Ahead of it to the north and east, rain with
embedded bands of moderate strength are streaming across the
region. Have mainly seen periodic drops into MVFR vsbys although
at KEUG, near ground has saturated and resulted in a VLIFR 003 cig
despite the next highest layer remaining at FL060. Winds have
remained somewhat light offshore aside from KTTD where Gorge
outflow continues to bring gusts 25-30 kts. May see some other
favored areas like KHIO saturate but confidence is fairly low at
this time.

Overnight, the occluded front wraps around the east side of the
parent low and gets closer to the coast. This will bring another
round of rain but this time with more widespread MVFR cigs and
gustier winds. Expect gusts 35-45 kts at the coastal terminals
but higher on the immediate beach. Inland gusts will range from
25-35 kts. This secondary cold front will cross the coast around
21Z and the inland terminals 23-01Z. Cigs should lift thereafter
with VFR conds following through most of the evening.

For detailed regional Pac NW aviation weather information, go
online to: https://weather.gov/zse

KPDX AND APPROACHES...Cigs will drop below FL040 early overnight
then fall below FL025 around the time of the morning boxer
arrivals. Cigs will stay there until after the secondary front
crosses 05/01Z. Easterly winds will continue with gusts around 20
kt until 04/17Z then switch southerly with gusts mainly 20-25 kt
through the afternoon. /JBonk

&&

.MARINE...Winds mostly sitting at 20 to 25 kt, with lighter winds
closer to shore. With first front about 100 miles offshore, will
see southerly wind picking up through early evening on the outer
waters, with gusts to 35 kt likely, especially as have showers
and a few thunderstorms along the front. Exception is for a few
stronger gusts around any thunderstorms. Closer to shore, winds
will remain south to southeasterly, but running a bit weaker.

But, another developing low, which was about 600 miles to
southwest of Newport (as of 2 pm), will push northeast tonight
and Thu. This system will bring tightening pressure gradients to
the coastal waters tonight into Thu, with solid southerly gales
expected. Strongest winds look to be from 4 am to 10 am Thu,
with winds gradually easing afterwards. Still, will likely
maintain gusts 30 to 35 kt through Thu afternoon. As such, Gale
warning up on the outer waters, with gale force winds spreading
to the inner waters later this evening. Will hold Gale up through
Thu evening.

Seas have been holding at 11 to 13 ft today, with higher seas
offshore. Interestingly, lot of this has been from a mostly
southwest swell direction. Not expecting much change in seas this
evening. But, as the winds arrive later tonight, will see lot of
wind- driven wave action, with combined seas building to 18 to
21 ft. Think as winds ease Thu afternoon, so will seas, running
15 to 17 ft in the afternoon, and 12 to 15 ft Thu night.
/Rockey

BEACH HAZARDS...Will see be a rough surf on along the coast later
tonight through Thu, creating hazardous conditions for beachgoers.
A Coastal Flood Advisory for tidal overflow remains in effect, as
will see some minor flooding of low-lying area in/near the surf
zone on Thu, primarily during the high tide around midday.
Surf waves, combined with the high tide, will result in minor
flooding up to one foot above ground level in the the low lying
areas near bays, sloughs, and the lower reaches of the rivers.

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory from 9 AM to 6 PM PDT Thursday for Greater
     Portland Metro Area-Lower Columbia.

     Coastal Flood Advisory from 10 AM to 4 PM PDT Thursday for
     North Oregon Coast.

     High Wind Warning until 1 PM PDT Thursday for Central Oregon
     Coast.

     Wind Advisory from 8 AM to 4 PM PDT Thursday for Central
     Willamette Valley-South Willamette Valley.

     High Wind Warning from 2 AM to 4 PM PDT Thursday for North
     Oregon Coast.

WA...Wind Advisory from 9 AM to 6 PM PDT Thursday for Greater
     Vancouver Area-I-5 Corridor in Cowlitz County.

     Coastal Flood Advisory from 10 AM to 4 PM PDT Thursday for
     South Washington Coast.

PZ...Gale Warning until 7 PM PDT Thursday for coastal waters from
     Cape Shoalwater WA to Florence OR from 10 to 60 nm.

     Small Craft Advisory until midnight PDT Thursday night for
     Columbia River Bar.

     Small Craft Advisory until midnight PDT tonight for coastal
     waters from Cape Shoalwater WA to Florence OR out 10 nm.

     Gale Warning until 7 PM PDT Thursday for coastal waters from
     Cape Shoalwater WA to Florence OR out 10 nm.

&&

www.weather.gov/portland

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