Tornado in Oregon, October 22, 2022

Area Forecast Discussion
National Weather Service Portland OR
316 PM PDT Sat Oct 22 2022

.SYNOPSIS...An active weather pattern will continue to bring periods
of valley rain and high mountain snow for much of the next week.

&&

.SHORT TERM...Tonight through Tuesday...Water vapor satellite imagery
this afternoon reveals a shortwave trough dropping southeastward into
the Great Basin. This is placing the Pacific Northwest in deep
northwesterly flow in the post frontal environment with plenty of
showers streaming southeastward across the area. A few short lived
thunderstorms have materialized offshore and near the coast, but have
remain rather isolated in nature to this point. As the inland valleys
warm up this afternoon cannot rule out an isolated thunderstorm or
two, but time is running out. NBM thunder probabilities are highest
across the southern Willamette Valley today.

Meanwhile, snow levels lowered to 3500-4000 feet this morning with
several inches of snow falling above 4000 feet. The current Winter
Weather Advisory looks on track with the highest snow amounts
expected near and above 5000 feet. Those traveling across the
Cascades should be prepared for winter-like travel conditions through
tonight. A flash freeze across the higher elevations of the Cascades
will be possible as the sun sets and clouds dissipate overnight.

Slightly drier air working its way into the region, weakening winds
and decreasing showers and clouds should allow many locations to drop
down into the 30s and low 40s tonight. The upper Hood River valley
should drop down near freezing so opted for a Frost Advisory. There
is 50% chance that temperatures actually drop below freezing across
the upper Hood River Valley.

Shortwave ridging building across the region should result in Sunday
being drying for most aside from a few light showers lingering along
the coast and Cascades around daybreak. Models and their ensembles
are in good agreement the next cold front will drop southeastward
across the region late Sunday night into Monday. This will bring
another round of valley rain and high mountain snow.  The parade of
storms continues into Tuesday as another storm system taking a
similar path the previous storms drops southeastward across the area.
/Neuman

.LONG TERM...Wednesdsay through Saturday...Models and their ensembles
are in relatively good agreement shortwave troughing will be
departing the Pacific Northwest and shifting into the Rocky Mountain
states on Wednesday. Nonetheless, there should be enough west to
northwesterly flow and post-frontal instabilty to keep PoPs high and
temperatures cool on Wednesday. The WPC cluster analysis does show
more uncertainty creeps into the forecast by Thursday as
approximately half of the ensemble solutions depict a pronounced
shortwave ridge pushing into the Pacific Northwest. This would likely
bring at least a 24-36 hour break in the wet weather. However, half
of the ensemble solutions suggest a much lower amplitude shortwave
ridge and the pattern being much more zonal. This would leave the
region open to additional wet weather under strong westerly flow
Thursday.

As we move into Friday and Saturday, ensembles are in better
agreement broad shortwave troughing will move into the Pacific
Northwest, but certainly very quite a bit in regards to its
magnitude. The end result is that area looks to remain cool with
additional rounds of light to moderate valley rain and high mountain
snow expected. /Neuman

&&

.AVIATION...00Z TAF early thoughts: The upper low pressure trough
will continue digging southeast over the interior western CONUS
tonight. Meanwhile, brief high pressure will transit the region
Sunday before another upper low approaches the coast beginning
late Sunday afternoon. Our region will remain west of the trough
axis under a generally northwest flow and unstable air mass
through this evening. Thunderstorms will remain possible over land
areas through sunset this evening around 0115Z with small hail
(less than 0.50 inches) and wind gusts 25-30 kts as the primary
threats. Still do not have enough confidence to say when and at
what TAF terminals any thunderstorms have a better chance to his
so continued leaving the mention out of the TAF for now. Will try
to update a little in advance, but they could just as easily form
right over the terminals today with the main threat being hail
less than 1/2 inch diameter and outflow gusts up to 30 kts.
Showers and any thunderstorms will diminish from northwest to
southeast with KSLE and KEUG holding on into the evening hours.
There then could be enough clearing overnight to produce some LIFR
conds under low clouds and/or fog. Any depreciated conditions
will improve by late morning.

KPDX AND APPROACHES...No significant notes aside from what was
mentioned above. /JBonk

&&

.MARINE...Seas have peaked earlier today reaching 15 seconds and
have easily verified the Hazardous Seas Warning issued earlier.
They are currently subsiding but buoy 50 is still sitting at 14
ft 11 seconds, so will likely hang onto the warning for at least a
couple more hours. Previous shifts saw another swell train
building which would've taken the seas into criteria once again
this evening, but latest wind and wave guidance seems to have
backed off. Adjusted the forecast downward but it still remains
just below the warning thresholds. Additionally, the winds have
peaked earlier with marginal and likely convective gale gusts.
Winds will continue to ease tonight as well.

High pressure will then briefly build into the area beginning
early Sunday morning, resulting in decreasing winds and subsiding
seas. However, the next storm system will result in winds and
seas climbing back into Small Craft Advisory thresholds Sunday
night into Monday with yet another storm system likely late Tuesday
into early Wednesday. In fact, seas are expected to peak around 13
to 15 ft yet again Monday evening. The active weather pattern
appears likely to continue thereafter.

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...Winter Weather Advisory until 11 PM PDT this evening for
     Cascades in Lane County-Northern Oregon Cascades.

     Frost Advisory from 2 AM to 8 AM PDT Sunday for Upper Hood River

     Valley.

WA...Winter Weather Advisory until 11 PM PDT this evening for South
     Washington Cascades.

PZ...Small Craft Advisory until 6 AM PDT Sunday for Columbia River
     Bar.

     Small Craft Advisory until 2 PM PDT Sunday for coastal waters
     from Cape Shoalwater WA to Florence OR out 10 nm.

     Hazardous Seas Warning until 5 AM PDT Sunday for coastal waters
     from Cape Shoalwater WA to Florence OR from 10 to 60 nm.

     Small Craft Advisory from 5 AM to 2 PM PDT Sunday for coastal
     waters from Cape Shoalwater WA to Florence OR from 10 to 60
     nm.
&&

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PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PORTLAND OR
1220 PM PDT SAT OCT 22 2022

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

0930 PM     NON-TSTM WND DMG 2 WSW POWELLHURST       45.48N 122.54W
10/21/2022                   MULTNOMAH          OR   BROADCAST MEDIA

            SEVERAL REPORTS OF DOWN TREES AT SE 115TH
            AND HAROLD ST. PER MEDIA. IT APPEARED TO BE
            TIED TO THE COLD FRONTAL PASSAGE AS A
            SURFACE LOW PASSED OVER CLARK COUNTY. TIME
            APPROXIMATED.

&&

NEUMAN