High Wind in Oregon, April 18, 2022

Area Forecast Discussion
National Weather Service Medford OR
1135 AM PDT Mon Apr 18 2022

.DISCUSSION...18/12Z NAM in.

Clouds are overspreading the Medford forecast area ahead of a cold
front approaching the coast. No precipitation has been reported
over land areas yet, but it will begin soon. Winds have picked up
though, mostly along the coast and in the Shasta Valley.

The front will move onshore this afternoon. This front will bring
a combination of strong, gusty winds and moderate rain and
mountain snow to the area. Light precipitation will start at the
coast later this morning then increase in intensity and spread
inland across western portions of the area and into the Cascades
through this afternoon. Rain and snow will spread east of the
Cascades this evening and tonight. Snow levels will be around 5000
to 5500 feet today, lowering to around 4500 feet with the frontal
passage this evening into tonight, then down to 3000 to 3500 feet
by early Tuesday morning.

There will be moderate to locally heavy snow accumulations in the
Southern Oregon Cascades, mainly above 4500 to 5000 feet, and in
the higher mountains in the Siskiyous, above 5000 feet. Peak
snowfall rates over the Southern Oregon Cascades are expected this
evening and may approach 1 inch per hour. Moderate to heavy
snowfall rates combined with gusty winds, especially in exposed
areas, may result in near white out conditions at times. Winter
Weather Advisories are in effect for above 4500 feet in the
south central Oregon Cascades and above 5000 feet in the Southern
Oregon Cascades and Siskiyous from late this afternoon through
late this evening. See PDXWSWMFR for details.

There will also be moderate snow accumulations across the higher
mountains above 5000 to 5500 feet in Siskiyou county. However,
this will mainly affect remote locations. East of the Cascades,
there will be a mix of rain and snow this evening into tonight,
changing to snow late tonight and early Tuesday morning. Mostly
light snow accumulations are expected, expect for locally moderate
snowfall possible in the higher mountains across far eastern
Klamath into western Lake County and over the Warner Mountains.

As far as winds go, they will be strong and gusty ahead of the
front, diminishing behind the front. South to southwest winds
will increase and become gusty across most all the area later this
morning into this afternoon. The strongest winds will occur in
the Shasta Valley as well as east of the Cascades over the higher
mountains and into the Summer Lake area, with winds gusting to 45
to 55 mph. A wind advisory remains in effect for these areas. See
PDXNPWMFR for details.

Western valleys may see gusts of 25 to 30 mph. Coastal areas will
see gusts of around 40 mph with higher gusts up to 55 mph across
coastal headlands. In eastern valleys, including near Klamath
Falls, winds will gust to around 30 to 40 mph.

Behind the front, unstable conditions supported by cold air
aloft will bring a slight chance for thunderstorms this evening
into tonight to the coastal waters and coast from around Cape
Blanco north.

Widespread post frontal showers will persist until the supporting
upper trough moves to the east of the area Tuesday. Snow levels
will be down to 3000 feet Tuesday morning, rising to around 4000
to 5000 feet Tuesday afternoon. Showers will be mainly light with
some heavier showers at times, especially over the mountains from
the Cascades west. Then shower are expected to decrease in
coverage and intensity Tuesday evening and Tuesday night.

A short wave ridge will move through Tuesday night, bringing a
relative break in the action, but that break will be short lived.
Another upper trough will move in, pushing another wet and windy
front onshore Wednesday.

&&

.AVIATION...18/18Z TAFs...Strong wind gusts are starting to show up
across the region as a cold front approaches from the west.  Look
for pockets of LLWS along the coast for the next few hours.  As
surface winds increase farther inland, the LLWS threat should
decrease.

MVFR to IFR ceilings are expected as the front begins to move
farther inland. The MVFR ceilings will likely persist for most of
the TAF period. Behind the front, showers will continue into the
evening and overnight hours.

-Smith

&&

.MARINE...Updated 800 AM PDT Monday, 18 April 2022...Gales and high
and very steep seas will be present this morning as a cold front
moves across the waters this morning. Winds will subside late
morning into early afternoon, but high and very steep seas will
remain overnight tonight.

After a brief break Tuesday, steep seas are likely Tuesday night
into Wednesday as another strong cold front moves into the waters.
At the very least, conditions will become hazardous to small craft.
However, gale force winds remain possible Tuesday night into
Wednesday. Guidance shows a high, long period swell moving into the
waters early Thursday morning with swell heights peaking out between
16 and 18 feet with a period between 16 and 17 seconds late Thursday
night. -Sven/DW

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory from 11 AM this morning to 5 AM PDT Tuesday for
        ORZ030-031.
     Winter Weather Advisory from 5 PM this afternoon to midnight PDT
        tonight above 5000 feet in the for ORZ028.
     Winter Weather Advisory from 4 PM this afternoon to midnight PDT
        tonight above 4500 feet in the for ORZ027.

CA...Wind Advisory from 11 AM this morning to 5 AM PDT Tuesday for
        CAZ085.
     Wind Advisory until 8 PM PDT this evening for CAZ081.

Pacific Coastal Waters...
     Gale Warning until 5 PM PDT this afternoon for
        PZZ350-356-370-376.
     Hazardous Seas Warning from 5 PM this afternoon to 5 AM PDT
        Tuesday for PZZ350-356-370-376.

15/16/16