High Wind in Oregon, March 9 to 10, 2024

Area Forecast Discussion
National Weather Service Medford OR
406 PM PST Sat Mar 9 2024

.UPDATE...Updated aviation section for 00z TAFs.

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.PREV DISCUSSION... /Issued 248 PM PST Sat Mar 9 2024/

SHORT TERM...Through Monday morning (3/11)...Scattered post-frontal
showers continue behind a weak warm front that passed over northern
California and southern Oregon early Saturday morning. A Wind
Advisory will remain over areas of southern Lake County and the
Warner Mountains through Saturday at 7 PM. Current RAWS observations
at Rock Creek and Coffee Pot Flat show that gusty winds are
continuing to reach 30 to 40 mph.

Winds and showers will calm overnight before another front arrives
Sunday. The first showers will reach the Oregon coast early Sunday
morning and the band of precipitation will move eastward through the
day. Higher rainfall amounts are expected across the area. 1 to 2
inches of rain are expected along the Oregon coast, with the higher
end amounts mostly south of Bandon. Southern coastal ranges will get
2 to 3 inches of rain, and other areas in Coos and Curry counties
will get between 0.5 and 1 inches. Downsloping will limit rainfall
in the Umpqua, Rogue, and Shasta valleys. The Cascades will minimize
precipitation farther east.

Snow levels of 3500 to 4500 feet will limit snowfall to higher
elevations, but the amount of moisture allows for the possibility
of impactful snowfall at those higher elevations. A number of
warning products will be in place on Sunday from 5 AM to 5 PM PDT
(Time change!) to highlight regional hazards. A Winter Weather
Advisory is in place for parts of western Siskiyou County above
3500 feet to highlight snowfall amounts between 4 and 8 inches and
up to 12 inches on ridges and mountaintops. While the heaviest
snowfall is mostly over remote areas, Sawyers Bar Road near Etna
is expected to see heavy snow. Any drop in snowfall levels
(especially due to heavy precipitation) could impact longer
portions of the road.

In the area around Mount Shasta, a Winter Weather Advisory is in
place for elevations above 3500 expecting 1 to 4 inches of snow.
This advisory includes Interstate 5 north of Dunsmuir and south of
Weed as well as Highway 89 east of McCloud. Additionally, a Winter
Storm Warning is in place for areas above 3500 feet expecting 6 to
12 inches of snowfall, including Snowman Peak on Highway 89. Amounts
in this area can be dependent on southerly flow as well as having
the right snow levels, but mean NBM outcomes match up with the
warning products.

A final Winter Weather Advisory is in place for higher terrain in
the Cascades as well as Mount Ashland where 5 to 10 inches of snow
are expected to fall. Highway 58 at Willamette Pass is also
included in this product, although amounts there are expected to
be closer to 5 inches of snowfall. Travel in any of these areas
may be significantly impacted by snowfall or elevated winds, and
extra caution is encouraged.

Winds will also be a concern as this front approaches on Sunday
morning, with gusts along the Oregon coast of 40 to 50 mph possible
and gusts at Cape Blanco expected to reach 60 mph. A High Wind
Warning is in place for areas along the coast expected to see the
highest winds from Saturday at 10 PM PST to Sunday at 8 AM PDT.
Gusty winds will also return to the Shasta Valley and areas east of
the Cascades, especially south of Klamath Falls and across Lake
County. Wind Advisories from Sunday at 5 AM through 5 PM PDT (Shasta
Valley) and 11 AM through 8 PM PDT (East side areas) will be in
place to communicate the timing of these gusty winds.

Post frontal showers are expected to follow this activity, with
moderate chances (30-60%) for precipitation remaining over the
Oregon coast and the Cascades into Sunday morning. -TAD

Long term...Monday morning (3/11) through Saturday night
(3/15)...The extended forecast begins with active weather as the
last in the series of fronts passes through the region late Monday
into Tuesday. A transition to high pressure with dry conditions and
unseasonably warm temperatures is anticipated around mid-week and
expected to continue through at least the following weekend.

The third and last front in the series of systems from the short
term will pass will begin impacting the region Monday afternoon as
winds increase ahead of the front expected Monday night into
Tuesday. This front looks weaker in terms of wind compared to the
Sunday system, with 700 mb winds maxing out around 35 to 45 kts. So
we don't currently expect this front to bring any warning level
winds to the region, but borderline advisory criteria is possible,
especially along the higher terrain east of the Cascades.
Additionally, we do expect another round of moderate snowfall with
this front with snow levels hovering around 4000 ft. With the
westerly orientation of mid-level jet (vs southwesterly with the
previous fronts), we do expect the Cascades to receive the bulk of
the snow with this system (around 10-16 inches) and additional
winter weather headlines will likely be needed for Monday night into
Tuesday. The main front looks to be through the region by Tuesday
morning, then as the upper trough pushes through, expect showers to
continue through the afternoon and evening. Showers will linger the
longest overnight into Wednesday morning along the coast, north of
the Umpqua Divide and along the Cascades.

Wednesday will be a transition day as an upper level ridge builds
over the eastern Pacific, bringing an end to showers and closing the
storm door for a while. High pressure amplifies Thursday and into
the weekend, gradually moving over the Pacific Northwest over the
weekend. Temperatures will trend warmer on Thursday with afternoon
highs in the low 60s (low 50s) west (east) of the Cascades. A
thermal trough also develops on Thursday, and this will induce east
to northeasterly flow across the region, aiding in the unseasonably
warm temperatures west of the Cascades through the weekend. Upper
60s to low 70s (maybe even mid 70s?) are anticipated Friday into the
weekend for locations west of the Cascades. Current records for mid-
March are roughly in the upper 70s to low 80s, so this doesn't look
like record challenging event at this time, though afternoon
temperatures will be more typical of May than mid-March. /BR-y

AVIATION...10/00Z TAFs.... The next front approaches the coast
tonight and passes through the region through Sunday morning. This
will bring the return of low level wind shear concerns (LLWS) by
this evening for all terminals at least through the 06z TAF cycle,
if not longer. Expect conditions to lower to MVFR/IFR with the
frontal passage starting around 12z at the coast, and pushing
inland west of the Cascades by 18z due to rain showers and snow
from around 4000 feet and above. Gusty winds are expected area
wide tonight into Sunday afternoon, strongest east of the
Cascades, across the higher terrain and in the Shasta/Scott
Valleys. The strength of this front could also generate an
isolated thunderstorm from midnight through Sunday afternoon near
the coast and inland as far as Roseburg. /BR-y/Miles

MARINE...Updated 145 PM Saturday, March 09, 2024...Seas will
continue to rise as another front moves into the region this
evening. We are expecting wind speeds to reach gale force with this
front. However, there is a low chance for isolated gusts to storm
force, mainly beyond 10 nm, but could still occur north of Cape
Blanco in the inner waters, too. We have maintained the gale warning
knowing if buoy observations show storm force winds we may need to
update the hazards on short notice, but have brought the ending time
forward as model agreement increases.

Behind this front, a long period, west swell will move into the
waters later on Sunday afternoon with a swell group around 15 to 17
feet at 14 to 15 seconds. This large swell and lingering fresh,
southerly swell will combine to maintain steep to very steep seas in
between this second front and a third front expected on Monday
evening.

The last front will push through the waters around Monday evening
with another chance of gales and high and steep seas. As high
pressure builds from Tuesday onwards, winds will shift out of the
north in a summer-like thermal trough pattern while moderate swell
continues to come in from the northwest. While this change in
pattern will lead to a net lowering of sea heights and a reduction
in steepness, current forecasts keep advisory conditions for large
portions of the area into the end of the work week.
-Miles

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.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory from 5 AM to 5 PM PST Sunday for ORZ029>031.

     High Wind Warning from 10 PM this evening to 8 AM PST Sunday for
     ORZ021-022.

     Winter Weather Advisory from 5 AM to 5 PM PST Sunday for ORZ027-
     028.

CA...Winter Weather Advisory until 4 PM PST this afternoon for CAZ080-
     082-083.

     Winter Weather Advisory from 5 AM to 5 PM PST Sunday above 3500
     feet for CAZ080.

     Wind Advisory from 5 AM to 5 PM PST Sunday for CAZ081-084-085.

     Winter Weather Advisory from 5 AM to 5 PM PST Sunday for CAZ082.

     Winter Storm Warning from 5 AM to 5 PM PST Sunday for CAZ082-
     083.

PACIFIC COASTAL WATERS...Hazardous Seas Warning until 7 PM PST this
     evening for PZZ350-356-370-376.

     Hazardous Seas Warning from 8 AM Sunday to 5 AM PST Monday for
     PZZ350-356-370-376.

     Gale Warning from 7 PM this evening to 8 AM PST Sunday for
     PZZ350-356-370-376.

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