Winter Storm in Oregon, April 1 to 2, 2026

Area Forecast Discussion
National Weather Service Medford OR
1043 PM PDT Tue Mar 31 2026

...Updated AVIATION discussion for 06Z TAFs...

.DISCUSSION...Overall, the forecast remains on track and the main
changes involved upgrading/updating various wind and winter
headlines for the Wednesday system. Shower activity continues
across the region this afternoon, focused mainly along and west of
the I-5 corridor. Widespread clouds mixed with some spots of
sunshine is resulting in near normal temperatures for the area.
Overall, not much change is expected through the afternoon and
into the evening.

A big change is coming beginning late tonight and continuing
Wednesday into Thursday. Models continue to show a strong upper
trough moving southward from the Gulf of Alaska. The leading edge of
this system will be a cold front that will approach the coast later
tonight, and move onshore Wednesday. The upper level cold pool will
then move onshore into Washington/Oregon Wednesday night into
Thursday. Pressure gradients in advance of this system increase
Wednesday afternoon, with mid-level winds peaking around 55 kt. It
will be windy everywhere, with gusts of 20-30 mph common, even for
West Side areas. We expect widespread peak wind gusts in the 40-50
mph range for areas from the Cascades eastward, perhaps 55 mph in
some areas. Wind advisories have been issued for portions of
Lake/Modoc counties where winds will be strongest. The Shasta Valley
will be breezy at least, due to the fairly strong pressure gradient,
but the mid level flow will not be aligned with the terrain, keeping
winds there weaker than may otherwise be expected, but still close
to advisory level strength. Peak gusts of 40-45 mph are possible,
but we'll forego an advisory for now. Strong winds are also expected
along the coast, but should remain just below warning levels. The
capes and headlands could briefly see gusts up to 60 mph, but
overall, gusts in the 40-50 mph range are the more likely scenario.

The main frontal band will be accompanied by a period of moderate
rainfall with the heaviest precipitation from the coast to the
Cascades from late Wednesday morning through the afternoon. We are
NOT concerned about flooding with this event, other than some
minor/typical nuisance ponding of water on roadways. Since river
levels are very low for this time of year, most of the rain expected
from this system will be beneficial/welcome. Amounts of 1-3 inches
are likely along the coast, with 0.50-1.00 inch common inland to the
Cascades with 0.25-0.50 inch over the East Side. Snow levels of 5000-
5500 feet Wednesday will drop to 2500-3000 feet by Thursday morning.

It looks like a pretty healthy snow storm for the Cascades and
Siskiyous with 6-12 inches common above 5000 feet. The Winter Storm
Watch has been upgraded to a Warning for the Cascades. A Winter
Weather Advisory remains in place for the Highway 97 corridor from
Chiloquin northward for Wednesday night into Thursday morning and
we've added the Warner Mountains of Modoc County and the mountains
of western Siskiyou County to the Advisory as well. The heaviest
snow will fall near Crater/Diamond Lakes and near Willamette Pass
where it will be a bit colder, with NBM probabilities showing a high
probability (>80%) of >12 inches of snow. At Crater Lake (~7000
feet), the 48-hour probability of >18 inches of snow ending Thursday
evening is now nearly 100%! All in all, expect winter travel impacts
in the mountains and over some of the higher passes, especially at
Lake of the Woods by Thursday morning. Main I-5 passes should be OK,
but some slippery spots could develop at Siskiyou Summit and/or
around Mt Shasta City/Snowman Summit early Thursday morning.

With the core of the cold pool shifting into northeast Oregon and
Idaho on Thursday, showers and even an isolated thunderstorm or two
will continue for a while into Thursday afternoon, but then diminish
rapidly around sunset Thursday evening as high pressure builds in.
It should be noted that models are still showing a fairly high
probability (50-70% chance) that temperatures drop into the low to
mid 30s for the west side valleys by Friday morning. So, that will
introduce some frost/freeze risk. Greatest risk of that occurring is
in the Illinois Valley (Cave Junction/Obrien/Selma). The probability
of temperatures less than 28F, however, are quite low, generally 10%
or less.

Models are showing the upper ridge rebuilding across the area Friday
into the weekend, so look for temperatures to rebound to above
normal levels again (highs in the 70s again west side valleys) along
with little to no chance at precipitation. -Spilde/BR-y

&&

.AVIATION...01/06Z TAFs...Scattered showers continue to move over
northern California and southern Oregon, but instability has eased
and additional thunderstorms are not expected. MVFR ceilings are
present in some areas, notably at North Bend as well as over some
east side areas, ahead of an approaching low pressure system.

This low pressure system will bring active weather through the TAF
period. Initial activity is expected over Curry County and the
Cascades, with precipitation becoming more widespread into the
afternoon afternoon. Moderate to heavy rain showers are possible
west of the Cascades. Snow levels start at 6000 feet early Wednesday
morning, then look to start dropping in the afternoon and reaching
3000 feet by Wednesday night. This will allow for snow showers over
higher terrain in western Siskiyou County as well as over and east
of the Cascades. Rain and snow showers could bring locally lower
ceilings and visibilities across the area as well as obscure
elevated terrain.

Most areas will see some amount of gusty winds, with these winds
persisting into the end of the TAF period along the coast and east
of the Cascades. Guidance shows areas of low level wind shear
developing along the Oregon coast then over elevated terrain from
west to east through the day. The inclusion of wind shear in the
forecast for North Bend covers the duration of shear over coastal
areas. Other terminals are not expected to have shear overhead. -TAD

&&

.MARINE...Updated 1230 PM PDT Tuesday, March 31, 2026...Conditions
generally improve today with seas subsiding to around 4 ft. However,
seas are forecast to become steep late tonight with south gales
eventually leading to very steep seas through early Wednesday
afternoon. A Gale Watch has been upgraded to a warning for all
waters. Steep to very steep seas are expected to become swell
dominated Wednesday night and build to a peak Thursday morning. A
hazardous seas warning has been issued to account for this threat
late Wednesday afternoon through Thursday morning. Advisory strength
north winds are likely to return late in the week while seas remain
steep.

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Winter Weather Advisory from 8 PM Wednesday to 11 AM PDT
     Thursday for ORZ029-030.

     Wind Advisory from 11 AM to 11 PM PDT Wednesday for ORZ031.

     Winter Storm Warning from 5 AM Wednesday to 5 PM PDT Thursday
     for ORZ025-027-028.

CA...Winter Weather Advisory from 8 PM Wednesday to 11 AM PDT
     Thursday for CAZ080-085.

     Wind Advisory from 11 AM to 11 PM PDT Wednesday for CAZ085.

PACIFIC COASTAL WATERS...Gale Warning from 2 AM to 2 PM PDT Wednesday
     for PZZ350-356-370-376.

     Hazardous Seas Warning from 2 PM Wednesday to 11 AM PDT Thursday
     for PZZ350-356-370-376.

&&

MNF/JWG