516
FXUS66 KMFR 051732
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
1032 AM PDT Sun May 5 2024

.UPDATE...Updated Aviation discussion for 18z TAFs.

&&

DISCUSSION...The forecast is on track for today. Cloud cover
remains over much of northern California and southern Oregon, but
activity is mostly limited to showers east of the Cascades.
Moderate shower chances (40-70%) will remain over the Oregon
coast and the Cascades today with lesser chances in between, but
any amounts will be light. For early Monday morning, a Freeze
Warning has been issued for the Shasta and Scott valleys for
expected temperatures in the high 20s to low 30s.

Please see the previous discussion for additional details on the
short- and long-term forecasts. -TAD

AVIATION...05/18Z TAFs...The worst conditions today will be along
and east of the Cascade Crest as MVFR/IFR conditions can be expected
due to snow showers reducing visibility and from lower Ceilings.
Klamath Falls  and other areas east of the Cascades will have some
gusty west winds (up to 30 kt at times).

West of the Cascades, expect mostly a mix of VFR/MVFR, with MVFR
ceilings/visibilities most likely in heavier showers primarily along
the coast and in Douglas County. Area wide, higher terrain will
experience obscuration at times.

A lessening in shower activity is expected from 00z to 06z, before
another front moves onshore during the 06z TAF window. Gusty
southerly winds and renewed shower activity should be expected when
the front moves through.
-Miles

MARINE...Updated 800 AM Sunday, May 5, 2024...Expect
scattered showers and dominant fresh swell today. Southwest winds
will increase to near gale force with another front tonight into
Monday morning. Moderate swell-dominated seas follow Monday into
Tuesday. A thermal trough will develop Tuesday afternoon with gusty
north winds and steep wind-driven seas, strongest south of Cape
Blanco. Wind speeds will peak late Wednesday, but strong northerly
winds will persist into Thursday night. The thermal trough will
weaken Friday into next weekend. -DW

PREV DISCUSSION... /Issued 502 AM PDT Sun May 5 2024/

DISCUSSION...Radar imagery is showing showers along and east of
the Cascades that appear to be almost stationary. Meanwhile, a few
isolated showers are moving across portions of the west side. This
is part of a low pressure system that is beginning to meander
across southern Oregon and northern California today. Snow levels
will be relatively low, around 3500 feet or so; but with the
showery nature of precipitation today, do not expect a lot of
impacts due to snow, especially with it being May. These showers
will begin to dissipate later this evening and tonight as the low
pushes eastward away from the area and a brief break is expected.

Additionally, we are tracking the potential for freezing
temperatures west of the Cascades, especially for the Scott and
Shasta Valleys in Siskiyou County. An 80 to 90 percent chance for
temperatures at or lower than 32 degrees is expected through 8 AM
this morning and a freeze warning remains in effect. Meanwhile, a
70 percent chance for freezing temperatures is expected once again
Sunday night into Monday morning despite temperatures being a
little warmer. For West Side Valleys in Oregon, the chances for
reaching freezing temperatures are lower--about 35% in the
southern Illinois and Applegate Valleys--this morning, and those
chances will further decrease again tonight as temperatures are
supposed to be a little warmer.

On Monday, another disturbance will push through the area, keeping
moderate temperatures and modest shower chances once again. A few
embedded thunderstorms may be possible as well. However, with the
weak nature of this impulse and the bulk of precipitation
occurring in showers should preclude any significant impacts due
to snowfall.

Once the impulse leaves the area, the weather pattern will change
as a ridge builds into the area. This will allow southern Oregon
and northern California to warm up and dry out. This ridge is
likely to linger through the extended forecast. -Schaaf

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...CA...Freeze Warning from 2 AM to 9 AM PDT Monday for CAZ080-081.

PACIFIC COASTAL WATERS...Small Craft Advisory until 8 PM PDT Monday
     for PZZ350-356-370-376.

&&

$$