366
FXUS66 KMFR 140545
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
945 PM PST Mon Jan 13 2025

...The aviation and marine sections have been updated...

.AVIATION...14/06Z TAFS...Conditions are still mainly VFR this
evening, with an area of LIFR stratus moving south into the Umpqua
Valley. Overnight, expect LIFR low clouds/fog to redevelop in the
west side valleys, including in Roseburg and Medford after 07Z, and
then mostly persist through Tuesday morning. The lower conditions
are expected to break to VFR by 20-22Z early Tuesday afternoon. The
remainder of the area will remain VFR through Tuesday evening. A
similar pattern of conditions is expected Tuesday night, with LIFR
west side valley fog developing late in the evening and overnight.
-DW

&&

.MARINE...Updated 800 PM Monday, January 13, 2025...There is
just enough of a wind/wave combination tonight to keep seas near 10
feet for steep seas over the outer waters south of Cape Arago. Winds
and swell will then increase on Tuesday in that area, and will show
little change during Tuesday night. So, a Small Craft Advisory is in
effect through Wednesday morning.

Most areas north of Cape Arago and inside 10 nm should have a period
with winds/seas below advisory levels. We do expect a period of time
Wednesday afternoon through Thursday morning where winds/seas are
below advisory levels for all areas.

Then, the thermal trough will likely reestablish and strengthen by
Thursday afternoon. Conditions become hazardous to small craft again
especially south of Cape Arago. Gusty north winds, strongest south
of Cape Blanco, could bring very steep seas to those areas Thursday
night into Friday. Though conditions improve slightly, steep seas
and advisory strength north winds may persist south of Cape Blanco
during the weekend. -Spilde/DW

&&

.PREV DISCUSSION... /Issued 231 PM PST Mon Jan 13 2025/

DISCUSSION...Ridging over the northeastern Pacific and broad
troughing over central North America will keep our forecast area
under general high pressure with north flow aloft. An upper level
trough to our south will close off and take up position offshore
of southern California and as a result, the Pacific ridge will
tilt inland over the Pacific Northwest. This ridge then remains in
control for the remainder of the week, either directly overhead or
centered just offshore.

All of this means that the weather will be dry, quiet, and fairly
consistent from day to day this week. Expect fog/freezing fog and
low clouds each overnight and morning for most valleys west of
the Cascades. Confidence is much lower, but valley fog is possible
east of the Cascades as well, although coverage may not be as
widespread or as consistent as to the west. Otherwise,
temperatures will generally see a gradual warming trend through
the week, although any areas in more persistent fog or low clouds
may stay cooler with very little change in temperature.

Air stagnation will be a concern through this time as well, with
strong valley inversions and very little mixing. An Air Stagnation
Advisory has been issued for area valleys through Thursday
morning. A weak front will pass just north and east of the area
Thursday, and this may help break the inversions at least
briefly, but continued high pressure after that is expected to
once again lock the area down under strong inversions. -BPN

BEACH HAZARDS...Updated 1000 AM PST Monday, January 13, 2025...
We extended the beach hazards statement. Seas are still in the
9-12 ft range at 16 seconds this morning and this could last
through this evening. Even though seas are expected to come down
briefly this afternoon and tonight, another long period west-
northwest swell (6-8 ft/19 seconds) will move in on Tuesday
maintaining a moderate risk of sneaker waves along southern Oregon
beaches. The risk is higher for west facing beaches and on
incoming tides. High tides during the event are this evening,
Tuesday morning and after 7 pm Tuesday evening.

Sneaker waves are a type of wave that can run higher up the beach
than a normal wave. Sneaker waves can possibly wash over pathways or
rock outcroppings. They can lift and carry logs, which can then
strike or pin beachgoers. Sneaker waves can knock a person off their
feet and carry them out to deeper waters, where hypothermia becomes
possible. Sneaker waves can pose a lethal threat. As these
conditions are expected while the sun is down, visibility will be
limited. Always keep your eyes on the sea and use extra caution.

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Air Stagnation Advisory until 10 AM PST Thursday for ORZ021-
     023>026-029>031.

     Beach Hazards Statement through Tuesday evening for ORZ021-022.

CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory until 10 AM PST
     Wednesday for PZZ370-376.

&&

$$