571
FXUS66 KMFR 231126
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
326 AM PST Sun Nov 23 2025

.DISCUSSION...Leveraging GOES-West nighttime microphysics
satellite imagery early this morning, have decided to go with a
dense fog advisory for portions of the Rogue, Illinois,
Applegate, Umpqua and Coquille valleys until 10 am PST. Web cams
are even foggier across a larger area than they were yesterday,
basically all up and down I-5 from Roseburg to Medford and also
the state highways (199, 42, 62, 140, 238, 138) that branch off
from I-5. Please use extra caution if traveling this morning.
Cyclists and pedestrians should also wear bright or reflective
clothing to make it easier for drivers to see you. In addition to
the dense fog, which could limit visibility to below 1/4 of a mile
at times, temperatures are near or even a touch below freezing,
especially in the Rogue Valley around Medford. This could result
in some slick spots on roadways, especially those that are
elevated like bridges and overpasses.

Some areas had difficulty getting rid of the fog/low clouds
yesterday (it`s getting to be that time of year with low sun angle
and shorter days), but there is a front approaching from the NW
today and expect this to lift the fog (at least somewhat). Some
high clouds are already advancing into the area and we expect some
stratus to develop with light precip (rain) breaking out along
the coast this afternoon. Precipitation then spreads inland this
evening/overnight. Upper level support for this front is meager,
so while precipitation will make it to the mountains (Cascades
and the Siskiyous of western Siskiyou County), it will mostly fall
apart south and east of there. Amounts in the west side valleys of
0.05-0.15" will be common with 0.20-0.40" most likely along the
coast and in the mountains (maybe isolated amounts up to 0.50").
Highway 97 could get a little late tonight/early Monday too, but
most east side areas and NorCal will get skipped over.
Accumulating snow with the front will be mostly above 5500 feet
(2" or less). Snow levels drop to around 3500-4000 feet Monday
morning, but precip should be mostly done by then.

It dries out all areas Monday afternoon/night with surface high
pressure building in, so we`ll go back into a nighttime/morning
low clouds/fog regime for west side valleys. Tuesday/Wednesday, a
warm front will pass by to our north and west. This will allow
snow levels to surge back to around or even above 7000 feet. Most
areas will remain dry, but this could result in some light rain
across NW sections. Highest PoPs (~60-70%) will be along the coast
north of Cape Blanco and along the Lane/Douglas County border.
Overall, travel weather leading up to Thanksgiving Day should be
OK, except for the potential for low clouds/fog during the
nights/mornings.

The upper trough offshore will eventually bring a cold front to
the coast Thanksgiving Day/night. There are many different
scenarios with this system, but the gist remains the same,
highest PoPs from the coast to the Cascades with little, if any
precip reaching south and east of the mountains. In fact, PoPs in
NE California don`t get above 10% until Friday. While uncertainty
in the details is fairly high for late in the week into next
weekend, models are fairly consistent in amplifying an upper ridge
along 140W into eastern Alaska. In these scenarios, usually we
get a system to come southward along the BC coast and eventually
carve out an upper trough in the western US/Great Basin. Best
estimate on timing of the initial system would be Friday
night/Saturday, followed by a shot of colder air (below normal
temps) and lower snow levels pushing southward out of western
Canada behind that. Given the expected position of the ridge
(between 130-140W), the coldest air would be felt east of the
Cascades. We`ve got plenty of time though to assess the details
though, so stay tuned. -Spilde


&&

.AVIATION...23/12z TAFs...LIFR conditions in fog/freezing fog in
west side valleys will persist through around 17-18Z this
morning, with patches of LIFR freezing fog also likely in east
side valleys early in the morning (around 13-17Z). This will be in
the same areas as occurred Saturday morning, including the Rogue,
Umpqua, and Illinois valleys.

A weak front will push into the west side this afternoon, which
could lift these low conditions a bit earlier than occurred
Saturday morning. But, it will also bring increasing MVFR
conditions and obscuration of the higher terrain from west to east
this afternoon into the evening. Given the front will be weak,
generally light winds are expected through the TAF period, with
some light rain developing at the coast first, then spreading to
the southern Oregon Cascades during the late afternoon and
continuing tonight. Lower conditions with areas of higher terrain
obscured can be expected tonight. -Spilde


&&

.MARINE...Updated 300 AM PST Sunday, November 23, 2025...Steep
seas will continue today due to long period west to northwest
swell. A weak front will bring a brief period of south to
southwest winds along with some rain through this evening. Sub-
advisory north winds return overnight into Monday. A warm front
will pass by to the north Tuesday and this will bring another
round of southerly advisory level winds around midweek. -Spilde

&&

.BEACH HAZARDS/HIGH SURF...Updated 300 AM PST Sunday, November
23, 2025...Wave heights of 10-15 feet with periods of 15-17
seconds will bring an increased risk of sneaker waves at the
beaches through this evening. A Beach Hazards Statement is in
effect for sneaker waves that can run up significantly farther on
beaches than normal. These waves can wash over rocks and jetties
and can suddenly knock people off of their feet and sweep them
into the ocean. They can also move logs or other objects which
could crush or trap anyone caught underneath. While sneaker waves
can occur at any time, the greatest risk is on an incoming tide.
Please be aware of the tides if venturing out onto the beaches
today. -Spilde

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Beach Hazards Statement through this evening for ORZ021-022.

     Dense Fog Advisory until 10 AM PST this morning for ORZ021-023-
     024-026.

CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory until 10 AM PST Monday
     for PZZ350-356-370-376.

&&

$$

MAS/MAS/MAS