604
FXUS66 KMFR 011229
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
429 AM PST Mon Dec 1 2025

.UPDATE...Aviation Discussion Updated.


&&

.AVIATION...01/12z TAFs...This morning, MVFR in stratus is occuring
the Umpqua Basin and Coquille valley with areas of LIFR/IFR in fog
the Rogue, Illinois and Applegate valleys. Relatively dry northeast
flow across the area should keep fog development limited along the
coast and east of the Cascades/Klamath Basin. So VFR conditions are
expected to prevail through the TAF period there. Valley low clouds
are fog are expected to clear to VFR around 18-21z. As a weak
disturbance moves into the region Monday night and early Tuesday,
high level cloud cover is expected across southwest Oregon. The will
likely limit the development of fog Monday night with more isolated
and patchy MVFR/IFR in valley fog. VFR conditions are expected to
prevail across northern California through the TAF period.


&&

.PREV DISCUSSION... /Issued 256 AM PST Mon Dec 1 2025/

DISCUSSION...A high pressure ridge, centered over the Pacific,
extends across the area. This ridge will remain in place through
late this week. A weak shortwave is forecast to move down the
eastern side of this ridge tonight and into eastern Washington,
northeast Oregon and Idaho on Tuesday. This will bring onshore,
moist flow into northwest portions of the area. The National Blend
of Models continues to indicate chances for light rainfall at the
coast (20-60%) and inland over Douglas County (10-40%). Any
rainfall that occurs would be very light, around a trace to a few
hundreths of an inch. Otherwise, dry weather with seasonable
temperatures is expected across the area through Wednesday.
Overnight and morning valley fog may be the main concern through
mid week, with strong inversions and lingering moisture allowing
for areas of fog each day, especially west of the Cascades.

North to northeasterly winds are expected aloft, bringing some
breezy winds to the ridges today. Additionally, breezy northerly
winds are expected along the coast this afternoon and evening, and
again Tuesday. Inland, winds will increase out of the northwest
on Tuesday with the passage of the shortwave trough. Breezy to
gusty northwest winds (gusts to 15-25 kt) are expected east of
the Cascades on Tuesday.

The shortwave trough will shift southeastward Tuesday night and
Wednesday, with the high pressure ridge strengthening again over
the region. There is high confidence of dry weather across the
area Tuesday night and Wednesday.

Late in the week, ensembles support a more active pattern moving
into the Pacific Northwest as frontal systems move over the ridge
and into the region. This will bring chances for light
precipitation by Friday, then increasing chances for precipitation
Friday night and Saturday. There is more variability in the models
beyond Saturday, with the ECMWF drying out by Sunday and the GFS
staying active through the weekend and into next week. Meteograms
for both models generally support their respective deterministic
patterns, although the ECMWF ensemble has ~20% of its members
showing continuing rainfall. If the GFS outcome holds true,
precipitation amounts and snow levels will be a focus of future
forecasts. We will continue to monitor this period and update as
confidence increases.

MARINE...Updated 200 AM PST Monday, December 1, 2025...Breezy to
gusty northerly winds will continue through Wednesday, with gusts
south of Port Orford reaching Small Craft Advisory strength.
Additionally, long period west swell will build into the waters
late today and tonight, then peak on Tuesday (with west swell
building to 8 to 9 feet at 16 seconds and combined seas of 9 to 11
feet). Steep seas are expected across the waters south of Cape
Blanco through at least Wednesday. Seas may also become steep
north of Cape Blanco Tuesday night and Wednesday. Conditions may
briefly improve for Thursday, but the pattern is likely to turn
more active late in the week.

BEACH HAZARDS/HIGH SURF...Updated 200 AM PST Monday, December
1, 2025...Guidance shows a long period swell arriving Monday,
first arriving at around 2 to 3 ft at 20 to 22 second this
morning. This swell is expected to build to around 7 to 9 ft at 16
to 18 seconds late this afternoon into Tuesday morning with
combined seas of 9 to 11 feet. While seas will be steep, high surf
conditions are not expected along beaches. However, these
conditions will bring a risk for dangerous sneaker waves. If you
have plans to visit the coast on Monday, please be aware of this
sneaker wave potential and consider rescheduling your ventures to
the beaches for another day. 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. Remember, NEVER turn your back on the ocean!

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Beach Hazards Statement from 7 AM PST this morning through
     Tuesday afternoon for ORZ021-022.

CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory from 10 AM this morning
     to 7 AM PST Wednesday for PZZ356.

     Small Craft Advisory until 7 AM PST Wednesday for PZZ376.

&&

$$