461
FXUS66 KMFR 291817
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
1017 AM PST Sat Nov 29 2025

.UPDATE...Updated aviation discussion.

&&

.AVIATION...29/18z TAFs...IFR/LIFR low clouds and fog persist late
this morning in the valleys west of the Cascades, along the coast
and also along portions of Highway 97 (north of Chiloquin) and the
Christmas Valley. Conditions should improve to VFR in most areas
this afternoon, but some places could hang onto MVFR ceilings into
the afternoon, especially at the coast. A weak disturbance will move
in from the north tonight with an IFR/MVFR mix. Isolated showers
are also possible, highest probability from the coast to interior
Douglas County (including Roseburg), in the mountains and across the
north from late this evening into early Sunday morning. Areas of
IFR/LIFR valley fog are expected to form again overnight
into Sunday morning. -Spilde

&&

.PREV DISCUSSION... /Issued 827 AM PST Sat Nov 29 2025/

UPDATE...Issued a dense fog advisory for portions of the Rogue,
Applegate, and Illinois valleys, as well as the lower Klamath
River Valley until 11 am PST for visibilities 1/4 of a mile or
less. With temperature near or below freezing, travelers,
bicyclists and pedestrians should be aware of potential slick
spots on surfaces. We also issued a freezing fog advisory for
portions of northern Klamath/Lake counties along Highway 97 north
of Chiloquin and also Highway 31 near Silver Lake/Christmas Valley
through 11 am PST. Reduced visibility and freezing conditions
could make for hazardous travel this morning there. -Spilde

PREV DISCUSSION... /Issued 521 AM PST Sat Nov 29 2025/

DISCUSSION...There is little change from the previous forecast
issuance, yesterday afternoon. Also, there will be an above
average day-to-day consistency in weather conditions through
Thursday, and possibly beyond.

We will remain in a north-northwest flow aloft with a series of
weak or very weak, low-impact "inside slider" weather
disturbances moving through over the top of a semi-permanent upper
ridge that will stay parked off the West Coast (out near 140W).
These disturbances are timed for late this evening into early
Sunday morning, Monday night into Tuesday night (with a focus on
the day-time hours of Tuesday), and Thursday night into Friday.
Much of our area will remain dry Today through Thursday, with the
highest probability of precipitation from any of the disturbances
at the coast and across the northern portions of Douglas and
Klamath counties.

Tonight`s system could produce a dusting of snow for the Cascades
from Lake of the Woods northward, with snow levels dropping from
around 5500 feet later this evening to around 4000 feet with the
last flakes around sunrise on Sunday. The probability of receiving
a measureable amount in the Rogue Valley has diminished, but the
slight chance mention remaining in the forecast looks appropriate.
There is also a slight chance of precipitation for Lake County
given its closer proximity to the passing trough, but most of
Klamath, Siskiyou, and Modoc counties are expected to remain dry.

The long term portion of the previous discussion is still valid
and follows below.

Another weak disturbance arrives in the NNW flow aloft across the
PacNW Monday night into Tuesday night. This one could cause an
uptick in afternoon N-NW breezes Tuesday, especially over the
higher terrain and east side. Again, precip chances look low with
slight chance to chance PoPs, highest over the mountains, but also
in the north and over the east side.

A strong upper high will then set up near 40N and 140W around mid
next week. This should provide dry weather Wednesday/Thursday as
upper trough energy settles into California/Great Basin. The
source of greatest uncertainty in the 12z models and ensembles for
late next week into next weekend is the development (or not) of
low pressure near the Great Basin/California and its progression
(or not) next Friday to next Sunday. Some solutions (mostly ECMWF)
favor consolidation of energy (upper low) near California
Wednesday with retrogression offshore and even the potential of a
rex block (high over low) off the West Coast by late next week.
This would displace the northern branch jet farther north and keep
our area more under the influence of the upper ridge (thus drier,
milder conditions). Weaker and more progressive solutions (mostly
GEFS, but also CMC) suggest potential for northern branch energy
to remain nearby late in the week (cooler, wetter). The trend in
the recent guidance has been for a drier solution during this time
period and this follows the CPC 6-10 day forecast, which shows
odds favoring below normal precip and above normal temps for SW
Oregon and norCal Dec 4-8. Current forecast for next Friday brings
an increase in PoPs, especially Cascades north and west, but this
will likely change based on the scenarios mentioned above. Keep
checking back for updates! -Spilde

AVIATION...29/12z TAFs...Coastal and valley LIFR/IFR will reach
peak coverage around sunrise, then gradually diminish in coverage
with improvement into the afternoon and early evening. VFR is
expected to be the predominant condition, but areas of MVFR are
expected to linger at and near the coast. Afterwards, a weak
disturbance will bring a IFR/MVFR mix with a chance of showers along
the coast and into Douglas County (including Roseburg) from late
this evening into early Sunday morning. Meantime, patches of IFR
valley fog are expected to form elsewhere overnight into Sunday
morning.

MARINE...Updated 200 AM PST Saturday, November 29, 2025...
Winds and seas will be at a minimum this morning. Northerly winds
then increase, with speeds approaching Small Craft Advisory strength
south of Cape Blanco as early as Sunday afternoon. North winds are
expected to further strengthen on Monday into Tuesday, but are most
likely to remain at Small Craft Advisory strength while a long
period west swell builds in the waters. The long period swell is
expected to peak at 7 to 10 ft at 16 to 19 seconds. Advisory level
conditions remain possible in the southern waters at mid-week into
Thursday.

BEACH HAZARDS/HIGH SURF...Updated 200 AM PST Saturday, November
29, 2025...There could be a brief period of a low sneaker wave
threat this afternoon as a 3-5 ft swell @ 14-16 seconds builds to a
peak (6-9 ft @ 14 seconds) this evening. The higher risk for sneak
waves, however, is expected on Monday morning into Tuesday
afternoon. A distant storm will create a long period swell, and buoy
guidance maintains the potential for this swell to bring a high
sneaker wave threat.

Guidance shows a long period swell arriving Monday, first arriving
at around 3 to 5 ft at 21 to 22 seconds early Monday morning, which
coincides with the incoming high tide that is anticipated by 8 am
PST Monday morning. While sneaker waves can occur at any time, the
greatest risk is on an incoming tide. A Beach Hazards Statement
remains in effect to highlight this risk for Monday morning into
Tuesday afternoon.

This swell is expected to peak at around 7 to 10 ft at 16 to 18
seconds Monday afternoon and evening, so while seas will be steep,
high surf conditions are not expected at beaches. If you have plans
to visit the coast next week, particularly on Monday, please be
aware of this potential and consider rescheduling your ventures to
the beaches for another day. Sneaker waves 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. Remember, NEVER turn
your back on the ocean! /BR-y

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Dense Fog Advisory until 11 AM PST this morning for ORZ024-026.

     Beach Hazards Statement from Monday morning through Tuesday
     afternoon for ORZ021-022.

     Freezing Fog Advisory until 11 AM PST this morning for
     ORZ028>031.

CA...Dense Fog Advisory until 11 AM PST this morning for CAZ080-081.

PACIFIC COASTAL WATERS...None.

&&

$$

MAS/MAS/MAS