247
FXUS66 KMFR 111757
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
957 AM PST Thu Dec 11 2025

.DISCUSSION...Updated aviation and marine discussions.


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.AVIATION...11/18z TAFs...We have reached the time of year where
the low sun angle is a significant factor in the sustainability of
low clouds/fog in the valleys west of the Cascades. Much like
yesterday, strong high pressure is in control and satellite
imagery is showing plenty of low-level moisture with stratus/fog
in just about every inland valley below 2500 feet. Moisture is
deeper farther north (Roseburg), so it is mainly an MVFR ceiling
there, but there is also some low-level wind (from the east) that
can be seen breaking up the stratus in the latest imagery. We
think it will break out to a scattered stratocumulus deck there
(Roseburg) this afternoon, at least for a few hours. Farther
south, the ceiling is IFR at Medford and isn`t showing signs of
breaking any time soon. We`ll maintain the stratus through the TAF
period there, perhaps with slight rise to low MVFR this
afternoon. Valleys south of the Siskiyous (Shasta/Scott/Klamath)
should see some erosion of the fog, but it probably won`t go away
completely. Elsewhere, east side areas are VFR (inclduing Klamath
Falls) and should remain that way through the TAF period. Some
MVFR at the coast north of Cape Blanco breaks up this afternoon.

West side valley areas that break from the low clouds/fog this
afternoon will likely see them return this evening/overnight.
Some areas won`t break at all and low conditions will persist.
Conditions are more likely to be IFR/LIFR tonight as the moist
layer should be somewhat shallower than the last couple of nights.
-Spilde


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.MARINE...Updated 830 AM PST Thursday, December 11, 2025...
We extended the small craft advisory until 1 pm PST this afternoon
since buoy observations are still showing seas of 10-11 feet/15
seconds. These conditions should improve late today into Saturday as
high pressure builds and seas lower. Winds will become northerly
late this afternoon and persist into Saturday morning but wind
speeds are expected to remain below small craft advisory levels.

The next big weather concern will be around Monday as a low deepens
out in the Pacific and models are showing a cold front swing through
the waters to our north. Right now, southerly gales are looking more
probable than not around 60 to 70 percent. -Spilde


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.PREV DISCUSSION... /Issued 918 AM PST Thu Dec 11 2025/

DISCUSSION...Satellite image shows low clouds confined to the
Rogue, Illinois, Scott, Klamath River, Shasta Valleys, and
portions of the Umpqua Basin this morning. The low clouds and
never broke out in the Illinois and Rogue Valley yesterday and
it`s possible it does not break out again in these areas today,
but there`s enough evidence to suggest the low clouds should burn
off early this afternoon and have trended the forecast in that
direction. Also have not seen any reports or web cams showing fog
and have removed it from the forecast. The exception will be in
the Scott and Shasta Valleys, where fog is present, but the fog
should lift to a lower overcast towards midday.

It will be dry today through the weekend and strong upper ridging
remains in place. This means a continuation of dry and stable
conditions, therefore we will likely have a repeat of low clouds
and perhaps fog in the same areas as the last couple of days.
-Petrucelli


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.MFR WATCHES/WARNINGS/ADVISORIES...
OR...None.

CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory until 1 PM PST this
     afternoon for PZZ350-370.

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MAS/MAP