737
FXUS66 KMFR 151135
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
335 AM PST Sat Nov 15 2025

.DISCUSSION...Satellite imagery this morning shows an area of high
level clouds streaming northeast to southwest across most of
southern Oregon and northwest California. There are some returns
on radar associated with this cloud cover, but given high cloud
bases, and lack of surface observations reporting precipitation,
these returns are likely just virga with precipitation evaporating
before reaching the ground. These high clouds are keeping
temperatures warmer across the West Side Valleys this morning and
limiting radiational cooling which, in turn, is hindering fog
development.

Overall, quiet weather is expected today with calm winds and dry
conditions. This cloud sheild will gradually lift northwest today,
and most of the area should see at least a few hours of mostly sunny
skies this afternoon. High temperatures today will similar to
yesterday with low to mid 60s along the coast and for West Side
Valleys, and mid to upper 50s for the East Side.

The pattern will transition later this evening into Sunday as low
pressure lingering off the coast of California gradually moves
inland this afternoon/evening. Cloud cover will increase this
afternoon across the southeastern corner of the forecast area as
this low opens into a trough and southerly flow brings increasing
moisture into the area. As this happens, southerly winds will begin
increasing in the Shasta Valley and across the higher terrain east
of the Cascades late tonight and persist into Sunday afternoon.
Winds look to remain below advisory criteria with this increase, but
gusts of 25-35 mph can be expected with some higher gusts up to 40
mph possible. Additionally, guidance shows precipitation moving
northward into southern Klamath/Lake/Siskiyou and Modoc Counties
late this evening, with snow levels remaining on the high side.

Meanwhile, the next Pacific storm system approaches the area Sunday
afternoon/evening, bringing the return of precipitation from west to
east along with another round of breezy winds. Once again, this
system will split with the southern branch taking most of the energy
and precipitation into California and the northern portion moving
through Washington and northern Oregon. This pattern will focus the
best precipitation chances and highest amounts south of the OR/CA
border and along the coast south of Cape Blanco. Downsloping flow
will likely result in far less precipitation amounts here in the
Rogue Valley. Initial snow levels with this system of 7000-8000 feet
will keep snowfall to the highest peaks and ridgelines. Snow levels
drop to 5000 feet through Monday, but with the bulk of the
precipitation already through the region, snowfall amounts will be
rather meager. Latest forecast and guidance shows snowfall amounts
at Crater Lake to be around 1-3 inches, with some ambitious outliers
predicting up to 5 inches of snow by Monday night.

Precipitation eases across the area Monday night but a cold air mass
could linger over the area into midweek, bringing daytime high
temperatures that are around 5 to 10 degrees below seasonal norms.
This could result in some chilly nights for the West Side Valleys
north of the OR/CA border with low temperatures falling to the low
to mid 30s in portions of the Rogue/Applegate/Illinois Valleys.
There`s more uncertainty for the Umpqua Basin where fog tends to
keep temperatures elevated and dewpoints remain higher. At this
time, it looks like Tuesday night/Wednesday morning could be the
coldest, and this will be a time we`ll need to watch for the
potential of frost or freeze conditions for West Side Valleys. Of
course, the fly in the ointment will be the potential for fog in
these valleys, which, like the Umpqua Basin, would keep temperatures
elevated and limit the extent of frost/freeze.

Another low pressure system approaches the area late Wednesday into
Thursday, but there remains uncertainty regarding how far inland
this trough makes it as it dives southward. Both ECMWF and GFS
deterministic imagery now show the system impacting at least areas
from the Cascades west, but the EC is farther inland as it dives
into California while the GFS keeps the low`s center more offshore.
These differing solutions will have implications on how much
rainfall and strength of the winds that impacts the region. For now,
the forecast utilizes the NBM which maintains snow levels hovering
around 5000 ft, so winter impacts should be limited as well.
Overall, for both the Sunday-Monday cold front and Wednesday-
Thursday low pressure system, widespread impacts look minimal at
this point.

&&

.AVIATION...15/12Z TAFs...High clouds stretching across much of
southern Oregon and northwestern California are generally inhibiting
fog development in West Side Valleys this morning, leading to
widespread VFR conditions. This cloud shield will gradually lift
northwest this morning, and there could be enough clearing by
sunrise for a brief period "sunrise surprise" in the Klamath Basin,
including at Klamath Falls. Otherwise, VFR conditions are expected
to continue into the evening with generally light winds at all TAF
sites this afternoon. LIFR conditions in fog/low clouds are possible
this evening along the coast and in the Umpqua Basin, but incoming
high clouds could limit the extent of development tonight.

&&

.MARINE...Updated 130 AM PST Saturday, November 15, 2025...Sub-
advisory winds and seas are expected to persist through at least
early Sunday. Another system approaches the region Sunday into
Monday, bringing the return of increased southerly winds Sunday
afternoon. This increase in south winds will be brief, with winds
quickly shifting to northwest Sunday evening. At this time, it looks
like the northwest winds will be stronger than the southerly winds,
but still likely only reaching high end advisory strength. Northwest
swell increases as well, peaking in the 13 to 16 ft range at around
13 seconds. This increase in swell combined with wind driven seas
could bring steep to very steep seas to all waters Sunday evening
into Monday. Conditions improve again late Monday into Tuesday with
winds becoming northerly. The pattern remains active next week, with
the next impactful system expected Thursday.

&&

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

CA...None.

PACIFIC COASTAL WATERS...None.

&&

$$