013
FXUS66 KMFR 051011
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
311 AM PDT Sun Oct 5 2025

.DISCUSSION...Shower activity in the area has come to an end early
this morning with no returns appearing on radar. We`ll transition
to a period of warmer and drier conditions beginning today as
upper level ridging builds in overhead from the west, and
offshore flow (east to northeasterly winds) develops, peaking
tonight but continuing into early Tuesday morning.

Low level cloud cover has lingered across the region this morning,
primarily in West Side Valleys, but also across northern Klamath
County and much of Lake County. This should keep temperatures up
some across the the Christmas Valley this morning, but we still
expect freezing temperatures this morning and again Tuesday, with
even the warmer areas still seeing lows near freezing. On the
coldest morning of this episode, a hard freeze is expected for
much of the East Side on Monday morning. Given the recent cold
mornings and that we`ve reached the time of year when normal low
temperatures average freezing, we`ll forego any additional freeze
warnings for the season. After a cool, cloudy start, skies will
quickly clear today under a drying air mass and increasing east to
northeast winds. We`ll see a warming trend west of the Cascades
by about 10 degrees compared to yesterday, with similar to a few
degrees warmer for the East Side. The Chetco Effect will bring
warm temperatures to the coast with Brookings already 10 degrees
warmer than surrounding areas early this morning, and forecast to
reach into the mid/upper 70s this afternoon. Meanwhile, West Side
Valleys will see highs also reach into the mid/upper 70s while
the East Side hovers in the 55-65 degree range (still about 10
degrees below normal).

With offshore flow strengthening tonight into Monday morning,
skies will remain clear for the whole forecast area. Though there
could be pockets of fog/low clouds in the deeper valleys west of
the Cascades, even the marine layer is likely to be non-existent
and clear skies are expected at the coast. Temperatures will trend
warmer again on Monday by about 5 degrees compared to Sunday`s
values for all areas, so even the East Side will see temperatures
closer to seasonal normals (upper 60s/low 70s). The Chetco Effect
will bring another day of elevated temperatures to the Brookings
area and even areas north of Cape Blanco are forecast to reach
into the upper 70s on Monday. Rinse and repeat for Monday night
into Tuesday, though east to northeast flow will begin to weaken
Monday night. Cooler temperatures are expected at the coast on
Tuesday, with similar values expected over West Side Valleys.
Meanwhile, temperatures trend warmer by about 5 degrees east of
the Cascades on Tuesday. /BR-y

Wednesday through Saturday...Models continue to show a closed low
developing over the Gulf of Alaska before digging south towards the
area later in the week. Models historically have difficulty with
determining where wobbly, broad, closed upper level troughs will
track, and this trough is no exception. The Wednesday into Thursday
period has the highest probability of being characterized by
increasing high clouds and a southerly flow, with a low, but highest
probability of light showers for the coast. Of note, the NBM
brings precipitation into the coast by Wednesday night, but the
vast majority of ensemble members across the EC and GFS suites do
not bring measurable precipitation to the coast or any other part
of the forecast area until at least 24 hours later. The forecast
was trimmed back, but some residual precipitation chances remain
due to current restraints on the forecasting process. Most likely,
though clouds will increase Wednesday, precipitation will not
arrive in the area until the trough approaches the area late
Thursday or Thursday night, then sticks around producing cooler
and wetter conditions through the weekend. -BPN


&&

.AVIATION...05/12Z TAFs...The remnants of a front have left enough
residual low level moisture for areas of mixed IFR/MVFR ceilings
along the coast north of Cape Blanco (including North Bend), and in
the Umpqua Basin (including Roseburg). Also, patchy fog and low
clouds have developed and could last for several hours this morning
in the valleys/basins of northern California and over the East Side
where it has recently rained. Northeast winds will develop and this
may cause some of these ceilings to erode early Sunday morning.

Elsewhere, area of VFR will prevail, and with dry east winds
developing across the area tonight, lower flight conditions are much
less likely to develop, even along the coast. -BPN/DW

&&

.MARINE...Updated 200 AM PDT Sunday, October 5, 2025...A thermal
trough along the coast will cause moderate to strong north winds
over the waters tonight into Monday. Winds and seas will be highest
south of Cape Blanco, though all areas will have conditions
hazardous to small craft. The thermal trough will weaken early next
week with winds and seas subsiding from east to west over the waters
on Monday. A brief period of calmer conditions is expected Monday
night into Tuesday, but north winds and steep seas could return for
Wednesday. -Spilde/BPN

&&

.FIRE WEATHER...Updated 200 AM PDT Sunday, October 5, 2025...A
thermal trough will set up along the coast the rest of this weekend
and this will result in a period of gusty east winds over the upper
slopes and ridges beginning tonight. However, RH recoveries tonight
should be good (80-100%) given the recent moisture/rainfall. Fuels
have also moderated substantially, with all locations in moderate
and/or low fire danger. We do expect things to dry out across the
landscape today through Tuesday with afternoon humidity bottoming
out in the in the 15-25% range. And, with gusty east winds
continuing tonight and Monday night over the upper slopes/ridges,
weather conditions may approach critical levels during this time
period. East winds are expected to peak tonight near critical values
over the ridgelines, but recoveries will remain moderate. Monday
night, ridgetop recoveries will trend poorer, but with weaker winds.
Despite these dry conditions, we don`t think fuels will return to
levels necessary for RFW. We`ll headline the Fire Weather planning
forecast to enhance the message that it will turn drier into mid
next week. Confidence beyond Wednesday is quite low with many
possible scenarios, though with a slight lean in favor of breezy,
cooler weather Thursday into next weekend with a chance of rain.
-Spilde/BPN

&&

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

PACIFIC COASTAL WATERS...Small Craft Advisory until 5 AM PDT Monday
     for PZZ350-356-370-376.

&&

$$