453
FXUS66 KMFR 040458
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
958 PM PDT Sat Oct 3 2026

...New Aviation Section...


.AVIATION (06Z TAFs)...

Low ceilings and visibility restrictions are still anticipated
along the coast resulting in LIFR/IFR conditions through much of
this cycle. Additionally, drizzle may be realized tonight into
Sunday morning. Expecting periods of relief through the afternoon
which could bring VFR to KOTH at times. For inland TAFs, expecting
mostly clear skies combined with light wind speeds through much of
this cycle.

-Guerrero

&&

.PREV DISCUSSION... /Issued 421 PM PDT Sat Oct 3 2026/

..New Aviation Section...

AVIATION (00Z TAFs)...

Conditions will be similar along the coast this evening/overnight
as last night with IFR/LIFR, drizzle, and limited visibility
under a marine stratus layer. Could also see intermittent periods
of VFR Sunday afternoon as the stratus waffles on/off the coast,
but most of this cycle will be LIFR/IFR. Inland TAFs should be
mostly VFR with mostly clear skies and light winds. Roseburg may
have a period of low clouds Sunday morning, but confidence wasn`t
high enough to put any categorical changes based on forecast
dewpoint depressions near the surface, but cannot completely rule
out some low clouds tonight.

-Guerrero

PREV DISCUSSION... /Issued 234 PM PDT Sat Oct 3 2026/

KEY MESSAGES...

* Night and morning low clouds and fog (patchy very light drizzle)
  at the coast north of Cape Blanco, and locally near Brookings
  during the next week.

* Inland high temperatures well above normal (10-20 degrees)
  through Thursday. Heat Risk is elevated for sensitive groups or
  those spending extended time outdoors without adequate
  cooling/hydration.

* Very warm and dry conditions bring elevated fire weather
  concerns due to near summer-like dryness. But, with weak winds,
  critical fire weather conditions are not expected.

* A weak upper level disturbance moves in later Sunday into
  Monday morning with an increase of high clouds. But, also...for
  southern Lake and southern Modoc counties...some virga along
  with a low chance (~15%) for showers and a very low chance (<5%)
  of thunderstorms.

* Late next week, Friday into Saturday, gusty SW->NW winds
  accompany a cold front with a 10-25% probability of rain
  showers. Temperatures trend sharply lower, getting back to near
  or perhaps even below normal values by Saturday.


DISCUSSION...Strong high pressure aloft is bringing warmth more
typical of mid-August than early October in southwest Oregon and
northern California this weekend. The late summer-like warmth
will be felt all across inland areas through much of next week.
High temperatures will be 10-20 degrees above normal. The
exception will be along the coast, where cooler temperatures and
low clouds, fog and even a bit of drizzle are expected. Low clouds
are likely to clear or partially clear in the afternoons each
day, but then redevelop during the early evenings. Some of this
low-level moisture could also result in low clouds/fog at times
in the Umpqua Basin, though the clouds should break for sunnier
afternoons. The warmth there (Roseburg) will be muted a bit with
high temps about 10F above normal (low to mid 80s).

Tonight, and to some degree each of the next several nights, a
strong inversion with light to breezy easterly winds (thermal
trough) are expected over the ridges. This will result in
moderate to locally poor ridgetop relative humidity recoveries.
Daytime humidities will also be low (in the lower teens for
valleys across northern California and east of the Cascades)
resulting in elevated fire weather concerns. However, winds are
expected to remain below critical levels.

Heat and dryness are the main concerns this weekend and next week.
With the late-summer like temperatures and dryness, dry grasses
and leaves will be present in many areas. Please be cautious if
you`re planning any activities that could create a spark.
Additionally, the above normal temperatures this weekend will
bring elevated HeatRisk to inland areas. HeatRisk is generally in
the minor category, or elevated for those sensitive to heat and
without cooling/hydration. If you are sensitive to heat or
spending extended time outdoors, take precautions. Seek shade and
stay hydrated. Overnight/morning temperatures are expected to
lower in the mid-50s for valleys west of the Cascades and in the
40s for valleys east of the Cascades which will help moderate
HeatRisk.

We should note that a weak shortwave will move into northern
California Sunday into Monday morning, then shift east of the
area late Monday. This disturbance will bring some mid level
moisture and elevated instability into far southeast areas (NE
Cal), mainly Modoc, but also southern Lake County. Given the
height of the moisture, above 600 mb and mainly above the freezing
level, the most likely scenario is this will just bring high
clouds/virga into the area. However, there is a slight chance of
showers (15% or less) and a very low chance (<5%) for
thunderstorms Sunday night/Monday morning.

Otherwise, expect a slightly weaker ridge pattern that
restrengthens Tuesday to Thursday. With this pattern, models and
ensembles are forecasting continued well above normal daytime
temperatures with highs around 15 degrees above normal. Modest
increases in SW breezes can be expected by Thursday afternoon in
NE California and east of the Cascades.

Friday into next weekend, models are showing a decided end to the
hot pattern with virtually all ensemble members showing a
significant cooling trend, perhaps even sharply cooler (by
Saturday). A strong upper trough and cold front will move in from
the northwest. This could lead to a breezy to windy day Friday,
especially in NorCal and east of the Cascades. A combination of
strong winds/low RH could also result in an elevated fire weather
concern. Models are still showing enough uncertainty in the timing
and strength of the front, so PoPs for rain remain fairly low
(mostly in the 10-25% chance range), but they have increased a bit
since yesterday.

Beyond that, a very unlikely scenario showed up in the guidance
this morning. The 12z deterministic ECMWF shows some of the
moisture/energy from Hurricane Rachel getting involved in the
pattern after Saturday and perhaps moving northward into
California Sunday. While this scenario remains in the envelope of
possibility, the probability that this moisture/energy reaches
this far north is around or <5%. The vast majority of ensemble
solutions keep the system well to our south. But, it`ll be
interesting to watch over the coming days. -Spilde

AVIATION...03/18Z TAFs...MVFR to IFR levels remain along parts of
the Oregon coast and into the Umpqua Valley under lingering
stratus, but satellite imagery shows these layers eroding at the
start of the TAF period. Once these areas clear, VFR levels are
expected across the area under passing high clouds into the
afternoon. Coastal stratus is expected to return, bringing
IFR/LIFR levels to North Bend and other coastal areas. Stratus
could also briefly return to the Umpqua Valley early Sunday
morning. Other areas look to remain at VFR levels through the TAF
period. -TAD

MARINE...Updated 200 PM PDT Saturday, October 3, 2026...A
persisting thermal trough will bring gusty northerly winds and
steep seas for much of the week ahead. For today, steep seas
continue south of Cape Arago. Winds ease slightly early Sunday
morning, bringing below advisory seas to inner waters while outer
waters remain steep. The thermal trough strengthens into Monday,
bringing more widespread gusty winds and steep seas to all waters.

Fluctuations in the thermal trough`s strength and position may
bring changes to where steep seas are through the week, but there
is an agreement in guidance that some amount of steep seas will be
present past midweek. A pattern change may bring active weather
towards the end of the week, with some guidance also showing
incoming long period westerly swell arriving at some point over
the weekend. Confidence is not high enough in these outcomes to
predict the sea state, but as this is the first signs of possibly
meaningful long-period swell for the season, acknowledging it is
worthwhile.

-TAD

&&

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

PACIFIC COASTAL WATERS...Small Craft Advisory from 11 PM Sunday to 11
     PM PDT Monday for PZZ350-356.

Small Craft Advisory until 2 AM PDT Sunday for PZZ350-356.

     Small Craft Advisory until 11 PM PDT Monday for PZZ370-376.

&&

$$