959
FXUS66 KMFR 111412
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
712 AM PDT Tue Aug 11 2026

.KEY MESSAGES...

* An uneventful upper level pattern will allow a weak cooling
  trend to continue, though with inland and Brookings highs still
  generally several degrees above normal through
  tomorrow/Wednesday. Breezy afternoon winds will also continue,
  with strength similar to that of yesterday.

* Coastal areas will see the marine stratus clear again today.
  But, a more widespread and thicker onshore push is expected
  early this evening into Wednesday morning, which is also
  expected to bring a deck of low clouds into the Umpqua Valley
  late this evening/overnight. Clearing on Wednesday will be
  slower than lately, toward afternoon inland with patches
  persisting through the day north of Cape Blanco.

* Periods of smoke accumulation are expected for Klamath, Lake,
  central/eastern Siskiyou, and northern/eastern Modoc counties.
  Areas around Klamath Falls are likely to see morning smoke
  accumulation, ahead of afternoon improvement.

* Slight chance thunderstorm probabilities Thursday through Sunday
  are focused upon Friday and Saturday and for northern portions
  of Klamath and Lake counties. But, not exclusively limited to
  that area.

&&

.DISCUSSION...One of two main changes today is a higher
confidence in a stronger marine push for the coast and Douglas
County arriving tonight, trending slightly weaker during
subsequent nights through the weekend. Also, increasing confidence
in the convective forecast. A weak upper level trough will track
southward and sharpen slightly over the Pacific today through
Thursday. A stable air mass persists through Wednesday with low
topped cumulus on Wednesday for northern California the east side, and
convective activity on Thursday being limited to taller, more
widespread cumulus buildups over south central Oregon and
northern California (although with a 10% risk of thunderstorms
near Fort Jones in California and also in northern Lake County).

The probability of thunderstorms is highest (around 15%) for
Friday afternoon in northern Klamath, northwest Lake, and western
Siskiyou counties as a wave rotating through the base of the upper
level trough carves out its own trough near the northern
California coast. Model solutions show a wider variation beginning
Saturday, but weekend agreement is better than it was yesterday.
This means a likely north and eastward shift of the convective
risk, with the southern extent of a slight chance risk still
covering at least northern Klamath County, at least on Saturday,
roughly from Crater Lake north and northeastward.

Low clouds from Cape Blanco northward and into the Coquille Valley
will clear this morning, but return quickly this evening. Low
clouds are then likely to fill the coast, and Coquille and Umpqua
valleys tonight and be slow to clear during Wednesday. Clearing
for the afternoon in the Umpqua, then by mid-morning on Thursday,
failing to fill the Umpqua Valley on Friday morning, and limited
to the coast and Coquille Valley on Saturday morning. Meantime,
low clouds south of Cape Blanco are expected to be most
extensive/widespread during Friday and Saturday mornings, with
continued though weaker northeast flow during the next few
mornings.

Beyond the weekend, model differences do become large with the GFS
cohort allowing for weak but broad coverage of ridging in our
region and a closed low far offshore. Meanwhile, the ECMWF is
more progressive and indicates the low will track toward the area
with more extensive cooling, at least mid and upper level cloud
cover, and even rain and thunderstorm chances. We will obviously,
be watching this closely.

&&

.AVIATION...11/12Z TAFs...Smoke will be concentrated south and east
of the Wright`s Spring Wildfire, across southern portions of Klamath
and Lake counties, central/eastern Siskiyou County, and
northern/eastern Modoc County. This likely includes MVFR ceilings
and visibility reductions at Klamath Falls this morning. Smoke is
not expected to be as concentrated at Lakeview and Alturas. Montague
may see a period of MVFR ceilings/visibilities in smoke later this
morning. Afternoon winds are expected to bring improvement to
Siskiyou County and western/northern Klamath County.

Marine stratus along the coast is bringing LIFR ceilings north of
Cape Blanco (including North Bend) and also near Brookings. Gradual
clearing is expected after 16z. Gusty afternoon winds are expected
again along the coast with gusts to around 30 kt. A thicker and more
extensive push of marine stratus is expected this evening into
Wednesday morning with LIFR/IFR at the coast, and MVFR stratus into
the Umpqua Valley (including Roseburg).

Otherwise, expect VFR conditions with areas of breezy winds this
afternoon and evening (gusts of around 20 kt).

&&

.MARINE...Updated 200 AM PDT Tuesday, August 11, 2026...Seas briefly
diminish for today in the area north of Cape Arago. But, gusty north
winds will continue through Wednesday evening, with areas of gales
and very steep seas south of Port Orford. Elsewhere, steep seas are
expected. Winds will begin to ease Thursday, with north winds at
Small Craft Advisory strength south of Port Orford. But, with the
combination of wind wave and fresh swell, steep seas are likely to
persist across the area into Friday morning. Weak winds and low seas
are expected for the weekend, and likely into early next week.

&&

.FIRE WEATHER...Updated 200 AM PDT Tuesday, August 11, 2026...The
two main changes this morning are a continued model trend of
reducing the probability of thunderstorms on Wednesday and Thursday,
and a increasing confidence in a slight chance of afternoon
thunderstorms on Friday and Saturday (especially Friday) that is
sufficient to declare the highest probability (15-20%) will be for
northern portions of Klamath and Lake counties, secondarily (15%)
for western Siskiyou County, and tertiarily (10-15%) connecting
those areas...across Jackson, far eastern Douglas, and far western
Klamath counties. Rather than rehashing things, the previous
discussion follows below.

Main message remains the same -- we expect dry conditions through
Wednesday, then slight chances of thunderstorms/lightning in NorCal
Thursday. These chances expand up the Cascades and over the East
Side Fri/Sat. Latest 12Z guidance has diminished the overall
risk/coverage area compared to yesterday, so confidence still
remains low, especially with the specifics of where activity will be
focused each day.

We`ll stay in a pattern of very warm, very dry, and breezy
conditions through Wednesday. This pattern includes overnight breezy
east to northeast winds at ridge tops of SW Oregon and NW California
(most notably the Coast Range and Kalmiopsis Wilderness) along with
poor to moderate RH recovery tonight/Tuesday morning, trending to
improved but still moderate recovery in subsequent mornings. A
channeling of winds down the Chetco could result in some
drier/warmer conditions along the SW Oregon coast as well (though
the marine influence has held so far at the beaches).

The trend through midweek will be to lower daytime MaxTs down by a
degree or two each day, and this should subsequently allow daytime
MinRHs to be slightly higher. Even so, it`ll be dry and unstable, so
any fires on the landscape will still have the ability to grow
significantly, especially during the peak burning periods during the
afternoons/evenings. Overnight RH recoveries haven`t been good the
last couple of nights, generally only in the 20-35% range for some
of the upper slopes and ridges. There should be slight nightly
improvement in recoveries from NW to SE through the period. Things
trend toward normal after Wednesday, but temperatures still probably
remain a few degrees above normal for most locations.

Models and ensemble guidance continue to show a weakness or upper
trough developing near the California coast Wed/Thu and also show an
increase in monsoonal moisture coming up from the south late week.
The best chance for isolated thunderstorms is Fri/Sat from NorCal up
the Cascades and across portions of the East Side. Given plenty of
uncertainty in strength of forcing mechanisms, overall instability
and moisture advection, confidence is low in the locations where
activity will be focused. Keep checking back for updates since any
lightning brings with it the risk of new fire starts. -Spilde

&&

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

PACIFIC COASTAL WATERS...Gale Warning until 11 PM PDT Wednesday for
     PZZ356-376.

Small Craft Advisory until 11 PM PDT Wednesday for PZZ350-356-
     370-376.

&&

$$