115
FXUS66 KMFR 121731
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
1031 AM PDT Sat Jul 12 2025

...Updated AVIATION discussion for 18Z TAFs...

.DISCUSSION...The forecast is on track for today. Warm and dry
weather continues across northern California and southern Oregon.
Extreme Heat Warnings are in place for this afternoon through
Monday evening for Jackson, Josephine, eastern Curry, and western
Siskiyou Counties. Heat Advisories are in place for Lake, Klamath,
Modoc, eastern Siskiyou, and central Douglas counties. Heat-
related impacts can affect anyone in these areas without adequate
cooling or hydration. Please use extra care while outdoors,
especially in the afternoon and evening. -TAD

&&

.AVIATION...12/18Z TAFs...marine stratus has cleared from along the
Oregon coast, bringing all areas to VFR levels this morning. Gusty
winds look to develop near the afternoon along the coast and into
the Umpqua Valley, with these winds easing through the evening.
Marine stratus is expected to return to the coast this afternoon,
bringing IFR or LIFR ceilings and visibilities into Sunday morning.

VFR levels continue in other areas with normal diurnal winds. -TAD

&&

.MARINE...Updated 800 AM PDT Friday, July 11, 2025...A thermal
trough will continue to strengthen over the next several days. This
pattern will bring gusty north winds and steep wind-driven seas to
the waters along with areas of gales and very steep seas south of
Cape Blanco. The strongest winds will occur south of Port Orford.
This pattern is expected to persist through early next week.

&&

.FIRE WEATHER...Updated 200 PM PDT Friday, July 11, 2025...A
developing upper level ridge is bringing seasonal temperatures
today. Daytime highs increase further on Saturday as the ridge
strengthens, then look to stay 5-10 degrees above normal across the
area through Wednesday. Normal diurnal breezes are expected with
lighter overnight winds. Easterly winds are possible overnight for
coastal ranges as well as the Klamath and Siskiyou mountains, which
may result in moderate to locally poor RH recoveries especially for
ridgetops where overnight gusts exceed 25 mph. Hazardously gusty
winds are not forecast, but the pattern is stable and these dry
conditions are expected to continue through much of the forecast
period.

While significant thunderstorm threats are not part of this period,
upper level instability could still develop on Sunday and move over
the area. Generally, this will support cumulus development over
elevated terrain. Slight thunderstorm chances are in the forecast
across Siskiyou, Modoc, and southern Klamath and Lake counties.
Under these conditions, smoke plumes or pyro-cumulus may be possible
as well.

Dry conditions continue and temperatures may cool on
Thursday and Friday, although daytime highs would remain up to 5
degrees above seasonal averages. -TAD


&&

.PREV DISCUSSION... /Issued 222 PM PDT Fri Jul 11 2025/

DISCUSSION...The main theme for the next week is `hot and dry.`
This will be due to the main feature of persistent ridging
extending from central and southern California into our region.
This includes easterly winds providing downslope warming for
Brookings (with day-time temperatures in the mid 70s to mid 80s),
likely from now into Tuesday morning. More broadly, the Heat
Advisory and Extreme Heat Warning remain in effect for inland
valleys through Monday evening. Thereafter, there is higher,
though still not high, confidence in around 2 or 3 degrees of
cooling for Tuesday into Wednesday. This cooling would be barely
perceptible, but could be just enough to nudge us below at least
the level of Extreme Heat criteria in Josephine, Jackson, and
western Siskiyou counties. The short term temperature forecast is
consistent with peak heating on Sunday, though perhaps it will be
a degree or so hotter on the east side on Monday...as the thermal
trough tracks inland. West side highs of 95 to 105 will be common,
except highs up to 111 in the Klamath River and Salmon River
valleys in far western Siskiyou County.

The most notable exception to the sunny skies will be areas of
night and morning low clouds and fog from Cape Blanco northward. A
thicker marine layer (with more or much more limited afternoon
clearing of low clouds) is likely for the Coos and Douglas coast
Monday night through Friday night. With temperatures in the 50s
for lows and 60s for highs, the coast (particularly north of Cape
Blanco) will be the most effective place to go to escape the heat.

Also of note, mid-level moisture aloft will mostly be limited and
ridging will provide a stable air mass. But, a few fair weather
cumulus may pop up from day-to-day over the higher terrain. A very
weak trough moving to the coast on Sunday with an embedded
shortwave could be just enough for a thunderstorm or two to pop up
in the evening in western Siskiyou County(with a 15% probability).
Meanwhile, the probability for the same period has kept to 10%
for Klamath County. Otherwise, the 12Z operational GFS is among a
sizable minority of model solutions that do indicate a weak but
broad trough forming offshore and moving slowly east late in the
week. This is still not a very progressive pattern, but by simply
not being stagnant, it makes it worth mentioning that some late
week very slight thunderstorm probabilities could eventually be
needed, with the east side having the highest probability. This
also directly leads to the GFS indicating a few to several degrees
of cooling late in the week, which is absent or at least far more
muted in the blended solution and majority of ensemble members.

Lastly, breezy afternoon westerly winds will be on the light to
typical scale at 10 to 15 mph today and Saturday. But, they will
pick up a bit on the east side on Sunday with 10 to 20 mph speeds
expected to be more common there in the afternoons and evenings
next week.

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Extreme Heat Warning from 2 PM this afternoon to 8 PM PDT Monday
     for ORZ024-026.

     Heat Advisory from 2 PM this afternoon to 8 PM PDT Monday for
     ORZ023-025-029>031.

CA...Extreme Heat Warning from 2 PM this afternoon to 8 PM PDT Monday
     for CAZ080-081.

     Heat Advisory from 2 PM this afternoon to 8 PM PDT Monday for
     CAZ082>085.

PACIFIC COASTAL WATERS...Gale Warning until 5 PM PDT Sunday for
     PZZ356-376.

     Small Craft Advisory until 5 PM PDT Sunday for PZZ350-370.

&&

$$