945
FXUS66 KEKA 111956
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1256 PM PDT Fri Jul 11 2025

.SYNOPSIS...High pressure has built in bringing hot weather to the
interior. This heat is likely to last the weekend into early next
week. Smoke and haze remains possible from nearby wildfires. There
is a slight chance for isolated dry thunderstorms Sunday afternoon
in northern Trinity County.


&&

.DISCUSSION...High pressure has built into the area, bringing a
shallow marine layer with dense fog at times along the coast and hot
weather to the interior. Smoke from the Butler and Green fires has
blown into the region this morning. Some improvement in air quality
is likely this afternoon, but any remaining in the valleys will
likely pool back in this evening and overnight. Smoke models are
showing the Trinity and Klamath River valleys with high smoke
concentrations overnight, and general haziness is possible across
the area.

As for the heat, high temperatures between 100-110 are possible,
with the highest temperatures likely in Trinity County along the
Trinity River Valley. Widespread haze may bring highs slightly below
what is forecast, but no major impact to temperatures are likely.
The overnight lows may actually be a few degrees warmer than
forecast (forecast being low to mid 60s) in the valleys as denser
smoke could trap some heat the valleys. Regardless, this heat does
bring Moderate to Major HeatRisk and is dangerous to those without
proper cooling and those sensitive to heat related illness.

Sunday, the ridge begins to move east slightly. This could support a
slightly deeper marine layer and temperatures a degree or two lower
in interior Del Norte and southern Humboldt. Still, temperatures
remain hot. Models are picking up a moisture intrusion from the east
by Sunday afternoon. CAMs within range are showing a low chance
(15%) for some activity in northern Trinity County. Model soundings
do show a weak capping inversion and moisture remains limited, so
confidence remains low.

Monday, the ridge continues to push east, which will allow the
marine layer to slowly and gradually deepen early next week. Triple
digit temperatures are likely to continue into at least Monday, with
"cooling" finally arriving by Tuesday and Wednesday. Temperatures
are likely to remain warm, with 90s expected for much of the
interior. JB


&&

.AVIATION...Coastal stratus layer is gradually being scoured out by
increasing northerly winds offshore. A strong marine inversion and
slight southerly reversal along the north coast has kept ACV beneath
IFR ceilings and reduced viz. Scattering is possible this afternoon
as winds and daytime temperatures increase. CEC remains clear and
gusty with gusts 25 to 35 knots possible this afternoon. Similarly,
UKI will remain clear with breezy WNW winds 10 to 15 knots. HREF
probabilities are only about 50% for IFR ceilings returning to ACV
after 06Z, although a broken <1000 ft layer with scattered mist/fog
is possible through sunrise. Probabilities for <4SM viz only about
30% through 16Z.


&&

.MARINE...A tight coastal pressure gradient continues to produce
strong northerly winds. Gale gusts likely in the outer waters with
gusts 40 to 45 knots possible in Z470 through Saturday. Steep and
hazardous wind driven seas 12 to 16 feet expected in the outer
waters. Near gale winds and steep seas 8 to 10 feet have already
been observed on buoys - these conditions may propagate into the
northern inner waters, especially nearshore of Point Saint George
and Cape Mendocino. Gale gusts and steepest seas expected to
retreat to the northern outer waters late Saturday into Sunday.
Winds and seas will still remain elevated in the southern outer
waters, with the southern inners waters slightly sheltered from
the strongest winds and waves. Gale conditions and steep seas
expected to persist through Tuesday before finally showing signs
of diminishing midweek.


&&

.FIRE WEATHER...Building high pressure along with offshore flow has
brought warming and drying to the interior and near-coastal areas.
Afternoon RHs remain very dry, into the teens and 20s across most
the interior. High elevation areas (above 2000-2500 ft or so)
continue to see moderate to poor overnight RH recoveries. Lower
elevations are largely seeing moderate to good overnight recoveries.
Offshore winds in the higher terrain are forecast to remain breezy
overnight, especially in Del Norte county, though at least Sunday
morning. Some marginal improvement is possible Sunday and Monday
nights, before finally easing by Tuesday night.

Upper-level moisture arrives from the east Sunday and Monday
afternoons. Elevated instability along with some moisture brings a
slight chance (10-15%) for isolated dry thunderstorms to northern
Trinity County. As of now, moisture looks more limited Monday, but
there is still a 5-10% chance for isolated dry thunderstorms.

The ridge begins to weaken Monday into early next week, which will
slowly deepen the marine layer into the middle of next week. RHs
will improve in the near-coastal areas with moderate to good
overnight recoveries possible in the highest terrain by the Tuesday
or Wednesday. JB


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Heat Advisory from 11 AM Saturday to 11 PM PDT Sunday for
     CAZ102-105.

     Extreme Heat Warning from 11 AM Saturday to 11 PM PDT
     Monday for CAZ102-105.

     Heat Advisory from 11 AM Saturday to 11 PM PDT Monday for
     CAZ106.

     Extreme Heat Warning until 11 PM PDT Monday for CAZ107-108.

     Heat Advisory until 11 PM PDT Sunday for CAZ110-111-113>115.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Hazardous Seas Warning until 11 AM PDT Saturday for PZZ450.

     Gale Warning until 11 PM PDT Saturday for PZZ470.

     Gale Warning until 11 AM PDT Saturday for PZZ475.

&&

$$

NOTE: The full forecast discussion is now regularly issued between
10 am/pm and 1 pm/am. Additional updates will be issued as needed.

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see the forecast zone map online:
https://www.weather.gov/images/eka/zonemap.png