Arcata, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

106
FXUS66 KEKA 240013
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1212 PM PDT Mon Jun 23 2025

.SYNOPSIS...Near to slightly above normal temperatures expected into
late week. Breezier winds possible mid to late week, bringing
elevated fire weather concerns. Much warmer temperatures possible
over the weekend.


&&

.DISCUSSION...Stratus and areas of patchy fog continues to blanket
much of the coast early this afternoon. A shortwave moving through
the area this evening and overnight is likely to bring only a few
high clouds into the area. Some drizzle/light rain is not completely
out of the question along the coast, but probabilities remain low
(less than 10%). Inland, average summertime conditions are expected
today and through the middle of the week, with near-normal high
temperatures of 80s or low 90s. Winds in the afternoons and evenings
may gust to 15-20 mph in the interior, particularly Lake County.

Breezier west-northwesterly winds are possible Wednesday through
Friday. NBM is showing around 30-50% probabilities for gusts over 25
mph in the valleys of Trinity, Lake, and interior Mendocino. Higher
gusts are possible over the surrounding ridges. Combining with warm
temperatures and low afternoon relative humidities, this could be a
fire concern. The coastal areas have similarly high probabilities,
especially around Pt St George and Pt Arena. As of now, NBM is
showing Thursday as having the highest probability for winds.

A ridge begins to build over the area late week into the weekend,
with a cutoff low forming off the coast of California. Confidence is
rising on hot temperatures for the interior this weekend. NBM is
showing 30-50% probabilities for the warmest valleys to see triple
digits by Saturday and 50-80% probabilities by Sunday. The influence
of the upper-level low off the coast along with the heat could
possibly bring dry thunderstorms. Confidence is low as the position
of the upper-level low is uncertain and will determine how much
moisture is available for convection. JB


&&

.AVIATION...18Z TAFs. The McKinleyville profiler and soundings show
a shallow marine layer under a strong inversion this afternoon. For
these reasons, CIGs and VIS have remained low at LIFR levels with
periods of patchy dense fog. The shallowness of the marine layer
will allow for some afternoon scattering or pullback over the ocean
waters. For tonight through Tuesday morning, the forecast signal is
complicated by the passing of a compact shortwave trough. High
resolution soundings point to a deepening marine layer and higher
CIGS from this feature. Outside of this quick passing disturbance,
the environmental setup is otherwise primed for shallow CIGS and
fog. Current thinking is that the shortwave will have a disruptive
influence on mainly visibility, but also ceiling heights. Confidence
is high for LIFR levels and visibility has a chance to enter fog
levels, especially into early Tuesday morning. Inland terminals,
including UKI will remain VFR with light surface winds.


Forecast Confidence:

Chance for LIFR CIGS High: Coastal Terminals have 60-80%, but
variability is possible.

Fog probability Low to Moderate: Coastal
Terminals 30-40% and variability is expected.


&&

.MARINE...Northerly winds have eased this afternoon in the northern
zones, particularly in the northern inner zone. Winds will remain
stronger in the southern zones, especially around the cape. Strong
breezes around 25 kts should be expected in the focused expansion
fan south of the cape this week. Light to moderate breezes up to 15
kts will remain in the northern waters for most of the week. The
northerlies will trend strong late in the week and likely through the
weekend. Other than short period northerly seas, minor mid period
northwesterly swells will enter the waters this week.


&&

.FIRE WEATHER...Warm and dry conditions are expected this week into
the weekend. Afternoon RH remain low, into the teens or 20s for much
of the interior. Overnight recoveries remain good in the valleys and
moderate to good in the higher terrain. Afternoon northwesterly
breezes could gust up to 15-20 mph in the valleys with slightly
higher gusts possible in the higher terrain of southern Mendocino
and Lake Counties. Slightly stronger northwesterly winds are
possible Wednesday to Friday, with gusts up to 25 mph possible in
the valleys and gusts to 30-35 mph possible in the highest terrain.
Late this week into the weekend, a ridge starts to build while an
upper-level low looks likely to form off the coast. Higher
temperatures are forecast with triple digits possible in the
valleys. If the upper-level low off the coast is positioned in a way
to bring enough moisture into the area, convection is not out of the
question with any thunderstorms likely to be dry. Confidence is low
(less than 5%) at this time. JB


&&

.TIDES/COASTAL FLOODING...The lunar cycle will go to a new moon on
Wednesday. This will create large tidal swings and possible some
minor coastal flooding around Humboldt Bay this week. Evening to
late night high tides this week will exceed 8 ft. Though levels may
falls short of advisory levels (8.8 ft), high tides plus a minor
positive anomaly will likely push tides to around 8.5 feet. Large
overnight to early morning tidal swings to -2 feet will also create
fast currents in channeled waterways.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 9 PM PDT this evening for PZZ455-
     470.

     Small Craft Advisory until 9 AM PDT Tuesday 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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For forecast zone information
see the forecast zone map online:
https://www.weather.gov/images/eka/zonemap.png