632
FXUS66 KEKA 180614
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1114 PM PDT Fri Oct 17 2025

.SYNOPSIS...Slight warming and drying will peak Saturday with mostly
clear skies. Cooler weather and very light coastal rain is expected
Sunday with warmer weather again early next week.


&&

.DISCUSSION...Transient high pressure will continue to
peak across the area Saturday, allowing for the hottest interior
valleys to reach near 80. A weak, shallow marine layer will persist
along the coast. Despite clearer skies, continued high dewpoints have
prevented any meaningful frost formation across the interior.

A weak upper level trough quickly move across the area on Sunday.
This will pool in cooler and more moist air alongside midlevel
clouds. Overall moisture advection will be weak, however, supporting
only very light rain right along the immediate coast. There has been
little change in the forecast with likely rain amounts currently
between 0.1 and 0.2 inches in Del Norte County with even 50% of
models showing little more than drizzle there. Looking south closer
to Humboldt Bay, less than 10% of models show any wetting rain.

Weak high pressure and slight warming will most likely quickly
reassert itself early next week, though low pressure passing to the
southeast will limit the amount of warming with only a moderate
chance (50%) of some highs even over 80. Strong offshore flow around
the low will likely help better dry conditions compared to the
currently high stubborn dewpoints. Widespread patchy frost will be
likely (60% chance) Monday morning, especially in Trinity County.

There is increasing confidence in long range forecasts that a
significant rain event will impact the area late next week. Though
high uncertainty remains, NBM already places a 95% chance of wetting
rain all the way along the North Coast with an 70% chance of 3 day
rainfall over 3 inches and a 25% chance of 3 day rainfall over 5
inches. Despite these high totals form the NBM, ensemble spreads
remains very large, indicating great potential for lower end
scenarios to still be realized. On the stronger end, such an event
would likely be accompanied by strong wind with such rainfall
amounts capable of moderate flood impacts. /JHW


&&

.AVIATION...18/06Z TAFs...IFR to LIFR ceilings around 300-500 feet
along the coastal terminals this evening, while visibility
variations between 4SM BR to P6SM. Expect lower ceilings and vsby
drop to 1/2SM in fog, with a period of 1/4SM in fog possible early
Saturday. There is an increasing chance (45-55%) for 1/2SM or less
after 12Z Saturday, especially at KACV. Low ceilings are expected to
gradually lift and scattered after 18Z. However, microscale eddy may
keep the shoreline with low clouds moving in and out, especially in
the vicinity of Humboldt Bay. Onshore flow will push back inland the
stratus and fog later in the afternoon and evening.

For inland areas, including UKI, mainly VFR conditions are expected
to prevail with light breezes. /ZVS


&&

.MARINE...Northerly winds will gradually diminish tonight through
Saturday. Generally light to moderate breezes is expected by
Saturday afternoon, with very light and variable winds nearshore.

A long period northwest swell at 2-5 feet at 18-20 seconds continue
building across the waters this evening, and peaking to 8-10 feet at
16 seconds Saturday afternoon.

Saturday night into Sunday morning, southerly winds will developed
briefly across the outer waters as a weak frontal system moves
through, before shifting to northerlies Saturday afternoon.
Northerly winds increase again on Sunday afternoon and continue
strengthening through early next week. Gale strength gusts are
forecast around and south of Cape Mendocino Sunday afternoon through
Sunday night.

Northerly winds will remain somewhat strengthened into mid next
week. The northerly wind pattern breaks down thereafter as a strong
trough takes aim at the vicinity of N CA. Strong southerly winds are
possible Thursday or Friday if this system take a more southerly
track. Chances for at least sustained gale strength southerlies and
large surf continue to increase through the weekend with modeled
potent NE PAC cyclones.

A long period west northwest swell will begin trickling in late this
afternoon with 20 second period forerunners. This swell will
continue building through Saturday afternoon, peaking around 10 ft
at 16 seconds. A second larger swell move in late Sunday through
Monday, and Breakers may reach 20 feet through that period.
Additional large swells are then likely through next week with an
active Pacific storm track. /ZVS&JJW


&&

.BEACH HAZARDS...A Beach Hazard Statement is in effect through
Saturday evening. A long period westerly swell will currently moving
across the waters will peak to 8 to 10 feet at 16 seconds Saturday
afternoon. This high energy swell has the potential to bring
moderate risk of sneaker waves, especially late afternoon/ early
evening on Saturday. Shorter period NW swell of 5-8 ft at 7-9
seconds may initially mitigate the risk during the morning and
afternoon hours on Saturday. Sneaker waves are a unique hazard, with
many minutes between waves. Pay attention and stay above the high
water line and any wet sand to stay safe. If the ground is wet,
waves have surged there recently. Stay safe and never turn your back
on the ocean! A potentially larger swell is then forecast to move in
late Sunday through Monday./ZVS


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Beach Hazards Statement through Saturday evening for CAZ101-
     103-104-109.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until noon PDT Saturday for PZZ450-455.

     Small Craft Advisory until 11 PM PDT Saturday for PZZ470.

     Small Craft Advisory until 11 PM PDT Sunday 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