848
FXUS66 KEKA 172105
AFDEKA

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

.SYNOPSIS...The warmer and drier pattern continues through Saturday.
There is a moderate risk for sneaker waves along the coast starting
this evening into Saturday. Light coastal rain or drizzle possible
Sunday. Larger storm systems possible starting mid to late next
week.


&&

.DISCUSSION...High pressure is continuing to gradually build over
the area. This will allow for slight warming and drying to continue
during the day with the warmest interior valleys reaching near 80.
That said, dewpoints have stubbornly remained near 40, largely
preventing overnight frost despite the increasingly long nights and
clear skies. High pressure will allow promote a diurnal, coastal
marine layer to at least briefly form tonight into Saturday.

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, most
likely supporting only very light rain right along the immediate
coast. Most likely rain amounts have trended further downward and
are currently a few hundredths of an inch in Del Norte County.
Looking south closer to Humboldt Bay, less than 10% of models show
any 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, but there is a 50%
chance of any highs over 80 in the warmest valleys. 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. There is an 80% chance of 3 day
rainfall over 3 inches over Del Norte and the interior mountains,
with 30-50% chances elsewhere. There is over a 50% chance of 3 day
rainfall over 5 inches in Del Norte and the King Range. Such an
event would likely be accompanied by strong south wind and rainfall
amounts capable of moderate flood impacts. Heavy mountain snow is
possible too, but there is more variability on how cold these
systems will be. /JHW&JB


&&

.AVIATION...Shallow stratus struggled to clear out of ACV
this afternoon, when otherwise full VFR conditions took hold earlier
over N CA. A highly localized eddy and shallow inversion is the
culprit for the lingering stratus around Humboldt Bay. Full clearing
is underway as the eddy breaks down. Northerly winds increase
through this afternoon, mainly around Del Norte and CEC where 20kt
gusts are forecast at the terminal. Winds will be lighter at most
remaining terminals. The widespread VFR conditions will not last
tonight.

The marine layer currently observed 60nm over west over the ocean is
forecast to push eastward into the coast this evening. Soundings
show strong indications the inversion will remain shallow, with even
shallower levels by early Saturday morning. Areas of dense fog with
VIS 1/4SM or less will be possible with this setup given what was
observed today at ACV and Mckinleyville profiler. Models continue to
poorly model stratus coverage towards CEC. Mesoscale to microscale
features around coastal wind eddies will likely steer the shallow
stratus and fog northward. The eddy will develop around 5Z Saturday,
and this is when the transport is expected northward.

ACV: Probabilities for IFR at ACV increase after 3Z Saturday (50%).
Chances for LIFR become significant after 7Z (45 to 55%).
Chances for fog are lower (30-40%), but the setup and observations
point to fog.

CEC: Probabilities are low, but the setup favors stratus and fog
transport into the terminal after 5Z Saturday. JJW


&&

.MARINE...Northerly winds remained strengthened across the
waters. Winds up to 25 kts persisting across the outer waters and
around Cape Mendocino will shift closer to the coast this afternoon,
mainly around Point St George and Cape Mendocino. Northerly winds
will generally ease Saturday into Sunday morning before increasing
again Sunday afternoon. 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. JJW


&&

.BEACH HAZARDS...A Beach Hazard Statement is in effect from 6 PM this
evening through Saturday evening. A long period westerly swell
will arrive this evening at 2 to 3 feet at 20 seconds, and 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 from 6 PM PDT this evening 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-
     475.

&&

$$

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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