869
FXUS66 KEKA 060029
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
529 PM PDT Sat Sep 5 2026

.KEY MESSAGES...

- Periods of unsettled weather for Del Norte County and extreme
  NE Humboldt and Trinity counties is expected over the weekend.

- Overnight temperatures for the interior will remain chilly, yet
  fog formation could inhibit any frost forming within inland valleys.

- A building Desert Southwest ridge will sharply increase interior
  temperatures Monday, followed by further warming to above
  average temperatures into late next week.


&&

.SYNOPSIS...A general troughing pattern will keep interior
temperatures cooler than average and continue and unsettled pattern
over the region bringing a chance for showers or isolated
thunderstorms this weekend in Del Norte and extreme NE Humbodlt and
Trinity counties. This unsettled pattern could also disrupt diurnal
coastal stratus this weekend. Colder morning temperatures could
occur for the coldest interior valleys this morning wherever fog
does not form. A sharp warmup in temperatures will begin Monday
and continue into late next week.


&&

.DISCUSSION...An upper level trough will continue to linger over
the Pacific Northwest through the weekend. This feature could aid
in sporadic coastal stratus development along the coast, light
rain showers for Del Norte and extreme NE Humbodlt and Trinity
counties, and cooler temperatures inland. Short wave disturbances
are anticipated to flow downstream over NW CA through the weekend
increasing the chances for light rain showers, especially for
Sunday. The interior will likely see morning cloud coverage that
will dissipate through the morning leading to cooler temperatures
through Monday. Low temperatures for interior valleys will be
colder than average over the next few days with some of the
climatologically colder valleys reaching down in the upper 30s to
low 40s. However, a frost advisory has not been issued due to the
likelihood of insulating cloud coverage for most major valleys.

Sunday, a shortwave disturbance passing over the forecast area is
increasing the rainfall chances for the Del Norte and the northern
portions of Trinity and Humboldt counties. A very slight
lightning chance exists for these areas well, yet NW storm motion
will likely cause any storms that do form to flow into Siskiyou
County quickly. Even the most extreme CAMs show very limited
coverage of short lived thunderstorms over the area. Little
chances for wetting rain (>0.10") exist for areas away from the
high terrain inland for Sunday as well.

A sharp warmup will begin Monday as a strong Desert Southwest ridge
develops. Temperatures in the interior valleys may near or reach 100
mid to late next week. There are remaining questions about whether
tropical moisture may stream northeast toward the region from
decaying tropical systems well off the CA coast. Model guidance has
a large variance in possibilities ranging from completely dry after
Sunday to several chances of showers and possibly thunderstorms mid
to late week.


&&

.AVIATION...Calm winds return this evening with around a 40
percent chance of IFR or lower ceilings at ACV through the late
evening/early morning. A deep marine layer set up may lead to
early dissipation again Sunday morning, and improvements in
ceiling heights, but southerly flow from a coastal wind eddy may
lock it in longer into the afternoon.


&&

.MARINE...A continuously evolving upper level trough over western
Oregon is beginning to weaken. As a result, northerly winds are
beginning to form. Waves during this time are expected to remain
below small craft advisory conditions. Northerlies are likely to
be between 8- 12kts with sporadic gusts up to 15kts with the
strongest winds in the far northern waters downwind of Cape Blanco
and in the southern waters downwind of Cape Mendocino where gusts
could reach 20kts or even 25kts. The northerlies do not look to
fully strengthen again until early next week. Hurricane Marie will
deliver a long period southerly swell Saturday. Though small, at
around 4 ft at 16 seconds, this swell is a larger than typical
swell from this direction at this time of year.


&&

.BEACH HAZARDS...Hurricane Marie is ushering in a long period
southerly swell of 3-5 feet at 17 seconds for south facing beaches
in Mendocino and Southern Humboldt counties, including the Lost
Coast Trail today through into Sunday. Thus, there could be a risk
of sneaker waves, especially if the swell comes in slightly
larger.

Sneaker waves are a unique hazard, with up to 30 minutes between
waves. Large, unexpected waves can sweep across the beach without
warning, sweeping people into the sea from rocks, jetties, and
beaches. These sneaker waves can also move large objects such as
logs, crushing anyone caught underneath. Even ankle to knee deep
water can knock you down and drag you out when a sneaker wave hits.
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!


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Beach Hazards Statement through Monday evening for CAZ104-
     109.

NORTHWEST CALIFORNIA COASTAL WATERS...
None.
&&

$$

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

Visit us at https://www.weather.gov/eureka

Follow us on Facebook and Twitter at:
https://www.facebook.com/NWSEureka
https://www.twitter.com/NWSEureka

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